| /* |
| * CDDL HEADER START |
| * |
| * The contents of this file are subject to the terms of the |
| * Common Development and Distribution License (the "License"). |
| * You may not use this file except in compliance with the License. |
| * |
| * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE |
| * or http://www.opensolaris.org/os/licensing. |
| * See the License for the specific language governing permissions |
| * and limitations under the License. |
| * |
| * When distributing Covered Code, include this CDDL HEADER in each |
| * file and include the License file at usr/src/OPENSOLARIS.LICENSE. |
| * If applicable, add the following below this CDDL HEADER, with the |
| * fields enclosed by brackets "[]" replaced with your own identifying |
| * information: Portions Copyright [yyyy] [name of copyright owner] |
| * |
| * CDDL HEADER END |
| */ |
| /* |
| * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved. |
| * Copyright (c) 2018, Joyent, Inc. |
| * Copyright (c) 2011, 2019 by Delphix. All rights reserved. |
| * Copyright (c) 2014 by Saso Kiselkov. All rights reserved. |
| * Copyright 2017 Nexenta Systems, Inc. All rights reserved. |
| */ |
| |
| /* |
| * DVA-based Adjustable Replacement Cache |
| * |
| * While much of the theory of operation used here is |
| * based on the self-tuning, low overhead replacement cache |
| * presented by Megiddo and Modha at FAST 2003, there are some |
| * significant differences: |
| * |
| * 1. The Megiddo and Modha model assumes any page is evictable. |
| * Pages in its cache cannot be "locked" into memory. This makes |
| * the eviction algorithm simple: evict the last page in the list. |
| * This also make the performance characteristics easy to reason |
| * about. Our cache is not so simple. At any given moment, some |
| * subset of the blocks in the cache are un-evictable because we |
| * have handed out a reference to them. Blocks are only evictable |
| * when there are no external references active. This makes |
| * eviction far more problematic: we choose to evict the evictable |
| * blocks that are the "lowest" in the list. |
| * |
| * There are times when it is not possible to evict the requested |
| * space. In these circumstances we are unable to adjust the cache |
| * size. To prevent the cache growing unbounded at these times we |
| * implement a "cache throttle" that slows the flow of new data |
| * into the cache until we can make space available. |
| * |
| * 2. The Megiddo and Modha model assumes a fixed cache size. |
| * Pages are evicted when the cache is full and there is a cache |
| * miss. Our model has a variable sized cache. It grows with |
| * high use, but also tries to react to memory pressure from the |
| * operating system: decreasing its size when system memory is |
| * tight. |
| * |
| * 3. The Megiddo and Modha model assumes a fixed page size. All |
| * elements of the cache are therefore exactly the same size. So |
| * when adjusting the cache size following a cache miss, its simply |
| * a matter of choosing a single page to evict. In our model, we |
| * have variable sized cache blocks (ranging from 512 bytes to |
| * 128K bytes). We therefore choose a set of blocks to evict to make |
| * space for a cache miss that approximates as closely as possible |
| * the space used by the new block. |
| * |
| * See also: "ARC: A Self-Tuning, Low Overhead Replacement Cache" |
| * by N. Megiddo & D. Modha, FAST 2003 |
| */ |
| |
| /* |
| * The locking model: |
| * |
| * A new reference to a cache buffer can be obtained in two |
| * ways: 1) via a hash table lookup using the DVA as a key, |
| * or 2) via one of the ARC lists. The arc_read() interface |
| * uses method 1, while the internal ARC algorithms for |
| * adjusting the cache use method 2. We therefore provide two |
| * types of locks: 1) the hash table lock array, and 2) the |
| * ARC list locks. |
| * |
| * Buffers do not have their own mutexes, rather they rely on the |
| * hash table mutexes for the bulk of their protection (i.e. most |
| * fields in the arc_buf_hdr_t are protected by these mutexes). |
| * |
| * buf_hash_find() returns the appropriate mutex (held) when it |
| * locates the requested buffer in the hash table. It returns |
| * NULL for the mutex if the buffer was not in the table. |
| * |
| * buf_hash_remove() expects the appropriate hash mutex to be |
| * already held before it is invoked. |
| * |
| * Each ARC state also has a mutex which is used to protect the |
| * buffer list associated with the state. When attempting to |
| * obtain a hash table lock while holding an ARC list lock you |
| * must use: mutex_tryenter() to avoid deadlock. Also note that |
| * the active state mutex must be held before the ghost state mutex. |
| * |
| * It as also possible to register a callback which is run when the |
| * arc_meta_limit is reached and no buffers can be safely evicted. In |
| * this case the arc user should drop a reference on some arc buffers so |
| * they can be reclaimed and the arc_meta_limit honored. For example, |
| * when using the ZPL each dentry holds a references on a znode. These |
| * dentries must be pruned before the arc buffer holding the znode can |
| * be safely evicted. |
| * |
| * Note that the majority of the performance stats are manipulated |
| * with atomic operations. |
| * |
| * The L2ARC uses the l2ad_mtx on each vdev for the following: |
| * |
| * - L2ARC buflist creation |
| * - L2ARC buflist eviction |
| * - L2ARC write completion, which walks L2ARC buflists |
| * - ARC header destruction, as it removes from L2ARC buflists |
| * - ARC header release, as it removes from L2ARC buflists |
| */ |
| |
| /* |
| * ARC operation: |
| * |
| * Every block that is in the ARC is tracked by an arc_buf_hdr_t structure. |
| * This structure can point either to a block that is still in the cache or to |
| * one that is only accessible in an L2 ARC device, or it can provide |
| * information about a block that was recently evicted. If a block is |
| * only accessible in the L2ARC, then the arc_buf_hdr_t only has enough |
| * information to retrieve it from the L2ARC device. This information is |
| * stored in the l2arc_buf_hdr_t sub-structure of the arc_buf_hdr_t. A block |
| * that is in this state cannot access the data directly. |
| * |
| * Blocks that are actively being referenced or have not been evicted |
| * are cached in the L1ARC. The L1ARC (l1arc_buf_hdr_t) is a structure within |
| * the arc_buf_hdr_t that will point to the data block in memory. A block can |
| * only be read by a consumer if it has an l1arc_buf_hdr_t. The L1ARC |
| * caches data in two ways -- in a list of ARC buffers (arc_buf_t) and |
| * also in the arc_buf_hdr_t's private physical data block pointer (b_pabd). |
| * |
| * The L1ARC's data pointer may or may not be uncompressed. The ARC has the |
| * ability to store the physical data (b_pabd) associated with the DVA of the |
| * arc_buf_hdr_t. Since the b_pabd is a copy of the on-disk physical block, |
| * it will match its on-disk compression characteristics. This behavior can be |
| * disabled by setting 'zfs_compressed_arc_enabled' to B_FALSE. When the |
| * compressed ARC functionality is disabled, the b_pabd will point to an |
| * uncompressed version of the on-disk data. |
| * |
| * Data in the L1ARC is not accessed by consumers of the ARC directly. Each |
| * arc_buf_hdr_t can have multiple ARC buffers (arc_buf_t) which reference it. |
| * Each ARC buffer (arc_buf_t) is being actively accessed by a specific ARC |
| * consumer. The ARC will provide references to this data and will keep it |
| * cached until it is no longer in use. The ARC caches only the L1ARC's physical |
| * data block and will evict any arc_buf_t that is no longer referenced. The |
| * amount of memory consumed by the arc_buf_ts' data buffers can be seen via the |
| * "overhead_size" kstat. |
| * |
| * Depending on the consumer, an arc_buf_t can be requested in uncompressed or |
| * compressed form. The typical case is that consumers will want uncompressed |
| * data, and when that happens a new data buffer is allocated where the data is |
| * decompressed for them to use. Currently the only consumer who wants |
| * compressed arc_buf_t's is "zfs send", when it streams data exactly as it |
| * exists on disk. When this happens, the arc_buf_t's data buffer is shared |
| * with the arc_buf_hdr_t. |
| * |
| * Here is a diagram showing an arc_buf_hdr_t referenced by two arc_buf_t's. The |
| * first one is owned by a compressed send consumer (and therefore references |
| * the same compressed data buffer as the arc_buf_hdr_t) and the second could be |
| * used by any other consumer (and has its own uncompressed copy of the data |
| * buffer). |
| * |
| * arc_buf_hdr_t |
| * +-----------+ |
| * | fields | |
| * | common to | |
| * | L1- and | |
| * | L2ARC | |
| * +-----------+ |
| * | l2arc_buf_hdr_t |
| * | | |
| * +-----------+ |
| * | l1arc_buf_hdr_t |
| * | | arc_buf_t |
| * | b_buf +------------>+-----------+ arc_buf_t |
| * | b_pabd +-+ |b_next +---->+-----------+ |
| * +-----------+ | |-----------| |b_next +-->NULL |
| * | |b_comp = T | +-----------+ |
| * | |b_data +-+ |b_comp = F | |
| * | +-----------+ | |b_data +-+ |
| * +->+------+ | +-----------+ | |
| * compressed | | | | |
| * data | |<--------------+ | uncompressed |
| * +------+ compressed, | data |
| * shared +-->+------+ |
| * data | | |
| * | | |
| * +------+ |
| * |
| * When a consumer reads a block, the ARC must first look to see if the |
| * arc_buf_hdr_t is cached. If the hdr is cached then the ARC allocates a new |
| * arc_buf_t and either copies uncompressed data into a new data buffer from an |
| * existing uncompressed arc_buf_t, decompresses the hdr's b_pabd buffer into a |
| * new data buffer, or shares the hdr's b_pabd buffer, depending on whether the |
| * hdr is compressed and the desired compression characteristics of the |
| * arc_buf_t consumer. If the arc_buf_t ends up sharing data with the |
| * arc_buf_hdr_t and both of them are uncompressed then the arc_buf_t must be |
| * the last buffer in the hdr's b_buf list, however a shared compressed buf can |
| * be anywhere in the hdr's list. |
| * |
| * The diagram below shows an example of an uncompressed ARC hdr that is |
| * sharing its data with an arc_buf_t (note that the shared uncompressed buf is |
| * the last element in the buf list): |
| * |
| * arc_buf_hdr_t |
| * +-----------+ |
| * | | |
| * | | |
| * | | |
| * +-----------+ |
| * l2arc_buf_hdr_t| | |
| * | | |
| * +-----------+ |
| * l1arc_buf_hdr_t| | |
| * | | arc_buf_t (shared) |
| * | b_buf +------------>+---------+ arc_buf_t |
| * | | |b_next +---->+---------+ |
| * | b_pabd +-+ |---------| |b_next +-->NULL |
| * +-----------+ | | | +---------+ |
| * | |b_data +-+ | | |
| * | +---------+ | |b_data +-+ |
| * +->+------+ | +---------+ | |
| * | | | | |
| * uncompressed | | | | |
| * data +------+ | | |
| * ^ +->+------+ | |
| * | uncompressed | | | |
| * | data | | | |
| * | +------+ | |
| * +---------------------------------+ |
| * |
| * Writing to the ARC requires that the ARC first discard the hdr's b_pabd |
| * since the physical block is about to be rewritten. The new data contents |
| * will be contained in the arc_buf_t. As the I/O pipeline performs the write, |
| * it may compress the data before writing it to disk. The ARC will be called |
| * with the transformed data and will bcopy the transformed on-disk block into |
| * a newly allocated b_pabd. Writes are always done into buffers which have |
| * either been loaned (and hence are new and don't have other readers) or |
| * buffers which have been released (and hence have their own hdr, if there |
| * were originally other readers of the buf's original hdr). This ensures that |
| * the ARC only needs to update a single buf and its hdr after a write occurs. |
| * |
| * When the L2ARC is in use, it will also take advantage of the b_pabd. The |
| * L2ARC will always write the contents of b_pabd to the L2ARC. This means |
| * that when compressed ARC is enabled that the L2ARC blocks are identical |
| * to the on-disk block in the main data pool. This provides a significant |
| * advantage since the ARC can leverage the bp's checksum when reading from the |
| * L2ARC to determine if the contents are valid. However, if the compressed |
| * ARC is disabled, then the L2ARC's block must be transformed to look |
| * like the physical block in the main data pool before comparing the |
| * checksum and determining its validity. |
| * |
| * The L1ARC has a slightly different system for storing encrypted data. |
| * Raw (encrypted + possibly compressed) data has a few subtle differences from |
| * data that is just compressed. The biggest difference is that it is not |
| * possible to decrypt encrypted data (or vice-versa) if the keys aren't loaded. |
| * The other difference is that encryption cannot be treated as a suggestion. |
| * If a caller would prefer compressed data, but they actually wind up with |
| * uncompressed data the worst thing that could happen is there might be a |
| * performance hit. If the caller requests encrypted data, however, we must be |
| * sure they actually get it or else secret information could be leaked. Raw |
| * data is stored in hdr->b_crypt_hdr.b_rabd. An encrypted header, therefore, |
| * may have both an encrypted version and a decrypted version of its data at |
| * once. When a caller needs a raw arc_buf_t, it is allocated and the data is |
| * copied out of this header. To avoid complications with b_pabd, raw buffers |
| * cannot be shared. |
| */ |
| |
| #include <sys/spa.h> |
| #include <sys/zio.h> |
| #include <sys/spa_impl.h> |
| #include <sys/zio_compress.h> |
| #include <sys/zio_checksum.h> |
| #include <sys/zfs_context.h> |
| #include <sys/arc.h> |
| #include <sys/refcount.h> |
| #include <sys/vdev.h> |
| #include <sys/vdev_impl.h> |
| #include <sys/dsl_pool.h> |
| #include <sys/zio_checksum.h> |
| #include <sys/multilist.h> |
| #include <sys/abd.h> |
| #include <sys/zil.h> |
| #include <sys/fm/fs/zfs.h> |
| #ifdef _KERNEL |
| #include <sys/shrinker.h> |
| #include <sys/vmsystm.h> |
| #include <sys/zpl.h> |
| #include <linux/page_compat.h> |
| #include <linux/mod_compat.h> |
| #endif |
| #include <sys/callb.h> |
| #include <sys/kstat.h> |
| #include <sys/zthr.h> |
| #include <zfs_fletcher.h> |
| #include <sys/arc_impl.h> |
| #include <sys/trace_arc.h> |
| #include <sys/aggsum.h> |
| #include <sys/cityhash.h> |
| |
| #ifndef _KERNEL |
| /* set with ZFS_DEBUG=watch, to enable watchpoints on frozen buffers */ |
| boolean_t arc_watch = B_FALSE; |
| #endif |
| |
| /* |
| * This thread's job is to keep enough free memory in the system, by |
| * calling arc_kmem_reap_soon() plus arc_reduce_target_size(), which improves |
| * arc_available_memory(). |
| */ |
| static zthr_t *arc_reap_zthr; |
| |
| /* |
| * This thread's job is to keep arc_size under arc_c, by calling |
| * arc_adjust(), which improves arc_is_overflowing(). |
| */ |
| static zthr_t *arc_adjust_zthr; |
| |
| static kmutex_t arc_adjust_lock; |
| static kcondvar_t arc_adjust_waiters_cv; |
| static boolean_t arc_adjust_needed = B_FALSE; |
| |
| /* |
| * The number of headers to evict in arc_evict_state_impl() before |
| * dropping the sublist lock and evicting from another sublist. A lower |
| * value means we're more likely to evict the "correct" header (i.e. the |
| * oldest header in the arc state), but comes with higher overhead |
| * (i.e. more invocations of arc_evict_state_impl()). |
| */ |
| int zfs_arc_evict_batch_limit = 10; |
| |
| /* number of seconds before growing cache again */ |
| static int arc_grow_retry = 5; |
| |
| /* |
| * Minimum time between calls to arc_kmem_reap_soon(). |
| */ |
| int arc_kmem_cache_reap_retry_ms = 1000; |
| |
| /* shift of arc_c for calculating overflow limit in arc_get_data_impl */ |
| int zfs_arc_overflow_shift = 8; |
| |
| /* shift of arc_c for calculating both min and max arc_p */ |
| int arc_p_min_shift = 4; |
| |
| /* log2(fraction of arc to reclaim) */ |
| static int arc_shrink_shift = 7; |
| |
| /* percent of pagecache to reclaim arc to */ |
| #ifdef _KERNEL |
| static uint_t zfs_arc_pc_percent = 0; |
| #endif |
| |
| /* |
| * log2(fraction of ARC which must be free to allow growing). |
| * I.e. If there is less than arc_c >> arc_no_grow_shift free memory, |
| * when reading a new block into the ARC, we will evict an equal-sized block |
| * from the ARC. |
| * |
| * This must be less than arc_shrink_shift, so that when we shrink the ARC, |
| * we will still not allow it to grow. |
| */ |
| int arc_no_grow_shift = 5; |
| |
| |
| /* |
| * minimum lifespan of a prefetch block in clock ticks |
| * (initialized in arc_init()) |
| */ |
| static int arc_min_prefetch_ms; |
| static int arc_min_prescient_prefetch_ms; |
| |
| /* |
| * If this percent of memory is free, don't throttle. |
| */ |
| int arc_lotsfree_percent = 10; |
| |
| /* |
| * hdr_recl() uses this to determine if the arc is up and running. |
| */ |
| static boolean_t arc_initialized; |
| |
| /* |
| * The arc has filled available memory and has now warmed up. |
| */ |
| static boolean_t arc_warm; |
| |
| /* |
| * log2 fraction of the zio arena to keep free. |
| */ |
| int arc_zio_arena_free_shift = 2; |
| |
| /* |
| * These tunables are for performance analysis. |
| */ |
| unsigned long zfs_arc_max = 0; |
| unsigned long zfs_arc_min = 0; |
| unsigned long zfs_arc_meta_limit = 0; |
| unsigned long zfs_arc_meta_min = 0; |
| unsigned long zfs_arc_dnode_limit = 0; |
| unsigned long zfs_arc_dnode_reduce_percent = 10; |
| int zfs_arc_grow_retry = 0; |
| int zfs_arc_shrink_shift = 0; |
| int zfs_arc_p_min_shift = 0; |
| int zfs_arc_average_blocksize = 8 * 1024; /* 8KB */ |
| |
| /* |
| * ARC dirty data constraints for arc_tempreserve_space() throttle. |
| */ |
| unsigned long zfs_arc_dirty_limit_percent = 50; /* total dirty data limit */ |
| unsigned long zfs_arc_anon_limit_percent = 25; /* anon block dirty limit */ |
| unsigned long zfs_arc_pool_dirty_percent = 20; /* each pool's anon allowance */ |
| |
| /* |
| * Enable or disable compressed arc buffers. |
| */ |
| int zfs_compressed_arc_enabled = B_TRUE; |
| |
| /* |
| * ARC will evict meta buffers that exceed arc_meta_limit. This |
| * tunable make arc_meta_limit adjustable for different workloads. |
| */ |
| unsigned long zfs_arc_meta_limit_percent = 75; |
| |
| /* |
| * Percentage that can be consumed by dnodes of ARC meta buffers. |
| */ |
| unsigned long zfs_arc_dnode_limit_percent = 10; |
| |
| /* |
| * These tunables are Linux specific |
| */ |
| unsigned long zfs_arc_sys_free = 0; |
| int zfs_arc_min_prefetch_ms = 0; |
| int zfs_arc_min_prescient_prefetch_ms = 0; |
| int zfs_arc_p_dampener_disable = 1; |
| int zfs_arc_meta_prune = 10000; |
| int zfs_arc_meta_strategy = ARC_STRATEGY_META_BALANCED; |
| int zfs_arc_meta_adjust_restarts = 4096; |
| int zfs_arc_lotsfree_percent = 10; |
| |
| /* The 6 states: */ |
| static arc_state_t ARC_anon; |
| static arc_state_t ARC_mru; |
| static arc_state_t ARC_mru_ghost; |
| static arc_state_t ARC_mfu; |
| static arc_state_t ARC_mfu_ghost; |
| static arc_state_t ARC_l2c_only; |
| |
| typedef struct arc_stats { |
| kstat_named_t arcstat_hits; |
| kstat_named_t arcstat_misses; |
| kstat_named_t arcstat_demand_data_hits; |
| kstat_named_t arcstat_demand_data_misses; |
| kstat_named_t arcstat_demand_metadata_hits; |
| kstat_named_t arcstat_demand_metadata_misses; |
| kstat_named_t arcstat_prefetch_data_hits; |
| kstat_named_t arcstat_prefetch_data_misses; |
| kstat_named_t arcstat_prefetch_metadata_hits; |
| kstat_named_t arcstat_prefetch_metadata_misses; |
| kstat_named_t arcstat_mru_hits; |
| kstat_named_t arcstat_mru_ghost_hits; |
| kstat_named_t arcstat_mfu_hits; |
| kstat_named_t arcstat_mfu_ghost_hits; |
| kstat_named_t arcstat_deleted; |
| /* |
| * Number of buffers that could not be evicted because the hash lock |
| * was held by another thread. The lock may not necessarily be held |
| * by something using the same buffer, since hash locks are shared |
| * by multiple buffers. |
| */ |
| kstat_named_t arcstat_mutex_miss; |
| /* |
| * Number of buffers skipped when updating the access state due to the |
| * header having already been released after acquiring the hash lock. |
| */ |
| kstat_named_t arcstat_access_skip; |
| /* |
| * Number of buffers skipped because they have I/O in progress, are |
| * indirect prefetch buffers that have not lived long enough, or are |
| * not from the spa we're trying to evict from. |
| */ |
| kstat_named_t arcstat_evict_skip; |
| /* |
| * Number of times arc_evict_state() was unable to evict enough |
| * buffers to reach its target amount. |
| */ |
| kstat_named_t arcstat_evict_not_enough; |
| kstat_named_t arcstat_evict_l2_cached; |
| kstat_named_t arcstat_evict_l2_eligible; |
| kstat_named_t arcstat_evict_l2_ineligible; |
| kstat_named_t arcstat_evict_l2_skip; |
| kstat_named_t arcstat_hash_elements; |
| kstat_named_t arcstat_hash_elements_max; |
| kstat_named_t arcstat_hash_collisions; |
| kstat_named_t arcstat_hash_chains; |
| kstat_named_t arcstat_hash_chain_max; |
| kstat_named_t arcstat_p; |
| kstat_named_t arcstat_c; |
| kstat_named_t arcstat_c_min; |
| kstat_named_t arcstat_c_max; |
| /* Not updated directly; only synced in arc_kstat_update. */ |
| kstat_named_t arcstat_size; |
| /* |
| * Number of compressed bytes stored in the arc_buf_hdr_t's b_pabd. |
| * Note that the compressed bytes may match the uncompressed bytes |
| * if the block is either not compressed or compressed arc is disabled. |
| */ |
| kstat_named_t arcstat_compressed_size; |
| /* |
| * Uncompressed size of the data stored in b_pabd. If compressed |
| * arc is disabled then this value will be identical to the stat |
| * above. |
| */ |
| kstat_named_t arcstat_uncompressed_size; |
| /* |
| * Number of bytes stored in all the arc_buf_t's. This is classified |
| * as "overhead" since this data is typically short-lived and will |
| * be evicted from the arc when it becomes unreferenced unless the |
| * zfs_keep_uncompressed_metadata or zfs_keep_uncompressed_level |
| * values have been set (see comment in dbuf.c for more information). |
| */ |
| kstat_named_t arcstat_overhead_size; |
| /* |
| * Number of bytes consumed by internal ARC structures necessary |
| * for tracking purposes; these structures are not actually |
| * backed by ARC buffers. This includes arc_buf_hdr_t structures |
| * (allocated via arc_buf_hdr_t_full and arc_buf_hdr_t_l2only |
| * caches), and arc_buf_t structures (allocated via arc_buf_t |
| * cache). |
| * Not updated directly; only synced in arc_kstat_update. |
| */ |
| kstat_named_t arcstat_hdr_size; |
| /* |
| * Number of bytes consumed by ARC buffers of type equal to |
| * ARC_BUFC_DATA. This is generally consumed by buffers backing |
| * on disk user data (e.g. plain file contents). |
| * Not updated directly; only synced in arc_kstat_update. |
| */ |
| kstat_named_t arcstat_data_size; |
| /* |
| * Number of bytes consumed by ARC buffers of type equal to |
| * ARC_BUFC_METADATA. This is generally consumed by buffers |
| * backing on disk data that is used for internal ZFS |
| * structures (e.g. ZAP, dnode, indirect blocks, etc). |
| * Not updated directly; only synced in arc_kstat_update. |
| */ |
| kstat_named_t arcstat_metadata_size; |
| /* |
| * Number of bytes consumed by dmu_buf_impl_t objects. |
| * Not updated directly; only synced in arc_kstat_update. |
| */ |
| kstat_named_t arcstat_dbuf_size; |
| /* |
| * Number of bytes consumed by dnode_t objects. |
| * Not updated directly; only synced in arc_kstat_update. |
| */ |
| kstat_named_t arcstat_dnode_size; |
| /* |
| * Number of bytes consumed by bonus buffers. |
| * Not updated directly; only synced in arc_kstat_update. |
| */ |
| kstat_named_t arcstat_bonus_size; |
| /* |
| * Total number of bytes consumed by ARC buffers residing in the |
| * arc_anon state. This includes *all* buffers in the arc_anon |
| * state; e.g. data, metadata, evictable, and unevictable buffers |
| * are all included in this value. |
| * Not updated directly; only synced in arc_kstat_update. |
| */ |
| kstat_named_t arcstat_anon_size; |
| /* |
| * Number of bytes consumed by ARC buffers that meet the |
| * following criteria: backing buffers of type ARC_BUFC_DATA, |
| * residing in the arc_anon state, and are eligible for eviction |
| * (e.g. have no outstanding holds on the buffer). |
| * Not updated directly; only synced in arc_kstat_update. |
| */ |
| kstat_named_t arcstat_anon_evictable_data; |
| /* |
| * Number of bytes consumed by ARC buffers that meet the |
| * following criteria: backing buffers of type ARC_BUFC_METADATA, |
| * residing in the arc_anon state, and are eligible for eviction |
| * (e.g. have no outstanding holds on the buffer). |
| * Not updated directly; only synced in arc_kstat_update. |
| */ |
| kstat_named_t arcstat_anon_evictable_metadata; |
| /* |
| * Total number of bytes consumed by ARC buffers residing in the |
| * arc_mru state. This includes *all* buffers in the arc_mru |
| * state; e.g. data, metadata, evictable, and unevictable buffers |
| * are all included in this value. |
| * Not updated directly; only synced in arc_kstat_update. |
| */ |
| kstat_named_t arcstat_mru_size; |
| /* |
| * Number of bytes consumed by ARC buffers that meet the |
| * following criteria: backing buffers of type ARC_BUFC_DATA, |
| * residing in the arc_mru state, and are eligible for eviction |
| * (e.g. have no outstanding holds on the buffer). |
| * Not updated directly; only synced in arc_kstat_update. |
| */ |
| kstat_named_t arcstat_mru_evictable_data; |
| /* |
| * Number of bytes consumed by ARC buffers that meet the |
| * following criteria: backing buffers of type ARC_BUFC_METADATA, |
| * residing in the arc_mru state, and are eligible for eviction |
| * (e.g. have no outstanding holds on the buffer). |
| * Not updated directly; only synced in arc_kstat_update. |
| */ |
| kstat_named_t arcstat_mru_evictable_metadata; |
| /* |
| * Total number of bytes that *would have been* consumed by ARC |
| * buffers in the arc_mru_ghost state. The key thing to note |
| * here, is the fact that this size doesn't actually indicate |
| * RAM consumption. The ghost lists only consist of headers and |
| * don't actually have ARC buffers linked off of these headers. |
| * Thus, *if* the headers had associated ARC buffers, these |
| * buffers *would have* consumed this number of bytes. |
| * Not updated directly; only synced in arc_kstat_update. |
| */ |
| kstat_named_t arcstat_mru_ghost_size; |
| /* |
| * Number of bytes that *would have been* consumed by ARC |
| * buffers that are eligible for eviction, of type |
| * ARC_BUFC_DATA, and linked off the arc_mru_ghost state. |
| * Not updated directly; only synced in arc_kstat_update. |
| */ |
| kstat_named_t arcstat_mru_ghost_evictable_data; |
| /* |
| * Number of bytes that *would have been* consumed by ARC |
| * buffers that are eligible for eviction, of type |
| * ARC_BUFC_METADATA, and linked off the arc_mru_ghost state. |
| * Not updated directly; only synced in arc_kstat_update. |
| */ |
| kstat_named_t arcstat_mru_ghost_evictable_metadata; |
| /* |
| * Total number of bytes consumed by ARC buffers residing in the |
| * arc_mfu state. This includes *all* buffers in the arc_mfu |
| * state; e.g. data, metadata, evictable, and unevictable buffers |
| * are all included in this value. |
| * Not updated directly; only synced in arc_kstat_update. |
| */ |
| kstat_named_t arcstat_mfu_size; |
| /* |
| * Number of bytes consumed by ARC buffers that are eligible for |
| * eviction, of type ARC_BUFC_DATA, and reside in the arc_mfu |
| * state. |
| * Not updated directly; only synced in arc_kstat_update. |
| */ |
| kstat_named_t arcstat_mfu_evictable_data; |
| /* |
| * Number of bytes consumed by ARC buffers that are eligible for |
| * eviction, of type ARC_BUFC_METADATA, and reside in the |
| * arc_mfu state. |
| * Not updated directly; only synced in arc_kstat_update. |
| */ |
| kstat_named_t arcstat_mfu_evictable_metadata; |
| /* |
| * Total number of bytes that *would have been* consumed by ARC |
| * buffers in the arc_mfu_ghost state. See the comment above |
| * arcstat_mru_ghost_size for more details. |
| * Not updated directly; only synced in arc_kstat_update. |
| */ |
| kstat_named_t arcstat_mfu_ghost_size; |
| /* |
| * Number of bytes that *would have been* consumed by ARC |
| * buffers that are eligible for eviction, of type |
| * ARC_BUFC_DATA, and linked off the arc_mfu_ghost state. |
| * Not updated directly; only synced in arc_kstat_update. |
| */ |
| kstat_named_t arcstat_mfu_ghost_evictable_data; |
| /* |
| * Number of bytes that *would have been* consumed by ARC |
| * buffers that are eligible for eviction, of type |
| * ARC_BUFC_METADATA, and linked off the arc_mru_ghost state. |
| * Not updated directly; only synced in arc_kstat_update. |
| */ |
| kstat_named_t arcstat_mfu_ghost_evictable_metadata; |
| kstat_named_t arcstat_l2_hits; |
| kstat_named_t arcstat_l2_misses; |
| kstat_named_t arcstat_l2_feeds; |
| kstat_named_t arcstat_l2_rw_clash; |
| kstat_named_t arcstat_l2_read_bytes; |
| kstat_named_t arcstat_l2_write_bytes; |
| kstat_named_t arcstat_l2_writes_sent; |
| kstat_named_t arcstat_l2_writes_done; |
| kstat_named_t arcstat_l2_writes_error; |
| kstat_named_t arcstat_l2_writes_lock_retry; |
| kstat_named_t arcstat_l2_evict_lock_retry; |
| kstat_named_t arcstat_l2_evict_reading; |
| kstat_named_t arcstat_l2_evict_l1cached; |
| kstat_named_t arcstat_l2_free_on_write; |
| kstat_named_t arcstat_l2_abort_lowmem; |
| kstat_named_t arcstat_l2_cksum_bad; |
| kstat_named_t arcstat_l2_io_error; |
| kstat_named_t arcstat_l2_lsize; |
| kstat_named_t arcstat_l2_psize; |
| /* Not updated directly; only synced in arc_kstat_update. */ |
| kstat_named_t arcstat_l2_hdr_size; |
| kstat_named_t arcstat_memory_throttle_count; |
| kstat_named_t arcstat_memory_direct_count; |
| kstat_named_t arcstat_memory_indirect_count; |
| kstat_named_t arcstat_memory_all_bytes; |
| kstat_named_t arcstat_memory_free_bytes; |
| kstat_named_t arcstat_memory_available_bytes; |
| kstat_named_t arcstat_no_grow; |
| kstat_named_t arcstat_tempreserve; |
| kstat_named_t arcstat_loaned_bytes; |
| kstat_named_t arcstat_prune; |
| /* Not updated directly; only synced in arc_kstat_update. */ |
| kstat_named_t arcstat_meta_used; |
| kstat_named_t arcstat_meta_limit; |
| kstat_named_t arcstat_dnode_limit; |
| kstat_named_t arcstat_meta_max; |
| kstat_named_t arcstat_meta_min; |
| kstat_named_t arcstat_async_upgrade_sync; |
| kstat_named_t arcstat_demand_hit_predictive_prefetch; |
| kstat_named_t arcstat_demand_hit_prescient_prefetch; |
| kstat_named_t arcstat_need_free; |
| kstat_named_t arcstat_sys_free; |
| kstat_named_t arcstat_raw_size; |
| } arc_stats_t; |
| |
| static arc_stats_t arc_stats = { |
| { "hits", KSTAT_DATA_UINT64 }, |
| { "misses", KSTAT_DATA_UINT64 }, |
| { "demand_data_hits", KSTAT_DATA_UINT64 }, |
| { "demand_data_misses", KSTAT_DATA_UINT64 }, |
| { "demand_metadata_hits", KSTAT_DATA_UINT64 }, |
| { "demand_metadata_misses", KSTAT_DATA_UINT64 }, |
| { "prefetch_data_hits", KSTAT_DATA_UINT64 }, |
| { "prefetch_data_misses", KSTAT_DATA_UINT64 }, |
| { "prefetch_metadata_hits", KSTAT_DATA_UINT64 }, |
| { "prefetch_metadata_misses", KSTAT_DATA_UINT64 }, |
| { "mru_hits", KSTAT_DATA_UINT64 }, |
| { "mru_ghost_hits", KSTAT_DATA_UINT64 }, |
| { "mfu_hits", KSTAT_DATA_UINT64 }, |
| { "mfu_ghost_hits", KSTAT_DATA_UINT64 }, |
| { "deleted", KSTAT_DATA_UINT64 }, |
| { "mutex_miss", KSTAT_DATA_UINT64 }, |
| { "access_skip", KSTAT_DATA_UINT64 }, |
| { "evict_skip", KSTAT_DATA_UINT64 }, |
| { "evict_not_enough", KSTAT_DATA_UINT64 }, |
| { "evict_l2_cached", KSTAT_DATA_UINT64 }, |
| { "evict_l2_eligible", KSTAT_DATA_UINT64 }, |
| { "evict_l2_ineligible", KSTAT_DATA_UINT64 }, |
| { "evict_l2_skip", KSTAT_DATA_UINT64 }, |
| { "hash_elements", KSTAT_DATA_UINT64 }, |
| { "hash_elements_max", KSTAT_DATA_UINT64 }, |
| { "hash_collisions", KSTAT_DATA_UINT64 }, |
| { "hash_chains", KSTAT_DATA_UINT64 }, |
| { "hash_chain_max", KSTAT_DATA_UINT64 }, |
| { "p", KSTAT_DATA_UINT64 }, |
| { "c", KSTAT_DATA_UINT64 }, |
| { "c_min", KSTAT_DATA_UINT64 }, |
| { "c_max", KSTAT_DATA_UINT64 }, |
| { "size", KSTAT_DATA_UINT64 }, |
| { "compressed_size", KSTAT_DATA_UINT64 }, |
| { "uncompressed_size", KSTAT_DATA_UINT64 }, |
| { "overhead_size", KSTAT_DATA_UINT64 }, |
| { "hdr_size", KSTAT_DATA_UINT64 }, |
| { "data_size", KSTAT_DATA_UINT64 }, |
| { "metadata_size", KSTAT_DATA_UINT64 }, |
| { "dbuf_size", KSTAT_DATA_UINT64 }, |
| { "dnode_size", KSTAT_DATA_UINT64 }, |
| { "bonus_size", KSTAT_DATA_UINT64 }, |
| { "anon_size", KSTAT_DATA_UINT64 }, |
| { "anon_evictable_data", KSTAT_DATA_UINT64 }, |
| { "anon_evictable_metadata", KSTAT_DATA_UINT64 }, |
| { "mru_size", KSTAT_DATA_UINT64 }, |
| { "mru_evictable_data", KSTAT_DATA_UINT64 }, |
| { "mru_evictable_metadata", KSTAT_DATA_UINT64 }, |
| { "mru_ghost_size", KSTAT_DATA_UINT64 }, |
| { "mru_ghost_evictable_data", KSTAT_DATA_UINT64 }, |
| { "mru_ghost_evictable_metadata", KSTAT_DATA_UINT64 }, |
| { "mfu_size", KSTAT_DATA_UINT64 }, |
| { "mfu_evictable_data", KSTAT_DATA_UINT64 }, |
| { "mfu_evictable_metadata", KSTAT_DATA_UINT64 }, |
| { "mfu_ghost_size", KSTAT_DATA_UINT64 }, |
| { "mfu_ghost_evictable_data", KSTAT_DATA_UINT64 }, |
| { "mfu_ghost_evictable_metadata", KSTAT_DATA_UINT64 }, |
| { "l2_hits", KSTAT_DATA_UINT64 }, |
| { "l2_misses", KSTAT_DATA_UINT64 }, |
| { "l2_feeds", KSTAT_DATA_UINT64 }, |
| { "l2_rw_clash", KSTAT_DATA_UINT64 }, |
| { "l2_read_bytes", KSTAT_DATA_UINT64 }, |
| { "l2_write_bytes", KSTAT_DATA_UINT64 }, |
| { "l2_writes_sent", KSTAT_DATA_UINT64 }, |
| { "l2_writes_done", KSTAT_DATA_UINT64 }, |
| { "l2_writes_error", KSTAT_DATA_UINT64 }, |
| { "l2_writes_lock_retry", KSTAT_DATA_UINT64 }, |
| { "l2_evict_lock_retry", KSTAT_DATA_UINT64 }, |
| { "l2_evict_reading", KSTAT_DATA_UINT64 }, |
| { "l2_evict_l1cached", KSTAT_DATA_UINT64 }, |
| { "l2_free_on_write", KSTAT_DATA_UINT64 }, |
| { "l2_abort_lowmem", KSTAT_DATA_UINT64 }, |
| { "l2_cksum_bad", KSTAT_DATA_UINT64 }, |
| { "l2_io_error", KSTAT_DATA_UINT64 }, |
| { "l2_size", KSTAT_DATA_UINT64 }, |
| { "l2_asize", KSTAT_DATA_UINT64 }, |
| { "l2_hdr_size", KSTAT_DATA_UINT64 }, |
| { "memory_throttle_count", KSTAT_DATA_UINT64 }, |
| { "memory_direct_count", KSTAT_DATA_UINT64 }, |
| { "memory_indirect_count", KSTAT_DATA_UINT64 }, |
| { "memory_all_bytes", KSTAT_DATA_UINT64 }, |
| { "memory_free_bytes", KSTAT_DATA_UINT64 }, |
| { "memory_available_bytes", KSTAT_DATA_INT64 }, |
| { "arc_no_grow", KSTAT_DATA_UINT64 }, |
| { "arc_tempreserve", KSTAT_DATA_UINT64 }, |
| { "arc_loaned_bytes", KSTAT_DATA_UINT64 }, |
| { "arc_prune", KSTAT_DATA_UINT64 }, |
| { "arc_meta_used", KSTAT_DATA_UINT64 }, |
| { "arc_meta_limit", KSTAT_DATA_UINT64 }, |
| { "arc_dnode_limit", KSTAT_DATA_UINT64 }, |
| { "arc_meta_max", KSTAT_DATA_UINT64 }, |
| { "arc_meta_min", KSTAT_DATA_UINT64 }, |
| { "async_upgrade_sync", KSTAT_DATA_UINT64 }, |
| { "demand_hit_predictive_prefetch", KSTAT_DATA_UINT64 }, |
| { "demand_hit_prescient_prefetch", KSTAT_DATA_UINT64 }, |
| { "arc_need_free", KSTAT_DATA_UINT64 }, |
| { "arc_sys_free", KSTAT_DATA_UINT64 }, |
| { "arc_raw_size", KSTAT_DATA_UINT64 } |
| }; |
| |
| #define ARCSTAT(stat) (arc_stats.stat.value.ui64) |
| |
| #define ARCSTAT_INCR(stat, val) \ |
| atomic_add_64(&arc_stats.stat.value.ui64, (val)) |
| |
| #define ARCSTAT_BUMP(stat) ARCSTAT_INCR(stat, 1) |
| #define ARCSTAT_BUMPDOWN(stat) ARCSTAT_INCR(stat, -1) |
| |
| #define ARCSTAT_MAX(stat, val) { \ |
| uint64_t m; \ |
| while ((val) > (m = arc_stats.stat.value.ui64) && \ |
| (m != atomic_cas_64(&arc_stats.stat.value.ui64, m, (val)))) \ |
| continue; \ |
| } |
| |
| #define ARCSTAT_MAXSTAT(stat) \ |
| ARCSTAT_MAX(stat##_max, arc_stats.stat.value.ui64) |
| |
| /* |
| * We define a macro to allow ARC hits/misses to be easily broken down by |
| * two separate conditions, giving a total of four different subtypes for |
| * each of hits and misses (so eight statistics total). |
| */ |
| #define ARCSTAT_CONDSTAT(cond1, stat1, notstat1, cond2, stat2, notstat2, stat) \ |
| if (cond1) { \ |
| if (cond2) { \ |
| ARCSTAT_BUMP(arcstat_##stat1##_##stat2##_##stat); \ |
| } else { \ |
| ARCSTAT_BUMP(arcstat_##stat1##_##notstat2##_##stat); \ |
| } \ |
| } else { \ |
| if (cond2) { \ |
| ARCSTAT_BUMP(arcstat_##notstat1##_##stat2##_##stat); \ |
| } else { \ |
| ARCSTAT_BUMP(arcstat_##notstat1##_##notstat2##_##stat);\ |
| } \ |
| } |
| |
| kstat_t *arc_ksp; |
| static arc_state_t *arc_anon; |
| static arc_state_t *arc_mru; |
| static arc_state_t *arc_mru_ghost; |
| static arc_state_t *arc_mfu; |
| static arc_state_t *arc_mfu_ghost; |
| static arc_state_t *arc_l2c_only; |
| |
| /* |
| * There are several ARC variables that are critical to export as kstats -- |
| * but we don't want to have to grovel around in the kstat whenever we wish to |
| * manipulate them. For these variables, we therefore define them to be in |
| * terms of the statistic variable. This assures that we are not introducing |
| * the possibility of inconsistency by having shadow copies of the variables, |
| * while still allowing the code to be readable. |
| */ |
| #define arc_p ARCSTAT(arcstat_p) /* target size of MRU */ |
| #define arc_c ARCSTAT(arcstat_c) /* target size of cache */ |
| #define arc_c_min ARCSTAT(arcstat_c_min) /* min target cache size */ |
| #define arc_c_max ARCSTAT(arcstat_c_max) /* max target cache size */ |
| #define arc_no_grow ARCSTAT(arcstat_no_grow) /* do not grow cache size */ |
| #define arc_tempreserve ARCSTAT(arcstat_tempreserve) |
| #define arc_loaned_bytes ARCSTAT(arcstat_loaned_bytes) |
| #define arc_meta_limit ARCSTAT(arcstat_meta_limit) /* max size for metadata */ |
| #define arc_dnode_limit ARCSTAT(arcstat_dnode_limit) /* max size for dnodes */ |
| #define arc_meta_min ARCSTAT(arcstat_meta_min) /* min size for metadata */ |
| #define arc_meta_max ARCSTAT(arcstat_meta_max) /* max size of metadata */ |
| #define arc_need_free ARCSTAT(arcstat_need_free) /* bytes to be freed */ |
| #define arc_sys_free ARCSTAT(arcstat_sys_free) /* target system free bytes */ |
| |
| /* size of all b_rabd's in entire arc */ |
| #define arc_raw_size ARCSTAT(arcstat_raw_size) |
| /* compressed size of entire arc */ |
| #define arc_compressed_size ARCSTAT(arcstat_compressed_size) |
| /* uncompressed size of entire arc */ |
| #define arc_uncompressed_size ARCSTAT(arcstat_uncompressed_size) |
| /* number of bytes in the arc from arc_buf_t's */ |
| #define arc_overhead_size ARCSTAT(arcstat_overhead_size) |
| |
| /* |
| * There are also some ARC variables that we want to export, but that are |
| * updated so often that having the canonical representation be the statistic |
| * variable causes a performance bottleneck. We want to use aggsum_t's for these |
| * instead, but still be able to export the kstat in the same way as before. |
| * The solution is to always use the aggsum version, except in the kstat update |
| * callback. |
| */ |
| aggsum_t arc_size; |
| aggsum_t arc_meta_used; |
| aggsum_t astat_data_size; |
| aggsum_t astat_metadata_size; |
| aggsum_t astat_dbuf_size; |
| aggsum_t astat_dnode_size; |
| aggsum_t astat_bonus_size; |
| aggsum_t astat_hdr_size; |
| aggsum_t astat_l2_hdr_size; |
| |
| static hrtime_t arc_growtime; |
| static list_t arc_prune_list; |
| static kmutex_t arc_prune_mtx; |
| static taskq_t *arc_prune_taskq; |
| |
| #define GHOST_STATE(state) \ |
| ((state) == arc_mru_ghost || (state) == arc_mfu_ghost || \ |
| (state) == arc_l2c_only) |
| |
| #define HDR_IN_HASH_TABLE(hdr) ((hdr)->b_flags & ARC_FLAG_IN_HASH_TABLE) |
| #define HDR_IO_IN_PROGRESS(hdr) ((hdr)->b_flags & ARC_FLAG_IO_IN_PROGRESS) |
| #define HDR_IO_ERROR(hdr) ((hdr)->b_flags & ARC_FLAG_IO_ERROR) |
| #define HDR_PREFETCH(hdr) ((hdr)->b_flags & ARC_FLAG_PREFETCH) |
| #define HDR_PRESCIENT_PREFETCH(hdr) \ |
| ((hdr)->b_flags & ARC_FLAG_PRESCIENT_PREFETCH) |
| #define HDR_COMPRESSION_ENABLED(hdr) \ |
| ((hdr)->b_flags & ARC_FLAG_COMPRESSED_ARC) |
| |
| #define HDR_L2CACHE(hdr) ((hdr)->b_flags & ARC_FLAG_L2CACHE) |
| #define HDR_L2_READING(hdr) \ |
| (((hdr)->b_flags & ARC_FLAG_IO_IN_PROGRESS) && \ |
| ((hdr)->b_flags & ARC_FLAG_HAS_L2HDR)) |
| #define HDR_L2_WRITING(hdr) ((hdr)->b_flags & ARC_FLAG_L2_WRITING) |
| #define HDR_L2_EVICTED(hdr) ((hdr)->b_flags & ARC_FLAG_L2_EVICTED) |
| #define HDR_L2_WRITE_HEAD(hdr) ((hdr)->b_flags & ARC_FLAG_L2_WRITE_HEAD) |
| #define HDR_PROTECTED(hdr) ((hdr)->b_flags & ARC_FLAG_PROTECTED) |
| #define HDR_NOAUTH(hdr) ((hdr)->b_flags & ARC_FLAG_NOAUTH) |
| #define HDR_SHARED_DATA(hdr) ((hdr)->b_flags & ARC_FLAG_SHARED_DATA) |
| |
| #define HDR_ISTYPE_METADATA(hdr) \ |
| ((hdr)->b_flags & ARC_FLAG_BUFC_METADATA) |
| #define HDR_ISTYPE_DATA(hdr) (!HDR_ISTYPE_METADATA(hdr)) |
| |
| #define HDR_HAS_L1HDR(hdr) ((hdr)->b_flags & ARC_FLAG_HAS_L1HDR) |
| #define HDR_HAS_L2HDR(hdr) ((hdr)->b_flags & ARC_FLAG_HAS_L2HDR) |
| #define HDR_HAS_RABD(hdr) \ |
| (HDR_HAS_L1HDR(hdr) && HDR_PROTECTED(hdr) && \ |
| (hdr)->b_crypt_hdr.b_rabd != NULL) |
| #define HDR_ENCRYPTED(hdr) \ |
| (HDR_PROTECTED(hdr) && DMU_OT_IS_ENCRYPTED((hdr)->b_crypt_hdr.b_ot)) |
| #define HDR_AUTHENTICATED(hdr) \ |
| (HDR_PROTECTED(hdr) && !DMU_OT_IS_ENCRYPTED((hdr)->b_crypt_hdr.b_ot)) |
| |
| /* For storing compression mode in b_flags */ |
| #define HDR_COMPRESS_OFFSET (highbit64(ARC_FLAG_COMPRESS_0) - 1) |
| |
| #define HDR_GET_COMPRESS(hdr) ((enum zio_compress)BF32_GET((hdr)->b_flags, \ |
| HDR_COMPRESS_OFFSET, SPA_COMPRESSBITS)) |
| #define HDR_SET_COMPRESS(hdr, cmp) BF32_SET((hdr)->b_flags, \ |
| HDR_COMPRESS_OFFSET, SPA_COMPRESSBITS, (cmp)); |
| |
| #define ARC_BUF_LAST(buf) ((buf)->b_next == NULL) |
| #define ARC_BUF_SHARED(buf) ((buf)->b_flags & ARC_BUF_FLAG_SHARED) |
| #define ARC_BUF_COMPRESSED(buf) ((buf)->b_flags & ARC_BUF_FLAG_COMPRESSED) |
| #define ARC_BUF_ENCRYPTED(buf) ((buf)->b_flags & ARC_BUF_FLAG_ENCRYPTED) |
| |
| /* |
| * Other sizes |
| */ |
| |
| #define HDR_FULL_CRYPT_SIZE ((int64_t)sizeof (arc_buf_hdr_t)) |
| #define HDR_FULL_SIZE ((int64_t)offsetof(arc_buf_hdr_t, b_crypt_hdr)) |
| #define HDR_L2ONLY_SIZE ((int64_t)offsetof(arc_buf_hdr_t, b_l1hdr)) |
| |
| /* |
| * Hash table routines |
| */ |
| |
| #define HT_LOCK_ALIGN 64 |
| #define HT_LOCK_PAD (P2NPHASE(sizeof (kmutex_t), (HT_LOCK_ALIGN))) |
| |
| struct ht_lock { |
| kmutex_t ht_lock; |
| #ifdef _KERNEL |
| unsigned char pad[HT_LOCK_PAD]; |
| #endif |
| }; |
| |
| #define BUF_LOCKS 8192 |
| typedef struct buf_hash_table { |
| uint64_t ht_mask; |
| arc_buf_hdr_t **ht_table; |
| struct ht_lock ht_locks[BUF_LOCKS]; |
| } buf_hash_table_t; |
| |
| static buf_hash_table_t buf_hash_table; |
| |
| #define BUF_HASH_INDEX(spa, dva, birth) \ |
| (buf_hash(spa, dva, birth) & buf_hash_table.ht_mask) |
| #define BUF_HASH_LOCK_NTRY(idx) (buf_hash_table.ht_locks[idx & (BUF_LOCKS-1)]) |
| #define BUF_HASH_LOCK(idx) (&(BUF_HASH_LOCK_NTRY(idx).ht_lock)) |
| #define HDR_LOCK(hdr) \ |
| (BUF_HASH_LOCK(BUF_HASH_INDEX(hdr->b_spa, &hdr->b_dva, hdr->b_birth))) |
| |
| uint64_t zfs_crc64_table[256]; |
| |
| /* |
| * Level 2 ARC |
| */ |
| |
| #define L2ARC_WRITE_SIZE (8 * 1024 * 1024) /* initial write max */ |
| #define L2ARC_HEADROOM 2 /* num of writes */ |
| |
| /* |
| * If we discover during ARC scan any buffers to be compressed, we boost |
| * our headroom for the next scanning cycle by this percentage multiple. |
| */ |
| #define L2ARC_HEADROOM_BOOST 200 |
| #define L2ARC_FEED_SECS 1 /* caching interval secs */ |
| #define L2ARC_FEED_MIN_MS 200 /* min caching interval ms */ |
| |
| /* |
| * We can feed L2ARC from two states of ARC buffers, mru and mfu, |
| * and each of the state has two types: data and metadata. |
| */ |
| #define L2ARC_FEED_TYPES 4 |
| |
| #define l2arc_writes_sent ARCSTAT(arcstat_l2_writes_sent) |
| #define l2arc_writes_done ARCSTAT(arcstat_l2_writes_done) |
| |
| /* L2ARC Performance Tunables */ |
| unsigned long l2arc_write_max = L2ARC_WRITE_SIZE; /* def max write size */ |
| unsigned long l2arc_write_boost = L2ARC_WRITE_SIZE; /* extra warmup write */ |
| unsigned long l2arc_headroom = L2ARC_HEADROOM; /* # of dev writes */ |
| unsigned long l2arc_headroom_boost = L2ARC_HEADROOM_BOOST; |
| unsigned long l2arc_feed_secs = L2ARC_FEED_SECS; /* interval seconds */ |
| unsigned long l2arc_feed_min_ms = L2ARC_FEED_MIN_MS; /* min interval msecs */ |
| int l2arc_noprefetch = B_TRUE; /* don't cache prefetch bufs */ |
| int l2arc_feed_again = B_TRUE; /* turbo warmup */ |
| int l2arc_norw = B_FALSE; /* no reads during writes */ |
| |
| /* |
| * L2ARC Internals |
| */ |
| static list_t L2ARC_dev_list; /* device list */ |
| static list_t *l2arc_dev_list; /* device list pointer */ |
| static kmutex_t l2arc_dev_mtx; /* device list mutex */ |
| static l2arc_dev_t *l2arc_dev_last; /* last device used */ |
| static list_t L2ARC_free_on_write; /* free after write buf list */ |
| static list_t *l2arc_free_on_write; /* free after write list ptr */ |
| static kmutex_t l2arc_free_on_write_mtx; /* mutex for list */ |
| static uint64_t l2arc_ndev; /* number of devices */ |
| |
| typedef struct l2arc_read_callback { |
| arc_buf_hdr_t *l2rcb_hdr; /* read header */ |
| blkptr_t l2rcb_bp; /* original blkptr */ |
| zbookmark_phys_t l2rcb_zb; /* original bookmark */ |
| int l2rcb_flags; /* original flags */ |
| abd_t *l2rcb_abd; /* temporary buffer */ |
| } l2arc_read_callback_t; |
| |
| typedef struct l2arc_data_free { |
| /* protected by l2arc_free_on_write_mtx */ |
| abd_t *l2df_abd; |
| size_t l2df_size; |
| arc_buf_contents_t l2df_type; |
| list_node_t l2df_list_node; |
| } l2arc_data_free_t; |
| |
| typedef enum arc_fill_flags { |
| ARC_FILL_LOCKED = 1 << 0, /* hdr lock is held */ |
| ARC_FILL_COMPRESSED = 1 << 1, /* fill with compressed data */ |
| ARC_FILL_ENCRYPTED = 1 << 2, /* fill with encrypted data */ |
| ARC_FILL_NOAUTH = 1 << 3, /* don't attempt to authenticate */ |
| ARC_FILL_IN_PLACE = 1 << 4 /* fill in place (special case) */ |
| } arc_fill_flags_t; |
| |
| static kmutex_t l2arc_feed_thr_lock; |
| static kcondvar_t l2arc_feed_thr_cv; |
| static uint8_t l2arc_thread_exit; |
| |
| enum arc_hdr_alloc_flags { |
| ARC_HDR_ALLOC_RDATA = 0x1, |
| ARC_HDR_DO_ADAPT = 0x2, |
| }; |
| |
| |
| static abd_t *arc_get_data_abd(arc_buf_hdr_t *, uint64_t, void *, boolean_t); |
| static void *arc_get_data_buf(arc_buf_hdr_t *, uint64_t, void *); |
| static void arc_get_data_impl(arc_buf_hdr_t *, uint64_t, void *, boolean_t); |
| static void arc_free_data_abd(arc_buf_hdr_t *, abd_t *, uint64_t, void *); |
| static void arc_free_data_buf(arc_buf_hdr_t *, void *, uint64_t, void *); |
| static void arc_free_data_impl(arc_buf_hdr_t *hdr, uint64_t size, void *tag); |
| static void arc_hdr_free_abd(arc_buf_hdr_t *, boolean_t); |
| static void arc_hdr_alloc_abd(arc_buf_hdr_t *, int); |
| static void arc_access(arc_buf_hdr_t *, kmutex_t *); |
| static boolean_t arc_is_overflowing(void); |
| static void arc_buf_watch(arc_buf_t *); |
| static void arc_tuning_update(void); |
| static void arc_prune_async(int64_t); |
| static uint64_t arc_all_memory(void); |
| |
| static arc_buf_contents_t arc_buf_type(arc_buf_hdr_t *); |
| static uint32_t arc_bufc_to_flags(arc_buf_contents_t); |
| static inline void arc_hdr_set_flags(arc_buf_hdr_t *hdr, arc_flags_t flags); |
| static inline void arc_hdr_clear_flags(arc_buf_hdr_t *hdr, arc_flags_t flags); |
| |
| static boolean_t l2arc_write_eligible(uint64_t, arc_buf_hdr_t *); |
| static void l2arc_read_done(zio_t *); |
| |
| |
| /* |
| * We use Cityhash for this. It's fast, and has good hash properties without |
| * requiring any large static buffers. |
| */ |
| static uint64_t |
| buf_hash(uint64_t spa, const dva_t *dva, uint64_t birth) |
| { |
| return (cityhash4(spa, dva->dva_word[0], dva->dva_word[1], birth)); |
| } |
| |
| #define HDR_EMPTY(hdr) \ |
| ((hdr)->b_dva.dva_word[0] == 0 && \ |
| (hdr)->b_dva.dva_word[1] == 0) |
| |
| #define HDR_EMPTY_OR_LOCKED(hdr) \ |
| (HDR_EMPTY(hdr) || MUTEX_HELD(HDR_LOCK(hdr))) |
| |
| #define HDR_EQUAL(spa, dva, birth, hdr) \ |
| ((hdr)->b_dva.dva_word[0] == (dva)->dva_word[0]) && \ |
| ((hdr)->b_dva.dva_word[1] == (dva)->dva_word[1]) && \ |
| ((hdr)->b_birth == birth) && ((hdr)->b_spa == spa) |
| |
| static void |
| buf_discard_identity(arc_buf_hdr_t *hdr) |
| { |
| hdr->b_dva.dva_word[0] = 0; |
| hdr->b_dva.dva_word[1] = 0; |
| hdr->b_birth = 0; |
| } |
| |
| static arc_buf_hdr_t * |
| buf_hash_find(uint64_t spa, const blkptr_t *bp, kmutex_t **lockp) |
| { |
| const dva_t *dva = BP_IDENTITY(bp); |
| uint64_t birth = BP_PHYSICAL_BIRTH(bp); |
| uint64_t idx = BUF_HASH_INDEX(spa, dva, birth); |
| kmutex_t *hash_lock = BUF_HASH_LOCK(idx); |
| arc_buf_hdr_t *hdr; |
| |
| mutex_enter(hash_lock); |
| for (hdr = buf_hash_table.ht_table[idx]; hdr != NULL; |
| hdr = hdr->b_hash_next) { |
| if (HDR_EQUAL(spa, dva, birth, hdr)) { |
| *lockp = hash_lock; |
| return (hdr); |
| } |
| } |
| mutex_exit(hash_lock); |
| *lockp = NULL; |
| return (NULL); |
| } |
| |
| /* |
| * Insert an entry into the hash table. If there is already an element |
| * equal to elem in the hash table, then the already existing element |
| * will be returned and the new element will not be inserted. |
| * Otherwise returns NULL. |
| * If lockp == NULL, the caller is assumed to already hold the hash lock. |
| */ |
| static arc_buf_hdr_t * |
| buf_hash_insert(arc_buf_hdr_t *hdr, kmutex_t **lockp) |
| { |
| uint64_t idx = BUF_HASH_INDEX(hdr->b_spa, &hdr->b_dva, hdr->b_birth); |
| kmutex_t *hash_lock = BUF_HASH_LOCK(idx); |
| arc_buf_hdr_t *fhdr; |
| uint32_t i; |
| |
| ASSERT(!DVA_IS_EMPTY(&hdr->b_dva)); |
| ASSERT(hdr->b_birth != 0); |
| ASSERT(!HDR_IN_HASH_TABLE(hdr)); |
| |
| if (lockp != NULL) { |
| *lockp = hash_lock; |
| mutex_enter(hash_lock); |
| } else { |
| ASSERT(MUTEX_HELD(hash_lock)); |
| } |
| |
| for (fhdr = buf_hash_table.ht_table[idx], i = 0; fhdr != NULL; |
| fhdr = fhdr->b_hash_next, i++) { |
| if (HDR_EQUAL(hdr->b_spa, &hdr->b_dva, hdr->b_birth, fhdr)) |
| return (fhdr); |
| } |
| |
| hdr->b_hash_next = buf_hash_table.ht_table[idx]; |
| buf_hash_table.ht_table[idx] = hdr; |
| arc_hdr_set_flags(hdr, ARC_FLAG_IN_HASH_TABLE); |
| |
| /* collect some hash table performance data */ |
| if (i > 0) { |
| ARCSTAT_BUMP(arcstat_hash_collisions); |
| if (i == 1) |
| ARCSTAT_BUMP(arcstat_hash_chains); |
| |
| ARCSTAT_MAX(arcstat_hash_chain_max, i); |
| } |
| |
| ARCSTAT_BUMP(arcstat_hash_elements); |
| ARCSTAT_MAXSTAT(arcstat_hash_elements); |
| |
| return (NULL); |
| } |
| |
| static void |
| buf_hash_remove(arc_buf_hdr_t *hdr) |
| { |
| arc_buf_hdr_t *fhdr, **hdrp; |
| uint64_t idx = BUF_HASH_INDEX(hdr->b_spa, &hdr->b_dva, hdr->b_birth); |
| |
| ASSERT(MUTEX_HELD(BUF_HASH_LOCK(idx))); |
| ASSERT(HDR_IN_HASH_TABLE(hdr)); |
| |
| hdrp = &buf_hash_table.ht_table[idx]; |
| while ((fhdr = *hdrp) != hdr) { |
| ASSERT3P(fhdr, !=, NULL); |
| hdrp = &fhdr->b_hash_next; |
| } |
| *hdrp = hdr->b_hash_next; |
| hdr->b_hash_next = NULL; |
| arc_hdr_clear_flags(hdr, ARC_FLAG_IN_HASH_TABLE); |
| |
| /* collect some hash table performance data */ |
| ARCSTAT_BUMPDOWN(arcstat_hash_elements); |
| |
| if (buf_hash_table.ht_table[idx] && |
| buf_hash_table.ht_table[idx]->b_hash_next == NULL) |
| ARCSTAT_BUMPDOWN(arcstat_hash_chains); |
| } |
| |
| /* |
| * Global data structures and functions for the buf kmem cache. |
| */ |
| |
| static kmem_cache_t *hdr_full_cache; |
| static kmem_cache_t *hdr_full_crypt_cache; |
| static kmem_cache_t *hdr_l2only_cache; |
| static kmem_cache_t *buf_cache; |
| |
| static void |
| buf_fini(void) |
| { |
| int i; |
| |
| #if defined(_KERNEL) |
| /* |
| * Large allocations which do not require contiguous pages |
| * should be using vmem_free() in the linux kernel\ |
| */ |
| vmem_free(buf_hash_table.ht_table, |
| (buf_hash_table.ht_mask + 1) * sizeof (void *)); |
| #else |
| kmem_free(buf_hash_table.ht_table, |
| (buf_hash_table.ht_mask + 1) * sizeof (void *)); |
| #endif |
| for (i = 0; i < BUF_LOCKS; i++) |
| mutex_destroy(&buf_hash_table.ht_locks[i].ht_lock); |
| kmem_cache_destroy(hdr_full_cache); |
| kmem_cache_destroy(hdr_full_crypt_cache); |
| kmem_cache_destroy(hdr_l2only_cache); |
| kmem_cache_destroy(buf_cache); |
| } |
| |
| /* |
| * Constructor callback - called when the cache is empty |
| * and a new buf is requested. |
| */ |
| /* ARGSUSED */ |
| static int |
| hdr_full_cons(void *vbuf, void *unused, int kmflag) |
| { |
| arc_buf_hdr_t *hdr = vbuf; |
| |
| bzero(hdr, HDR_FULL_SIZE); |
| hdr->b_l1hdr.b_byteswap = DMU_BSWAP_NUMFUNCS; |
| cv_init(&hdr->b_l1hdr.b_cv, NULL, CV_DEFAULT, NULL); |
| zfs_refcount_create(&hdr->b_l1hdr.b_refcnt); |
| mutex_init(&hdr->b_l1hdr.b_freeze_lock, NULL, MUTEX_DEFAULT, NULL); |
| list_link_init(&hdr->b_l1hdr.b_arc_node); |
| list_link_init(&hdr->b_l2hdr.b_l2node); |
| multilist_link_init(&hdr->b_l1hdr.b_arc_node); |
| arc_space_consume(HDR_FULL_SIZE, ARC_SPACE_HDRS); |
| |
| return (0); |
| } |
| |
| /* ARGSUSED */ |
| static int |
| hdr_full_crypt_cons(void *vbuf, void *unused, int kmflag) |
| { |
| arc_buf_hdr_t *hdr = vbuf; |
| |
| hdr_full_cons(vbuf, unused, kmflag); |
| bzero(&hdr->b_crypt_hdr, sizeof (hdr->b_crypt_hdr)); |
| arc_space_consume(sizeof (hdr->b_crypt_hdr), ARC_SPACE_HDRS); |
| |
| return (0); |
| } |
| |
| /* ARGSUSED */ |
| static int |
| hdr_l2only_cons(void *vbuf, void *unused, int kmflag) |
| { |
| arc_buf_hdr_t *hdr = vbuf; |
| |
| bzero(hdr, HDR_L2ONLY_SIZE); |
| arc_space_consume(HDR_L2ONLY_SIZE, ARC_SPACE_L2HDRS); |
| |
| return (0); |
| } |
| |
| /* ARGSUSED */ |
| static int |
| buf_cons(void *vbuf, void *unused, int kmflag) |
| { |
| arc_buf_t *buf = vbuf; |
| |
| bzero(buf, sizeof (arc_buf_t)); |
| mutex_init(&buf->b_evict_lock, NULL, MUTEX_DEFAULT, NULL); |
| arc_space_consume(sizeof (arc_buf_t), ARC_SPACE_HDRS); |
| |
| return (0); |
| } |
| |
| /* |
| * Destructor callback - called when a cached buf is |
| * no longer required. |
| */ |
| /* ARGSUSED */ |
| static void |
| hdr_full_dest(void *vbuf, void *unused) |
| { |
| arc_buf_hdr_t *hdr = vbuf; |
| |
| ASSERT(HDR_EMPTY(hdr)); |
| cv_destroy(&hdr->b_l1hdr.b_cv); |
| zfs_refcount_destroy(&hdr->b_l1hdr.b_refcnt); |
| mutex_destroy(&hdr->b_l1hdr.b_freeze_lock); |
| ASSERT(!multilist_link_active(&hdr->b_l1hdr.b_arc_node)); |
| arc_space_return(HDR_FULL_SIZE, ARC_SPACE_HDRS); |
| } |
| |
| /* ARGSUSED */ |
| static void |
| hdr_full_crypt_dest(void *vbuf, void *unused) |
| { |
| arc_buf_hdr_t *hdr = vbuf; |
| |
| hdr_full_dest(vbuf, unused); |
| arc_space_return(sizeof (hdr->b_crypt_hdr), ARC_SPACE_HDRS); |
| } |
| |
| /* ARGSUSED */ |
| static void |
| hdr_l2only_dest(void *vbuf, void *unused) |
| { |
| ASSERTV(arc_buf_hdr_t *hdr = vbuf); |
| |
| ASSERT(HDR_EMPTY(hdr)); |
| arc_space_return(HDR_L2ONLY_SIZE, ARC_SPACE_L2HDRS); |
| } |
| |
| /* ARGSUSED */ |
| static void |
| buf_dest(void *vbuf, void *unused) |
| { |
| arc_buf_t *buf = vbuf; |
| |
| mutex_destroy(&buf->b_evict_lock); |
| arc_space_return(sizeof (arc_buf_t), ARC_SPACE_HDRS); |
| } |
| |
| /* |
| * Reclaim callback -- invoked when memory is low. |
| */ |
| /* ARGSUSED */ |
| static void |
| hdr_recl(void *unused) |
| { |
| dprintf("hdr_recl called\n"); |
| /* |
| * umem calls the reclaim func when we destroy the buf cache, |
| * which is after we do arc_fini(). |
| */ |
| if (arc_initialized) |
| zthr_wakeup(arc_reap_zthr); |
| } |
| |
| static void |
| buf_init(void) |
| { |
| uint64_t *ct = NULL; |
| uint64_t hsize = 1ULL << 12; |
| int i, j; |
| |
| /* |
| * The hash table is big enough to fill all of physical memory |
| * with an average block size of zfs_arc_average_blocksize (default 8K). |
| * By default, the table will take up |
| * totalmem * sizeof(void*) / 8K (1MB per GB with 8-byte pointers). |
| */ |
| while (hsize * zfs_arc_average_blocksize < arc_all_memory()) |
| hsize <<= 1; |
| retry: |
| buf_hash_table.ht_mask = hsize - 1; |
| #if defined(_KERNEL) |
| /* |
| * Large allocations which do not require contiguous pages |
| * should be using vmem_alloc() in the linux kernel |
| */ |
| buf_hash_table.ht_table = |
| vmem_zalloc(hsize * sizeof (void*), KM_SLEEP); |
| #else |
| buf_hash_table.ht_table = |
| kmem_zalloc(hsize * sizeof (void*), KM_NOSLEEP); |
| #endif |
| if (buf_hash_table.ht_table == NULL) { |
| ASSERT(hsize > (1ULL << 8)); |
| hsize >>= 1; |
| goto retry; |
| } |
| |
| hdr_full_cache = kmem_cache_create("arc_buf_hdr_t_full", HDR_FULL_SIZE, |
| 0, hdr_full_cons, hdr_full_dest, hdr_recl, NULL, NULL, 0); |
| hdr_full_crypt_cache = kmem_cache_create("arc_buf_hdr_t_full_crypt", |
| HDR_FULL_CRYPT_SIZE, 0, hdr_full_crypt_cons, hdr_full_crypt_dest, |
| hdr_recl, NULL, NULL, 0); |
| hdr_l2only_cache = kmem_cache_create("arc_buf_hdr_t_l2only", |
| HDR_L2ONLY_SIZE, 0, hdr_l2only_cons, hdr_l2only_dest, hdr_recl, |
| NULL, NULL, 0); |
| buf_cache = kmem_cache_create("arc_buf_t", sizeof (arc_buf_t), |
| 0, buf_cons, buf_dest, NULL, NULL, NULL, 0); |
| |
| for (i = 0; i < 256; i++) |
| for (ct = zfs_crc64_table + i, *ct = i, j = 8; j > 0; j--) |
| *ct = (*ct >> 1) ^ (-(*ct & 1) & ZFS_CRC64_POLY); |
| |
| for (i = 0; i < BUF_LOCKS; i++) { |
| mutex_init(&buf_hash_table.ht_locks[i].ht_lock, |
| NULL, MUTEX_DEFAULT, NULL); |
| } |
| } |
| |
| #define ARC_MINTIME (hz>>4) /* 62 ms */ |
| |
| /* |
| * This is the size that the buf occupies in memory. If the buf is compressed, |
| * it will correspond to the compressed size. You should use this method of |
| * getting the buf size unless you explicitly need the logical size. |
| */ |
| uint64_t |
| arc_buf_size(arc_buf_t *buf) |
| { |
| return (ARC_BUF_COMPRESSED(buf) ? |
| HDR_GET_PSIZE(buf->b_hdr) : HDR_GET_LSIZE(buf->b_hdr)); |
| } |
| |
| uint64_t |
| arc_buf_lsize(arc_buf_t *buf) |
| { |
| return (HDR_GET_LSIZE(buf->b_hdr)); |
| } |
| |
| /* |
| * This function will return B_TRUE if the buffer is encrypted in memory. |
| * This buffer can be decrypted by calling arc_untransform(). |
| */ |
| boolean_t |
| arc_is_encrypted(arc_buf_t *buf) |
| { |
| return (ARC_BUF_ENCRYPTED(buf) != 0); |
| } |
| |
| /* |
| * Returns B_TRUE if the buffer represents data that has not had its MAC |
| * verified yet. |
| */ |
| boolean_t |
| arc_is_unauthenticated(arc_buf_t *buf) |
| { |
| return (HDR_NOAUTH(buf->b_hdr) != 0); |
| } |
| |
| void |
| arc_get_raw_params(arc_buf_t *buf, boolean_t *byteorder, uint8_t *salt, |
| uint8_t *iv, uint8_t *mac) |
| { |
| arc_buf_hdr_t *hdr = buf->b_hdr; |
| |
| ASSERT(HDR_PROTECTED(hdr)); |
| |
| bcopy(hdr->b_crypt_hdr.b_salt, salt, ZIO_DATA_SALT_LEN); |
| bcopy(hdr->b_crypt_hdr.b_iv, iv, ZIO_DATA_IV_LEN); |
| bcopy(hdr->b_crypt_hdr.b_mac, mac, ZIO_DATA_MAC_LEN); |
| *byteorder = (hdr->b_l1hdr.b_byteswap == DMU_BSWAP_NUMFUNCS) ? |
| ZFS_HOST_BYTEORDER : !ZFS_HOST_BYTEORDER; |
| } |
| |
| /* |
| * Indicates how this buffer is compressed in memory. If it is not compressed |
| * the value will be ZIO_COMPRESS_OFF. It can be made normally readable with |
| * arc_untransform() as long as it is also unencrypted. |
| */ |
| enum zio_compress |
| arc_get_compression(arc_buf_t *buf) |
| { |
| return (ARC_BUF_COMPRESSED(buf) ? |
| HDR_GET_COMPRESS(buf->b_hdr) : ZIO_COMPRESS_OFF); |
| } |
| |
| /* |
| * Return the compression algorithm used to store this data in the ARC. If ARC |
| * compression is enabled or this is an encrypted block, this will be the same |
| * as what's used to store it on-disk. Otherwise, this will be ZIO_COMPRESS_OFF. |
| */ |
| static inline enum zio_compress |
| arc_hdr_get_compress(arc_buf_hdr_t *hdr) |
| { |
| return (HDR_COMPRESSION_ENABLED(hdr) ? |
| HDR_GET_COMPRESS(hdr) : ZIO_COMPRESS_OFF); |
| } |
| |
| static inline boolean_t |
| arc_buf_is_shared(arc_buf_t *buf) |
| { |
| boolean_t shared = (buf->b_data != NULL && |
| buf->b_hdr->b_l1hdr.b_pabd != NULL && |
| abd_is_linear(buf->b_hdr->b_l1hdr.b_pabd) && |
| buf->b_data == abd_to_buf(buf->b_hdr->b_l1hdr.b_pabd)); |
| IMPLY(shared, HDR_SHARED_DATA(buf->b_hdr)); |
| IMPLY(shared, ARC_BUF_SHARED(buf)); |
| IMPLY(shared, ARC_BUF_COMPRESSED(buf) || ARC_BUF_LAST(buf)); |
| |
| /* |
| * It would be nice to assert arc_can_share() too, but the "hdr isn't |
| * already being shared" requirement prevents us from doing that. |
| */ |
| |
| return (shared); |
| } |
| |
| /* |
| * Free the checksum associated with this header. If there is no checksum, this |
| * is a no-op. |
| */ |
| static inline void |
| arc_cksum_free(arc_buf_hdr_t *hdr) |
| { |
| ASSERT(HDR_HAS_L1HDR(hdr)); |
| |
| mutex_enter(&hdr->b_l1hdr.b_freeze_lock); |
| if (hdr->b_l1hdr.b_freeze_cksum != NULL) { |
| kmem_free(hdr->b_l1hdr.b_freeze_cksum, sizeof (zio_cksum_t)); |
| hdr->b_l1hdr.b_freeze_cksum = NULL; |
| } |
| mutex_exit(&hdr->b_l1hdr.b_freeze_lock); |
| } |
| |
| /* |
| * Return true iff at least one of the bufs on hdr is not compressed. |
| * Encrypted buffers count as compressed. |
| */ |
| static boolean_t |
| arc_hdr_has_uncompressed_buf(arc_buf_hdr_t *hdr) |
| { |
| ASSERT(hdr->b_l1hdr.b_state == arc_anon || HDR_EMPTY_OR_LOCKED(hdr)); |
| |
| for (arc_buf_t *b = hdr->b_l1hdr.b_buf; b != NULL; b = b->b_next) { |
| if (!ARC_BUF_COMPRESSED(b)) { |
| return (B_TRUE); |
| } |
| } |
| return (B_FALSE); |
| } |
| |
| |
| /* |
| * If we've turned on the ZFS_DEBUG_MODIFY flag, verify that the buf's data |
| * matches the checksum that is stored in the hdr. If there is no checksum, |
| * or if the buf is compressed, this is a no-op. |
| */ |
| static void |
| arc_cksum_verify(arc_buf_t *buf) |
| { |
| arc_buf_hdr_t *hdr = buf->b_hdr; |
| zio_cksum_t zc; |
| |
| if (!(zfs_flags & ZFS_DEBUG_MODIFY)) |
| return; |
| |
| if (ARC_BUF_COMPRESSED(buf)) |
| return; |
| |
| ASSERT(HDR_HAS_L1HDR(hdr)); |
| |
| mutex_enter(&hdr->b_l1hdr.b_freeze_lock); |
| |
| if (hdr->b_l1hdr.b_freeze_cksum == NULL || HDR_IO_ERROR(hdr)) { |
| mutex_exit(&hdr->b_l1hdr.b_freeze_lock); |
| return; |
| } |
| |
| fletcher_2_native(buf->b_data, arc_buf_size(buf), NULL, &zc); |
| if (!ZIO_CHECKSUM_EQUAL(*hdr->b_l1hdr.b_freeze_cksum, zc)) |
| panic("buffer modified while frozen!"); |
| mutex_exit(&hdr->b_l1hdr.b_freeze_lock); |
| } |
| |
| /* |
| * This function makes the assumption that data stored in the L2ARC |
| * will be transformed exactly as it is in the main pool. Because of |
| * this we can verify the checksum against the reading process's bp. |
| */ |
| static boolean_t |
| arc_cksum_is_equal(arc_buf_hdr_t *hdr, zio_t *zio) |
| { |
| ASSERT(!BP_IS_EMBEDDED(zio->io_bp)); |
| VERIFY3U(BP_GET_PSIZE(zio->io_bp), ==, HDR_GET_PSIZE(hdr)); |
| |
| /* |
| * Block pointers always store the checksum for the logical data. |
| * If the block pointer has the gang bit set, then the checksum |
| * it represents is for the reconstituted data and not for an |
| * individual gang member. The zio pipeline, however, must be able to |
| * determine the checksum of each of the gang constituents so it |
| * treats the checksum comparison differently than what we need |
| * for l2arc blocks. This prevents us from using the |
| * zio_checksum_error() interface directly. Instead we must call the |
| * zio_checksum_error_impl() so that we can ensure the checksum is |
| * generated using the correct checksum algorithm and accounts for the |
| * logical I/O size and not just a gang fragment. |
| */ |
| return (zio_checksum_error_impl(zio->io_spa, zio->io_bp, |
| BP_GET_CHECKSUM(zio->io_bp), zio->io_abd, zio->io_size, |
| zio->io_offset, NULL) == 0); |
| } |
| |
| /* |
| * Given a buf full of data, if ZFS_DEBUG_MODIFY is enabled this computes a |
| * checksum and attaches it to the buf's hdr so that we can ensure that the buf |
| * isn't modified later on. If buf is compressed or there is already a checksum |
| * on the hdr, this is a no-op (we only checksum uncompressed bufs). |
| */ |
| static void |
| arc_cksum_compute(arc_buf_t *buf) |
| { |
| arc_buf_hdr_t *hdr = buf->b_hdr; |
| |
| if (!(zfs_flags & ZFS_DEBUG_MODIFY)) |
| return; |
| |
| ASSERT(HDR_HAS_L1HDR(hdr)); |
| |
| mutex_enter(&buf->b_hdr->b_l1hdr.b_freeze_lock); |
| if (hdr->b_l1hdr.b_freeze_cksum != NULL || ARC_BUF_COMPRESSED(buf)) { |
| mutex_exit(&hdr->b_l1hdr.b_freeze_lock); |
| return; |
| } |
| |
| ASSERT(!ARC_BUF_ENCRYPTED(buf)); |
| ASSERT(!ARC_BUF_COMPRESSED(buf)); |
| hdr->b_l1hdr.b_freeze_cksum = kmem_alloc(sizeof (zio_cksum_t), |
| KM_SLEEP); |
| fletcher_2_native(buf->b_data, arc_buf_size(buf), NULL, |
| hdr->b_l1hdr.b_freeze_cksum); |
| mutex_exit(&hdr->b_l1hdr.b_freeze_lock); |
| arc_buf_watch(buf); |
| } |
| |
| #ifndef _KERNEL |
| void |
| arc_buf_sigsegv(int sig, siginfo_t *si, void *unused) |
| { |
| panic("Got SIGSEGV at address: 0x%lx\n", (long)si->si_addr); |
| } |
| #endif |
| |
| /* ARGSUSED */ |
| static void |
| arc_buf_unwatch(arc_buf_t *buf) |
| { |
| #ifndef _KERNEL |
| if (arc_watch) { |
| ASSERT0(mprotect(buf->b_data, arc_buf_size(buf), |
| PROT_READ | PROT_WRITE)); |
| } |
| #endif |
| } |
| |
| /* ARGSUSED */ |
| static void |
| arc_buf_watch(arc_buf_t *buf) |
| { |
| #ifndef _KERNEL |
| if (arc_watch) |
| ASSERT0(mprotect(buf->b_data, arc_buf_size(buf), |
| PROT_READ)); |
| #endif |
| } |
| |
| static arc_buf_contents_t |
| arc_buf_type(arc_buf_hdr_t *hdr) |
| { |
| arc_buf_contents_t type; |
| if (HDR_ISTYPE_METADATA(hdr)) { |
| type = ARC_BUFC_METADATA; |
| } else { |
| type = ARC_BUFC_DATA; |
| } |
| VERIFY3U(hdr->b_type, ==, type); |
| return (type); |
| } |
| |
| boolean_t |
| arc_is_metadata(arc_buf_t *buf) |
| { |
| return (HDR_ISTYPE_METADATA(buf->b_hdr) != 0); |
| } |
| |
| static uint32_t |
| arc_bufc_to_flags(arc_buf_contents_t type) |
| { |
| switch (type) { |
| case ARC_BUFC_DATA: |
| /* metadata field is 0 if buffer contains normal data */ |
| return (0); |
| case ARC_BUFC_METADATA: |
| return (ARC_FLAG_BUFC_METADATA); |
| default: |
| break; |
| } |
| panic("undefined ARC buffer type!"); |
| return ((uint32_t)-1); |
| } |
| |
| void |
| arc_buf_thaw(arc_buf_t *buf) |
| { |
| arc_buf_hdr_t *hdr = buf->b_hdr; |
| |
| ASSERT3P(hdr->b_l1hdr.b_state, ==, arc_anon); |
| ASSERT(!HDR_IO_IN_PROGRESS(hdr)); |
| |
| arc_cksum_verify(buf); |
| |
| /* |
| * Compressed buffers do not manipulate the b_freeze_cksum. |
| */ |
| if (ARC_BUF_COMPRESSED(buf)) |
| return; |
| |
| ASSERT(HDR_HAS_L1HDR(hdr)); |
| arc_cksum_free(hdr); |
| arc_buf_unwatch(buf); |
| } |
| |
| void |
| arc_buf_freeze(arc_buf_t *buf) |
| { |
| if (!(zfs_flags & ZFS_DEBUG_MODIFY)) |
| return; |
| |
| if (ARC_BUF_COMPRESSED(buf)) |
| return; |
| |
| ASSERT(HDR_HAS_L1HDR(buf->b_hdr)); |
| arc_cksum_compute(buf); |
| } |
| |
| /* |
| * The arc_buf_hdr_t's b_flags should never be modified directly. Instead, |
| * the following functions should be used to ensure that the flags are |
| * updated in a thread-safe way. When manipulating the flags either |
| * the hash_lock must be held or the hdr must be undiscoverable. This |
| * ensures that we're not racing with any other threads when updating |
| * the flags. |
| */ |
| static inline void |
| arc_hdr_set_flags(arc_buf_hdr_t *hdr, arc_flags_t flags) |
| { |
| ASSERT(HDR_EMPTY_OR_LOCKED(hdr)); |
| hdr->b_flags |= flags; |
| } |
| |
| static inline void |
| arc_hdr_clear_flags(arc_buf_hdr_t *hdr, arc_flags_t flags) |
| { |
| ASSERT(HDR_EMPTY_OR_LOCKED(hdr)); |
| hdr->b_flags &= ~flags; |
| } |
| |
| /* |
| * Setting the compression bits in the arc_buf_hdr_t's b_flags is |
| * done in a special way since we have to clear and set bits |
| * at the same time. Consumers that wish to set the compression bits |
| * must use this function to ensure that the flags are updated in |
| * thread-safe manner. |
| */ |
| static void |
| arc_hdr_set_compress(arc_buf_hdr_t *hdr, enum zio_compress cmp) |
| { |
| ASSERT(HDR_EMPTY_OR_LOCKED(hdr)); |
| |
| /* |
| * Holes and embedded blocks will always have a psize = 0 so |
| * we ignore the compression of the blkptr and set the |
| * want to uncompress them. Mark them as uncompressed. |
| */ |
| if (!zfs_compressed_arc_enabled || HDR_GET_PSIZE(hdr) == 0) { |
| arc_hdr_clear_flags(hdr, ARC_FLAG_COMPRESSED_ARC); |
| ASSERT(!HDR_COMPRESSION_ENABLED(hdr)); |
| } else { |
| arc_hdr_set_flags(hdr, ARC_FLAG_COMPRESSED_ARC); |
| ASSERT(HDR_COMPRESSION_ENABLED(hdr)); |
| } |
| |
| HDR_SET_COMPRESS(hdr, cmp); |
| ASSERT3U(HDR_GET_COMPRESS(hdr), ==, cmp); |
| } |
| |
| /* |
| * Looks for another buf on the same hdr which has the data decompressed, copies |
| * from it, and returns true. If no such buf exists, returns false. |
| */ |
| static boolean_t |
| arc_buf_try_copy_decompressed_data(arc_buf_t *buf) |
| { |
| arc_buf_hdr_t *hdr = buf->b_hdr; |
| boolean_t copied = B_FALSE; |
| |
| ASSERT(HDR_HAS_L1HDR(hdr)); |
| ASSERT3P(buf->b_data, !=, NULL); |
| ASSERT(!ARC_BUF_COMPRESSED(buf)); |
| |
| for (arc_buf_t *from = hdr->b_l1hdr.b_buf; from != NULL; |
| from = from->b_next) { |
| /* can't use our own data buffer */ |
| if (from == buf) { |
| continue; |
| } |
| |
| if (!ARC_BUF_COMPRESSED(from)) { |
| bcopy(from->b_data, buf->b_data, arc_buf_size(buf)); |
| copied = B_TRUE; |
| break; |
| } |
| } |
| |
| /* |
| * There were no decompressed bufs, so there should not be a |
| * checksum on the hdr either. |
| */ |
| if (zfs_flags & ZFS_DEBUG_MODIFY) |
| EQUIV(!copied, hdr->b_l1hdr.b_freeze_cksum == NULL); |
| |
| return (copied); |
| } |
| |
| /* |
| * Return the size of the block, b_pabd, that is stored in the arc_buf_hdr_t. |
| */ |
| static uint64_t |
| arc_hdr_size(arc_buf_hdr_t *hdr) |
| { |
| uint64_t size; |
| |
| if (arc_hdr_get_compress(hdr) != ZIO_COMPRESS_OFF && |
| HDR_GET_PSIZE(hdr) > 0) { |
| size = HDR_GET_PSIZE(hdr); |
| } else { |
| ASSERT3U(HDR_GET_LSIZE(hdr), !=, 0); |
| size = HDR_GET_LSIZE(hdr); |
| } |
| return (size); |
| } |
| |
| static int |
| arc_hdr_authenticate(arc_buf_hdr_t *hdr, spa_t *spa, uint64_t dsobj) |
| { |
| int ret; |
| uint64_t csize; |
| uint64_t lsize = HDR_GET_LSIZE(hdr); |
| uint64_t psize = HDR_GET_PSIZE(hdr); |
| void *tmpbuf = NULL; |
| abd_t *abd = hdr->b_l1hdr.b_pabd; |
| |
| ASSERT(HDR_EMPTY_OR_LOCKED(hdr)); |
| ASSERT(HDR_AUTHENTICATED(hdr)); |
| ASSERT3P(hdr->b_l1hdr.b_pabd, !=, NULL); |
| |
| /* |
| * The MAC is calculated on the compressed data that is stored on disk. |
| * However, if compressed arc is disabled we will only have the |
| * decompressed data available to us now. Compress it into a temporary |
| * abd so we can verify the MAC. The performance overhead of this will |
| * be relatively low, since most objects in an encrypted objset will |
| * be encrypted (instead of authenticated) anyway. |
| */ |
| if (HDR_GET_COMPRESS(hdr) != ZIO_COMPRESS_OFF && |
| !HDR_COMPRESSION_ENABLED(hdr)) { |
| tmpbuf = zio_buf_alloc(lsize); |
| abd = abd_get_from_buf(tmpbuf, lsize); |
| abd_take_ownership_of_buf(abd, B_TRUE); |
| |
| csize = zio_compress_data(HDR_GET_COMPRESS(hdr), |
| hdr->b_l1hdr.b_pabd, tmpbuf, lsize); |
| ASSERT3U(csize, <=, psize); |
| abd_zero_off(abd, csize, psize - csize); |
| } |
| |
| /* |
| * Authentication is best effort. We authenticate whenever the key is |
| * available. If we succeed we clear ARC_FLAG_NOAUTH. |
| */ |
| if (hdr->b_crypt_hdr.b_ot == DMU_OT_OBJSET) { |
| ASSERT3U(HDR_GET_COMPRESS(hdr), ==, ZIO_COMPRESS_OFF); |
| ASSERT3U(lsize, ==, psize); |
| ret = spa_do_crypt_objset_mac_abd(B_FALSE, spa, dsobj, abd, |
| psize, hdr->b_l1hdr.b_byteswap != DMU_BSWAP_NUMFUNCS); |
| } else { |
| ret = spa_do_crypt_mac_abd(B_FALSE, spa, dsobj, abd, psize, |
| hdr->b_crypt_hdr.b_mac); |
| } |
| |
| if (ret == 0) |
| arc_hdr_clear_flags(hdr, ARC_FLAG_NOAUTH); |
| else if (ret != ENOENT) |
| goto error; |
| |
| if (tmpbuf != NULL) |
| abd_free(abd); |
| |
| return (0); |
| |
| error: |
| if (tmpbuf != NULL) |
| abd_free(abd); |
| |
| return (ret); |
| } |
| |
| /* |
| * This function will take a header that only has raw encrypted data in |
| * b_crypt_hdr.b_rabd and decrypt it into a new buffer which is stored in |
| * b_l1hdr.b_pabd. If designated in the header flags, this function will |
| * also decompress the data. |
| */ |
| static int |
| arc_hdr_decrypt(arc_buf_hdr_t *hdr, spa_t *spa, const zbookmark_phys_t *zb) |
| { |
| int ret; |
| abd_t *cabd = NULL; |
| void *tmp = NULL; |
| boolean_t no_crypt = B_FALSE; |
| boolean_t bswap = (hdr->b_l1hdr.b_byteswap != DMU_BSWAP_NUMFUNCS); |
| |
| ASSERT(HDR_EMPTY_OR_LOCKED(hdr)); |
| ASSERT(HDR_ENCRYPTED(hdr)); |
| |
| arc_hdr_alloc_abd(hdr, ARC_HDR_DO_ADAPT); |
| |
| ret = spa_do_crypt_abd(B_FALSE, spa, zb, hdr->b_crypt_hdr.b_ot, |
| B_FALSE, bswap, hdr->b_crypt_hdr.b_salt, hdr->b_crypt_hdr.b_iv, |
| hdr->b_crypt_hdr.b_mac, HDR_GET_PSIZE(hdr), hdr->b_l1hdr.b_pabd, |
| hdr->b_crypt_hdr.b_rabd, &no_crypt); |
| if (ret != 0) |
| goto error; |
| |
| if (no_crypt) { |
| abd_copy(hdr->b_l1hdr.b_pabd, hdr->b_crypt_hdr.b_rabd, |
| HDR_GET_PSIZE(hdr)); |
| } |
| |
| /* |
| * If this header has disabled arc compression but the b_pabd is |
| * compressed after decrypting it, we need to decompress the newly |
| * decrypted data. |
| */ |
| if (HDR_GET_COMPRESS(hdr) != ZIO_COMPRESS_OFF && |
| !HDR_COMPRESSION_ENABLED(hdr)) { |
| /* |
| * We want to make sure that we are correctly honoring the |
| * zfs_abd_scatter_enabled setting, so we allocate an abd here |
| * and then loan a buffer from it, rather than allocating a |
| * linear buffer and wrapping it in an abd later. |
| */ |
| cabd = arc_get_data_abd(hdr, arc_hdr_size(hdr), hdr, B_TRUE); |
| tmp = abd_borrow_buf(cabd, arc_hdr_size(hdr)); |
| |
| ret = zio_decompress_data(HDR_GET_COMPRESS(hdr), |
| hdr->b_l1hdr.b_pabd, tmp, HDR_GET_PSIZE(hdr), |
| HDR_GET_LSIZE(hdr)); |
| if (ret != 0) { |
| abd_return_buf(cabd, tmp, arc_hdr_size(hdr)); |
| goto error; |
| } |
| |
| abd_return_buf_copy(cabd, tmp, arc_hdr_size(hdr)); |
| arc_free_data_abd(hdr, hdr->b_l1hdr.b_pabd, |
| arc_hdr_size(hdr), hdr); |
| hdr->b_l1hdr.b_pabd = cabd; |
| } |
| |
| return (0); |
| |
| error: |
| arc_hdr_free_abd(hdr, B_FALSE); |
| if (cabd != NULL) |
| arc_free_data_buf(hdr, cabd, arc_hdr_size(hdr), hdr); |
| |
| return (ret); |
| } |
| |
| /* |
| * This function is called during arc_buf_fill() to prepare the header's |
| * abd plaintext pointer for use. This involves authenticated protected |
| * data and decrypting encrypted data into the plaintext abd. |
| */ |
| static int |
| arc_fill_hdr_crypt(arc_buf_hdr_t *hdr, kmutex_t *hash_lock, spa_t *spa, |
| const zbookmark_phys_t *zb, boolean_t noauth) |
| { |
| int ret; |
| |
| ASSERT(HDR_PROTECTED(hdr)); |
| |
| if (hash_lock != NULL) |
| mutex_enter(hash_lock); |
| |
| if (HDR_NOAUTH(hdr) && !noauth) { |
| /* |
| * The caller requested authenticated data but our data has |
| * not been authenticated yet. Verify the MAC now if we can. |
| */ |
| ret = arc_hdr_authenticate(hdr, spa, zb->zb_objset); |
| if (ret != 0) |
| goto error; |
| } else if (HDR_HAS_RABD(hdr) && hdr->b_l1hdr.b_pabd == NULL) { |
| /* |
| * If we only have the encrypted version of the data, but the |
| * unencrypted version was requested we take this opportunity |
| * to store the decrypted version in the header for future use. |
| */ |
| ret = arc_hdr_decrypt(hdr, spa, zb); |
| if (ret != 0) |
| goto error; |
| } |
| |
| ASSERT3P(hdr->b_l1hdr.b_pabd, !=, NULL); |
| |
| if (hash_lock != NULL) |
| mutex_exit(hash_lock); |
| |
| return (0); |
| |
| error: |
| if (hash_lock != NULL) |
| mutex_exit(hash_lock); |
| |
| return (ret); |
| } |
| |
| /* |
| * This function is used by the dbuf code to decrypt bonus buffers in place. |
| * The dbuf code itself doesn't have any locking for decrypting a shared dnode |
| * block, so we use the hash lock here to protect against concurrent calls to |
| * arc_buf_fill(). |
| */ |
| static void |
| arc_buf_untransform_in_place(arc_buf_t *buf, kmutex_t *hash_lock) |
| { |
| arc_buf_hdr_t *hdr = buf->b_hdr; |
| |
| ASSERT(HDR_ENCRYPTED(hdr)); |
| ASSERT3U(hdr->b_crypt_hdr.b_ot, ==, DMU_OT_DNODE); |
| ASSERT(HDR_EMPTY_OR_LOCKED(hdr)); |
| ASSERT3P(hdr->b_l1hdr.b_pabd, !=, NULL); |
| |
| zio_crypt_copy_dnode_bonus(hdr->b_l1hdr.b_pabd, buf->b_data, |
| arc_buf_size(buf)); |
| buf->b_flags &= ~ARC_BUF_FLAG_ENCRYPTED; |
| buf->b_flags &= ~ARC_BUF_FLAG_COMPRESSED; |
| hdr->b_crypt_hdr.b_ebufcnt -= 1; |
| } |
| |
| /* |
| * Given a buf that has a data buffer attached to it, this function will |
| * efficiently fill the buf with data of the specified compression setting from |
| * the hdr and update the hdr's b_freeze_cksum if necessary. If the buf and hdr |
| * are already sharing a data buf, no copy is performed. |
| * |
| * If the buf is marked as compressed but uncompressed data was requested, this |
| * will allocate a new data buffer for the buf, remove that flag, and fill the |
| * buf with uncompressed data. You can't request a compressed buf on a hdr with |
| * uncompressed data, and (since we haven't added support for it yet) if you |
| * want compressed data your buf must already be marked as compressed and have |
| * the correct-sized data buffer. |
| */ |
| static int |
| arc_buf_fill(arc_buf_t *buf, spa_t *spa, const zbookmark_phys_t *zb, |
| arc_fill_flags_t flags) |
| { |
| int error = 0; |
| arc_buf_hdr_t *hdr = buf->b_hdr; |
| boolean_t hdr_compressed = |
| (arc_hdr_get_compress(hdr) != ZIO_COMPRESS_OFF); |
| boolean_t compressed = (flags & ARC_FILL_COMPRESSED) != 0; |
| boolean_t encrypted = (flags & ARC_FILL_ENCRYPTED) != 0; |
| dmu_object_byteswap_t bswap = hdr->b_l1hdr.b_byteswap; |
| kmutex_t *hash_lock = (flags & ARC_FILL_LOCKED) ? NULL : HDR_LOCK(hdr); |
| |
| ASSERT3P(buf->b_data, !=, NULL); |
| IMPLY(compressed, hdr_compressed || ARC_BUF_ENCRYPTED(buf)); |
| IMPLY(compressed, ARC_BUF_COMPRESSED(buf)); |
| IMPLY(encrypted, HDR_ENCRYPTED(hdr)); |
| IMPLY(encrypted, ARC_BUF_ENCRYPTED(buf)); |
| IMPLY(encrypted, ARC_BUF_COMPRESSED(buf)); |
| IMPLY(encrypted, !ARC_BUF_SHARED(buf)); |
| |
| /* |
| * If the caller wanted encrypted data we just need to copy it from |
| * b_rabd and potentially byteswap it. We won't be able to do any |
| * further transforms on it. |
| */ |
| if (encrypted) { |
| ASSERT(HDR_HAS_RABD(hdr)); |
| abd_copy_to_buf(buf->b_data, hdr->b_crypt_hdr.b_rabd, |
| HDR_GET_PSIZE(hdr)); |
| goto byteswap; |
| } |
| |
| /* |
| * Adjust encrypted and authenticated headers to accommodate |
| * the request if needed. Dnode blocks (ARC_FILL_IN_PLACE) are |
| * allowed to fail decryption due to keys not being loaded |
| * without being marked as an IO error. |
| */ |
| if (HDR_PROTECTED(hdr)) { |
| error = arc_fill_hdr_crypt(hdr, hash_lock, spa, |
| zb, !!(flags & ARC_FILL_NOAUTH)); |
| if (error == EACCES && (flags & ARC_FILL_IN_PLACE) != 0) { |
| return (error); |
| } else if (error != 0) { |
| if (hash_lock != NULL) |
| mutex_enter(hash_lock); |
| arc_hdr_set_flags(hdr, ARC_FLAG_IO_ERROR); |
| if (hash_lock != NULL) |
| mutex_exit(hash_lock); |
| return (error); |
| } |
| } |
| |
| /* |
| * There is a special case here for dnode blocks which are |
| * decrypting their bonus buffers. These blocks may request to |
| * be decrypted in-place. This is necessary because there may |
| * be many dnodes pointing into this buffer and there is |
| * currently no method to synchronize replacing the backing |
| * b_data buffer and updating all of the pointers. Here we use |
| * the hash lock to ensure there are no races. If the need |
| * arises for other types to be decrypted in-place, they must |
| * add handling here as well. |
| */ |
| if ((flags & ARC_FILL_IN_PLACE) != 0) { |
| ASSERT(!hdr_compressed); |
| ASSERT(!compressed); |
| ASSERT(!encrypted); |
| |
| if (HDR_ENCRYPTED(hdr) && ARC_BUF_ENCRYPTED(buf)) { |
| ASSERT3U(hdr->b_crypt_hdr.b_ot, ==, DMU_OT_DNODE); |
| |
| if (hash_lock != NULL) |
| mutex_enter(hash_lock); |
| arc_buf_untransform_in_place(buf, hash_lock); |
| if (hash_lock != NULL) |
| mutex_exit(hash_lock); |
| |
| /* Compute the hdr's checksum if necessary */ |
| arc_cksum_compute(buf); |
| } |
| |
| return (0); |
| } |
| |
| if (hdr_compressed == compressed) { |
| if (!arc_buf_is_shared(buf)) { |
| abd_copy_to_buf(buf->b_data, hdr->b_l1hdr.b_pabd, |
| arc_buf_size(buf)); |
| } |
| } else { |
| ASSERT(hdr_compressed); |
| ASSERT(!compressed); |
| ASSERT3U(HDR_GET_LSIZE(hdr), !=, HDR_GET_PSIZE(hdr)); |
| |
| /* |
| * If the buf is sharing its data with the hdr, unlink it and |
| * allocate a new data buffer for the buf. |
| */ |
| if (arc_buf_is_shared(buf)) { |
| ASSERT(ARC_BUF_COMPRESSED(buf)); |
| |
| /* We need to give the buf its own b_data */ |
| buf->b_flags &= ~ARC_BUF_FLAG_SHARED; |
| buf->b_data = |
| arc_get_data_buf(hdr, HDR_GET_LSIZE(hdr), buf); |
| arc_hdr_clear_flags(hdr, ARC_FLAG_SHARED_DATA); |
| |
| /* Previously overhead was 0; just add new overhead */ |
| ARCSTAT_INCR(arcstat_overhead_size, HDR_GET_LSIZE(hdr)); |
| } else if (ARC_BUF_COMPRESSED(buf)) { |
| /* We need to reallocate the buf's b_data */ |
| arc_free_data_buf(hdr, buf->b_data, HDR_GET_PSIZE(hdr), |
| buf); |
| buf->b_data = |
| arc_get_data_buf(hdr, HDR_GET_LSIZE(hdr), buf); |
| |
| /* We increased the size of b_data; update overhead */ |
| ARCSTAT_INCR(arcstat_overhead_size, |
| HDR_GET_LSIZE(hdr) - HDR_GET_PSIZE(hdr)); |
| } |
| |
| /* |
| * Regardless of the buf's previous compression settings, it |
| * should not be compressed at the end of this function. |
| */ |
| buf->b_flags &= ~ARC_BUF_FLAG_COMPRESSED; |
| |
| /* |
| * Try copying the data from another buf which already has a |
| * decompressed version. If that's not possible, it's time to |
| * bite the bullet and decompress the data from the hdr. |
| */ |
| if (arc_buf_try_copy_decompressed_data(buf)) { |
| /* Skip byteswapping and checksumming (already done) */ |
| return (0); |
| } else { |
| error = zio_decompress_data(HDR_GET_COMPRESS(hdr), |
| hdr->b_l1hdr.b_pabd, buf->b_data, |
| HDR_GET_PSIZE(hdr), HDR_GET_LSIZE(hdr)); |
| |
| /* |
| * Absent hardware errors or software bugs, this should |
| * be impossible, but log it anyway so we can debug it. |
| */ |
| if (error != 0) { |
| zfs_dbgmsg( |
| "hdr %px, compress %d, psize %d, lsize %d", |
| hdr, arc_hdr_get_compress(hdr), |
| HDR_GET_PSIZE(hdr), HDR_GET_LSIZE(hdr)); |
| if (hash_lock != NULL) |
| mutex_enter(hash_lock); |
| arc_hdr_set_flags(hdr, ARC_FLAG_IO_ERROR); |
| if (hash_lock != NULL) |
| mutex_exit(hash_lock); |
| return (SET_ERROR(EIO)); |
| } |
| } |
| } |
| |
| byteswap: |
| /* Byteswap the buf's data if necessary */ |
| if (bswap != DMU_BSWAP_NUMFUNCS) { |
| ASSERT(!HDR_SHARED_DATA(hdr)); |
| ASSERT3U(bswap, <, DMU_BSWAP_NUMFUNCS); |
| dmu_ot_byteswap[bswap].ob_func(buf->b_data, HDR_GET_LSIZE(hdr)); |
| } |
| |
| /* Compute the hdr's checksum if necessary */ |
| arc_cksum_compute(buf); |
| |
| return (0); |
| } |
| |
| /* |
| * If this function is being called to decrypt an encrypted buffer or verify an |
| * authenticated one, the key must be loaded and a mapping must be made |
| * available in the keystore via spa_keystore_create_mapping() or one of its |
| * callers. |
| */ |
| int |
| arc_untransform(arc_buf_t *buf, spa_t *spa, const zbookmark_phys_t *zb, |
| boolean_t in_place) |
| { |
| int ret; |
| arc_fill_flags_t flags = 0; |
| |
| if (in_place) |
| flags |= ARC_FILL_IN_PLACE; |
| |
| ret = arc_buf_fill(buf, spa, zb, flags); |
| if (ret == ECKSUM) { |
| /* |
| * Convert authentication and decryption errors to EIO |
| * (and generate an ereport) before leaving the ARC. |
| */ |
| ret = SET_ERROR(EIO); |
| spa_log_error(spa, zb); |
| zfs_ereport_post(FM_EREPORT_ZFS_AUTHENTICATION, |
| spa, NULL, zb, NULL, 0, 0); |
| } |
| |
| return (ret); |
| } |
| |
| /* |
| * Increment the amount of evictable space in the arc_state_t's refcount. |
| * We account for the space used by the hdr and the arc buf individually |
| * so that we can add and remove them from the refcount individually. |
| */ |
| static void |
| arc_evictable_space_increment(arc_buf_hdr_t *hdr, arc_state_t *state) |
| { |
| arc_buf_contents_t type = arc_buf_type(hdr); |
| |
| ASSERT(HDR_HAS_L1HDR(hdr)); |
| |
| if (GHOST_STATE(state)) { |
| ASSERT0(hdr->b_l1hdr.b_bufcnt); |
| ASSERT3P(hdr->b_l1hdr.b_buf, ==, NULL); |
| ASSERT3P(hdr->b_l1hdr.b_pabd, ==, NULL); |
| ASSERT(!HDR_HAS_RABD(hdr)); |
| (void) zfs_refcount_add_many(&state->arcs_esize[type], |
| HDR_GET_LSIZE(hdr), hdr); |
| return; |
| } |
| |
| ASSERT(!GHOST_STATE(state)); |
| if (hdr->b_l1hdr.b_pabd != NULL) { |
| (void) zfs_refcount_add_many(&state->arcs_esize[type], |
| arc_hdr_size(hdr), hdr); |
| } |
| if (HDR_HAS_RABD(hdr)) { |
| (void) zfs_refcount_add_many(&state->arcs_esize[type], |
| HDR_GET_PSIZE(hdr), hdr); |
| } |
| |
| for (arc_buf_t *buf = hdr->b_l1hdr.b_buf; buf != NULL; |
| buf = buf->b_next) { |
| if (arc_buf_is_shared(buf)) |
| continue; |
| (void) zfs_refcount_add_many(&state->arcs_esize[type], |
| arc_buf_size(buf), buf); |
| } |
| } |
| |
| /* |
| * Decrement the amount of evictable space in the arc_state_t's refcount. |
| * We account for the space used by the hdr and the arc buf individually |
| * so that we can add and remove them from the refcount individually. |
| */ |
| static void |
| arc_evictable_space_decrement(arc_buf_hdr_t *hdr, arc_state_t *state) |
| { |
| arc_buf_contents_t type = arc_buf_type(hdr); |
| |
| ASSERT(HDR_HAS_L1HDR(hdr)); |
| |
| if (GHOST_STATE(state)) { |
| ASSERT0(hdr->b_l1hdr.b_bufcnt); |
| ASSERT3P(hdr->b_l1hdr.b_buf, ==, NULL); |
| ASSERT3P(hdr->b_l1hdr.b_pabd, ==, NULL); |
| ASSERT(!HDR_HAS_RABD(hdr)); |
| (void) zfs_refcount_remove_many(&state->arcs_esize[type], |
| HDR_GET_LSIZE(hdr), hdr); |
| return; |
| } |
| |
| ASSERT(!GHOST_STATE(state)); |
| if (hdr->b_l1hdr.b_pabd != NULL) { |
| (void) zfs_refcount_remove_many(&state->arcs_esize[type], |
| arc_hdr_size(hdr), hdr); |
| } |
| if (HDR_HAS_RABD(hdr)) { |
| (void) zfs_refcount_remove_many(&state->arcs_esize[type], |
| HDR_GET_PSIZE(hdr), hdr); |
| } |
| |
| for (arc_buf_t *buf = hdr->b_l1hdr.b_buf; buf != NULL; |
| buf = buf->b_next) { |
| if (arc_buf_is_shared(buf)) |
| continue; |
| (void) zfs_refcount_remove_many(&state->arcs_esize[type], |
| arc_buf_size(buf), buf); |
| } |
| } |
| |
| /* |
| * Add a reference to this hdr indicating that someone is actively |
| * referencing that memory. When the refcount transitions from 0 to 1, |
| * we remove it from the respective arc_state_t list to indicate that |
| * it is not evictable. |
| */ |
| static void |
| add_reference(arc_buf_hdr_t *hdr, void *tag) |
| { |
| arc_state_t *state; |
| |
| ASSERT(HDR_HAS_L1HDR(hdr)); |
| if (!HDR_EMPTY(hdr) && !MUTEX_HELD(HDR_LOCK(hdr))) { |
| ASSERT(hdr->b_l1hdr.b_state == arc_anon); |
| ASSERT(zfs_refcount_is_zero(&hdr->b_l1hdr.b_refcnt)); |
| ASSERT3P(hdr->b_l1hdr.b_buf, ==, NULL); |
| } |
| |
| state = hdr->b_l1hdr.b_state; |
| |
| if ((zfs_refcount_add(&hdr->b_l1hdr.b_refcnt, tag) == 1) && |
| (state != arc_anon)) { |
| /* We don't use the L2-only state list. */ |
| if (state != arc_l2c_only) { |
| multilist_remove(state->arcs_list[arc_buf_type(hdr)], |
| hdr); |
| arc_evictable_space_decrement(hdr, state); |
| } |
| /* remove the prefetch flag if we get a reference */ |
| arc_hdr_clear_flags(hdr, ARC_FLAG_PREFETCH); |
| } |
| } |
| |
| /* |
| * Remove a reference from this hdr. When the reference transitions from |
| * 1 to 0 and we're not anonymous, then we add this hdr to the arc_state_t's |
| * list making it eligible for eviction. |
| */ |
| static int |
| remove_reference(arc_buf_hdr_t *hdr, kmutex_t *hash_lock, void *tag) |
| { |
| int cnt; |
| arc_state_t *state = hdr->b_l1hdr.b_state; |
| |
| ASSERT(HDR_HAS_L1HDR(hdr)); |
| ASSERT(state == arc_anon || MUTEX_HELD(hash_lock)); |
| ASSERT(!GHOST_STATE(state)); |
| |
| /* |
| * arc_l2c_only counts as a ghost state so we don't need to explicitly |
| * check to prevent usage of the arc_l2c_only list. |
| */ |
| if (((cnt = zfs_refcount_remove(&hdr->b_l1hdr.b_refcnt, tag)) == 0) && |
| (state != arc_anon)) { |
| multilist_insert(state->arcs_list[arc_buf_type(hdr)], hdr); |
| ASSERT3U(hdr->b_l1hdr.b_bufcnt, >, 0); |
| arc_evictable_space_increment(hdr, state); |
| } |
| return (cnt); |
| } |
| |
| /* |
| * Returns detailed information about a specific arc buffer. When the |
| * state_index argument is set the function will calculate the arc header |
| * list position for its arc state. Since this requires a linear traversal |
| * callers are strongly encourage not to do this. However, it can be helpful |
| * for targeted analysis so the functionality is provided. |
| */ |
| void |
| arc_buf_info(arc_buf_t *ab, arc_buf_info_t *abi, int state_index) |
| { |
| arc_buf_hdr_t *hdr = ab->b_hdr; |
| l1arc_buf_hdr_t *l1hdr = NULL; |
| l2arc_buf_hdr_t *l2hdr = NULL; |
| arc_state_t *state = NULL; |
| |
| memset(abi, 0, sizeof (arc_buf_info_t)); |
| |
| if (hdr == NULL) |
| return; |
| |
| abi->abi_flags = hdr->b_flags; |
| |
| if (HDR_HAS_L1HDR(hdr)) { |
| l1hdr = &hdr->b_l1hdr; |
| state = l1hdr->b_state; |
| } |
| if (HDR_HAS_L2HDR(hdr)) |
| l2hdr = &hdr->b_l2hdr; |
| |
| if (l1hdr) { |
| abi->abi_bufcnt = l1hdr->b_bufcnt; |
| abi->abi_access = l1hdr->b_arc_access; |
| abi->abi_mru_hits = l1hdr->b_mru_hits; |
| abi->abi_mru_ghost_hits = l1hdr->b_mru_ghost_hits; |
| abi->abi_mfu_hits = l1hdr->b_mfu_hits; |
| abi->abi_mfu_ghost_hits = l1hdr->b_mfu_ghost_hits; |
| abi->abi_holds = zfs_refcount_count(&l1hdr->b_refcnt); |
| } |
| |
| if (l2hdr) { |
| abi->abi_l2arc_dattr = l2hdr->b_daddr; |
| abi->abi_l2arc_hits = l2hdr->b_hits; |
| } |
| |
| abi->abi_state_type = state ? state->arcs_state : ARC_STATE_ANON; |
| abi->abi_state_contents = arc_buf_type(hdr); |
| abi->abi_size = arc_hdr_size(hdr); |
| } |
| |
| /* |
| * Move the supplied buffer to the indicated state. The hash lock |
| * for the buffer must be held by the caller. |
| */ |
| static void |
| arc_change_state(arc_state_t *new_state, arc_buf_hdr_t *hdr, |
| kmutex_t *hash_lock) |
| { |
| arc_state_t *old_state; |
| int64_t refcnt; |
| uint32_t bufcnt; |
| boolean_t update_old, update_new; |
| arc_buf_contents_t buftype = arc_buf_type(hdr); |
| |
| /* |
| * We almost always have an L1 hdr here, since we call arc_hdr_realloc() |
| * in arc_read() when bringing a buffer out of the L2ARC. However, the |
| * L1 hdr doesn't always exist when we change state to arc_anon before |
| * destroying a header, in which case reallocating to add the L1 hdr is |
| * pointless. |
| */ |
| if (HDR_HAS_L1HDR(hdr)) { |
| old_state = hdr->b_l1hdr.b_state; |
| refcnt = zfs_refcount_count(&hdr->b_l1hdr.b_refcnt); |
| bufcnt = hdr->b_l1hdr.b_bufcnt; |
| update_old = (bufcnt > 0 || hdr->b_l1hdr.b_pabd != NULL || |
| HDR_HAS_RABD(hdr)); |
| } else { |
| old_state = arc_l2c_only; |
| refcnt = 0; |
| bufcnt = 0; |
| update_old = B_FALSE; |
| } |
| update_new = update_old; |
| |
| ASSERT(MUTEX_HELD(hash_lock)); |
| ASSERT3P(new_state, !=, old_state); |
| ASSERT(!GHOST_STATE(new_state) || bufcnt == 0); |
| ASSERT(old_state != arc_anon || bufcnt <= 1); |
| |
| /* |
| * If this buffer is evictable, transfer it from the |
| * old state list to the new state list. |
| */ |
| if (refcnt == 0) { |
| if (old_state != arc_anon && old_state != arc_l2c_only) { |
| ASSERT(HDR_HAS_L1HDR(hdr)); |
| multilist_remove(old_state->arcs_list[buftype], hdr); |
| |
| if (GHOST_STATE(old_state)) { |
| ASSERT0(bufcnt); |
| ASSERT3P(hdr->b_l1hdr.b_buf, ==, NULL); |
| update_old = B_TRUE; |
| } |
| arc_evictable_space_decrement(hdr, old_state); |
| } |
| if (new_state != arc_anon && new_state != arc_l2c_only) { |
| /* |
| * An L1 header always exists here, since if we're |
| * moving to some L1-cached state (i.e. not l2c_only or |
| * anonymous), we realloc the header to add an L1hdr |
| * beforehand. |
| */ |
| ASSERT(HDR_HAS_L1HDR(hdr)); |
| multilist_insert(new_state->arcs_list[buftype], hdr); |
| |
| if (GHOST_STATE(new_state)) { |
| ASSERT0(bufcnt); |
| ASSERT3P(hdr->b_l1hdr.b_buf, ==, NULL); |
| update_new = B_TRUE; |
| } |
| arc_evictable_space_increment(hdr, new_state); |
| } |
| } |
| |
| ASSERT(!HDR_EMPTY(hdr)); |
| if (new_state == arc_anon && HDR_IN_HASH_TABLE(hdr)) |
| buf_hash_remove(hdr); |
| |
| /* adjust state sizes (ignore arc_l2c_only) */ |
| |
| if (update_new && new_state != arc_l2c_only) { |
| ASSERT(HDR_HAS_L1HDR(hdr)); |
| if (GHOST_STATE(new_state)) { |
| ASSERT0(bufcnt); |
| |
| /* |
| * When moving a header to a ghost state, we first |
| * remove all arc buffers. Thus, we'll have a |
| * bufcnt of zero, and no arc buffer to use for |
| * the reference. As a result, we use the arc |
| * header pointer for the reference. |
| */ |
| (void) zfs_refcount_add_many(&new_state->arcs_size, |
| HDR_GET_LSIZE(hdr), hdr); |
| ASSERT3P(hdr->b_l1hdr.b_pabd, ==, NULL); |
| ASSERT(!HDR_HAS_RABD(hdr)); |
| } else { |
| uint32_t buffers = 0; |
| |
| /* |
| * Each individual buffer holds a unique reference, |
| * thus we must remove each of these references one |
| * at a time. |
| */ |
| for (arc_buf_t *buf = hdr->b_l1hdr.b_buf; buf != NULL; |
| buf = buf->b_next) { |
| ASSERT3U(bufcnt, !=, 0); |
| buffers++; |
| |
| /* |
| * When the arc_buf_t is sharing the data |
| * block with the hdr, the owner of the |
| * reference belongs to the hdr. Only |
| * add to the refcount if the arc_buf_t is |
| * not shared. |
| */ |
| if (arc_buf_is_shared(buf)) |
| continue; |
| |
| (void) zfs_refcount_add_many( |
| &new_state->arcs_size, |
| arc_buf_size(buf), buf); |
| } |
| ASSERT3U(bufcnt, ==, buffers); |
| |
| if (hdr->b_l1hdr.b_pabd != NULL) { |
| (void) zfs_refcount_add_many( |
| &new_state->arcs_size, |
| arc_hdr_size(hdr), hdr); |
| } |
| |
| if (HDR_HAS_RABD(hdr)) { |
| (void) zfs_refcount_add_many( |
| &new_state->arcs_size, |
| HDR_GET_PSIZE(hdr), hdr); |
| } |
| } |
| } |
| |
| if (update_old && old_state != arc_l2c_only) { |
| ASSERT(HDR_HAS_L1HDR(hdr)); |
| if (GHOST_STATE(old_state)) { |
| ASSERT0(bufcnt); |
| ASSERT3P(hdr->b_l1hdr.b_pabd, ==, NULL); |
| ASSERT(!HDR_HAS_RABD(hdr)); |
| |
| /* |
| * When moving a header off of a ghost state, |
| * the header will not contain any arc buffers. |
| * We use the arc header pointer for the reference |
| * which is exactly what we did when we put the |
| * header on the ghost state. |
| */ |
| |
| (void) zfs_refcount_remove_many(&old_state->arcs_size, |
| HDR_GET_LSIZE(hdr), hdr); |
| } else { |
| uint32_t buffers = 0; |
| |
| /* |
| * Each individual buffer holds a unique reference, |
| * thus we must remove each of these references one |
| * at a time. |
| */ |
| for (arc_buf_t *buf = hdr->b_l1hdr.b_buf; buf != NULL; |
| buf = buf->b_next) { |
| ASSERT3U(bufcnt, !=, 0); |
| buffers++; |
| |
| /* |
| * When the arc_buf_t is sharing the data |
| * block with the hdr, the owner of the |
| * reference belongs to the hdr. Only |
| * add to the refcount if the arc_buf_t is |
| * not shared. |
| */ |
| if (arc_buf_is_shared(buf)) |
| continue; |
| |
| (void) zfs_refcount_remove_many( |
| &old_state->arcs_size, arc_buf_size(buf), |
| buf); |
| } |
| ASSERT3U(bufcnt, ==, buffers); |
| ASSERT(hdr->b_l1hdr.b_pabd != NULL || |
| HDR_HAS_RABD(hdr)); |
| |
| if (hdr->b_l1hdr.b_pabd != NULL) { |
| (void) zfs_refcount_remove_many( |
| &old_state->arcs_size, arc_hdr_size(hdr), |
| hdr); |
| } |
| |
| if (HDR_HAS_RABD(hdr)) { |
| (void) zfs_refcount_remove_many( |
| &old_state->arcs_size, HDR_GET_PSIZE(hdr), |
| hdr); |
| } |
| } |
| } |
| |
| if (HDR_HAS_L1HDR(hdr)) |
| hdr->b_l1hdr.b_state = new_state; |
| |
| /* |
| * L2 headers should never be on the L2 state list since they don't |
| * have L1 headers allocated. |
| */ |
| ASSERT(multilist_is_empty(arc_l2c_only->arcs_list[ARC_BUFC_DATA]) && |
| multilist_is_empty(arc_l2c_only->arcs_list[ARC_BUFC_METADATA])); |
| } |
| |
| void |
| arc_space_consume(uint64_t space, arc_space_type_t type) |
| { |
| ASSERT(type >= 0 && type < ARC_SPACE_NUMTYPES); |
| |
| switch (type) { |
| default: |
| break; |
| case ARC_SPACE_DATA: |
| aggsum_add(&astat_data_size, space); |
| break; |
| case ARC_SPACE_META: |
| aggsum_add(&astat_metadata_size, space); |
| break; |
| case ARC_SPACE_BONUS: |
| aggsum_add(&astat_bonus_size, space); |
| break; |
| case ARC_SPACE_DNODE: |
| aggsum_add(&astat_dnode_size, space); |
| break; |
| case ARC_SPACE_DBUF: |
| aggsum_add(&astat_dbuf_size, space); |
| break; |
| case ARC_SPACE_HDRS: |
| aggsum_add(&astat_hdr_size, space); |
| break; |
| case ARC_SPACE_L2HDRS: |
| aggsum_add(&astat_l2_hdr_size, space); |
| break; |
| } |
| |
| if (type != ARC_SPACE_DATA) |
| aggsum_add(&arc_meta_used, space); |
| |
| aggsum_add(&arc_size, space); |
| } |
| |
| void |
| arc_space_return(uint64_t space, arc_space_type_t type) |
| { |
| ASSERT(type >= 0 && type < ARC_SPACE_NUMTYPES); |
| |
| switch (type) { |
| default: |
| break; |
| case ARC_SPACE_DATA: |
| aggsum_add(&astat_data_size, -space); |
| break; |
| case ARC_SPACE_META: |
| aggsum_add(&astat_metadata_size, -space); |
| break; |
| case ARC_SPACE_BONUS: |
| aggsum_add(&astat_bonus_size, -space); |
| break; |
| case ARC_SPACE_DNODE: |
| aggsum_add(&astat_dnode_size, -space); |
| break; |
| case ARC_SPACE_DBUF: |
| aggsum_add(&astat_dbuf_size, -space); |
| break; |
| case ARC_SPACE_HDRS: |
| aggsum_add(&astat_hdr_size, -space); |
| break; |
| case ARC_SPACE_L2HDRS: |
| aggsum_add(&astat_l2_hdr_size, -space); |
| break; |
| } |
| |
| if (type != ARC_SPACE_DATA) { |
| ASSERT(aggsum_compare(&arc_meta_used, space) >= 0); |
| /* |
| * We use the upper bound here rather than the precise value |
| * because the arc_meta_max value doesn't need to be |
| * precise. It's only consumed by humans via arcstats. |
| */ |
| if (arc_meta_max < aggsum_upper_bound(&arc_meta_used)) |
| arc_meta_max = aggsum_upper_bound(&arc_meta_used); |
| aggsum_add(&arc_meta_used, -space); |
| } |
| |
| ASSERT(aggsum_compare(&arc_size, space) >= 0); |
| aggsum_add(&arc_size, -space); |
| } |
| |
| /* |
| * Given a hdr and a buf, returns whether that buf can share its b_data buffer |
| * with the hdr's b_pabd. |
| */ |
| static boolean_t |
| arc_can_share(arc_buf_hdr_t *hdr, arc_buf_t *buf) |
| { |
| /* |
| * The criteria for sharing a hdr's data are: |
| * 1. the buffer is not encrypted |
| * 2. the hdr's compression matches the buf's compression |
| * 3. the hdr doesn't need to be byteswapped |
| * 4. the hdr isn't already being shared |
| * 5. the buf is either compressed or it is the last buf in the hdr list |
| * |
| * Criterion #5 maintains the invariant that shared uncompressed |
| * bufs must be the final buf in the hdr's b_buf list. Reading this, you |
| * might ask, "if a compressed buf is allocated first, won't that be the |
| * last thing in the list?", but in that case it's impossible to create |
| * a shared uncompressed buf anyway (because the hdr must be compressed |
| * to have the compressed buf). You might also think that #3 is |
| * sufficient to make this guarantee, however it's possible |
| * (specifically in the rare L2ARC write race mentioned in |
| * arc_buf_alloc_impl()) there will be an existing uncompressed buf that |
| * is shareable, but wasn't at the time of its allocation. Rather than |
| * allow a new shared uncompressed buf to be created and then shuffle |
| * the list around to make it the last element, this simply disallows |
| * sharing if the new buf isn't the first to be added. |
| */ |
| ASSERT3P(buf->b_hdr, ==, hdr); |
| boolean_t hdr_compressed = |
| arc_hdr_get_compress(hdr) != ZIO_COMPRESS_OFF; |
| boolean_t buf_compressed = ARC_BUF_COMPRESSED(buf) != 0; |
| return (!ARC_BUF_ENCRYPTED(buf) && |
| buf_compressed == hdr_compressed && |
| hdr->b_l1hdr.b_byteswap == DMU_BSWAP_NUMFUNCS && |
| !HDR_SHARED_DATA(hdr) && |
| (ARC_BUF_LAST(buf) || ARC_BUF_COMPRESSED(buf))); |
| } |
| |
| /* |
| * Allocate a buf for this hdr. If you care about the data that's in the hdr, |
| * or if you want a compressed buffer, pass those flags in. Returns 0 if the |
| * copy was made successfully, or an error code otherwise. |
| */ |
| static int |
| arc_buf_alloc_impl(arc_buf_hdr_t *hdr, spa_t *spa, const zbookmark_phys_t *zb, |
| void *tag, boolean_t encrypted, boolean_t compressed, boolean_t noauth, |
| boolean_t fill, arc_buf_t **ret) |
| { |
| arc_buf_t *buf; |
| arc_fill_flags_t flags = ARC_FILL_LOCKED; |
| |
| ASSERT(HDR_HAS_L1HDR(hdr)); |
| ASSERT3U(HDR_GET_LSIZE(hdr), >, 0); |
| VERIFY(hdr->b_type == ARC_BUFC_DATA || |
| hdr->b_type == ARC_BUFC_METADATA); |
| ASSERT3P(ret, !=, NULL); |
| ASSERT3P(*ret, ==, NULL); |
| IMPLY(encrypted, compressed); |
| |
| hdr->b_l1hdr.b_mru_hits = 0; |
| hdr->b_l1hdr.b_mru_ghost_hits = 0; |
| hdr->b_l1hdr.b_mfu_hits = 0; |
| hdr->b_l1hdr.b_mfu_ghost_hits = 0; |
| hdr->b_l1hdr.b_l2_hits = 0; |
| |
| buf = *ret = kmem_cache_alloc(buf_cache, KM_PUSHPAGE); |
| buf->b_hdr = hdr; |
| buf->b_data = NULL; |
| buf->b_next = hdr->b_l1hdr.b_buf; |
| buf->b_flags = 0; |
| |
| add_reference(hdr, tag); |
| |
| /* |
| * We're about to change the hdr's b_flags. We must either |
| * hold the hash_lock or be undiscoverable. |
| */ |
| ASSERT(HDR_EMPTY_OR_LOCKED(hdr)); |
| |
| /* |
| * Only honor requests for compressed bufs if the hdr is actually |
| * compressed. This must be overridden if the buffer is encrypted since |
| * encrypted buffers cannot be decompressed. |
| */ |
| if (encrypted) { |
| buf->b_flags |= ARC_BUF_FLAG_COMPRESSED; |
| buf->b_flags |= ARC_BUF_FLAG_ENCRYPTED; |
| flags |= ARC_FILL_COMPRESSED | ARC_FILL_ENCRYPTED; |
| } else if (compressed && |
| arc_hdr_get_compress(hdr) != ZIO_COMPRESS_OFF) { |
| buf->b_flags |= ARC_BUF_FLAG_COMPRESSED; |
| flags |= ARC_FILL_COMPRESSED; |
| } |
| |
| if (noauth) { |
| ASSERT0(encrypted); |
| flags |= ARC_FILL_NOAUTH; |
| } |
| |
| /* |
| * If the hdr's data can be shared then we share the data buffer and |
| * set the appropriate bit in the hdr's b_flags to indicate the hdr is |
| * sharing it's b_pabd with the arc_buf_t. Otherwise, we allocate a new |
| * buffer to store the buf's data. |
| * |
| * There are two additional restrictions here because we're sharing |
| * hdr -> buf instead of the usual buf -> hdr. First, the hdr can't be |
| * actively involved in an L2ARC write, because if this buf is used by |
| * an arc_write() then the hdr's data buffer will be released when the |
| * write completes, even though the L2ARC write might still be using it. |
| * Second, the hdr's ABD must be linear so that the buf's user doesn't |
| * need to be ABD-aware. It must be allocated via |
| * zio_[data_]buf_alloc(), not as a page, because we need to be able |
| * to abd_release_ownership_of_buf(), which isn't allowed on "linear |
| * page" buffers because the ABD code needs to handle freeing them |
| * specially. |
| */ |
| boolean_t can_share = arc_can_share(hdr, buf) && |
| !HDR_L2_WRITING(hdr) && |
| hdr->b_l1hdr.b_pabd != NULL && |
| abd_is_linear(hdr->b_l1hdr.b_pabd) && |
| !abd_is_linear_page(hdr->b_l1hdr.b_pabd); |
| |
| /* Set up b_data and sharing */ |
| if (can_share) { |
| buf->b_data = abd_to_buf(hdr->b_l1hdr.b_pabd); |
| buf->b_flags |= ARC_BUF_FLAG_SHARED; |
| arc_hdr_set_flags(hdr, ARC_FLAG_SHARED_DATA); |
| } else { |
| buf->b_data = |
| arc_get_data_buf(hdr, arc_buf_size(buf), buf); |
| ARCSTAT_INCR(arcstat_overhead_size, arc_buf_size(buf)); |
| } |
| VERIFY3P(buf->b_data, !=, NULL); |
| |
| hdr->b_l1hdr.b_buf = buf; |
| hdr->b_l1hdr.b_bufcnt += 1; |
| if (encrypted) |
| hdr->b_crypt_hdr.b_ebufcnt += 1; |
| |
| /* |
| * If the user wants the data from the hdr, we need to either copy or |
| * decompress the data. |
| */ |
| if (fill) { |
| ASSERT3P(zb, !=, NULL); |
| return (arc_buf_fill(buf, spa, zb, flags)); |
| } |
| |
| return (0); |
| } |
| |
| static char *arc_onloan_tag = "onloan"; |
| |
| static inline void |
| arc_loaned_bytes_update(int64_t delta) |
| { |
| atomic_add_64(&arc_loaned_bytes, delta); |
| |
| /* assert that it did not wrap around */ |
| ASSERT3S(atomic_add_64_nv(&arc_loaned_bytes, 0), >=, 0); |
| } |
| |
| /* |
| * Loan out an anonymous arc buffer. Loaned buffers are not counted as in |
| * flight data by arc_tempreserve_space() until they are "returned". Loaned |
| * buffers must be returned to the arc before they can be used by the DMU or |
| * freed. |
| */ |
| arc_buf_t * |
| arc_loan_buf(spa_t *spa, boolean_t is_metadata, int size) |
| { |
| arc_buf_t *buf = arc_alloc_buf(spa, arc_onloan_tag, |
| is_metadata ? ARC_BUFC_METADATA : ARC_BUFC_DATA, size); |
| |
| arc_loaned_bytes_update(arc_buf_size(buf)); |
| |
| return (buf); |
| } |
| |
| arc_buf_t * |
| arc_loan_compressed_buf(spa_t *spa, uint64_t psize, uint64_t lsize, |
| enum zio_compress compression_type) |
| { |
| arc_buf_t *buf = arc_alloc_compressed_buf(spa, arc_onloan_tag, |
| psize, lsize, compression_type); |
| |
| arc_loaned_bytes_update(arc_buf_size(buf)); |
| |
| return (buf); |
| } |
| |
| arc_buf_t * |
| arc_loan_raw_buf(spa_t *spa, uint64_t dsobj, boolean_t byteorder, |
| const uint8_t *salt, const uint8_t *iv, const uint8_t *mac, |
| dmu_object_type_t ot, uint64_t psize, uint64_t lsize, |
| enum zio_compress compression_type) |
| { |
| arc_buf_t *buf = arc_alloc_raw_buf(spa, arc_onloan_tag, dsobj, |
| byteorder, salt, iv, mac, ot, psize, lsize, compression_type); |
| |
| atomic_add_64(&arc_loaned_bytes, psize); |
| return (buf); |
| } |
| |
| |
| /* |
| * Return a loaned arc buffer to the arc. |
| */ |
| void |
| arc_return_buf(arc_buf_t *buf, void *tag) |
| { |
| arc_buf_hdr_t *hdr = buf->b_hdr; |
| |
| ASSERT3P(buf->b_data, !=, NULL); |
| ASSERT(HDR_HAS_L1HDR(hdr)); |
| (void) zfs_refcount_add(&hdr->b_l1hdr.b_refcnt, tag); |
| (void) zfs_refcount_remove(&hdr->b_l1hdr.b_refcnt, arc_onloan_tag); |
| |
| arc_loaned_bytes_update(-arc_buf_size(buf)); |
| } |
| |
| /* Detach an arc_buf from a dbuf (tag) */ |
| void |
| arc_loan_inuse_buf(arc_buf_t *buf, void *tag) |
| { |
| arc_buf_hdr_t *hdr = buf->b_hdr; |
| |
| ASSERT3P(buf->b_data, !=, NULL); |
| ASSERT(HDR_HAS_L1HDR(hdr)); |
| (void) zfs_refcount_add(&hdr->b_l1hdr.b_refcnt, arc_onloan_tag); |
| (void) zfs_refcount_remove(&hdr->b_l1hdr.b_refcnt, tag); |
| |
| arc_loaned_bytes_update(arc_buf_size(buf)); |
| } |
| |
| static void |
| l2arc_free_abd_on_write(abd_t *abd, size_t size, arc_buf_contents_t type) |
| { |
| l2arc_data_free_t *df = kmem_alloc(sizeof (*df), KM_SLEEP); |
| |
| df->l2df_abd = abd; |
| df->l2df_size = size; |
| df->l2df_type = type; |
| mutex_enter(&l2arc_free_on_write_mtx); |
| list_insert_head(l2arc_free_on_write, df); |
| mutex_exit(&l2arc_free_on_write_mtx); |
| } |
| |
| static void |
| arc_hdr_free_on_write(arc_buf_hdr_t *hdr, boolean_t free_rdata) |
| { |
| arc_state_t *state = hdr->b_l1hdr.b_state; |
| arc_buf_contents_t type = arc_buf_type(hdr); |
| uint64_t size = (free_rdata) ? HDR_GET_PSIZE(hdr) : arc_hdr_size(hdr); |
| |
| /* protected by hash lock, if in the hash table */ |
| if (multilist_link_active(&hdr->b_l1hdr.b_arc_node)) { |
| ASSERT(zfs_refcount_is_zero(&hdr->b_l1hdr.b_refcnt)); |
| ASSERT(state != arc_anon && state != arc_l2c_only); |
| |
| (void) zfs_refcount_remove_many(&state->arcs_esize[type], |
| size, hdr); |
| } |
| (void) zfs_refcount_remove_many(&state->arcs_size, size, hdr); |
| if (type == ARC_BUFC_METADATA) { |
| arc_space_return(size, ARC_SPACE_META); |
| } else { |
| ASSERT(type == ARC_BUFC_DATA); |
| arc_space_return(size, ARC_SPACE_DATA); |
| } |
| |
| if (free_rdata) { |
| l2arc_free_abd_on_write(hdr->b_crypt_hdr.b_rabd, size, type); |
| } else { |
| l2arc_free_abd_on_write(hdr->b_l1hdr.b_pabd, size, type); |
| } |
| } |
| |
| /* |
| * Share the arc_buf_t's data with the hdr. Whenever we are sharing the |
| * data buffer, we transfer the refcount ownership to the hdr and update |
| * the appropriate kstats. |
| */ |
| static void |
| arc_share_buf(arc_buf_hdr_t *hdr, arc_buf_t *buf) |
| { |
| ASSERT(arc_can_share(hdr, buf)); |
| ASSERT3P(hdr->b_l1hdr.b_pabd, ==, NULL); |
| ASSERT(!ARC_BUF_ENCRYPTED(buf)); |
| ASSERT(HDR_EMPTY_OR_LOCKED(hdr)); |
| |
| /* |
| * Start sharing the data buffer. We transfer the |
| * refcount ownership to the hdr since it always owns |
| * the refcount whenever an arc_buf_t is shared. |
| */ |
| zfs_refcount_transfer_ownership_many(&hdr->b_l1hdr.b_state->arcs_size, |
| arc_hdr_size(hdr), buf, hdr); |
| hdr->b_l1hdr.b_pabd = abd_get_from_buf(buf->b_data, arc_buf_size(buf)); |
| abd_take_ownership_of_buf(hdr->b_l1hdr.b_pabd, |
| HDR_ISTYPE_METADATA(hdr)); |
| arc_hdr_set_flags(hdr, ARC_FLAG_SHARED_DATA); |
| buf->b_flags |= ARC_BUF_FLAG_SHARED; |
| |
| /* |
| * Since we've transferred ownership to the hdr we need |
| * to increment its compressed and uncompressed kstats and |
| * decrement the overhead size. |
| */ |
| ARCSTAT_INCR(arcstat_compressed_size, arc_hdr_size(hdr)); |
| ARCSTAT_INCR(arcstat_uncompressed_size, HDR_GET_LSIZE(hdr)); |
| ARCSTAT_INCR(arcstat_overhead_size, -arc_buf_size(buf)); |
| } |
| |
| static void |
| arc_unshare_buf(arc_buf_hdr_t *hdr, arc_buf_t *buf) |
| { |
| ASSERT(arc_buf_is_shared(buf)); |
| ASSERT3P(hdr->b_l1hdr.b_pabd, !=, NULL); |
| ASSERT(HDR_EMPTY_OR_LOCKED(hdr)); |
| |
| /* |
| * We are no longer sharing this buffer so we need |
| * to transfer its ownership to the rightful owner. |
| */ |
| zfs_refcount_transfer_ownership_many(&hdr->b_l1hdr.b_state->arcs_size, |
| arc_hdr_size(hdr), hdr, buf); |
| arc_hdr_clear_flags(hdr, ARC_FLAG_SHARED_DATA); |
| abd_release_ownership_of_buf(hdr->b_l1hdr.b_pabd); |
| abd_put(hdr->b_l1hdr.b_pabd); |
| hdr->b_l1hdr.b_pabd = NULL; |
| buf->b_flags &= ~ARC_BUF_FLAG_SHARED; |
| |
| /* |
| * Since the buffer is no longer shared between |
| * the arc buf and the hdr, count it as overhead. |
| */ |
| ARCSTAT_INCR(arcstat_compressed_size, -arc_hdr_size(hdr)); |
| ARCSTAT_INCR(arcstat_uncompressed_size, -HDR_GET_LSIZE(hdr)); |
| ARCSTAT_INCR(arcstat_overhead_size, arc_buf_size(buf)); |
| } |
| |
| /* |
| * Remove an arc_buf_t from the hdr's buf list and return the last |
| * arc_buf_t on the list. If no buffers remain on the list then return |
| * NULL. |
| */ |
| static arc_buf_t * |
| arc_buf_remove(arc_buf_hdr_t *hdr, arc_buf_t *buf) |
| { |
| ASSERT(HDR_HAS_L1HDR(hdr)); |
| ASSERT(HDR_EMPTY_OR_LOCKED(hdr)); |
| |
| arc_buf_t **bufp = &hdr->b_l1hdr.b_buf; |
| arc_buf_t *lastbuf = NULL; |
| |
| /* |
| * Remove the buf from the hdr list and locate the last |
| * remaining buffer on the list. |
| */ |
| while (*bufp != NULL) { |
| if (*bufp == buf) |
| *bufp = buf->b_next; |
| |
| /* |
| * If we've removed a buffer in the middle of |
| * the list then update the lastbuf and update |
| * bufp. |
| */ |
| if (*bufp != NULL) { |
| lastbuf = *bufp; |
| bufp = &(*bufp)->b_next; |
| } |
| } |
| buf->b_next = NULL; |
| ASSERT3P(lastbuf, !=, buf); |
| IMPLY(hdr->b_l1hdr.b_bufcnt > 0, lastbuf != NULL); |
| IMPLY(hdr->b_l1hdr.b_bufcnt > 0, hdr->b_l1hdr.b_buf != NULL); |
| IMPLY(lastbuf != NULL, ARC_BUF_LAST(lastbuf)); |
| |
| return (lastbuf); |
| } |
| |
| /* |
| * Free up buf->b_data and pull the arc_buf_t off of the arc_buf_hdr_t's |
| * list and free it. |
| */ |
| static void |
| arc_buf_destroy_impl(arc_buf_t *buf) |
| { |
| arc_buf_hdr_t *hdr = buf->b_hdr; |
| |
| /* |
| * Free up the data associated with the buf but only if we're not |
| * sharing this with the hdr. If we are sharing it with the hdr, the |
| * hdr is responsible for doing the free. |
| */ |
| if (buf->b_data != NULL) { |
| /* |
| * We're about to change the hdr's b_flags. We must either |
| * hold the hash_lock or be undiscoverable. |
| */ |
| ASSERT(HDR_EMPTY_OR_LOCKED(hdr)); |
| |
| arc_cksum_verify(buf); |
| arc_buf_unwatch(buf); |
| |
| if (arc_buf_is_shared(buf)) { |
| arc_hdr_clear_flags(hdr, ARC_FLAG_SHARED_DATA); |
| } else { |
| uint64_t size = arc_buf_size(buf); |
| arc_free_data_buf(hdr, buf->b_data, size, buf); |
| ARCSTAT_INCR(arcstat_overhead_size, -size); |
| } |
| buf->b_data = NULL; |
| |
| ASSERT(hdr->b_l1hdr.b_bufcnt > 0); |
| hdr->b_l1hdr.b_bufcnt -= 1; |
| |
| if (ARC_BUF_ENCRYPTED(buf)) { |
| hdr->b_crypt_hdr.b_ebufcnt -= 1; |
| |
| /* |
| * If we have no more encrypted buffers and we've |
| * already gotten a copy of the decrypted data we can |
| * free b_rabd to save some space. |
| */ |
| if (hdr->b_crypt_hdr.b_ebufcnt == 0 && |
| HDR_HAS_RABD(hdr) && hdr->b_l1hdr.b_pabd != NULL && |
| !HDR_IO_IN_PROGRESS(hdr)) { |
| arc_hdr_free_abd(hdr, B_TRUE); |
| } |
| } |
| } |
| |
| arc_buf_t *lastbuf = arc_buf_remove(hdr, buf); |
| |
| if (ARC_BUF_SHARED(buf) && !ARC_BUF_COMPRESSED(buf)) { |
| /* |
| * If the current arc_buf_t is sharing its data buffer with the |
| * hdr, then reassign the hdr's b_pabd to share it with the new |
| * buffer at the end of the list. The shared buffer is always |
| * the last one on the hdr's buffer list. |
| * |
| * There is an equivalent case for compressed bufs, but since |
| * they aren't guaranteed to be the last buf in the list and |
| * that is an exceedingly rare case, we just allow that space be |
| * wasted temporarily. We must also be careful not to share |
| * encrypted buffers, since they cannot be shared. |
| */ |
| if (lastbuf != NULL && !ARC_BUF_ENCRYPTED(lastbuf)) { |
| /* Only one buf can be shared at once */ |
| VERIFY(!arc_buf_is_shared(lastbuf)); |
| /* hdr is uncompressed so can't have compressed buf */ |
| VERIFY(!ARC_BUF_COMPRESSED(lastbuf)); |
| |
| ASSERT3P(hdr->b_l1hdr.b_pabd, !=, NULL); |
| arc_hdr_free_abd(hdr, B_FALSE); |
| |
| /* |
| * We must setup a new shared block between the |
| * last buffer and the hdr. The data would have |
| * been allocated by the arc buf so we need to transfer |
| * ownership to the hdr since it's now being shared. |
| */ |
| arc_share_buf(hdr, lastbuf); |
| } |
| } else if (HDR_SHARED_DATA(hdr)) { |
| /* |
| * Uncompressed shared buffers are always at the end |
| * of the list. Compressed buffers don't have the |
| * same requirements. This makes it hard to |
| * simply assert that the lastbuf is shared so |
| * we rely on the hdr's compression flags to determine |
| * if we have a compressed, shared buffer. |
| */ |
| ASSERT3P(lastbuf, !=, NULL); |
| ASSERT(arc_buf_is_shared(lastbuf) || |
| arc_hdr_get_compress(hdr) != ZIO_COMPRESS_OFF); |
| } |
| |
| /* |
| * Free the checksum if we're removing the last uncompressed buf from |
| * this hdr. |
| */ |
| if (!arc_hdr_has_uncompressed_buf(hdr)) { |
| arc_cksum_free(hdr); |
| } |
| |
| /* clean up the buf */ |
| buf->b_hdr = NULL; |
| kmem_cache_free(buf_cache, buf); |
| } |
| |
| static void |
| arc_hdr_alloc_abd(arc_buf_hdr_t *hdr, int alloc_flags) |
| { |
| uint64_t size; |
| boolean_t alloc_rdata = ((alloc_flags & ARC_HDR_ALLOC_RDATA) != 0); |
| boolean_t do_adapt = ((alloc_flags & ARC_HDR_DO_ADAPT) != 0); |
| |
| ASSERT3U(HDR_GET_LSIZE(hdr), >, 0); |
| ASSERT(HDR_HAS_L1HDR(hdr)); |
| ASSERT(!HDR_SHARED_DATA(hdr) || alloc_rdata); |
| IMPLY(alloc_rdata, HDR_PROTECTED(hdr)); |
| |
| if (alloc_rdata) { |
| size = HDR_GET_PSIZE(hdr); |
| ASSERT3P(hdr->b_crypt_hdr.b_rabd, ==, NULL); |
| hdr->b_crypt_hdr.b_rabd = arc_get_data_abd(hdr, size, hdr, |
| do_adapt); |
| ASSERT3P(hdr->b_crypt_hdr.b_rabd, !=, NULL); |
| ARCSTAT_INCR(arcstat_raw_size, size); |
| } else { |
| size = arc_hdr_size(hdr); |
| ASSERT3P(hdr->b_l1hdr.b_pabd, ==, NULL); |
| hdr->b_l1hdr.b_pabd = arc_get_data_abd(hdr, size, hdr, |
| do_adapt); |
| ASSERT3P(hdr->b_l1hdr.b_pabd, !=, NULL); |
| } |
| |
| ARCSTAT_INCR(arcstat_compressed_size, size); |
| ARCSTAT_INCR(arcstat_uncompressed_size, HDR_GET_LSIZE(hdr)); |
| } |
| |
| static void |
| arc_hdr_free_abd(arc_buf_hdr_t *hdr, boolean_t free_rdata) |
| { |
| uint64_t size = (free_rdata) ? HDR_GET_PSIZE(hdr) : arc_hdr_size(hdr); |
| |
| ASSERT(HDR_HAS_L1HDR(hdr)); |
| ASSERT(hdr->b_l1hdr.b_pabd != NULL || HDR_HAS_RABD(hdr)); |
| IMPLY(free_rdata, HDR_HAS_RABD(hdr)); |
| |
| /* |
| * If the hdr is currently being written to the l2arc then |
| * we defer freeing the data by adding it to the l2arc_free_on_write |
| * list. The l2arc will free the data once it's finished |
| * writing it to the l2arc device. |
| */ |
| if (HDR_L2_WRITING(hdr)) { |
| arc_hdr_free_on_write(hdr, free_rdata); |
| ARCSTAT_BUMP(arcstat_l2_free_on_write); |
| } else if (free_rdata) { |
| arc_free_data_abd(hdr, hdr->b_crypt_hdr.b_rabd, size, hdr); |
| } else { |
| arc_free_data_abd(hdr, hdr->b_l1hdr.b_pabd, size, hdr); |
| } |
| |
| if (free_rdata) { |
| hdr->b_crypt_hdr.b_rabd = NULL; |
| ARCSTAT_INCR(arcstat_raw_size, -size); |
| } else { |
| hdr->b_l1hdr.b_pabd = NULL; |
| } |
| |
| if (hdr->b_l1hdr.b_pabd == NULL && !HDR_HAS_RABD(hdr)) |
| hdr->b_l1hdr.b_byteswap = DMU_BSWAP_NUMFUNCS; |
| |
| ARCSTAT_INCR(arcstat_compressed_size, -size); |
| ARCSTAT_INCR(arcstat_uncompressed_size, -HDR_GET_LSIZE(hdr)); |
| } |
| |
| static arc_buf_hdr_t * |
| arc_hdr_alloc(uint64_t spa, int32_t psize, int32_t lsize, |
| boolean_t protected, enum zio_compress compression_type, |
| arc_buf_contents_t type, boolean_t alloc_rdata) |
| { |
| arc_buf_hdr_t *hdr; |
| int flags = ARC_HDR_DO_ADAPT; |
| |
| VERIFY(type == ARC_BUFC_DATA || type == ARC_BUFC_METADATA); |
| if (protected) { |
| hdr = kmem_cache_alloc(hdr_full_crypt_cache, KM_PUSHPAGE); |
| } else { |
| hdr = kmem_cache_alloc(hdr_full_cache, KM_PUSHPAGE); |
| } |
| flags |= alloc_rdata ? ARC_HDR_ALLOC_RDATA : 0; |
| |
| ASSERT(HDR_EMPTY(hdr)); |
| ASSERT3P(hdr->b_l1hdr.b_freeze_cksum, ==, NULL); |
| HDR_SET_PSIZE(hdr, psize); |
| HDR_SET_LSIZE(hdr, lsize); |
| hdr->b_spa = spa; |
| hdr->b_type = type; |
| hdr->b_flags = 0; |
| arc_hdr_set_flags(hdr, arc_bufc_to_flags(type) | ARC_FLAG_HAS_L1HDR); |
| arc_hdr_set_compress(hdr, compression_type); |
| if (protected) |
| arc_hdr_set_flags(hdr, ARC_FLAG_PROTECTED); |
| |
| hdr->b_l1hdr.b_state = arc_anon; |
| hdr->b_l1hdr.b_arc_access = 0; |
| hdr->b_l1hdr.b_bufcnt = 0; |
| hdr->b_l1hdr.b_buf = NULL; |
| |
| /* |
| * Allocate the hdr's buffer. This will contain either |
| * the compressed or uncompressed data depending on the block |
| * it references and compressed arc enablement. |
| */ |
| arc_hdr_alloc_abd(hdr, flags); |
| ASSERT(zfs_refcount_is_zero(&hdr->b_l1hdr.b_refcnt)); |
| |
| return (hdr); |
| } |
| |
| /* |
| * Transition between the two allocation states for the arc_buf_hdr struct. |
| * The arc_buf_hdr struct can be allocated with (hdr_full_cache) or without |
| * (hdr_l2only_cache) the fields necessary for the L1 cache - the smaller |
| * version is used when a cache buffer is only in the L2ARC in order to reduce |
| * memory usage. |
| */ |
| static arc_buf_hdr_t * |
| arc_hdr_realloc(arc_buf_hdr_t *hdr, kmem_cache_t *old, kmem_cache_t *new) |
| { |
| ASSERT(HDR_HAS_L2HDR(hdr)); |
| |
| arc_buf_hdr_t *nhdr; |
| l2arc_dev_t *dev = hdr->b_l2hdr.b_dev; |
| |
| ASSERT((old == hdr_full_cache && new == hdr_l2only_cache) || |
| (old == hdr_l2only_cache && new == hdr_full_cache)); |
| |
| /* |
| * if the caller wanted a new full header and the header is to be |
| * encrypted we will actually allocate the header from the full crypt |
| * cache instead. The same applies to freeing from the old cache. |
| */ |
| if (HDR_PROTECTED(hdr) && new == hdr_full_cache) |
| new = hdr_full_crypt_cache; |
| if (HDR_PROTECTED(hdr) && old == hdr_full_cache) |
| old = hdr_full_crypt_cache; |
| |
| nhdr = kmem_cache_alloc(new, KM_PUSHPAGE); |
| |
| ASSERT(MUTEX_HELD(HDR_LOCK(hdr))); |
| buf_hash_remove(hdr); |
| |
| bcopy(hdr, nhdr, HDR_L2ONLY_SIZE); |
| |
| if (new == hdr_full_cache || new == hdr_full_crypt_cache) { |
| arc_hdr_set_flags(nhdr, ARC_FLAG_HAS_L1HDR); |
| /* |
| * arc_access and arc_change_state need to be aware that a |
| * header has just come out of L2ARC, so we set its state to |
| * l2c_only even though it's about to change. |
| */ |
| nhdr->b_l1hdr.b_state = arc_l2c_only; |
| |
| /* Verify previous threads set to NULL before freeing */ |
| ASSERT3P(nhdr->b_l1hdr.b_pabd, ==, NULL); |
| ASSERT(!HDR_HAS_RABD(hdr)); |
| } else { |
| ASSERT3P(hdr->b_l1hdr.b_buf, ==, NULL); |
| ASSERT0(hdr->b_l1hdr.b_bufcnt); |
| ASSERT3P(hdr->b_l1hdr.b_freeze_cksum, ==, NULL); |
| |
| /* |
| * If we've reached here, We must have been called from |
| * arc_evict_hdr(), as such we should have already been |
| * removed from any ghost list we were previously on |
| * (which protects us from racing with arc_evict_state), |
| * thus no locking is needed during this check. |
| */ |
| ASSERT(!multilist_link_active(&hdr->b_l1hdr.b_arc_node)); |
| |
| /* |
| * A buffer must not be moved into the arc_l2c_only |
| * state if it's not finished being written out to the |
| * l2arc device. Otherwise, the b_l1hdr.b_pabd field |
| * might try to be accessed, even though it was removed. |
| */ |
| VERIFY(!HDR_L2_WRITING(hdr)); |
| VERIFY3P(hdr->b_l1hdr.b_pabd, ==, NULL); |
| ASSERT(!HDR_HAS_RABD(hdr)); |
| |
| arc_hdr_clear_flags(nhdr, ARC_FLAG_HAS_L1HDR); |
| } |
| /* |
| * The header has been reallocated so we need to re-insert it into any |
| * lists it was on. |
| */ |
| (void) buf_hash_insert(nhdr, NULL); |
| |
| ASSERT(list_link_active(&hdr->b_l2hdr.b_l2node)); |
| |
| mutex_enter(&dev->l2ad_mtx); |
| |
| /* |
| * We must place the realloc'ed header back into the list at |
| * the same spot. Otherwise, if it's placed earlier in the list, |
| * l2arc_write_buffers() could find it during the function's |
| * write phase, and try to write it out to the l2arc. |
| */ |
| list_insert_after(&dev->l2ad_buflist, hdr, nhdr); |
| list_remove(&dev->l2ad_buflist, hdr); |
| |
| mutex_exit(&dev->l2ad_mtx); |
| |
| /* |
| * Since we're using the pointer address as the tag when |
| * incrementing and decrementing the l2ad_alloc refcount, we |
| * must remove the old pointer (that we're about to destroy) and |
| * add the new pointer to the refcount. Otherwise we'd remove |
| * the wrong pointer address when calling arc_hdr_destroy() later. |
| */ |
| |
| (void) zfs_refcount_remove_many(&dev->l2ad_alloc, |
| arc_hdr_size(hdr), hdr); |
| (void) zfs_refcount_add_many(&dev->l2ad_alloc, |
| arc_hdr_size(nhdr), nhdr); |
| |
| buf_discard_identity(hdr); |
| kmem_cache_free(old, hdr); |
| |
| return (nhdr); |
| } |
| |
| /* |
| * This function allows an L1 header to be reallocated as a crypt |
| * header and vice versa. If we are going to a crypt header, the |
| * new fields will be zeroed out. |
| */ |
| static arc_buf_hdr_t * |
| arc_hdr_realloc_crypt(arc_buf_hdr_t *hdr, boolean_t need_crypt) |
| { |
| arc_buf_hdr_t *nhdr; |
| arc_buf_t *buf; |
| kmem_cache_t *ncache, *ocache; |
| unsigned nsize, osize; |
| |
| /* |
| * This function requires that hdr is in the arc_anon state. |
| * Therefore it won't have any L2ARC data for us to worry |
| * about copying. |
| */ |
| ASSERT(HDR_HAS_L1HDR(hdr)); |
| ASSERT(!HDR_HAS_L2HDR(hdr)); |
| ASSERT3U(!!HDR_PROTECTED(hdr), !=, need_crypt); |
| ASSERT3P(hdr->b_l1hdr.b_state, ==, arc_anon); |
| ASSERT(!multilist_link_active(&hdr->b_l1hdr.b_arc_node)); |
| ASSERT(!list_link_active(&hdr->b_l2hdr.b_l2node)); |
| ASSERT3P(hdr->b_hash_next, ==, NULL); |
| |
| if (need_crypt) { |
| ncache = hdr_full_crypt_cache; |
| nsize = sizeof (hdr->b_crypt_hdr); |
| ocache = hdr_full_cache; |
| osize = HDR_FULL_SIZE; |
| } else { |
| ncache = hdr_full_cache; |
| nsize = HDR_FULL_SIZE; |
| ocache = hdr_full_crypt_cache; |
| osize = sizeof (hdr->b_crypt_hdr); |
| } |
| |
| nhdr = kmem_cache_alloc(ncache, KM_PUSHPAGE); |
| |
| /* |
| * Copy all members that aren't locks or condvars to the new header. |
| * No lists are pointing to us (as we asserted above), so we don't |
| * need to worry about the list nodes. |
| */ |
| nhdr->b_dva = hdr->b_dva; |
| nhdr->b_birth = hdr->b_birth; |
| nhdr->b_type = hdr->b_type; |
| nhdr->b_flags = hdr->b_flags; |
| nhdr->b_psize = hdr->b_psize; |
| nhdr->b_lsize = hdr->b_lsize; |
| nhdr->b_spa = hdr->b_spa; |
| nhdr->b_l1hdr.b_freeze_cksum = hdr->b_l1hdr.b_freeze_cksum; |
| nhdr->b_l1hdr.b_bufcnt = hdr->b_l1hdr.b_bufcnt; |
| nhdr->b_l1hdr.b_byteswap = hdr->b_l1hdr.b_byteswap; |
| nhdr->b_l1hdr.b_state = hdr->b_l1hdr.b_state; |
| nhdr->b_l1hdr.b_arc_access = hdr->b_l1hdr.b_arc_access; |
| nhdr->b_l1hdr.b_mru_hits = hdr->b_l1hdr.b_mru_hits; |
| nhdr->b_l1hdr.b_mru_ghost_hits = hdr->b_l1hdr.b_mru_ghost_hits; |
| nhdr->b_l1hdr.b_mfu_hits = hdr->b_l1hdr.b_mfu_hits; |
| nhdr->b_l1hdr.b_mfu_ghost_hits = hdr->b_l1hdr.b_mfu_ghost_hits; |
| nhdr->b_l1hdr.b_l2_hits = hdr->b_l1hdr.b_l2_hits; |
| nhdr->b_l1hdr.b_acb = hdr->b_l1hdr.b_acb; |
| nhdr->b_l1hdr.b_pabd = hdr->b_l1hdr.b_pabd; |
| |
| /* |
| * This zfs_refcount_add() exists only to ensure that the individual |
| * arc buffers always point to a header that is referenced, avoiding |
| * a small race condition that could trigger ASSERTs. |
| */ |
| (void) zfs_refcount_add(&nhdr->b_l1hdr.b_refcnt, FTAG); |
| nhdr->b_l1hdr.b_buf = hdr->b_l1hdr.b_buf; |
| for (buf = nhdr->b_l1hdr.b_buf; buf != NULL; buf = buf->b_next) { |
| mutex_enter(&buf->b_evict_lock); |
| buf->b_hdr = nhdr; |
| mutex_exit(&buf->b_evict_lock); |
| } |
| |
| zfs_refcount_transfer(&nhdr->b_l1hdr.b_refcnt, &hdr->b_l1hdr.b_refcnt); |
| (void) zfs_refcount_remove(&nhdr->b_l1hdr.b_refcnt, FTAG); |
| ASSERT0(zfs_refcount_count(&hdr->b_l1hdr.b_refcnt)); |
| |
| if (need_crypt) { |
| arc_hdr_set_flags(nhdr, ARC_FLAG_PROTECTED); |
| } else { |
| arc_hdr_clear_flags(nhdr, ARC_FLAG_PROTECTED); |
| } |
| |
| /* unset all members of the original hdr */ |
| bzero(&hdr->b_dva, sizeof (dva_t)); |
| hdr->b_birth = 0; |
| hdr->b_type = ARC_BUFC_INVALID; |
| hdr->b_flags = 0; |
| hdr->b_psize = 0; |
| hdr->b_lsize = 0; |
| hdr->b_spa = 0; |
| hdr->b_l1hdr.b_freeze_cksum = NULL; |
| hdr->b_l1hdr.b_buf = NULL; |
| hdr->b_l1hdr.b_bufcnt = 0; |
| hdr->b_l1hdr.b_byteswap = 0; |
| hdr->b_l1hdr.b_state = NULL; |
| hdr->b_l1hdr.b_arc_access = 0; |
| hdr->b_l1hdr.b_mru_hits = 0; |
| hdr->b_l1hdr.b_mru_ghost_hits = 0; |
| hdr->b_l1hdr.b_mfu_hits = 0; |
| hdr->b_l1hdr.b_mfu_ghost_hits = 0; |
| hdr->b_l1hdr.b_l2_hits = 0; |
| hdr->b_l1hdr.b_acb = NULL; |
| hdr->b_l1hdr.b_pabd = NULL; |
| |
| if (ocache == hdr_full_crypt_cache) { |
| ASSERT(!HDR_HAS_RABD(hdr)); |
| hdr->b_crypt_hdr.b_ot = DMU_OT_NONE; |
| hdr->b_crypt_hdr.b_ebufcnt = 0; |
| hdr->b_crypt_hdr.b_dsobj = 0; |
| bzero(hdr->b_crypt_hdr.b_salt, ZIO_DATA_SALT_LEN); |
| bzero(hdr->b_crypt_hdr.b_iv, ZIO_DATA_IV_LEN); |
| bzero(hdr->b_crypt_hdr.b_mac, ZIO_DATA_MAC_LEN); |
| } |
| |
| buf_discard_identity(hdr); |
| kmem_cache_free(ocache, hdr); |
| |
| return (nhdr); |
| } |
| |
| /* |
| * This function is used by the send / receive code to convert a newly |
| * allocated arc_buf_t to one that is suitable for a raw encrypted write. It |
| * is also used to allow the root objset block to be updated without altering |
| * its embedded MACs. Both block types will always be uncompressed so we do not |
| * have to worry about compression type or psize. |
| */ |
| void |
| arc_convert_to_raw(arc_buf_t *buf, uint64_t dsobj, boolean_t byteorder, |
| dmu_object_type_t ot, const uint8_t *salt, const uint8_t *iv, |
| const uint8_t *mac) |
| { |
| arc_buf_hdr_t *hdr = buf->b_hdr; |
| |
| ASSERT(ot == DMU_OT_DNODE || ot == DMU_OT_OBJSET); |
| ASSERT(HDR_HAS_L1HDR(hdr)); |
| ASSERT3P(hdr->b_l1hdr.b_state, ==, arc_anon); |
| |
| buf->b_flags |= (ARC_BUF_FLAG_COMPRESSED | ARC_BUF_FLAG_ENCRYPTED); |
| if (!HDR_PROTECTED(hdr)) |
| hdr = arc_hdr_realloc_crypt(hdr, B_TRUE); |
| hdr->b_crypt_hdr.b_dsobj = dsobj; |
| hdr->b_crypt_hdr.b_ot = ot; |
| hdr->b_l1hdr.b_byteswap = (byteorder == ZFS_HOST_BYTEORDER) ? |
| DMU_BSWAP_NUMFUNCS : DMU_OT_BYTESWAP(ot); |
| if (!arc_hdr_has_uncompressed_buf(hdr)) |
| arc_cksum_free(hdr); |
| |
| if (salt != NULL) |
| bcopy(salt, hdr->b_crypt_hdr.b_salt, ZIO_DATA_SALT_LEN); |
| if (iv != NULL) |
| bcopy(iv, hdr->b_crypt_hdr.b_iv, ZIO_DATA_IV_LEN); |
| if (mac != NULL) |
| bcopy(mac, hdr->b_crypt_hdr.b_mac, ZIO_DATA_MAC_LEN); |
| } |
| |
| /* |
| * Allocate a new arc_buf_hdr_t and arc_buf_t and return the buf to the caller. |
| * The buf is returned thawed since we expect the consumer to modify it. |
| */ |
| arc_buf_t * |
| arc_alloc_buf(spa_t *spa, void *tag, arc_buf_contents_t type, int32_t size) |
| { |
| arc_buf_hdr_t *hdr = arc_hdr_alloc(spa_load_guid(spa), size, size, |
| B_FALSE, ZIO_COMPRESS_OFF, type, B_FALSE); |
| |
| arc_buf_t *buf = NULL; |
| VERIFY0(arc_buf_alloc_impl(hdr, spa, NULL, tag, B_FALSE, B_FALSE, |
| B_FALSE, B_FALSE, &buf)); |
| arc_buf_thaw(buf); |
| |
| return (buf); |
| } |
| |
| /* |
| * Allocate a compressed buf in the same manner as arc_alloc_buf. Don't use this |
| * for bufs containing metadata. |
| */ |
| arc_buf_t * |
| arc_alloc_compressed_buf(spa_t *spa, void *tag, uint64_t psize, uint64_t lsize, |
| enum zio_compress compression_type) |
| { |
| ASSERT3U(lsize, >, 0); |
| ASSERT3U(lsize, >=, psize); |
| ASSERT3U(compression_type, >, ZIO_COMPRESS_OFF); |
| ASSERT3U(compression_type, <, ZIO_COMPRESS_FUNCTIONS); |
| |
| arc_buf_hdr_t *hdr = arc_hdr_alloc(spa_load_guid(spa), psize, lsize, |
| B_FALSE, compression_type, ARC_BUFC_DATA, B_FALSE); |
| |
| arc_buf_t *buf = NULL; |
| VERIFY0(arc_buf_alloc_impl(hdr, spa, NULL, tag, B_FALSE, |
| B_TRUE, B_FALSE, B_FALSE, &buf)); |
| arc_buf_thaw(buf); |
| ASSERT3P(hdr->b_l1hdr.b_freeze_cksum, ==, NULL); |
| |
| if (!arc_buf_is_shared(buf)) { |
| /* |
| * To ensure that the hdr has the correct data in it if we call |
| * arc_untransform() on this buf before it's been written to |
| * disk, it's easiest if we just set up sharing between the |
| * buf and the hdr. |
| */ |
| arc_hdr_free_abd(hdr, B_FALSE); |
| arc_share_buf(hdr, buf); |
| } |
| |
| return (buf); |
| } |
| |
| arc_buf_t * |
| arc_alloc_raw_buf(spa_t *spa, void *tag, uint64_t dsobj, boolean_t byteorder, |
| const uint8_t *salt, const uint8_t *iv, const uint8_t *mac, |
| dmu_object_type_t ot, uint64_t psize, uint64_t lsize, |
| enum zio_compress compression_type) |
| { |
| arc_buf_hdr_t *hdr; |
| arc_buf_t *buf; |
| arc_buf_contents_t type = DMU_OT_IS_METADATA(ot) ? |
| ARC_BUFC_METADATA : ARC_BUFC_DATA; |
| |
| ASSERT3U(lsize, >, 0); |
| ASSERT3U(lsize, >=, psize); |
| ASSERT3U(compression_type, >=, ZIO_COMPRESS_OFF); |
| ASSERT3U(compression_type, <, ZIO_COMPRESS_FUNCTIONS); |
| |
| hdr = arc_hdr_alloc(spa_load_guid(spa), psize, lsize, B_TRUE, |
| compression_type, type, B_TRUE); |
| |
| hdr->b_crypt_hdr.b_dsobj = dsobj; |
| hdr->b_crypt_hdr.b_ot = ot; |
| hdr->b_l1hdr.b_byteswap = (byteorder == ZFS_HOST_BYTEORDER) ? |
| DMU_BSWAP_NUMFUNCS : DMU_OT_BYTESWAP(ot); |
| bcopy(salt, hdr->b_crypt_hdr.b_salt, ZIO_DATA_SALT_LEN); |
| bcopy(iv, hdr->b_crypt_hdr.b_iv, ZIO_DATA_IV_LEN); |
| bcopy(mac, hdr->b_crypt_hdr.b_mac, ZIO_DATA_MAC_LEN); |
| |
| /* |
| * This buffer will be considered encrypted even if the ot is not an |
| * encrypted type. It will become authenticated instead in |
| * arc_write_ready(). |
| */ |
| buf = NULL; |
| VERIFY0(arc_buf_alloc_impl(hdr, spa, NULL, tag, B_TRUE, B_TRUE, |
| B_FALSE, B_FALSE, &buf)); |
| arc_buf_thaw(buf); |
| ASSERT3P(hdr->b_l1hdr.b_freeze_cksum, ==, NULL); |
| |
| return (buf); |
| } |
| |
| static void |
| arc_hdr_l2hdr_destroy(arc_buf_hdr_t *hdr) |
| { |
| l2arc_buf_hdr_t *l2hdr = &hdr->b_l2hdr; |
| l2arc_dev_t *dev = l2hdr->b_dev; |
| uint64_t psize = HDR_GET_PSIZE(hdr); |
| uint64_t asize = vdev_psize_to_asize(dev->l2ad_vdev, psize); |
| |
| ASSERT(MUTEX_HELD(&dev->l2ad_mtx)); |
| ASSERT(HDR_HAS_L2HDR(hdr)); |
| |
| list_remove(&dev->l2ad_buflist, hdr); |
| |
| ARCSTAT_INCR(arcstat_l2_psize, -psize); |
| ARCSTAT_INCR(arcstat_l2_lsize, -HDR_GET_LSIZE(hdr)); |
| |
| vdev_space_update(dev->l2ad_vdev, -asize, 0, 0); |
| |
| (void) zfs_refcount_remove_many(&dev->l2ad_alloc, arc_hdr_size(hdr), |
| hdr); |
| arc_hdr_clear_flags(hdr, ARC_FLAG_HAS_L2HDR); |
| } |
| |
| static void |
| arc_hdr_destroy(arc_buf_hdr_t *hdr) |
| { |
| if (HDR_HAS_L1HDR(hdr)) { |
| ASSERT(hdr->b_l1hdr.b_buf == NULL || |
| hdr->b_l1hdr.b_bufcnt > 0); |
| ASSERT(zfs_refcount_is_zero(&hdr->b_l1hdr.b_refcnt)); |
| ASSERT3P(hdr->b_l1hdr.b_state, ==, arc_anon); |
| } |
| ASSERT(!HDR_IO_IN_PROGRESS(hdr)); |
| ASSERT(!HDR_IN_HASH_TABLE(hdr)); |
| |
| if (HDR_HAS_L2HDR(hdr)) { |
| l2arc_dev_t *dev = hdr->b_l2hdr.b_dev; |
| boolean_t buflist_held = MUTEX_HELD(&dev->l2ad_mtx); |
| |
| if (!buflist_held) |
| mutex_enter(&dev->l2ad_mtx); |
| |
| /* |
| * Even though we checked this conditional above, we |
| * need to check this again now that we have the |
| * l2ad_mtx. This is because we could be racing with |
| * another thread calling l2arc_evict() which might have |
| * destroyed this header's L2 portion as we were waiting |
| * to acquire the l2ad_mtx. If that happens, we don't |
| * want to re-destroy the header's L2 portion. |
| */ |
| if (HDR_HAS_L2HDR(hdr)) |
| arc_hdr_l2hdr_destroy(hdr); |
| |
| if (!buflist_held) |
| mutex_exit(&dev->l2ad_mtx); |
| } |
| |
| /* |
| * The header's identify can only be safely discarded once it is no |
| * longer discoverable. This requires removing it from the hash table |
| * and the l2arc header list. After this point the hash lock can not |
| * be used to protect the header. |
| */ |
| if (!HDR_EMPTY(hdr)) |
| buf_discard_identity(hdr); |
| |
| if (HDR_HAS_L1HDR(hdr)) { |
| arc_cksum_free(hdr); |
| |
| while (hdr->b_l1hdr.b_buf != NULL) |
| arc_buf_destroy_impl(hdr->b_l1hdr.b_buf); |
| |
| if (hdr->b_l1hdr.b_pabd != NULL) |
| arc_hdr_free_abd(hdr, B_FALSE); |
| |
| if (HDR_HAS_RABD(hdr)) |
| arc_hdr_free_abd(hdr, B_TRUE); |
| } |
| |
| ASSERT3P(hdr->b_hash_next, ==, NULL); |
| if (HDR_HAS_L1HDR(hdr)) { |
| ASSERT(!multilist_link_active(&hdr->b_l1hdr.b_arc_node)); |
| ASSERT3P(hdr->b_l1hdr.b_acb, ==, NULL); |
| |
| if (!HDR_PROTECTED(hdr)) { |
| kmem_cache_free(hdr_full_cache, hdr); |
| } else { |
| kmem_cache_free(hdr_full_crypt_cache, hdr); |
| } |
| } else { |
| kmem_cache_free(hdr_l2only_cache, hdr); |
| } |
| } |
| |
| void |
| arc_buf_destroy(arc_buf_t *buf, void* tag) |
| { |
| arc_buf_hdr_t *hdr = buf->b_hdr; |
| |
| if (hdr->b_l1hdr.b_state == arc_anon) { |
| ASSERT3U(hdr->b_l1hdr.b_bufcnt, ==, 1); |
| ASSERT(!HDR_IO_IN_PROGRESS(hdr)); |
| VERIFY0(remove_reference(hdr, NULL, tag)); |
| arc_hdr_destroy(hdr); |
| return; |
| } |
| |
| kmutex_t *hash_lock = HDR_LOCK(hdr); |
| mutex_enter(hash_lock); |
| |
| ASSERT3P(hdr, ==, buf->b_hdr); |
| ASSERT(hdr->b_l1hdr.b_bufcnt > 0); |
| ASSERT3P(hash_lock, ==, HDR_LOCK(hdr)); |
| ASSERT3P(hdr->b_l1hdr.b_state, !=, arc_anon); |
| ASSERT3P(buf->b_data, !=, NULL); |
| |
| (void) remove_reference(hdr, hash_lock, tag); |
| arc_buf_destroy_impl(buf); |
| mutex_exit(hash_lock); |
| } |
| |
| /* |
| * Evict the arc_buf_hdr that is provided as a parameter. The resultant |
| * state of the header is dependent on its state prior to entering this |
| * function. The following transitions are possible: |
| * |
| * - arc_mru -> arc_mru_ghost |
| * - arc_mfu -> arc_mfu_ghost |
| * - arc_mru_ghost -> arc_l2c_only |
| * - arc_mru_ghost -> deleted |
| * - arc_mfu_ghost -> arc_l2c_only |
| * - arc_mfu_ghost -> deleted |
| */ |
| static int64_t |
| arc_evict_hdr(arc_buf_hdr_t *hdr, kmutex_t *hash_lock) |
| { |
| arc_state_t *evicted_state, *state; |
| int64_t bytes_evicted = 0; |
| int min_lifetime = HDR_PRESCIENT_PREFETCH(hdr) ? |
| arc_min_prescient_prefetch_ms : arc_min_prefetch_ms; |
| |
| ASSERT(MUTEX_HELD(hash_lock)); |
| ASSERT(HDR_HAS_L1HDR(hdr)); |
| |
| state = hdr->b_l1hdr.b_state; |
| if (GHOST_STATE(state)) { |
| ASSERT(!HDR_IO_IN_PROGRESS(hdr)); |
| ASSERT3P(hdr->b_l1hdr.b_buf, ==, NULL); |
| |
| /* |
| * l2arc_write_buffers() relies on a header's L1 portion |
| * (i.e. its b_pabd field) during it's write phase. |
| * Thus, we cannot push a header onto the arc_l2c_only |
| * state (removing its L1 piece) until the header is |
| * done being written to the l2arc. |
| */ |
| if (HDR_HAS_L2HDR(hdr) && HDR_L2_WRITING(hdr)) { |
| ARCSTAT_BUMP(arcstat_evict_l2_skip); |
| return (bytes_evicted); |
| } |
| |
| ARCSTAT_BUMP(arcstat_deleted); |
| bytes_evicted += HDR_GET_LSIZE(hdr); |
| |
| DTRACE_PROBE1(arc__delete, arc_buf_hdr_t *, hdr); |
| |
| if (HDR_HAS_L2HDR(hdr)) { |
| ASSERT(hdr->b_l1hdr.b_pabd == NULL); |
| ASSERT(!HDR_HAS_RABD(hdr)); |
| /* |
| * This buffer is cached on the 2nd Level ARC; |
| * don't destroy the header. |
| */ |
| arc_change_state(arc_l2c_only, hdr, hash_lock); |
| /* |
| * dropping from L1+L2 cached to L2-only, |
| * realloc to remove the L1 header. |
| */ |
| hdr = arc_hdr_realloc(hdr, hdr_full_cache, |
| hdr_l2only_cache); |
| } else { |
| arc_change_state(arc_anon, hdr, hash_lock); |
| arc_hdr_destroy(hdr); |
| } |
| return (bytes_evicted); |
| } |
| |
| ASSERT(state == arc_mru || state == arc_mfu); |
| evicted_state = (state == arc_mru) ? arc_mru_ghost : arc_mfu_ghost; |
| |
| /* prefetch buffers have a minimum lifespan */ |
| if (HDR_IO_IN_PROGRESS(hdr) || |
| ((hdr->b_flags & (ARC_FLAG_PREFETCH | ARC_FLAG_INDIRECT)) && |
| ddi_get_lbolt() - hdr->b_l1hdr.b_arc_access < |
| MSEC_TO_TICK(min_lifetime))) { |
| ARCSTAT_BUMP(arcstat_evict_skip); |
| return (bytes_evicted); |
| } |
| |
| ASSERT0(zfs_refcount_count(&hdr->b_l1hdr.b_refcnt)); |
| while (hdr->b_l1hdr.b_buf) { |
| arc_buf_t *buf = hdr->b_l1hdr.b_buf; |
| if (!mutex_tryenter(&buf->b_evict_lock)) { |
| ARCSTAT_BUMP(arcstat_mutex_miss); |
| break; |
| } |
| if (buf->b_data != NULL) |
| bytes_evicted += HDR_GET_LSIZE(hdr); |
| mutex_exit(&buf->b_evict_lock); |
| arc_buf_destroy_impl(buf); |
| } |
| |
| if (HDR_HAS_L2HDR(hdr)) { |
| ARCSTAT_INCR(arcstat_evict_l2_cached, HDR_GET_LSIZE(hdr)); |
| } else { |
| if (l2arc_write_eligible(hdr->b_spa, hdr)) { |
| ARCSTAT_INCR(arcstat_evict_l2_eligible, |
| HDR_GET_LSIZE(hdr)); |
| } else { |
| ARCSTAT_INCR(arcstat_evict_l2_ineligible, |
| HDR_GET_LSIZE(hdr)); |
| } |
| } |
| |
| if (hdr->b_l1hdr.b_bufcnt == 0) { |
| arc_cksum_free(hdr); |
| |
| bytes_evicted += arc_hdr_size(hdr); |
| |
| /* |
| * If this hdr is being evicted and has a compressed |
| * buffer then we discard it here before we change states. |
| * This ensures that the accounting is updated correctly |
| * in arc_free_data_impl(). |
| */ |
| if (hdr->b_l1hdr.b_pabd != NULL) |
| arc_hdr_free_abd(hdr, B_FALSE); |
| |
| if (HDR_HAS_RABD(hdr)) |
| arc_hdr_free_abd(hdr, B_TRUE); |
| |
| arc_change_state(evicted_state, hdr, hash_lock); |
| ASSERT(HDR_IN_HASH_TABLE(hdr)); |
| arc_hdr_set_flags(hdr, ARC_FLAG_IN_HASH_TABLE); |
| DTRACE_PROBE1(arc__evict, arc_buf_hdr_t *, hdr); |
| } |
| |
| return (bytes_evicted); |
| } |
| |
| static uint64_t |
| arc_evict_state_impl(multilist_t *ml, int idx, arc_buf_hdr_t *marker, |
| uint64_t spa, int64_t bytes) |
| { |
| multilist_sublist_t *mls; |
| uint64_t bytes_evicted = 0; |
| arc_buf_hdr_t *hdr; |
| kmutex_t *hash_lock; |
| int evict_count = 0; |
| |
| ASSERT3P(marker, !=, NULL); |
| IMPLY(bytes < 0, bytes == ARC_EVICT_ALL); |
| |
| mls = multilist_sublist_lock(ml, idx); |
| |
| for (hdr = multilist_sublist_prev(mls, marker); hdr != NULL; |
| hdr = multilist_sublist_prev(mls, marker)) { |
| if ((bytes != ARC_EVICT_ALL && bytes_evicted >= bytes) || |
| (evict_count >= zfs_arc_evict_batch_limit)) |
| break; |
| |
| /* |
| * To keep our iteration location, move the marker |
| * forward. Since we're not holding hdr's hash lock, we |
| * must be very careful and not remove 'hdr' from the |
| * sublist. Otherwise, other consumers might mistake the |
| * 'hdr' as not being on a sublist when they call the |
| * multilist_link_active() function (they all rely on |
| * the hash lock protecting concurrent insertions and |
| * removals). multilist_sublist_move_forward() was |
| * specifically implemented to ensure this is the case |
| * (only 'marker' will be removed and re-inserted). |
| */ |
| multilist_sublist_move_forward(mls, marker); |
| |
| /* |
| * The only case where the b_spa field should ever be |
| * zero, is the marker headers inserted by |
| * arc_evict_state(). It's possible for multiple threads |
| * to be calling arc_evict_state() concurrently (e.g. |
| * dsl_pool_close() and zio_inject_fault()), so we must |
| * skip any markers we see from these other threads. |
| */ |
| if (hdr->b_spa == 0) |
| continue; |
| |
| /* we're only interested in evicting buffers of a certain spa */ |
| if (spa != 0 && hdr->b_spa != spa) { |
| ARCSTAT_BUMP(arcstat_evict_skip); |
| continue; |
| } |
| |
| hash_lock = HDR_LOCK(hdr); |
| |
| /* |
| * We aren't calling this function from any code path |
| * that would already be holding a hash lock, so we're |
| * asserting on this assumption to be defensive in case |
| * this ever changes. Without this check, it would be |
| * possible to incorrectly increment arcstat_mutex_miss |
| * below (e.g. if the code changed such that we called |
| * this function with a hash lock held). |
| */ |
| ASSERT(!MUTEX_HELD(hash_lock)); |
| |
| if (mutex_tryenter(hash_lock)) { |
| uint64_t evicted = arc_evict_hdr(hdr, hash_lock); |
| mutex_exit(hash_lock); |
| |
| bytes_evicted += evicted; |
| |
| /* |
| * If evicted is zero, arc_evict_hdr() must have |
| * decided to skip this header, don't increment |
| * evict_count in this case. |
| */ |
| if (evicted != 0) |
| evict_count++; |
| |
| /* |
| * If arc_size isn't overflowing, signal any |
| * threads that might happen to be waiting. |
| * |
| * For each header evicted, we wake up a single |
| * thread. If we used cv_broadcast, we could |
| * wake up "too many" threads causing arc_size |
| * to significantly overflow arc_c; since |
| * arc_get_data_impl() doesn't check for overflow |
| * when it's woken up (it doesn't because it's |
| * possible for the ARC to be overflowing while |
| * full of un-evictable buffers, and the |
| * function should proceed in this case). |
| * |
| * If threads are left sleeping, due to not |
| * using cv_broadcast here, they will be woken |
| * up via cv_broadcast in arc_adjust_cb() just |
| * before arc_adjust_zthr sleeps. |
| */ |
| mutex_enter(&arc_adjust_lock); |
| if (!arc_is_overflowing()) |
| cv_signal(&arc_adjust_waiters_cv); |
| mutex_exit(&arc_adjust_lock); |
| } else { |
| ARCSTAT_BUMP(arcstat_mutex_miss); |
| } |
| } |
| |
| multilist_sublist_unlock(mls); |
| |
| return (bytes_evicted); |
| } |
| |
| /* |
| * Evict buffers from the given arc state, until we've removed the |
| * specified number of bytes. Move the removed buffers to the |
| * appropriate evict state. |
| * |
| * This function makes a "best effort". It skips over any buffers |
| * it can't get a hash_lock on, and so, may not catch all candidates. |
| * It may also return without evicting as much space as requested. |
| * |
| * If bytes is specified using the special value ARC_EVICT_ALL, this |
| * will evict all available (i.e. unlocked and evictable) buffers from |
| * the given arc state; which is used by arc_flush(). |
| */ |
| static uint64_t |
| arc_evict_state(arc_state_t *state, uint64_t spa, int64_t bytes, |
| arc_buf_contents_t type) |
| { |
| uint64_t total_evicted = 0; |
| multilist_t *ml = state->arcs_list[type]; |
| int num_sublists; |
| arc_buf_hdr_t **markers; |
| |
| IMPLY(bytes < 0, bytes == ARC_EVICT_ALL); |
| |
| num_sublists = multilist_get_num_sublists(ml); |
| |
| /* |
| * If we've tried to evict from each sublist, made some |
| * progress, but still have not hit the target number of bytes |
| * to evict, we want to keep trying. The markers allow us to |
| * pick up where we left off for each individual sublist, rather |
| * than starting from the tail each time. |
| */ |
| markers = kmem_zalloc(sizeof (*markers) * num_sublists, KM_SLEEP); |
| for (int i = 0; i < num_sublists; i++) { |
| multilist_sublist_t *mls; |
| |
| markers[i] = kmem_cache_alloc(hdr_full_cache, KM_SLEEP); |
| |
| /* |
| * A b_spa of 0 is used to indicate that this header is |
| * a marker. This fact is used in arc_adjust_type() and |
| * arc_evict_state_impl(). |
| */ |
| markers[i]->b_spa = 0; |
| |
| mls = multilist_sublist_lock(ml, i); |
| multilist_sublist_insert_tail(mls, markers[i]); |
| multilist_sublist_unlock(mls); |
| } |
| |
| /* |
| * While we haven't hit our target number of bytes to evict, or |
| * we're evicting all available buffers. |
| */ |
| while (total_evicted < bytes || bytes == ARC_EVICT_ALL) { |
| int sublist_idx = multilist_get_random_index(ml); |
| uint64_t scan_evicted = 0; |
| |
| /* |
| * Try to reduce pinned dnodes with a floor of arc_dnode_limit. |
| * Request that 10% of the LRUs be scanned by the superblock |
| * shrinker. |
| */ |
| if (type == ARC_BUFC_DATA && aggsum_compare(&astat_dnode_size, |
| arc_dnode_limit) > 0) { |
| arc_prune_async((aggsum_upper_bound(&astat_dnode_size) - |
| arc_dnode_limit) / sizeof (dnode_t) / |
| zfs_arc_dnode_reduce_percent); |
| } |
| |
| /* |
| * Start eviction using a randomly selected sublist, |
| * this is to try and evenly balance eviction across all |
| * sublists. Always starting at the same sublist |
| * (e.g. index 0) would cause evictions to favor certain |
| * sublists over others. |
| */ |
| for (int i = 0; i < num_sublists; i++) { |
| uint64_t bytes_remaining; |
| uint64_t bytes_evicted; |
| |
| if (bytes == ARC_EVICT_ALL) |
| bytes_remaining = ARC_EVICT_ALL; |
| else if (total_evicted < bytes) |
| bytes_remaining = bytes - total_evicted; |
| else |
| break; |
| |
| bytes_evicted = arc_evict_state_impl(ml, sublist_idx, |
| markers[sublist_idx], spa, bytes_remaining); |
| |
| scan_evicted += bytes_evicted; |
| total_evicted += bytes_evicted; |
| |
| /* we've reached the end, wrap to the beginning */ |
| if (++sublist_idx >= num_sublists) |
| sublist_idx = 0; |
| } |
| |
| /* |
| * If we didn't evict anything during this scan, we have |
| * no reason to believe we'll evict more during another |
| * scan, so break the loop. |
| */ |
| if (scan_evicted == 0) { |
| /* This isn't possible, let's make that obvious */ |
| ASSERT3S(bytes, !=, 0); |
| |
| /* |
| * When bytes is ARC_EVICT_ALL, the only way to |
| * break the loop is when scan_evicted is zero. |
| * In that case, we actually have evicted enough, |
| * so we don't want to increment the kstat. |
| */ |
| if (bytes != ARC_EVICT_ALL) { |
| ASSERT3S(total_evicted, <, bytes); |
| ARCSTAT_BUMP(arcstat_evict_not_enough); |
| } |
| |
| break; |
| } |
| } |
| |
| for (int i = 0; i < num_sublists; i++) { |
| multilist_sublist_t *mls = multilist_sublist_lock(ml, i); |
| multilist_sublist_remove(mls, markers[i]); |
| multilist_sublist_unlock(mls); |
| |
| kmem_cache_free(hdr_full_cache, markers[i]); |
| } |
| kmem_free(markers, sizeof (*markers) * num_sublists); |
| |
| return (total_evicted); |
| } |
| |
| /* |
| * Flush all "evictable" data of the given type from the arc state |
| * specified. This will not evict any "active" buffers (i.e. referenced). |
| * |
| * When 'retry' is set to B_FALSE, the function will make a single pass |
| * over the state and evict any buffers that it can. Since it doesn't |
| * continually retry the eviction, it might end up leaving some buffers |
| * in the ARC due to lock misses. |
| * |
| * When 'retry' is set to B_TRUE, the function will continually retry the |
| * eviction until *all* evictable buffers have been removed from the |
| * state. As a result, if concurrent insertions into the state are |
| * allowed (e.g. if the ARC isn't shutting down), this function might |
| * wind up in an infinite loop, continually trying to evict buffers. |
| */ |
| static uint64_t |
| arc_flush_state(arc_state_t *state, uint64_t spa, arc_buf_contents_t type, |
| boolean_t retry) |
| { |
| uint64_t evicted = 0; |
| |
| while (zfs_refcount_count(&state->arcs_esize[type]) != 0) { |
| evicted += arc_evict_state(state, spa, ARC_EVICT_ALL, type); |
| |
| if (!retry) |
| break; |
| } |
| |
| return (evicted); |
| } |
| |
| /* |
| * Helper function for arc_prune_async() it is responsible for safely |
| * handling the execution of a registered arc_prune_func_t. |
| */ |
| static void |
| arc_prune_task(void *ptr) |
| { |
| arc_prune_t *ap = (arc_prune_t *)ptr; |
| arc_prune_func_t *func = ap->p_pfunc; |
| |
| if (func != NULL) |
| func(ap->p_adjust, ap->p_private); |
| |
| zfs_refcount_remove(&ap->p_refcnt, func); |
| } |
| |
| /* |
| * Notify registered consumers they must drop holds on a portion of the ARC |
| * buffered they reference. This provides a mechanism to ensure the ARC can |
| * honor the arc_meta_limit and reclaim otherwise pinned ARC buffers. This |
| * is analogous to dnlc_reduce_cache() but more generic. |
| * |
| * This operation is performed asynchronously so it may be safely called |
| * in the context of the arc_reclaim_thread(). A reference is taken here |
| * for each registered arc_prune_t and the arc_prune_task() is responsible |
| * for releasing it once the registered arc_prune_func_t has completed. |
| */ |
| static void |
| arc_prune_async(int64_t adjust) |
| { |
| arc_prune_t *ap; |
| |
| mutex_enter(&arc_prune_mtx); |
| for (ap = list_head(&arc_prune_list); ap != NULL; |
| ap = list_next(&arc_prune_list, ap)) { |
| |
| if (zfs_refcount_count(&ap->p_refcnt) >= 2) |
| continue; |
| |
| zfs_refcount_add(&ap->p_refcnt, ap->p_pfunc); |
| ap->p_adjust = adjust; |
| if (taskq_dispatch(arc_prune_taskq, arc_prune_task, |
| ap, TQ_SLEEP) == TASKQID_INVALID) { |
| zfs_refcount_remove(&ap->p_refcnt, ap->p_pfunc); |
| continue; |
| } |
| ARCSTAT_BUMP(arcstat_prune); |
| } |
| mutex_exit(&arc_prune_mtx); |
| } |
| |
| /* |
| * Evict the specified number of bytes from the state specified, |
| * restricting eviction to the spa and type given. This function |
| * prevents us from trying to evict more from a state's list than |
| * is "evictable", and to skip evicting altogether when passed a |
| * negative value for "bytes". In contrast, arc_evict_state() will |
| * evict everything it can, when passed a negative value for "bytes". |
| */ |
| static uint64_t |
| arc_adjust_impl(arc_state_t *state, uint64_t spa, int64_t bytes, |
| arc_buf_contents_t type) |
| { |
| int64_t delta; |
| |
| if (bytes > 0 && zfs_refcount_count(&state->arcs_esize[type]) > 0) { |
| delta = MIN(zfs_refcount_count(&state->arcs_esize[type]), |
| bytes); |
| return (arc_evict_state(state, spa, delta, type)); |
| } |
| |
| return (0); |
| } |
| |
| /* |
| * The goal of this function is to evict enough meta data buffers from the |
| * ARC in order to enforce the arc_meta_limit. Achieving this is slightly |
| * more complicated than it appears because it is common for data buffers |
| * to have holds on meta data buffers. In addition, dnode meta data buffers |
| * will be held by the dnodes in the block preventing them from being freed. |
| * This means we can't simply traverse the ARC and expect to always find |
| * enough unheld meta data buffer to release. |
| * |
| * Therefore, this function has been updated to make alternating passes |
| * over the ARC releasing data buffers and then newly unheld meta data |
| * buffers. This ensures forward progress is maintained and meta_used |
| * will decrease. Normally this is sufficient, but if required the ARC |
| * will call the registered prune callbacks causing dentry and inodes to |
| * be dropped from the VFS cache. This will make dnode meta data buffers |
| * available for reclaim. |
| */ |
| static uint64_t |
| arc_adjust_meta_balanced(uint64_t meta_used) |
| { |
| int64_t delta, prune = 0, adjustmnt; |
| uint64_t total_evicted = 0; |
| arc_buf_contents_t type = ARC_BUFC_DATA; |
| int restarts = MAX(zfs_arc_meta_adjust_restarts, 0); |
| |
| restart: |
| /* |
| * This slightly differs than the way we evict from the mru in |
| * arc_adjust because we don't have a "target" value (i.e. no |
| * "meta" arc_p). As a result, I think we can completely |
| * cannibalize the metadata in the MRU before we evict the |
| * metadata from the MFU. I think we probably need to implement a |
| * "metadata arc_p" value to do this properly. |
| */ |
| adjustmnt = meta_used - arc_meta_limit; |
| |
| if (adjustmnt > 0 && |
| zfs_refcount_count(&arc_mru->arcs_esize[type]) > 0) { |
| delta = MIN(zfs_refcount_count(&arc_mru->arcs_esize[type]), |
| adjustmnt); |
| total_evicted += arc_adjust_impl(arc_mru, 0, delta, type); |
| adjustmnt -= delta; |
| } |
| |
| /* |
| * We can't afford to recalculate adjustmnt here. If we do, |
| * new metadata buffers can sneak into the MRU or ANON lists, |
| * thus penalize the MFU metadata. Although the fudge factor is |
| * small, it has been empirically shown to be significant for |
| * certain workloads (e.g. creating many empty directories). As |
| * such, we use the original calculation for adjustmnt, and |
| * simply decrement the amount of data evicted from the MRU. |
| */ |
| |
| if (adjustmnt > 0 && |
| zfs_refcount_count(&arc_mfu->arcs_esize[type]) > 0) { |
| delta = MIN(zfs_refcount_count(&arc_mfu->arcs_esize[type]), |
| adjustmnt); |
| total_evicted += arc_adjust_impl(arc_mfu, 0, delta, type); |
| } |
| |
| adjustmnt = meta_used - arc_meta_limit; |
| |
| if (adjustmnt > 0 && |
| zfs_refcount_count(&arc_mru_ghost->arcs_esize[type]) > 0) { |
| delta = MIN(adjustmnt, |
| zfs_refcount_count(&arc_mru_ghost->arcs_esize[type])); |
| total_evicted += arc_adjust_impl(arc_mru_ghost, 0, delta, type); |
| adjustmnt -= delta; |
| } |
| |
| if (adjustmnt > 0 && |
| zfs_refcount_count(&arc_mfu_ghost->arcs_esize[type]) > 0) { |
| delta = MIN(adjustmnt, |
| zfs_refcount_count(&arc_mfu_ghost->arcs_esize[type])); |
| total_evicted += arc_adjust_impl(arc_mfu_ghost, 0, delta, type); |
| } |
| |
| /* |
| * If after attempting to make the requested adjustment to the ARC |
| * the meta limit is still being exceeded then request that the |
| * higher layers drop some cached objects which have holds on ARC |
| * meta buffers. Requests to the upper layers will be made with |
| * increasingly large scan sizes until the ARC is below the limit. |
| */ |
| if (meta_used > arc_meta_limit) { |
| if (type == ARC_BUFC_DATA) { |
| type = ARC_BUFC_METADATA; |
| } else { |
| type = ARC_BUFC_DATA; |
| |
| if (zfs_arc_meta_prune) { |
| prune += zfs_arc_meta_prune; |
| arc_prune_async(prune); |
| } |
| } |
| |
| if (restarts > 0) { |
| restarts--; |
| goto restart; |
| } |
| } |
| return (total_evicted); |
| } |
| |
| /* |
| * Evict metadata buffers from the cache, such that arc_meta_used is |
| * capped by the arc_meta_limit tunable. |
| */ |
| static uint64_t |
| arc_adjust_meta_only(uint64_t meta_used) |
| { |
| uint64_t total_evicted = 0; |
| int64_t target; |
| |
| /* |
| * If we're over the meta limit, we want to evict enough |
| * metadata to get back under the meta limit. We don't want to |
| * evict so much that we drop the MRU below arc_p, though. If |
| * we're over the meta limit more than we're over arc_p, we |
| * evict some from the MRU here, and some from the MFU below. |
| */ |
| target = MIN((int64_t)(meta_used - arc_meta_limit), |
| (int64_t)(zfs_refcount_count(&arc_anon->arcs_size) + |
| zfs_refcount_count(&arc_mru->arcs_size) - arc_p)); |
| |
| total_evicted += arc_adjust_impl(arc_mru, 0, target, ARC_BUFC_METADATA); |
| |
| /* |
| * Similar to the above, we want to evict enough bytes to get us |
| * below the meta limit, but not so much as to drop us below the |
| * space allotted to the MFU (which is defined as arc_c - arc_p). |
| */ |
| target = MIN((int64_t)(meta_used - arc_meta_limit), |
| (int64_t)(zfs_refcount_count(&arc_mfu->arcs_size) - |
| (arc_c - arc_p))); |
| |
| total_evicted += arc_adjust_impl(arc_mfu, 0, target, ARC_BUFC_METADATA); |
| |
| return (total_evicted); |
| } |
| |
| static uint64_t |
| arc_adjust_meta(uint64_t meta_used) |
| { |
| if (zfs_arc_meta_strategy == ARC_STRATEGY_META_ONLY) |
| return (arc_adjust_meta_only(meta_used)); |
| else |
| return (arc_adjust_meta_balanced(meta_used)); |
| } |
| |
| /* |
| * Return the type of the oldest buffer in the given arc state |
| * |
| * This function will select a random sublist of type ARC_BUFC_DATA and |
| * a random sublist of type ARC_BUFC_METADATA. The tail of each sublist |
| * is compared, and the type which contains the "older" buffer will be |
| * returned. |
| */ |
| static arc_buf_contents_t |
| arc_adjust_type(arc_state_t *state) |
| { |
| multilist_t *data_ml = state->arcs_list[ARC_BUFC_DATA]; |
| multilist_t *meta_ml = state->arcs_list[ARC_BUFC_METADATA]; |
| int data_idx = multilist_get_random_index(data_ml); |
| int meta_idx = multilist_get_random_index(meta_ml); |
| multilist_sublist_t *data_mls; |
| multilist_sublist_t *meta_mls; |
| arc_buf_contents_t type; |
| arc_buf_hdr_t *data_hdr; |
| arc_buf_hdr_t *meta_hdr; |
| |
| /* |
| * We keep the sublist lock until we're finished, to prevent |
| * the headers from being destroyed via arc_evict_state(). |
| */ |
| data_mls = multilist_sublist_lock(data_ml, data_idx); |
| meta_mls = multilist_sublist_lock(meta_ml, meta_idx); |
| |
| /* |
| * These two loops are to ensure we skip any markers that |
| * might be at the tail of the lists due to arc_evict_state(). |
| */ |
| |
| for (data_hdr = multilist_sublist_tail(data_mls); data_hdr != NULL; |
| data_hdr = multilist_sublist_prev(data_mls, data_hdr)) { |
| if (data_hdr->b_spa != 0) |
| break; |
| } |
| |
| for (meta_hdr = multilist_sublist_tail(meta_mls); meta_hdr != NULL; |
| meta_hdr = multilist_sublist_prev(meta_mls, meta_hdr)) { |
| if (meta_hdr->b_spa != 0) |
| break; |
| } |
| |
| if (data_hdr == NULL && meta_hdr == NULL) { |
| type = ARC_BUFC_DATA; |
| } else if (data_hdr == NULL) { |
| ASSERT3P(meta_hdr, !=, NULL); |
| type = ARC_BUFC_METADATA; |
| } else if (meta_hdr == NULL) { |
| ASSERT3P(data_hdr, !=, NULL); |
| type = ARC_BUFC_DATA; |
| } else { |
| ASSERT3P(data_hdr, !=, NULL); |
| ASSERT3P(meta_hdr, !=, NULL); |
| |
| /* The headers can't be on the sublist without an L1 header */ |
| ASSERT(HDR_HAS_L1HDR(data_hdr)); |
| ASSERT(HDR_HAS_L1HDR(meta_hdr)); |
| |
| if (data_hdr->b_l1hdr.b_arc_access < |
| meta_hdr->b_l1hdr.b_arc_access) { |
| type = ARC_BUFC_DATA; |
| } else { |
| type = ARC_BUFC_METADATA; |
| } |
| } |
| |
| multilist_sublist_unlock(meta_mls); |
| multilist_sublist_unlock(data_mls); |
| |
| return (type); |
| } |
| |
| /* |
| * Evict buffers from the cache, such that arc_size is capped by arc_c. |
| */ |
| static uint64_t |
| arc_adjust(void) |
| { |
| uint64_t total_evicted = 0; |
| uint64_t bytes; |
| int64_t target; |
| uint64_t asize = aggsum_value(&arc_size); |
| uint64_t ameta = aggsum_value(&arc_meta_used); |
| |
| /* |
| * If we're over arc_meta_limit, we want to correct that before |
| * potentially evicting data buffers below. |
| */ |
| total_evicted += arc_adjust_meta(ameta); |
| |
| /* |
| * Adjust MRU size |
| * |
| * If we're over the target cache size, we want to evict enough |
| * from the list to get back to our target size. We don't want |
| * to evict too much from the MRU, such that it drops below |
| * arc_p. So, if we're over our target cache size more than |
| * the MRU is over arc_p, we'll evict enough to get back to |
| * arc_p here, and then evict more from the MFU below. |
| */ |
| target = MIN((int64_t)(asize - arc_c), |
| (int64_t)(zfs_refcount_count(&arc_anon->arcs_size) + |
| zfs_refcount_count(&arc_mru->arcs_size) + ameta - arc_p)); |
| |
| /* |
| * If we're below arc_meta_min, always prefer to evict data. |
| * Otherwise, try to satisfy the requested number of bytes to |
| * evict from the type which contains older buffers; in an |
| * effort to keep newer buffers in the cache regardless of their |
| * type. If we cannot satisfy the number of bytes from this |
| * type, spill over into the next type. |
| */ |
| if (arc_adjust_type(arc_mru) == ARC_BUFC_METADATA && |
| ameta > arc_meta_min) { |
| bytes = arc_adjust_impl(arc_mru, 0, target, ARC_BUFC_METADATA); |
| total_evicted += bytes; |
| |
| /* |
| * If we couldn't evict our target number of bytes from |
| * metadata, we try to get the rest from data. |
| */ |
| target -= bytes; |
| |
| total_evicted += |
| arc_adjust_impl(arc_mru, 0, target, ARC_BUFC_DATA); |
| } else { |
| bytes = arc_adjust_impl(arc_mru, 0, target, ARC_BUFC_DATA); |
| total_evicted += bytes; |
| |
| /* |
| * If we couldn't evict our target number of bytes from |
| * data, we try to get the rest from metadata. |
| */ |
| target -= bytes; |
| |
| total_evicted += |
| arc_adjust_impl(arc_mru, 0, target, ARC_BUFC_METADATA); |
| } |
| |
| /* |
| * Re-sum ARC stats after the first round of evictions. |
| */ |
| asize = aggsum_value(&arc_size); |
| ameta = aggsum_value(&arc_meta_used); |
| |
| |
| /* |
| * Adjust MFU size |
| * |
| * Now that we've tried to evict enough from the MRU to get its |
| * size back to arc_p, if we're still above the target cache |
| * size, we evict the rest from the MFU. |
| */ |
| target = asize - arc_c; |
| |
| if (arc_adjust_type(arc_mfu) == ARC_BUFC_METADATA && |
| ameta > arc_meta_min) { |
| bytes = arc_adjust_impl(arc_mfu, 0, target, ARC_BUFC_METADATA); |
| total_evicted += bytes; |
| |
| /* |
| * If we couldn't evict our target number of bytes from |
| * metadata, we try to get the rest from data. |
| */ |
| target -= bytes; |
| |
| total_evicted += |
| arc_adjust_impl(arc_mfu, 0, target, ARC_BUFC_DATA); |
| } else { |
| bytes = arc_adjust_impl(arc_mfu, 0, target, ARC_BUFC_DATA); |
| total_evicted += bytes; |
| |
| /* |
| * If we couldn't evict our target number of bytes from |
| * data, we try to get the rest from data. |
| */ |
| target -= bytes; |
| |
| total_evicted += |
| arc_adjust_impl(arc_mfu, 0, target, ARC_BUFC_METADATA); |
| } |
| |
| /* |
| * Adjust ghost lists |
| * |
| * In addition to the above, the ARC also defines target values |
| * for the ghost lists. The sum of the mru list and mru ghost |
| * list should never exceed the target size of the cache, and |
| * the sum of the mru list, mfu list, mru ghost list, and mfu |
| * ghost list should never exceed twice the target size of the |
| * cache. The following logic enforces these limits on the ghost |
| * caches, and evicts from them as needed. |
| */ |
| target = zfs_refcount_count(&arc_mru->arcs_size) + |
| zfs_refcount_count(&arc_mru_ghost->arcs_size) - arc_c; |
| |
| bytes = arc_adjust_impl(arc_mru_ghost, 0, target, ARC_BUFC_DATA); |
| total_evicted += bytes; |
| |
| target -= bytes; |
| |
| total_evicted += |
| arc_adjust_impl(arc_mru_ghost, 0, target, ARC_BUFC_METADATA); |
| |
| /* |
| * We assume the sum of the mru list and mfu list is less than |
| * or equal to arc_c (we enforced this above), which means we |
| * can use the simpler of the two equations below: |
| * |
| * mru + mfu + mru ghost + mfu ghost <= 2 * arc_c |
| * mru ghost + mfu ghost <= arc_c |
| */ |
| target = zfs_refcount_count(&arc_mru_ghost->arcs_size) + |
| zfs_refcount_count(&arc_mfu_ghost->arcs_size) - arc_c; |
| |
| bytes = arc_adjust_impl(arc_mfu_ghost, 0, target, ARC_BUFC_DATA); |
| total_evicted += bytes; |
| |
| target -= bytes; |
| |
| total_evicted += |
| arc_adjust_impl(arc_mfu_ghost, 0, target, ARC_BUFC_METADATA); |
| |
| return (total_evicted); |
| } |
| |
| void |
| arc_flush(spa_t *spa, boolean_t retry) |
| { |
| uint64_t guid = 0; |
| |
| /* |
| * If retry is B_TRUE, a spa must not be specified since we have |
| * no good way to determine if all of a spa's buffers have been |
| * evicted from an arc state. |
| */ |
| ASSERT(!retry || spa == 0); |
| |
| if (spa != NULL) |
| guid = spa_load_guid(spa); |
| |
| (void) arc_flush_state(arc_mru, guid, ARC_BUFC_DATA, retry); |
| (void) arc_flush_state(arc_mru, guid, ARC_BUFC_METADATA, retry); |
| |
| (void) arc_flush_state(arc_mfu, guid, ARC_BUFC_DATA, retry); |
| (void) arc_flush_state(arc_mfu, guid, ARC_BUFC_METADATA, retry); |
| |
| (void) arc_flush_state(arc_mru_ghost, guid, ARC_BUFC_DATA, retry); |
| (void) arc_flush_state(arc_mru_ghost, guid, ARC_BUFC_METADATA, retry); |
| |
| (void) arc_flush_state(arc_mfu_ghost, guid, ARC_BUFC_DATA, retry); |
| (void) arc_flush_state(arc_mfu_ghost, guid, ARC_BUFC_METADATA, retry); |
| } |
| |
| static void |
| arc_reduce_target_size(int64_t to_free) |
| { |
| uint64_t asize = aggsum_value(&arc_size); |
| uint64_t c = arc_c; |
| |
| if (c > to_free && c - to_free > arc_c_min) { |
| arc_c = c - to_free; |
| atomic_add_64(&arc_p, -(arc_p >> arc_shrink_shift)); |
| if (arc_p > arc_c) |
| arc_p = (arc_c >> 1); |
| ASSERT(arc_c >= arc_c_min); |
| ASSERT((int64_t)arc_p >= 0); |
| } else { |
| arc_c = arc_c_min; |
| } |
| |
| if (asize > arc_c) { |
| /* See comment in arc_adjust_cb_check() on why lock+flag */ |
| mutex_enter(&arc_adjust_lock); |
| arc_adjust_needed = B_TRUE; |
| mutex_exit(&arc_adjust_lock); |
| zthr_wakeup(arc_adjust_zthr); |
| } |
| } |
| /* |
| * Return maximum amount of memory that we could possibly use. Reduced |
| * to half of all memory in user space which is primarily used for testing. |
| */ |
| static uint64_t |
| arc_all_memory(void) |
| { |
| #ifdef _KERNEL |
| #ifdef CONFIG_HIGHMEM |
| return (ptob(zfs_totalram_pages - zfs_totalhigh_pages)); |
| #else |
| return (ptob(zfs_totalram_pages)); |
| #endif /* CONFIG_HIGHMEM */ |
| #else |
| return (ptob(physmem) / 2); |
| #endif /* _KERNEL */ |
| } |
| |
| /* |
| * Return the amount of memory that is considered free. In user space |
| * which is primarily used for testing we pretend that free memory ranges |
| * from 0-20% of all memory. |
| */ |
| static uint64_t |
| arc_free_memory(void) |
| { |
| #ifdef _KERNEL |
| #ifdef CONFIG_HIGHMEM |
| struct sysinfo si; |
| si_meminfo(&si); |
| return (ptob(si.freeram - si.freehigh)); |
| #else |
| return (ptob(nr_free_pages() + |
| nr_inactive_file_pages() + |
| nr_inactive_anon_pages())); |
| |
| #endif /* CONFIG_HIGHMEM */ |
| #else |
| return (spa_get_random(arc_all_memory() * 20 / 100)); |
| #endif /* _KERNEL */ |
| } |
| |
| typedef enum free_memory_reason_t { |
| FMR_UNKNOWN, |
| FMR_NEEDFREE, |
| FMR_LOTSFREE, |
| FMR_SWAPFS_MINFREE, |
| FMR_PAGES_PP_MAXIMUM, |
| FMR_HEAP_ARENA, |
| FMR_ZIO_ARENA, |
| } free_memory_reason_t; |
| |
| int64_t last_free_memory; |
| free_memory_reason_t last_free_reason; |
| |
| #ifdef _KERNEL |
| /* |
| * Additional reserve of pages for pp_reserve. |
| */ |
| int64_t arc_pages_pp_reserve = 64; |
| |
| /* |
| * Additional reserve of pages for swapfs. |
| */ |
| int64_t arc_swapfs_reserve = 64; |
| #endif /* _KERNEL */ |
| |
| /* |
| * Return the amount of memory that can be consumed before reclaim will be |
| * needed. Positive if there is sufficient free memory, negative indicates |
| * the amount of memory that needs to be freed up. |
| */ |
| static int64_t |
| arc_available_memory(void) |
| { |
| int64_t lowest = INT64_MAX; |
| free_memory_reason_t r = FMR_UNKNOWN; |
| #ifdef _KERNEL |
| int64_t n; |
| #ifdef __linux__ |
| #ifdef freemem |
| #undef freemem |
| #endif |
| pgcnt_t needfree = btop(arc_need_free); |
| pgcnt_t lotsfree = btop(arc_sys_free); |
| pgcnt_t desfree = 0; |
| pgcnt_t freemem = btop(arc_free_memory()); |
| #endif |
| |
| if (needfree > 0) { |
| n = PAGESIZE * (-needfree); |
| if (n < lowest) { |
| lowest = n; |
| r = FMR_NEEDFREE; |
| } |
| } |
| |
| /* |
| * check that we're out of range of the pageout scanner. It starts to |
| * schedule paging if freemem is less than lotsfree and needfree. |
| * lotsfree is the high-water mark for pageout, and needfree is the |
| * number of needed free pages. We add extra pages here to make sure |
| * the scanner doesn't start up while we're freeing memory. |
| */ |
| n = PAGESIZE * (freemem - lotsfree - needfree - desfree); |
| if (n < lowest) { |
| lowest = n; |
| r = FMR_LOTSFREE; |
| } |
| |
| #ifndef __linux__ |
| /* |
| * check to make sure that swapfs has enough space so that anon |
| * reservations can still succeed. anon_resvmem() checks that the |
| * availrmem is greater than swapfs_minfree, and the number of reserved |
| * swap pages. We also add a bit of extra here just to prevent |
| * circumstances from getting really dire. |
| */ |
| n = PAGESIZE * (availrmem - swapfs_minfree - swapfs_reserve - |
| desfree - arc_swapfs_reserve); |
| if (n < lowest) { |
| lowest = n; |
| r = FMR_SWAPFS_MINFREE; |
| } |
| |
| /* |
| * Check that we have enough availrmem that memory locking (e.g., via |
| * mlock(3C) or memcntl(2)) can still succeed. (pages_pp_maximum |
| * stores the number of pages that cannot be locked; when availrmem |
| * drops below pages_pp_maximum, page locking mechanisms such as |
| * page_pp_lock() will fail.) |
| */ |
| n = PAGESIZE * (availrmem - pages_pp_maximum - |
| arc_pages_pp_reserve); |
| if (n < lowest) { |
| lowest = n; |
| r = FMR_PAGES_PP_MAXIMUM; |
| } |
| #endif |
| |
| #if defined(_ILP32) |
| /* |
| * If we're on a 32-bit platform, it's possible that we'll exhaust the |
| * kernel heap space before we ever run out of available physical |
| * memory. Most checks of the size of the heap_area compare against |
| * tune.t_minarmem, which is the minimum available real memory that we |
| * can have in the system. However, this is generally fixed at 25 pages |
| * which is so low that it's useless. In this comparison, we seek to |
| * calculate the total heap-size, and reclaim if more than 3/4ths of the |
| * heap is allocated. (Or, in the calculation, if less than 1/4th is |
| * free) |
| */ |
| n = vmem_size(heap_arena, VMEM_FREE) - |
| (vmem_size(heap_arena, VMEM_FREE | VMEM_ALLOC) >> 2); |
| if (n < lowest) { |
| lowest = n; |
| r = FMR_HEAP_ARENA; |
| } |
| #endif |
| |
| /* |
| * If zio data pages are being allocated out of a separate heap segment, |
| * then enforce that the size of available vmem for this arena remains |
| * above about 1/4th (1/(2^arc_zio_arena_free_shift)) free. |
| * |
| * Note that reducing the arc_zio_arena_free_shift keeps more virtual |
| * memory (in the zio_arena) free, which can avoid memory |
| * fragmentation issues. |
| */ |
| if (zio_arena != NULL) { |
| n = (int64_t)vmem_size(zio_arena, VMEM_FREE) - |
| (vmem_size(zio_arena, VMEM_ALLOC) >> |
| arc_zio_arena_free_shift); |
| if (n < lowest) { |
| lowest = n; |
| r = FMR_ZIO_ARENA; |
| } |
| } |
| #else /* _KERNEL */ |
| /* Every 100 calls, free a small amount */ |
| if (spa_get_random(100) == 0) |
| lowest = -1024; |
| #endif /* _KERNEL */ |
| |
| last_free_memory = lowest; |
| last_free_reason = r; |
| |
| return (lowest); |
| } |
| |
| /* |
| * Determine if the system is under memory pressure and is asking |
| * to reclaim memory. A return value of B_TRUE indicates that the system |
| * is under memory pressure and that the arc should adjust accordingly. |
| */ |
| static boolean_t |
| arc_reclaim_needed(void) |
| { |
| return (arc_available_memory() < 0); |
| } |
| |
| static void |
| arc_kmem_reap_soon(void) |
| { |
| size_t i; |
| kmem_cache_t *prev_cache = NULL; |
| kmem_cache_t *prev_data_cache = NULL; |
| extern kmem_cache_t *zio_buf_cache[]; |
| extern kmem_cache_t *zio_data_buf_cache[]; |
| extern kmem_cache_t *range_seg_cache; |
| |
| #ifdef _KERNEL |
| if ((aggsum_compare(&arc_meta_used, arc_meta_limit) >= 0) && |
| zfs_arc_meta_prune) { |
| /* |
| * We are exceeding our meta-data cache limit. |
| * Prune some entries to release holds on meta-data. |
| */ |
| arc_prune_async(zfs_arc_meta_prune); |
| } |
| #if defined(_ILP32) |
| /* |
| * Reclaim unused memory from all kmem caches. |
| */ |
| kmem_reap(); |
| #endif |
| #endif |
| |
| for (i = 0; i < SPA_MAXBLOCKSIZE >> SPA_MINBLOCKSHIFT; i++) { |
| #if defined(_ILP32) |
| /* reach upper limit of cache size on 32-bit */ |
| if (zio_buf_cache[i] == NULL) |
| break; |
| #endif |
| if (zio_buf_cache[i] != prev_cache) { |
| prev_cache = zio_buf_cache[i]; |
| kmem_cache_reap_now(zio_buf_cache[i]); |
| } |
| if (zio_data_buf_cache[i] != prev_data_cache) { |
| prev_data_cache = zio_data_buf_cache[i]; |
| kmem_cache_reap_now(zio_data_buf_cache[i]); |
| } |
| } |
| kmem_cache_reap_now(buf_cache); |
| kmem_cache_reap_now(hdr_full_cache); |
| kmem_cache_reap_now(hdr_l2only_cache); |
| kmem_cache_reap_now(range_seg_cache); |
| |
| if (zio_arena != NULL) { |
| /* |
| * Ask the vmem arena to reclaim unused memory from its |
| * quantum caches. |
| */ |
| vmem_qcache_reap(zio_arena); |
| } |
| } |
| |
| /* ARGSUSED */ |
| static boolean_t |
| arc_adjust_cb_check(void *arg, zthr_t *zthr) |
| { |
| if (!arc_initialized) |
| return (B_FALSE); |
| |
| /* |
| * This is necessary so that any changes which may have been made to |
| * many of the zfs_arc_* module parameters will be propagated to |
| * their actual internal variable counterparts. Without this, |
| * changing those module params at runtime would have no effect. |
| */ |
| arc_tuning_update(); |
| |
| /* |
| * This is necessary in order to keep the kstat information |
| * up to date for tools that display kstat data such as the |
| * mdb ::arc dcmd and the Linux crash utility. These tools |
| * typically do not call kstat's update function, but simply |
| * dump out stats from the most recent update. Without |
| * this call, these commands may show stale stats for the |
| * anon, mru, mru_ghost, mfu, and mfu_ghost lists. Even |
| * with this change, the data might be up to 1 second |
| * out of date(the arc_adjust_zthr has a maximum sleep |
| * time of 1 second); but that should suffice. The |
| * arc_state_t structures can be queried directly if more |
| * accurate information is needed. |
| */ |
| if (arc_ksp != NULL) |
| arc_ksp->ks_update(arc_ksp, KSTAT_READ); |
| |
| /* |
| * We have to rely on arc_get_data_impl() to tell us when to adjust, |
| * rather than checking if we are overflowing here, so that we are |
| * sure to not leave arc_get_data_impl() waiting on |
| * arc_adjust_waiters_cv. If we have become "not overflowing" since |
| * arc_get_data_impl() checked, we need to wake it up. We could |
| * broadcast the CV here, but arc_get_data_impl() may have not yet |
| * gone to sleep. We would need to use a mutex to ensure that this |
| * function doesn't broadcast until arc_get_data_impl() has gone to |
| * sleep (e.g. the arc_adjust_lock). However, the lock ordering of |
| * such a lock would necessarily be incorrect with respect to the |
| * zthr_lock, which is held before this function is called, and is |
| * held by arc_get_data_impl() when it calls zthr_wakeup(). |
| */ |
| return (arc_adjust_needed); |
| } |
| |
| /* |
| * Keep arc_size under arc_c by running arc_adjust which evicts data |
| * from the ARC. |
| */ |
| /* ARGSUSED */ |
| static void |
| arc_adjust_cb(void *arg, zthr_t *zthr) |
| { |
| uint64_t evicted = 0; |
| fstrans_cookie_t cookie = spl_fstrans_mark(); |
| |
| /* Evict from cache */ |
| evicted = arc_adjust(); |
| |
| /* |
| * If evicted is zero, we couldn't evict anything |
| * via arc_adjust(). This could be due to hash lock |
| * collisions, but more likely due to the majority of |
| * arc buffers being unevictable. Therefore, even if |
| * arc_size is above arc_c, another pass is unlikely to |
| * be helpful and could potentially cause us to enter an |
| * infinite loop. Additionally, zthr_iscancelled() is |
| * checked here so that if the arc is shutting down, the |
| * broadcast will wake any remaining arc adjust waiters. |
| */ |
| mutex_enter(&arc_adjust_lock); |
| arc_adjust_needed = !zthr_iscancelled(arc_adjust_zthr) && |
| evicted > 0 && aggsum_compare(&arc_size, arc_c) > 0; |
| if (!arc_adjust_needed) { |
| /* |
| * We're either no longer overflowing, or we |
| * can't evict anything more, so we should wake |
| * arc_get_data_impl() sooner. |
| */ |
| cv_broadcast(&arc_adjust_waiters_cv); |
| arc_need_free = 0; |
| } |
| mutex_exit(&arc_adjust_lock); |
| spl_fstrans_unmark(cookie); |
| } |
| |
| /* ARGSUSED */ |
| static boolean_t |
| arc_reap_cb_check(void *arg, zthr_t *zthr) |
| { |
| if (!arc_initialized) |
| return (B_FALSE); |
| |
| int64_t free_memory = arc_available_memory(); |
| |
| /* |
| * If a kmem reap is already active, don't schedule more. We must |
| * check for this because kmem_cache_reap_soon() won't actually |
| * block on the cache being reaped (this is to prevent callers from |
| * becoming implicitly blocked by a system-wide kmem reap -- which, |
| * on a system with many, many full magazines, can take minutes). |
| */ |
| if (!kmem_cache_reap_active() && free_memory < 0) { |
| |
| arc_no_grow = B_TRUE; |
| arc_warm = B_TRUE; |
| /* |
| * Wait at least zfs_grow_retry (default 5) seconds |
| * before considering growing. |
| */ |
| arc_growtime = gethrtime() + SEC2NSEC(arc_grow_retry); |
| return (B_TRUE); |
| } else if (free_memory < arc_c >> arc_no_grow_shift) { |
| arc_no_grow = B_TRUE; |
| } else if (gethrtime() >= arc_growtime) { |
| arc_no_grow = B_FALSE; |
| } |
| |
| return (B_FALSE); |
| } |
| |
| /* |
| * Keep enough free memory in the system by reaping the ARC's kmem |
| * caches. To cause more slabs to be reapable, we may reduce the |
| * target size of the cache (arc_c), causing the arc_adjust_cb() |
| * to free more buffers. |
| */ |
| /* ARGSUSED */ |
| static void |
| arc_reap_cb(void *arg, zthr_t *zthr) |
| { |
| int64_t free_memory; |
| fstrans_cookie_t cookie = spl_fstrans_mark(); |
| |
| /* |
| * Kick off asynchronous kmem_reap()'s of all our caches. |
| */ |
| arc_kmem_reap_soon(); |
| |
| /* |
| * Wait at least arc_kmem_cache_reap_retry_ms between |
| * arc_kmem_reap_soon() calls. Without this check it is possible to |
| * end up in a situation where we spend lots of time reaping |
| * caches, while we're near arc_c_min. Waiting here also gives the |
| * subsequent free memory check a chance of finding that the |
| * asynchronous reap has already freed enough memory, and we don't |
| * need to call arc_reduce_target_size(). |
| */ |
| delay((hz * arc_kmem_cache_reap_retry_ms + 999) / 1000); |
| |
| /* |
| * Reduce the target size as needed to maintain the amount of free |
| * memory in the system at a fraction of the arc_size (1/128th by |
| * default). If oversubscribed (free_memory < 0) then reduce the |
| * target arc_size by the deficit amount plus the fractional |
| * amount. If free memory is positive but less then the fractional |
| * amount, reduce by what is needed to hit the fractional amount. |
| */ |
| free_memory = arc_available_memory(); |
| |
| int64_t to_free = |
| (arc_c >> arc_shrink_shift) - free_memory; |
| if (to_free > 0) { |
| #ifdef _KERNEL |
| to_free = MAX(to_free, arc_need_free); |
| #endif |
| arc_reduce_target_size(to_free); |
| } |
| spl_fstrans_unmark(cookie); |
| } |
| |
| #ifdef _KERNEL |
| /* |
| * Determine the amount of memory eligible for eviction contained in the |
| * ARC. All clean data reported by the ghost lists can always be safely |
| * evicted. Due to arc_c_min, the same does not hold for all clean data |
| * contained by the regular mru and mfu lists. |
| * |
| * In the case of the regular mru and mfu lists, we need to report as |
| * much clean data as possible, such that evicting that same reported |
| * data will not bring arc_size below arc_c_min. Thus, in certain |
| * circumstances, the total amount of clean data in the mru and mfu |
| * lists might not actually be evictable. |
| * |
| * The following two distinct cases are accounted for: |
| * |
| * 1. The sum of the amount of dirty data contained by both the mru and |
| * mfu lists, plus the ARC's other accounting (e.g. the anon list), |
| * is greater than or equal to arc_c_min. |
| * (i.e. amount of dirty data >= arc_c_min) |
| * |
| * This is the easy case; all clean data contained by the mru and mfu |
| * lists is evictable. Evicting all clean data can only drop arc_size |
| * to the amount of dirty data, which is greater than arc_c_min. |
| * |
| * 2. The sum of the amount of dirty data contained by both the mru and |
| * mfu lists, plus the ARC's other accounting (e.g. the anon list), |
| * is less than arc_c_min. |
| * (i.e. arc_c_min > amount of dirty data) |
| * |
| * 2.1. arc_size is greater than or equal arc_c_min. |
| * (i.e. arc_size >= arc_c_min > amount of dirty data) |
| * |
| * In this case, not all clean data from the regular mru and mfu |
| * lists is actually evictable; we must leave enough clean data |
| * to keep arc_size above arc_c_min. Thus, the maximum amount of |
| * evictable data from the two lists combined, is exactly the |
| * difference between arc_size and arc_c_min. |
| * |
| * 2.2. arc_size is less than arc_c_min |
| * (i.e. arc_c_min > arc_size > amount of dirty data) |
| * |
| * In this case, none of the data contained in the mru and mfu |
| * lists is evictable, even if it's clean. Since arc_size is |
| * already below arc_c_min, evicting any more would only |
| * increase this negative difference. |
| */ |
| static uint64_t |
| arc_evictable_memory(void) |
| { |
| int64_t asize = aggsum_value(&arc_size); |
| uint64_t arc_clean = |
| zfs_refcount_count(&arc_mru->arcs_esize[ARC_BUFC_DATA]) + |
| zfs_refcount_count(&arc_mru->arcs_esize[ARC_BUFC_METADATA]) + |
| zfs_refcount_count(&arc_mfu->arcs_esize[ARC_BUFC_DATA]) + |
| zfs_refcount_count(&arc_mfu->arcs_esize[ARC_BUFC_METADATA]); |
| uint64_t arc_dirty = MAX((int64_t)asize - (int64_t)arc_clean, 0); |
| |
| /* |
| * Scale reported evictable memory in proportion to page cache, cap |
| * at specified min/max. |
| */ |
| uint64_t min = (ptob(nr_file_pages()) / 100) * zfs_arc_pc_percent; |
| min = MAX(arc_c_min, MIN(arc_c_max, min)); |
| |
| if (arc_dirty >= min) |
| return (arc_clean); |
| |
| return (MAX((int64_t)asize - (int64_t)min, 0)); |
| } |
| |
| /* |
| * If sc->nr_to_scan is zero, the caller is requesting a query of the |
| * number of objects which can potentially be freed. If it is nonzero, |
| * the request is to free that many objects. |
| * |
| * Linux kernels >= 3.12 have the count_objects and scan_objects callbacks |
| * in struct shrinker and also require the shrinker to return the number |
| * of objects freed. |
| * |
| * Older kernels require the shrinker to return the number of freeable |
| * objects following the freeing of nr_to_free. |
| */ |
| static spl_shrinker_t |
| __arc_shrinker_func(struct shrinker *shrink, struct shrink_control *sc) |
| { |
| int64_t pages; |
| |
| /* The arc is considered warm once reclaim has occurred */ |
| if (unlikely(arc_warm == B_FALSE)) |
| arc_warm = B_TRUE; |
| |
| /* Return the potential number of reclaimable pages */ |
| pages = btop((int64_t)arc_evictable_memory()); |
| if (sc->nr_to_scan == 0) |
| return (pages); |
| |
| /* Not allowed to perform filesystem reclaim */ |
| if (!(sc->gfp_mask & __GFP_FS)) |
| return (SHRINK_STOP); |
| |
| /* Reclaim in progress */ |
| if (mutex_tryenter(&arc_adjust_lock) == 0) { |
| ARCSTAT_INCR(arcstat_need_free, ptob(sc->nr_to_scan)); |
| return (0); |
| } |
| |
| mutex_exit(&arc_adjust_lock); |
| |
| /* |
| * Evict the requested number of pages by shrinking arc_c the |
| * requested amount. |
| */ |
| if (pages > 0) { |
| arc_reduce_target_size(ptob(sc->nr_to_scan)); |
| if (current_is_kswapd()) |
| arc_kmem_reap_soon(); |
| #ifdef HAVE_SPLIT_SHRINKER_CALLBACK |
| pages = MAX((int64_t)pages - |
| (int64_t)btop(arc_evictable_memory()), 0); |
| #else |
| pages = btop(arc_evictable_memory()); |
| #endif |
| /* |
| * We've shrunk what we can, wake up threads. |
| */ |
| cv_broadcast(&arc_adjust_waiters_cv); |
| } else |
| pages = SHRINK_STOP; |
| |
| /* |
| * When direct reclaim is observed it usually indicates a rapid |
| * increase in memory pressure. This occurs because the kswapd |
| * threads were unable to asynchronously keep enough free memory |
| * available. In this case set arc_no_grow to briefly pause arc |
| * growth to avoid compounding the memory pressure. |
| */ |
| if (current_is_kswapd()) { |
| ARCSTAT_BUMP(arcstat_memory_indirect_count); |
| } else { |
| arc_no_grow = B_TRUE; |
| arc_kmem_reap_soon(); |
| ARCSTAT_BUMP(arcstat_memory_direct_count); |
| } |
| |
| return (pages); |
| } |
| SPL_SHRINKER_CALLBACK_WRAPPER(arc_shrinker_func); |
| |
| SPL_SHRINKER_DECLARE(arc_shrinker, arc_shrinker_func, DEFAULT_SEEKS); |
| #endif /* _KERNEL */ |
| |
| /* |
| * Adapt arc info given the number of bytes we are trying to add and |
| * the state that we are coming from. This function is only called |
| * when we are adding new content to the cache. |
| */ |
| static void |
| arc_adapt(int bytes, arc_state_t *state) |
| { |
| int mult; |
| uint64_t arc_p_min = (arc_c >> arc_p_min_shift); |
| int64_t mrug_size = zfs_refcount_count(&arc_mru_ghost->arcs_size); |
| int64_t mfug_size = zfs_refcount_count(&arc_mfu_ghost->arcs_size); |
| |
| if (state == arc_l2c_only) |
| return; |
| |
| ASSERT(bytes > 0); |
| /* |
| * Adapt the target size of the MRU list: |
| * - if we just hit in the MRU ghost list, then increase |
| * the target size of the MRU list. |
| * - if we just hit in the MFU ghost list, then increase |
| * the target size of the MFU list by decreasing the |
| * target size of the MRU list. |
| */ |
| if (state == arc_mru_ghost) { |
| mult = (mrug_size >= mfug_size) ? 1 : (mfug_size / mrug_size); |
| if (!zfs_arc_p_dampener_disable) |
| mult = MIN(mult, 10); /* avoid wild arc_p adjustment */ |
| |
| arc_p = MIN(arc_c - arc_p_min, arc_p + bytes * mult); |
| } else if (state == arc_mfu_ghost) { |
| uint64_t delta; |
| |
| mult = (mfug_size >= mrug_size) ? 1 : (mrug_size / mfug_size); |
| if (!zfs_arc_p_dampener_disable) |
| mult = MIN(mult, 10); |
| |
| delta = MIN(bytes * mult, arc_p); |
| arc_p = MAX(arc_p_min, arc_p - delta); |
| } |
| ASSERT((int64_t)arc_p >= 0); |
| |
| /* |
| * Wake reap thread if we do not have any available memory |
| */ |
| if (arc_reclaim_needed()) { |
| zthr_wakeup(arc_reap_zthr); |
| return; |
| } |
| |
| if (arc_no_grow) |
| return; |
| |
| if (arc_c >= arc_c_max) |
| return; |
| |
| /* |
| * If we're within (2 * maxblocksize) bytes of the target |
| * cache size, increment the target cache size |
| */ |
| ASSERT3U(arc_c, >=, 2ULL << SPA_MAXBLOCKSHIFT); |
| if (aggsum_compare(&arc_size, arc_c - (2ULL << SPA_MAXBLOCKSHIFT)) >= |
| 0) { |
| atomic_add_64(&arc_c, (int64_t)bytes); |
| if (arc_c > arc_c_max) |
| arc_c = arc_c_max; |
| else if (state == arc_anon) |
| atomic_add_64(&arc_p, (int64_t)bytes); |
| if (arc_p > arc_c) |
| arc_p = arc_c; |
| } |
| ASSERT((int64_t)arc_p >= 0); |
| } |
| |
| /* |
| * Check if arc_size has grown past our upper threshold, determined by |
| * zfs_arc_overflow_shift. |
| */ |
| static boolean_t |
| arc_is_overflowing(void) |
| { |
| /* Always allow at least one block of overflow */ |
| int64_t overflow = MAX(SPA_MAXBLOCKSIZE, |
| arc_c >> zfs_arc_overflow_shift); |
| |
| /* |
| * We just compare the lower bound here for performance reasons. Our |
| * primary goals are to make sure that the arc never grows without |
| * bound, and that it can reach its maximum size. This check |
| * accomplishes both goals. The maximum amount we could run over by is |
| * 2 * aggsum_borrow_multiplier * NUM_CPUS * the average size of a block |
| * in the ARC. In practice, that's in the tens of MB, which is low |
| * enough to be safe. |
| */ |
| return (aggsum_lower_bound(&arc_size) >= (int64_t)arc_c + overflow); |
| } |
| |
| static abd_t * |
| arc_get_data_abd(arc_buf_hdr_t *hdr, uint64_t size, void *tag, |
| boolean_t do_adapt) |
| { |
| arc_buf_contents_t type = arc_buf_type(hdr); |
| |
| arc_get_data_impl(hdr, size, tag, do_adapt); |
| if (type == ARC_BUFC_METADATA) { |
| return (abd_alloc(size, B_TRUE)); |
| } else { |
| ASSERT(type == ARC_BUFC_DATA); |
| return (abd_alloc(size, B_FALSE)); |
| } |
| } |
| |
| static void * |
| arc_get_data_buf(arc_buf_hdr_t *hdr, uint64_t size, void *tag) |
| { |
| arc_buf_contents_t type = arc_buf_type(hdr); |
| |
| arc_get_data_impl(hdr, size, tag, B_TRUE); |
| if (type == ARC_BUFC_METADATA) { |
| return (zio_buf_alloc(size)); |
| } else { |
| ASSERT(type == ARC_BUFC_DATA); |
| return (zio_data_buf_alloc(size)); |
| } |
| } |
| |
| /* |
| * Allocate a block and return it to the caller. If we are hitting the |
| * hard limit for the cache size, we must sleep, waiting for the eviction |
| * thread to catch up. If we're past the target size but below the hard |
| * limit, we'll only signal the reclaim thread and continue on. |
| */ |
| static void |
| arc_get_data_impl(arc_buf_hdr_t *hdr, uint64_t size, void *tag, |
| boolean_t do_adapt) |
| { |
| arc_state_t *state = hdr->b_l1hdr.b_state; |
| arc_buf_contents_t type = arc_buf_type(hdr); |
| |
| if (do_adapt) |
| arc_adapt(size, state); |
| |
| /* |
| * If arc_size is currently overflowing, and has grown past our |
| * upper limit, we must be adding data faster than the evict |
| * thread can evict. Thus, to ensure we don't compound the |
| * problem by adding more data and forcing arc_size to grow even |
| * further past it's target size, we halt and wait for the |
| * eviction thread to catch up. |
| * |
| * It's also possible that the reclaim thread is unable to evict |
| * enough buffers to get arc_size below the overflow limit (e.g. |
| * due to buffers being un-evictable, or hash lock collisions). |
| * In this case, we want to proceed regardless if we're |
| * overflowing; thus we don't use a while loop here. |
| */ |
| if (arc_is_overflowing()) { |
| mutex_enter(&arc_adjust_lock); |
| |
| /* |
| * Now that we've acquired the lock, we may no longer be |
| * over the overflow limit, lets check. |
| * |
| * We're ignoring the case of spurious wake ups. If that |
| * were to happen, it'd let this thread consume an ARC |
| * buffer before it should have (i.e. before we're under |
| * the overflow limit and were signalled by the reclaim |
| * thread). As long as that is a rare occurrence, it |
| * shouldn't cause any harm. |
| */ |
| if (arc_is_overflowing()) { |
| arc_adjust_needed = B_TRUE; |
| zthr_wakeup(arc_adjust_zthr); |
| (void) cv_wait(&arc_adjust_waiters_cv, |
| &arc_adjust_lock); |
| } |
| mutex_exit(&arc_adjust_lock); |
| } |
| |
| VERIFY3U(hdr->b_type, ==, type); |
| if (type == ARC_BUFC_METADATA) { |
| arc_space_consume(size, ARC_SPACE_META); |
| } else { |
| arc_space_consume(size, ARC_SPACE_DATA); |
| } |
| |
| /* |
| * Update the state size. Note that ghost states have a |
| * "ghost size" and so don't need to be updated. |
| */ |
| if (!GHOST_STATE(state)) { |
| |
| (void) zfs_refcount_add_many(&state->arcs_size, size, tag); |
| |
| /* |
| * If this is reached via arc_read, the link is |
| * protected by the hash lock. If reached via |
| * arc_buf_alloc, the header should not be accessed by |
| * any other thread. And, if reached via arc_read_done, |
| * the hash lock will protect it if it's found in the |
| * hash table; otherwise no other thread should be |
| * trying to [add|remove]_reference it. |
| */ |
| if (multilist_link_active(&hdr->b_l1hdr.b_arc_node)) { |
| ASSERT(zfs_refcount_is_zero(&hdr->b_l1hdr.b_refcnt)); |
| (void) zfs_refcount_add_many(&state->arcs_esize[type], |
| size, tag); |
| } |
| |
| /* |
| * If we are growing the cache, and we are adding anonymous |
| * data, and we have outgrown arc_p, update arc_p |
| */ |
| if (aggsum_upper_bound(&arc_size) < arc_c && |
| hdr->b_l1hdr.b_state == arc_anon && |
| (zfs_refcount_count(&arc_anon->arcs_size) + |
| zfs_refcount_count(&arc_mru->arcs_size) > arc_p)) |
| arc_p = MIN(arc_c, arc_p + size); |
| } |
| } |
| |
| static void |
| arc_free_data_abd(arc_buf_hdr_t *hdr, abd_t *abd, uint64_t size, void *tag) |
| { |
| arc_free_data_impl(hdr, size, tag); |
| abd_free(abd); |
| } |
| |
| static void |
| arc_free_data_buf(arc_buf_hdr_t *hdr, void *buf, uint64_t size, void *tag) |
| { |
| arc_buf_contents_t type = arc_buf_type(hdr); |
| |
| arc_free_data_impl(hdr, size, tag); |
| if (type == ARC_BUFC_METADATA) { |
| zio_buf_free(buf, size); |
| } else { |
| ASSERT(type == ARC_BUFC_DATA); |
| zio_data_buf_free(buf, size); |
| } |
| } |
| |
| /* |
| * Free the arc data buffer. |
| */ |
| static void |
| arc_free_data_impl(arc_buf_hdr_t *hdr, uint64_t size, void *tag) |
| { |
| arc_state_t *state = hdr->b_l1hdr.b_state; |
| arc_buf_contents_t type = arc_buf_type(hdr); |
| |
| /* protected by hash lock, if in the hash table */ |
| if (multilist_link_active(&hdr->b_l1hdr.b_arc_node)) { |
| ASSERT(zfs_refcount_is_zero(&hdr->b_l1hdr.b_refcnt)); |
| ASSERT(state != arc_anon && state != arc_l2c_only); |
| |
| (void) zfs_refcount_remove_many(&state->arcs_esize[type], |
| size, tag); |
| } |
| (void) zfs_refcount_remove_many(&state->arcs_size, size, tag); |
| |
| VERIFY3U(hdr->b_type, ==, type); |
| if (type == ARC_BUFC_METADATA) { |
| arc_space_return(size, ARC_SPACE_META); |
| } else { |
| ASSERT(type == ARC_BUFC_DATA); |
| arc_space_return(size, ARC_SPACE_DATA); |
| } |
| } |
| |
| /* |
| * This routine is called whenever a buffer is accessed. |
| * NOTE: the hash lock is dropped in this function. |
| */ |
| static void |
| arc_access(arc_buf_hdr_t *hdr, kmutex_t *hash_lock) |
| { |
| clock_t now; |
| |
| ASSERT(MUTEX_HELD(hash_lock)); |
| ASSERT(HDR_HAS_L1HDR(hdr)); |
| |
| if (hdr->b_l1hdr.b_state == arc_anon) { |
| /* |
| * This buffer is not in the cache, and does not |
| * appear in our "ghost" list. Add the new buffer |
| * to the MRU state. |
| */ |
| |
| ASSERT0(hdr->b_l1hdr.b_arc_access); |
| hdr->b_l1hdr.b_arc_access = ddi_get_lbolt(); |
| DTRACE_PROBE1(new_state__mru, arc_buf_hdr_t *, hdr); |
| arc_change_state(arc_mru, hdr, hash_lock); |
| |
| } else if (hdr->b_l1hdr.b_state == arc_mru) { |
| now = ddi_get_lbolt(); |
| |
| /* |
| * If this buffer is here because of a prefetch, then either: |
| * - clear the flag if this is a "referencing" read |
| * (any subsequent access will bump this into the MFU state). |
| * or |
| * - move the buffer to the head of the list if this is |
| * another prefetch (to make it less likely to be evicted). |
| */ |
| if (HDR_PREFETCH(hdr) || HDR_PRESCIENT_PREFETCH(hdr)) { |
| if (zfs_refcount_count(&hdr->b_l1hdr.b_refcnt) == 0) { |
| /* link protected by hash lock */ |
| ASSERT(multilist_link_active( |
| &hdr->b_l1hdr.b_arc_node)); |
| } else { |
| arc_hdr_clear_flags(hdr, |
| ARC_FLAG_PREFETCH | |
| ARC_FLAG_PRESCIENT_PREFETCH); |
| atomic_inc_32(&hdr->b_l1hdr.b_mru_hits); |
| ARCSTAT_BUMP(arcstat_mru_hits); |
| } |
| hdr->b_l1hdr.b_arc_access = now; |
| return; |
| } |
| |
| /* |
| * This buffer has been "accessed" only once so far, |
| * but it is still in the cache. Move it to the MFU |
| * state. |
| */ |
| if (ddi_time_after(now, hdr->b_l1hdr.b_arc_access + |
| ARC_MINTIME)) { |
| /* |
| * More than 125ms have passed since we |
| * instantiated this buffer. Move it to the |
| * most frequently used state. |
| */ |
| hdr->b_l1hdr.b_arc_access = now; |
| DTRACE_PROBE1(new_state__mfu, arc_buf_hdr_t *, hdr); |
| arc_change_state(arc_mfu, hdr, hash_lock); |
| } |
| atomic_inc_32(&hdr->b_l1hdr.b_mru_hits); |
| ARCSTAT_BUMP(arcstat_mru_hits); |
| } else if (hdr->b_l1hdr.b_state == arc_mru_ghost) { |
| arc_state_t *new_state; |
| /* |
| * This buffer has been "accessed" recently, but |
| * was evicted from the cache. Move it to the |
| * MFU state. |
| */ |
| |
| if (HDR_PREFETCH(hdr) || HDR_PRESCIENT_PREFETCH(hdr)) { |
| new_state = arc_mru; |
| if (zfs_refcount_count(&hdr->b_l1hdr.b_refcnt) > 0) { |
| arc_hdr_clear_flags(hdr, |
| ARC_FLAG_PREFETCH | |
| ARC_FLAG_PRESCIENT_PREFETCH); |
| } |
| DTRACE_PROBE1(new_state__mru, arc_buf_hdr_t *, hdr); |
| } else { |
| new_state = arc_mfu; |
| DTRACE_PROBE1(new_state__mfu, arc_buf_hdr_t *, hdr); |
| } |
| |
| hdr->b_l1hdr.b_arc_access = ddi_get_lbolt(); |
| arc_change_state(new_state, hdr, hash_lock); |
| |
| atomic_inc_32(&hdr->b_l1hdr.b_mru_ghost_hits); |
| ARCSTAT_BUMP(arcstat_mru_ghost_hits); |
| } else if (hdr->b_l1hdr.b_state == arc_mfu) { |
| /* |
| * This buffer has been accessed more than once and is |
| * still in the cache. Keep it in the MFU state. |
| * |
| * NOTE: an add_reference() that occurred when we did |
| * the arc_read() will have kicked this off the list. |
| * If it was a prefetch, we will explicitly move it to |
| * the head of the list now. |
| */ |
| |
| atomic_inc_32(&hdr->b_l1hdr.b_mfu_hits); |
| ARCSTAT_BUMP(arcstat_mfu_hits); |
| hdr->b_l1hdr.b_arc_access = ddi_get_lbolt(); |
| } else if (hdr->b_l1hdr.b_state == arc_mfu_ghost) { |
| arc_state_t *new_state = arc_mfu; |
| /* |
| * This buffer has been accessed more than once but has |
| * been evicted from the cache. Move it back to the |
| * MFU state. |
| */ |
| |
| if (HDR_PREFETCH(hdr) || HDR_PRESCIENT_PREFETCH(hdr)) { |
| /* |
| * This is a prefetch access... |
| * move this block back to the MRU state. |
| */ |
| new_state = arc_mru; |
| } |
| |
| hdr->b_l1hdr.b_arc_access = ddi_get_lbolt(); |
| DTRACE_PROBE1(new_state__mfu, arc_buf_hdr_t *, hdr); |
| arc_change_state(new_state, hdr, hash_lock); |
| |
| atomic_inc_32(&hdr->b_l1hdr.b_mfu_ghost_hits); |
| ARCSTAT_BUMP(arcstat_mfu_ghost_hits); |
| } else if (hdr->b_l1hdr.b_state == arc_l2c_only) { |
| /* |
| * This buffer is on the 2nd Level ARC. |
| */ |
| |
| hdr->b_l1hdr.b_arc_access = ddi_get_lbolt(); |
| DTRACE_PROBE1(new_state__mfu, arc_buf_hdr_t *, hdr); |
| arc_change_state(arc_mfu, hdr, hash_lock); |
| } else { |
| cmn_err(CE_PANIC, "invalid arc state 0x%p", |
| hdr->b_l1hdr.b_state); |
| } |
| } |
| |
| /* |
| * This routine is called by dbuf_hold() to update the arc_access() state |
| * which otherwise would be skipped for entries in the dbuf cache. |
| */ |
| void |
| arc_buf_access(arc_buf_t *buf) |
| { |
| mutex_enter(&buf->b_evict_lock); |
| arc_buf_hdr_t *hdr = buf->b_hdr; |
| |
| /* |
| * Avoid taking the hash_lock when possible as an optimization. |
| * The header must be checked again under the hash_lock in order |
| * to handle the case where it is concurrently being released. |
| */ |
| if (hdr->b_l1hdr.b_state == arc_anon || HDR_EMPTY(hdr)) { |
| mutex_exit(&buf->b_evict_lock); |
| return; |
| } |
| |
| kmutex_t *hash_lock = HDR_LOCK(hdr); |
| mutex_enter(hash_lock); |
| |
| if (hdr->b_l1hdr.b_state == arc_anon || HDR_EMPTY(hdr)) { |
| mutex_exit(hash_lock); |
| mutex_exit(&buf->b_evict_lock); |
| ARCSTAT_BUMP(arcstat_access_skip); |
| return; |
| } |
| |
| mutex_exit(&buf->b_evict_lock); |
| |
| ASSERT(hdr->b_l1hdr.b_state == arc_mru || |
| hdr->b_l1hdr.b_state == arc_mfu); |
| |
| DTRACE_PROBE1(arc__hit, arc_buf_hdr_t *, hdr); |
| arc_access(hdr, hash_lock); |
| mutex_exit(hash_lock); |
| |
| ARCSTAT_BUMP(arcstat_hits); |
| ARCSTAT_CONDSTAT(!HDR_PREFETCH(hdr) && !HDR_PRESCIENT_PREFETCH(hdr), |
| demand, prefetch, !HDR_ISTYPE_METADATA(hdr), data, metadata, hits); |
| } |
| |
| /* a generic arc_read_done_func_t which you can use */ |
| /* ARGSUSED */ |
| void |
| arc_bcopy_func(zio_t *zio, const zbookmark_phys_t *zb, const blkptr_t *bp, |
| arc_buf_t *buf, void *arg) |
| { |
| if (buf == NULL) |
| return; |
| |
| bcopy(buf->b_data, arg, arc_buf_size(buf)); |
| arc_buf_destroy(buf, arg); |
| } |
| |
| /* a generic arc_read_done_func_t */ |
| /* ARGSUSED */ |
| void |
| arc_getbuf_func(zio_t *zio, const zbookmark_phys_t *zb, const blkptr_t *bp, |
| arc_buf_t *buf, void *arg) |
| { |
| arc_buf_t **bufp = arg; |
| |
| if (buf == NULL) { |
| ASSERT(zio == NULL || zio->io_error != 0); |
| *bufp = NULL; |
| } else { |
| ASSERT(zio == NULL || zio->io_error == 0); |
| *bufp = buf; |
| ASSERT(buf->b_data != NULL); |
| } |
| } |
| |
| static void |
| arc_hdr_verify(arc_buf_hdr_t *hdr, blkptr_t *bp) |
| { |
| if (BP_IS_HOLE(bp) || BP_IS_EMBEDDED(bp)) { |
| ASSERT3U(HDR_GET_PSIZE(hdr), ==, 0); |
| ASSERT3U(arc_hdr_get_compress(hdr), ==, ZIO_COMPRESS_OFF); |
| } else { |
| if (HDR_COMPRESSION_ENABLED(hdr)) { |
| ASSERT3U(arc_hdr_get_compress(hdr), ==, |
| BP_GET_COMPRESS(bp)); |
| } |
| ASSERT3U(HDR_GET_LSIZE(hdr), ==, BP_GET_LSIZE(bp)); |
| ASSERT3U(HDR_GET_PSIZE(hdr), ==, BP_GET_PSIZE(bp)); |
| ASSERT3U(!!HDR_PROTECTED(hdr), ==, BP_IS_PROTECTED(bp)); |
| } |
| } |
| |
| static void |
| arc_read_done(zio_t *zio) |
| { |
| blkptr_t *bp = zio->io_bp; |
| arc_buf_hdr_t *hdr = zio->io_private; |
| kmutex_t *hash_lock = NULL; |
| arc_callback_t *callback_list; |
| arc_callback_t *acb; |
| boolean_t freeable = B_FALSE; |
| |
| /* |
| * The hdr was inserted into hash-table and removed from lists |
| * prior to starting I/O. We should find this header, since |
| * it's in the hash table, and it should be legit since it's |
| * not possible to evict it during the I/O. The only possible |
| * reason for it not to be found is if we were freed during the |
| * read. |
| */ |
| if (HDR_IN_HASH_TABLE(hdr)) { |
| arc_buf_hdr_t *found; |
| |
| ASSERT3U(hdr->b_birth, ==, BP_PHYSICAL_BIRTH(zio->io_bp)); |
| ASSERT3U(hdr->b_dva.dva_word[0], ==, |
| BP_IDENTITY(zio->io_bp)->dva_word[0]); |
| ASSERT3U(hdr->b_dva.dva_word[1], ==, |
| BP_IDENTITY(zio->io_bp)->dva_word[1]); |
| |
| found = buf_hash_find(hdr->b_spa, zio->io_bp, &hash_lock); |
| |
| ASSERT((found == hdr && |
| DVA_EQUAL(&hdr->b_dva, BP_IDENTITY(zio->io_bp))) || |
| (found == hdr && HDR_L2_READING(hdr))); |
| ASSERT3P(hash_lock, !=, NULL); |
| } |
| |
| if (BP_IS_PROTECTED(bp)) { |
| hdr->b_crypt_hdr.b_ot = BP_GET_TYPE(bp); |
| hdr->b_crypt_hdr.b_dsobj = zio->io_bookmark.zb_objset; |
| zio_crypt_decode_params_bp(bp, hdr->b_crypt_hdr.b_salt, |
| hdr->b_crypt_hdr.b_iv); |
| |
| if (BP_GET_TYPE(bp) == DMU_OT_INTENT_LOG) { |
| void *tmpbuf; |
| |
| tmpbuf = abd_borrow_buf_copy(zio->io_abd, |
| sizeof (zil_chain_t)); |
| zio_crypt_decode_mac_zil(tmpbuf, |
| hdr->b_crypt_hdr.b_mac); |
| abd_return_buf(zio->io_abd, tmpbuf, |
| sizeof (zil_chain_t)); |
| } else { |
| zio_crypt_decode_mac_bp(bp, hdr->b_crypt_hdr.b_mac); |
| } |
| } |
| |
| if (zio->io_error == 0) { |
| /* byteswap if necessary */ |
| if (BP_SHOULD_BYTESWAP(zio->io_bp)) { |
| if (BP_GET_LEVEL(zio->io_bp) > 0) { |
| hdr->b_l1hdr.b_byteswap = DMU_BSWAP_UINT64; |
| } else { |
| hdr->b_l1hdr.b_byteswap = |
| DMU_OT_BYTESWAP(BP_GET_TYPE(zio->io_bp)); |
| } |
| } else { |
| hdr->b_l1hdr.b_byteswap = DMU_BSWAP_NUMFUNCS; |
| } |
| } |
| |
| arc_hdr_clear_flags(hdr, ARC_FLAG_L2_EVICTED); |
| if (l2arc_noprefetch && HDR_PREFETCH(hdr)) |
| arc_hdr_clear_flags(hdr, ARC_FLAG_L2CACHE); |
| |
| callback_list = hdr->b_l1hdr.b_acb; |
| ASSERT3P(callback_list, !=, NULL); |
| |
| if (hash_lock && zio->io_error == 0 && |
| hdr->b_l1hdr.b_state == arc_anon) { |
| /* |
| * Only call arc_access on anonymous buffers. This is because |
| * if we've issued an I/O for an evicted buffer, we've already |
| * called arc_access (to prevent any simultaneous readers from |
| * getting confused). |
| */ |
| arc_access(hdr, hash_lock); |
| } |
| |
| /* |
| * If a read request has a callback (i.e. acb_done is not NULL), then we |
| * make a buf containing the data according to the parameters which were |
| * passed in. The implementation of arc_buf_alloc_impl() ensures that we |
| * aren't needlessly decompressing the data multiple times. |
| */ |
| int callback_cnt = 0; |
| for (acb = callback_list; acb != NULL; acb = acb->acb_next) { |
| if (!acb->acb_done) |
| continue; |
| |
| callback_cnt++; |
| |
| if (zio->io_error != 0) |
| continue; |
| |
| int error = arc_buf_alloc_impl(hdr, zio->io_spa, |
| &acb->acb_zb, acb->acb_private, acb->acb_encrypted, |
| acb->acb_compressed, acb->acb_noauth, B_TRUE, |
| &acb->acb_buf); |
| |
| /* |
| * Assert non-speculative zios didn't fail because an |
| * encryption key wasn't loaded |
| */ |
| ASSERT((zio->io_flags & ZIO_FLAG_SPECULATIVE) || |
| error != EACCES); |
| |
| /* |
| * If we failed to decrypt, report an error now (as the zio |
| * layer would have done if it had done the transforms). |
| */ |
| if (error == ECKSUM) { |
| ASSERT(BP_IS_PROTECTED(bp)); |
| error = SET_ERROR(EIO); |
| if ((zio->io_flags & ZIO_FLAG_SPECULATIVE) == 0) { |
| spa_log_error(zio->io_spa, &acb->acb_zb); |
| zfs_ereport_post(FM_EREPORT_ZFS_AUTHENTICATION, |
| zio->io_spa, NULL, &acb->acb_zb, zio, 0, 0); |
| } |
| } |
| |
| if (error != 0) { |
| /* |
| * Decompression or decryption failed. Set |
| * io_error so that when we call acb_done |
| * (below), we will indicate that the read |
| * failed. Note that in the unusual case |
| * where one callback is compressed and another |
| * uncompressed, we will mark all of them |
| * as failed, even though the uncompressed |
| * one can't actually fail. In this case, |
| * the hdr will not be anonymous, because |
| * if there are multiple callbacks, it's |
| * because multiple threads found the same |
| * arc buf in the hash table. |
| */ |
| zio->io_error = error; |
| } |
| } |
| |
| /* |
| * If there are multiple callbacks, we must have the hash lock, |
| * because the only way for multiple threads to find this hdr is |
| * in the hash table. This ensures that if there are multiple |
| * callbacks, the hdr is not anonymous. If it were anonymous, |
| * we couldn't use arc_buf_destroy() in the error case below. |
| */ |
| ASSERT(callback_cnt < 2 || hash_lock != NULL); |
| |
| hdr->b_l1hdr.b_acb = NULL; |
| arc_hdr_clear_flags(hdr, ARC_FLAG_IO_IN_PROGRESS); |
| if (callback_cnt == 0) |
| ASSERT(hdr->b_l1hdr.b_pabd != NULL || HDR_HAS_RABD(hdr)); |
| |
| ASSERT(zfs_refcount_is_zero(&hdr->b_l1hdr.b_refcnt) || |
| callback_list != NULL); |
| |
| if (zio->io_error == 0) { |
| arc_hdr_verify(hdr, zio->io_bp); |
| } else { |
| arc_hdr_set_flags(hdr, ARC_FLAG_IO_ERROR); |
| if (hdr->b_l1hdr.b_state != arc_anon) |
| arc_change_state(arc_anon, hdr, hash_lock); |
| if (HDR_IN_HASH_TABLE(hdr)) |
| buf_hash_remove(hdr); |
| freeable = zfs_refcount_is_zero(&hdr->b_l1hdr.b_refcnt); |
| } |
| |
| /* |
| * Broadcast before we drop the hash_lock to avoid the possibility |
| * that the hdr (and hence the cv) might be freed before we get to |
| * the cv_broadcast(). |
| */ |
| cv_broadcast(&hdr->b_l1hdr.b_cv); |
| |
| if (hash_lock != NULL) { |
| mutex_exit(hash_lock); |
| } else { |
| /* |
| * This block was freed while we waited for the read to |
| * complete. It has been removed from the hash table and |
| * moved to the anonymous state (so that it won't show up |
| * in the cache). |
| */ |
| ASSERT3P(hdr->b_l1hdr.b_state, ==, arc_anon); |
| freeable = zfs_refcount_is_zero(&hdr->b_l1hdr.b_refcnt); |
| } |
| |
| /* execute each callback and free its structure */ |
| while ((acb = callback_list) != NULL) { |
| if (acb->acb_done != NULL) { |
| if (zio->io_error != 0 && acb->acb_buf != NULL) { |
| /* |
| * If arc_buf_alloc_impl() fails during |
| * decompression, the buf will still be |
| * allocated, and needs to be freed here. |
| */ |
| arc_buf_destroy(acb->acb_buf, |
| acb->acb_private); |
| acb->acb_buf = NULL; |
| } |
| acb->acb_done(zio, &zio->io_bookmark, zio->io_bp, |
| acb->acb_buf, acb->acb_private); |
| } |
| |
| if (acb->acb_zio_dummy != NULL) { |
| acb->acb_zio_dummy->io_error = zio->io_error; |
| zio_nowait(acb->acb_zio_dummy); |
| } |
| |
| callback_list = acb->acb_next; |
| kmem_free(acb, sizeof (arc_callback_t)); |
| } |
| |
| if (freeable) |
| arc_hdr_destroy(hdr); |
| } |
| |
| /* |
| * "Read" the block at the specified DVA (in bp) via the |
| * cache. If the block is found in the cache, invoke the provided |
| * callback immediately and return. Note that the `zio' parameter |
| * in the callback will be NULL in this case, since no IO was |
| * required. If the block is not in the cache pass the read request |
| * on to the spa with a substitute callback function, so that the |
| * requested block will be added to the cache. |
| * |
| * If a read request arrives for a block that has a read in-progress, |
| * either wait for the in-progress read to complete (and return the |
| * results); or, if this is a read with a "done" func, add a record |
| * to the read to invoke the "done" func when the read completes, |
| * and return; or just return. |
| * |
| * arc_read_done() will invoke all the requested "done" functions |
| * for readers of this block. |
| */ |
| int |
| arc_read(zio_t *pio, spa_t *spa, const blkptr_t *bp, |
| arc_read_done_func_t *done, void *private, zio_priority_t priority, |
| int zio_flags, arc_flags_t *arc_flags, const zbookmark_phys_t *zb) |
| { |
| arc_buf_hdr_t *hdr = NULL; |
| kmutex_t *hash_lock = NULL; |
| zio_t *rzio; |
| uint64_t guid = spa_load_guid(spa); |
| boolean_t compressed_read = (zio_flags & ZIO_FLAG_RAW_COMPRESS) != 0; |
| boolean_t encrypted_read = BP_IS_ENCRYPTED(bp) && |
| (zio_flags & ZIO_FLAG_RAW_ENCRYPT) != 0; |
| boolean_t noauth_read = BP_IS_AUTHENTICATED(bp) && |
| (zio_flags & ZIO_FLAG_RAW_ENCRYPT) != 0; |
| boolean_t embedded_bp = !!BP_IS_EMBEDDED(bp); |
| int rc = 0; |
| |
| ASSERT(!embedded_bp || |
| BPE_GET_ETYPE(bp) == BP_EMBEDDED_TYPE_DATA); |
| |
| /* |
| * Normally SPL_FSTRANS will already be set since kernel threads which |
| * expect to call the DMU interfaces will set it when created. System |
| * calls are similarly handled by setting/cleaning the bit in the |
| * registered callback (module/os/.../zfs/zpl_*). |
| * |
| * External consumers such as Lustre which call the exported DMU |
| * interfaces may not have set SPL_FSTRANS. To avoid a deadlock |
| * on the hash_lock always set and clear the bit. |
| */ |
| fstrans_cookie_t cookie = spl_fstrans_mark(); |
| top: |
| if (!embedded_bp) { |
| /* |
| * Embedded BP's have no DVA and require no I/O to "read". |
| * Create an anonymous arc buf to back it. |
| */ |
| hdr = buf_hash_find(guid, bp, &hash_lock); |
| } |
| |
| /* |
| * Determine if we have an L1 cache hit or a cache miss. For simplicity |
| * we maintain encrypted data separately from compressed / uncompressed |
| * data. If the user is requesting raw encrypted data and we don't have |
| * that in the header we will read from disk to guarantee that we can |
| * get it even if the encryption keys aren't loaded. |
| */ |
| if (hdr != NULL && HDR_HAS_L1HDR(hdr) && (HDR_HAS_RABD(hdr) || |
| (hdr->b_l1hdr.b_pabd != NULL && !encrypted_read))) { |
| arc_buf_t *buf = NULL; |
| *arc_flags |= ARC_FLAG_CACHED; |
| |
| if (HDR_IO_IN_PROGRESS(hdr)) { |
| zio_t *head_zio = hdr->b_l1hdr.b_acb->acb_zio_head; |
| |
| ASSERT3P(head_zio, !=, NULL); |
| if ((hdr->b_flags & ARC_FLAG_PRIO_ASYNC_READ) && |
| priority == ZIO_PRIORITY_SYNC_READ) { |
| /* |
| * This is a sync read that needs to wait for |
| * an in-flight async read. Request that the |
| * zio have its priority upgraded. |
| */ |
| zio_change_priority(head_zio, priority); |
| DTRACE_PROBE1(arc__async__upgrade__sync, |
| arc_buf_hdr_t *, hdr); |
| ARCSTAT_BUMP(arcstat_async_upgrade_sync); |
| } |
| if (hdr->b_flags & ARC_FLAG_PREDICTIVE_PREFETCH) { |
| arc_hdr_clear_flags(hdr, |
| ARC_FLAG_PREDICTIVE_PREFETCH); |
| } |
| |
| if (*arc_flags & ARC_FLAG_WAIT) { |
| cv_wait(&hdr->b_l1hdr.b_cv, hash_lock); |
| mutex_exit(hash_lock); |
| goto top; |
| } |
| ASSERT(*arc_flags & ARC_FLAG_NOWAIT); |
| |
| if (done) { |
| arc_callback_t *acb = NULL; |
| |
| acb = kmem_zalloc(sizeof (arc_callback_t), |
| KM_SLEEP); |
| acb->acb_done = done; |
| acb->acb_private = private; |
| acb->acb_compressed = compressed_read; |
| acb->acb_encrypted = encrypted_read; |
| acb->acb_noauth = noauth_read; |
| acb->acb_zb = *zb; |
| if (pio != NULL) |
| acb->acb_zio_dummy = zio_null(pio, |
| spa, NULL, NULL, NULL, zio_flags); |
| |
| ASSERT3P(acb->acb_done, !=, NULL); |
| acb->acb_zio_head = head_zio; |
| acb->acb_next = hdr->b_l1hdr.b_acb; |
| hdr->b_l1hdr.b_acb = acb; |
| mutex_exit(hash_lock); |
| goto out; |
| } |
| mutex_exit(hash_lock); |
| goto out; |
| } |
| |
| ASSERT(hdr->b_l1hdr.b_state == arc_mru || |
| hdr->b_l1hdr.b_state == arc_mfu); |
| |
| if (done) { |
| if (hdr->b_flags & ARC_FLAG_PREDICTIVE_PREFETCH) { |
| /* |
| * This is a demand read which does not have to |
| * wait for i/o because we did a predictive |
| * prefetch i/o for it, which has completed. |
| */ |
| DTRACE_PROBE1( |
| arc__demand__hit__predictive__prefetch, |
| arc_buf_hdr_t *, hdr); |
| ARCSTAT_BUMP( |
| arcstat_demand_hit_predictive_prefetch); |
| arc_hdr_clear_flags(hdr, |
| ARC_FLAG_PREDICTIVE_PREFETCH); |
| } |
| |
| if (hdr->b_flags & ARC_FLAG_PRESCIENT_PREFETCH) { |
| ARCSTAT_BUMP( |
| arcstat_demand_hit_prescient_prefetch); |
| arc_hdr_clear_flags(hdr, |
| ARC_FLAG_PRESCIENT_PREFETCH); |
| } |
| |
| ASSERT(!embedded_bp || !BP_IS_HOLE(bp)); |
| |
| /* Get a buf with the desired data in it. */ |
| rc = arc_buf_alloc_impl(hdr, spa, zb, private, |
| encrypted_read, compressed_read, noauth_read, |
| B_TRUE, &buf); |
| if (rc == ECKSUM) { |
| /* |
| * Convert authentication and decryption errors |
| * to EIO (and generate an ereport if needed) |
| * before leaving the ARC. |
| */ |
| rc = SET_ERROR(EIO); |
| if ((zio_flags & ZIO_FLAG_SPECULATIVE) == 0) { |
| spa_log_error(spa, zb); |
| zfs_ereport_post( |
| FM_EREPORT_ZFS_AUTHENTICATION, |
| spa, NULL, zb, NULL, 0, 0); |
| } |
| } |
| if (rc != 0) { |
| (void) remove_reference(hdr, hash_lock, |
| private); |
| arc_buf_destroy_impl(buf); |
| buf = NULL; |
| } |
| |
| /* assert any errors weren't due to unloaded keys */ |
| ASSERT((zio_flags & ZIO_FLAG_SPECULATIVE) || |
| rc != EACCES); |
| } else if (*arc_flags & ARC_FLAG_PREFETCH && |
| zfs_refcount_count(&hdr->b_l1hdr.b_refcnt) == 0) { |
| arc_hdr_set_flags(hdr, ARC_FLAG_PREFETCH); |
| } |
| DTRACE_PROBE1(arc__hit, arc_buf_hdr_t *, hdr); |
| arc_access(hdr, hash_lock); |
| if (*arc_flags & ARC_FLAG_PRESCIENT_PREFETCH) |
| arc_hdr_set_flags(hdr, ARC_FLAG_PRESCIENT_PREFETCH); |
| if (*arc_flags & ARC_FLAG_L2CACHE) |
| arc_hdr_set_flags(hdr, ARC_FLAG_L2CACHE); |
| mutex_exit(hash_lock); |
| ARCSTAT_BUMP(arcstat_hits); |
| ARCSTAT_CONDSTAT(!HDR_PREFETCH(hdr), |
| demand, prefetch, !HDR_ISTYPE_METADATA(hdr), |
| data, metadata, hits); |
| |
| if (done) |
| done(NULL, zb, bp, buf, private); |
| } else { |
| uint64_t lsize = BP_GET_LSIZE(bp); |
| uint64_t psize = BP_GET_PSIZE(bp); |
| arc_callback_t *acb; |
| vdev_t *vd = NULL; |
| uint64_t addr = 0; |
| boolean_t devw = B_FALSE; |
| uint64_t size; |
| abd_t *hdr_abd; |
| int alloc_flags = encrypted_read ? ARC_HDR_ALLOC_RDATA : 0; |
| |
| /* |
| * Gracefully handle a damaged logical block size as a |
| * checksum error. |
| */ |
| if (lsize > spa_maxblocksize(spa)) { |
| rc = SET_ERROR(ECKSUM); |
| goto out; |
| } |
| |
| if (hdr == NULL) { |
| /* |
| * This block is not in the cache or it has |
| * embedded data. |
| */ |
| arc_buf_hdr_t *exists = NULL; |
| arc_buf_contents_t type = BP_GET_BUFC_TYPE(bp); |
| hdr = arc_hdr_alloc(spa_load_guid(spa), psize, lsize, |
| BP_IS_PROTECTED(bp), BP_GET_COMPRESS(bp), type, |
| encrypted_read); |
| |
| if (!embedded_bp) { |
| hdr->b_dva = *BP_IDENTITY(bp); |
| hdr->b_birth = BP_PHYSICAL_BIRTH(bp); |
| exists = buf_hash_insert(hdr, &hash_lock); |
| } |
| if (exists != NULL) { |
| /* somebody beat us to the hash insert */ |
| mutex_exit(hash_lock); |
| buf_discard_identity(hdr); |
| arc_hdr_destroy(hdr); |
| goto top; /* restart the IO request */ |
| } |
| } else { |
| /* |
| * This block is in the ghost cache or encrypted data |
| * was requested and we didn't have it. If it was |
| * L2-only (and thus didn't have an L1 hdr), |
| * we realloc the header to add an L1 hdr. |
| */ |
| if (!HDR_HAS_L1HDR(hdr)) { |
| hdr = arc_hdr_realloc(hdr, hdr_l2only_cache, |
| hdr_full_cache); |
| } |
| |
| if (GHOST_STATE(hdr->b_l1hdr.b_state)) { |
| ASSERT3P(hdr->b_l1hdr.b_pabd, ==, NULL); |
| ASSERT(!HDR_HAS_RABD(hdr)); |
| ASSERT(!HDR_IO_IN_PROGRESS(hdr)); |
| ASSERT0(zfs_refcount_count( |
| &hdr->b_l1hdr.b_refcnt)); |
| ASSERT3P(hdr->b_l1hdr.b_buf, ==, NULL); |
| ASSERT3P(hdr->b_l1hdr.b_freeze_cksum, ==, NULL); |
| } else if (HDR_IO_IN_PROGRESS(hdr)) { |
| /* |
| * If this header already had an IO in progress |
| * and we are performing another IO to fetch |
| * encrypted data we must wait until the first |
| * IO completes so as not to confuse |
| * arc_read_done(). This should be very rare |
| * and so the performance impact shouldn't |
| * matter. |
| */ |
| cv_wait(&hdr->b_l1hdr.b_cv, hash_lock); |
| mutex_exit(hash_lock); |
| goto top; |
| } |
| |
| /* |
| * This is a delicate dance that we play here. |
| * This hdr might be in the ghost list so we access |
| * it to move it out of the ghost list before we |
| * initiate the read. If it's a prefetch then |
| * it won't have a callback so we'll remove the |
| * reference that arc_buf_alloc_impl() created. We |
| * do this after we've called arc_access() to |
| * avoid hitting an assert in remove_reference(). |
| */ |
| arc_adapt(arc_hdr_size(hdr), hdr->b_l1hdr.b_state); |
| arc_access(hdr, hash_lock); |
| arc_hdr_alloc_abd(hdr, alloc_flags); |
| } |
| |
| if (encrypted_read) { |
| ASSERT(HDR_HAS_RABD(hdr)); |
| size = HDR_GET_PSIZE(hdr); |
| hdr_abd = hdr->b_crypt_hdr.b_rabd; |
| zio_flags |= ZIO_FLAG_RAW; |
| } else { |
| ASSERT3P(hdr->b_l1hdr.b_pabd, !=, NULL); |
| size = arc_hdr_size(hdr); |
| hdr_abd = hdr->b_l1hdr.b_pabd; |
| |
| if (arc_hdr_get_compress(hdr) != ZIO_COMPRESS_OFF) { |
| zio_flags |= ZIO_FLAG_RAW_COMPRESS; |
| } |
| |
| /* |
| * For authenticated bp's, we do not ask the ZIO layer |
| * to authenticate them since this will cause the entire |
| * IO to fail if the key isn't loaded. Instead, we |
| * defer authentication until arc_buf_fill(), which will |
| * verify the data when the key is available. |
| */ |
| if (BP_IS_AUTHENTICATED(bp)) |
| zio_flags |= ZIO_FLAG_RAW_ENCRYPT; |
| } |
| |
| if (*arc_flags & ARC_FLAG_PREFETCH && |
| zfs_refcount_is_zero(&hdr->b_l1hdr.b_refcnt)) |
| arc_hdr_set_flags(hdr, ARC_FLAG_PREFETCH); |
| if (*arc_flags & ARC_FLAG_PRESCIENT_PREFETCH) |
| arc_hdr_set_flags(hdr, ARC_FLAG_PRESCIENT_PREFETCH); |
| if (*arc_flags & ARC_FLAG_L2CACHE) |
| arc_hdr_set_flags(hdr, ARC_FLAG_L2CACHE); |
| if (BP_IS_AUTHENTICATED(bp)) |
| arc_hdr_set_flags(hdr, ARC_FLAG_NOAUTH); |
| if (BP_GET_LEVEL(bp) > 0) |
| arc_hdr_set_flags(hdr, ARC_FLAG_INDIRECT); |
| if (*arc_flags & ARC_FLAG_PREDICTIVE_PREFETCH) |
| arc_hdr_set_flags(hdr, ARC_FLAG_PREDICTIVE_PREFETCH); |
| ASSERT(!GHOST_STATE(hdr->b_l1hdr.b_state)); |
| |
| acb = kmem_zalloc(sizeof (arc_callback_t), KM_SLEEP); |
| acb->acb_done = done; |
| acb->acb_private = private; |
| acb->acb_compressed = compressed_read; |
| acb->acb_encrypted = encrypted_read; |
| acb->acb_noauth = noauth_read; |
| acb->acb_zb = *zb; |
| |
| ASSERT3P(hdr->b_l1hdr.b_acb, ==, NULL); |
| hdr->b_l1hdr.b_acb = acb; |
| arc_hdr_set_flags(hdr, ARC_FLAG_IO_IN_PROGRESS); |
| |
| if (HDR_HAS_L2HDR(hdr) && |
| (vd = hdr->b_l2hdr.b_dev->l2ad_vdev) != NULL) { |
| devw = hdr->b_l2hdr.b_dev->l2ad_writing; |
| addr = hdr->b_l2hdr.b_daddr; |
| /* |
| * Lock out L2ARC device removal. |
| */ |
| if (vdev_is_dead(vd) || |
| !spa_config_tryenter(spa, SCL_L2ARC, vd, RW_READER)) |
| vd = NULL; |
| } |
| |
| /* |
| * We count both async reads and scrub IOs as asynchronous so |
| * that both can be upgraded in the event of a cache hit while |
| * the read IO is still in-flight. |
| */ |
| if (priority == ZIO_PRIORITY_ASYNC_READ || |
| priority == ZIO_PRIORITY_SCRUB) |
| arc_hdr_set_flags(hdr, ARC_FLAG_PRIO_ASYNC_READ); |
| else |
| arc_hdr_clear_flags(hdr, ARC_FLAG_PRIO_ASYNC_READ); |
| |
| /* |
| * At this point, we have a level 1 cache miss or a blkptr |
| * with embedded data. Try again in L2ARC if possible. |
| */ |
| ASSERT3U(HDR_GET_LSIZE(hdr), ==, lsize); |
| |
| /* |
| * Skip ARC stat bump for block pointers with embedded |
| * data. The data are read from the blkptr itself via |
| * decode_embedded_bp_compressed(). |
| */ |
| if (!embedded_bp) { |
| DTRACE_PROBE4(arc__miss, arc_buf_hdr_t *, hdr, |
| blkptr_t *, bp, uint64_t, lsize, |
| zbookmark_phys_t *, zb); |
| ARCSTAT_BUMP(arcstat_misses); |
| ARCSTAT_CONDSTAT(!HDR_PREFETCH(hdr), |
| demand, prefetch, !HDR_ISTYPE_METADATA(hdr), data, |
| metadata, misses); |
| } |
| |
| if (vd != NULL && l2arc_ndev != 0 && !(l2arc_norw && devw)) { |
| /* |
| * Read from the L2ARC if the following are true: |
| * 1. The L2ARC vdev was previously cached. |
| * 2. This buffer still has L2ARC metadata. |
| * 3. This buffer isn't currently writing to the L2ARC. |
| * 4. The L2ARC entry wasn't evicted, which may |
| * also have invalidated the vdev. |
| * 5. This isn't prefetch and l2arc_noprefetch is set. |
| */ |
| if (HDR_HAS_L2HDR(hdr) && |
| !HDR_L2_WRITING(hdr) && !HDR_L2_EVICTED(hdr) && |
| !(l2arc_noprefetch && HDR_PREFETCH(hdr))) { |
| l2arc_read_callback_t *cb; |
| abd_t *abd; |
| uint64_t asize; |
| |
| DTRACE_PROBE1(l2arc__hit, arc_buf_hdr_t *, hdr); |
| ARCSTAT_BUMP(arcstat_l2_hits); |
| atomic_inc_32(&hdr->b_l2hdr.b_hits); |
| |
| cb = kmem_zalloc(sizeof (l2arc_read_callback_t), |
| KM_SLEEP); |
| cb->l2rcb_hdr = hdr; |
| cb->l2rcb_bp = *bp; |
| cb->l2rcb_zb = *zb; |
| cb->l2rcb_flags = zio_flags; |
| |
| asize = vdev_psize_to_asize(vd, size); |
| if (asize != size) { |
| abd = abd_alloc_for_io(asize, |
| HDR_ISTYPE_METADATA(hdr)); |
| cb->l2rcb_abd = abd; |
| } else { |
| abd = hdr_abd; |
| } |
| |
| ASSERT(addr >= VDEV_LABEL_START_SIZE && |
| addr + asize <= vd->vdev_psize - |
| VDEV_LABEL_END_SIZE); |
| |
| /* |
| * l2arc read. The SCL_L2ARC lock will be |
| * released by l2arc_read_done(). |
| * Issue a null zio if the underlying buffer |
| * was squashed to zero size by compression. |
| */ |
| ASSERT3U(arc_hdr_get_compress(hdr), !=, |
| ZIO_COMPRESS_EMPTY); |
| rzio = zio_read_phys(pio, vd, addr, |
| asize, abd, |
| ZIO_CHECKSUM_OFF, |
| l2arc_read_done, cb, priority, |
| zio_flags | ZIO_FLAG_DONT_CACHE | |
| ZIO_FLAG_CANFAIL | |
| ZIO_FLAG_DONT_PROPAGATE | |
| ZIO_FLAG_DONT_RETRY, B_FALSE); |
| acb->acb_zio_head = rzio; |
| |
| if (hash_lock != NULL) |
| mutex_exit(hash_lock); |
| |
| DTRACE_PROBE2(l2arc__read, vdev_t *, vd, |
| zio_t *, rzio); |
| ARCSTAT_INCR(arcstat_l2_read_bytes, |
| HDR_GET_PSIZE(hdr)); |
| |
| if (*arc_flags & ARC_FLAG_NOWAIT) { |
| zio_nowait(rzio); |
| goto out; |
| } |
| |
| ASSERT(*arc_flags & ARC_FLAG_WAIT); |
| if (zio_wait(rzio) == 0) |
| goto out; |
| |
| /* l2arc read error; goto zio_read() */ |
| if (hash_lock != NULL) |
| mutex_enter(hash_lock); |
| } else { |
| DTRACE_PROBE1(l2arc__miss, |
| arc_buf_hdr_t *, hdr); |
| ARCSTAT_BUMP(arcstat_l2_misses); |
| if (HDR_L2_WRITING(hdr)) |
| ARCSTAT_BUMP(arcstat_l2_rw_clash); |
| spa_config_exit(spa, SCL_L2ARC, vd); |
| } |
| } else { |
| if (vd != NULL) |
| spa_config_exit(spa, SCL_L2ARC, vd); |
| /* |
| * Skip ARC stat bump for block pointers with |
| * embedded data. The data are read from the blkptr |
| * itself via decode_embedded_bp_compressed(). |
| */ |
| if (l2arc_ndev != 0 && !embedded_bp) { |
| DTRACE_PROBE1(l2arc__miss, |
| arc_buf_hdr_t *, hdr); |
| ARCSTAT_BUMP(arcstat_l2_misses); |
| } |
| } |
| |
| rzio = zio_read(pio, spa, bp, hdr_abd, size, |
| arc_read_done, hdr, priority, zio_flags, zb); |
| acb->acb_zio_head = rzio; |
| |
| if (hash_lock != NULL) |
| mutex_exit(hash_lock); |
| |
| if (*arc_flags & ARC_FLAG_WAIT) { |
| rc = zio_wait(rzio); |
| goto out; |
| } |
| |
| ASSERT(*arc_flags & ARC_FLAG_NOWAIT); |
| zio_nowait(rzio); |
| } |
| |
| out: |
| /* embedded bps don't actually go to disk */ |
| if (!embedded_bp) |
| spa_read_history_add(spa, zb, *arc_flags); |
| spl_fstrans_unmark(cookie); |
| return (rc); |
| } |
| |
| arc_prune_t * |
| arc_add_prune_callback(arc_prune_func_t *func, void *private) |
| { |
| arc_prune_t *p; |
| |
| p = kmem_alloc(sizeof (*p), KM_SLEEP); |
| p->p_pfunc = func; |
| p->p_private = private; |
| list_link_init(&p->p_node); |
| zfs_refcount_create(&p->p_refcnt); |
| |
| mutex_enter(&arc_prune_mtx); |
| zfs_refcount_add(&p->p_refcnt, &arc_prune_list); |
| list_insert_head(&arc_prune_list, p); |
| mutex_exit(&arc_prune_mtx); |
| |
| return (p); |
| } |
| |
| void |
| arc_remove_prune_callback(arc_prune_t *p) |
| { |
| boolean_t wait = B_FALSE; |
| mutex_enter(&arc_prune_mtx); |
| list_remove(&arc_prune_list, p); |
| if (zfs_refcount_remove(&p->p_refcnt, &arc_prune_list) > 0) |
| wait = B_TRUE; |
| mutex_exit(&arc_prune_mtx); |
| |
| /* wait for arc_prune_task to finish */ |
| if (wait) |
| taskq_wait_outstanding(arc_prune_taskq, 0); |
| ASSERT0(zfs_refcount_count(&p->p_refcnt)); |
| zfs_refcount_destroy(&p->p_refcnt); |
| kmem_free(p, sizeof (*p)); |
| } |
| |
| /* |
| * Notify the arc that a block was freed, and thus will never be used again. |
| */ |
| void |
| arc_freed(spa_t *spa, const blkptr_t *bp) |
| { |
| arc_buf_hdr_t *hdr; |
| kmutex_t *hash_lock; |
| uint64_t guid = spa_load_guid(spa); |
| |
| ASSERT(!BP_IS_EMBEDDED(bp)); |
| |
| hdr = buf_hash_find(guid, bp, &hash_lock); |
| if (hdr == NULL) |
| return; |
| |
| /* |
| * We might be trying to free a block that is still doing I/O |
| * (i.e. prefetch) or has a reference (i.e. a dedup-ed, |
| * dmu_sync-ed block). If this block is being prefetched, then it |
| * would still have the ARC_FLAG_IO_IN_PROGRESS flag set on the hdr |
| * until the I/O completes. A block may also have a reference if it is |
| * part of a dedup-ed, dmu_synced write. The dmu_sync() function would |
| * have written the new block to its final resting place on disk but |
| * without the dedup flag set. This would have left the hdr in the MRU |
| * state and discoverable. When the txg finally syncs it detects that |
| * the block was overridden in open context and issues an override I/O. |
| * Since this is a dedup block, the override I/O will determine if the |
| * block is already in the DDT. If so, then it will replace the io_bp |
| * with the bp from the DDT and allow the I/O to finish. When the I/O |
| * reaches the done callback, dbuf_write_override_done, it will |
| * check to see if the io_bp and io_bp_override are identical. |
| * If they are not, then it indicates that the bp was replaced with |
| * the bp in the DDT and the override bp is freed. This allows |
| * us to arrive here with a reference on a block that is being |
| * freed. So if we have an I/O in progress, or a reference to |
| * this hdr, then we don't destroy the hdr. |
| */ |
| if (!HDR_HAS_L1HDR(hdr) || (!HDR_IO_IN_PROGRESS(hdr) && |
| zfs_refcount_is_zero(&hdr->b_l1hdr.b_refcnt))) { |
| arc_change_state(arc_anon, hdr, hash_lock); |
| arc_hdr_destroy(hdr); |
| mutex_exit(hash_lock); |
| } else { |
| mutex_exit(hash_lock); |
| } |
| |
| } |
| |
| /* |
| * Release this buffer from the cache, making it an anonymous buffer. This |
| * must be done after a read and prior to modifying the buffer contents. |
| * If the buffer has more than one reference, we must make |
| * a new hdr for the buffer. |
| */ |
| void |
| arc_release(arc_buf_t *buf, void *tag) |
| { |
| arc_buf_hdr_t *hdr = buf->b_hdr; |
| |
| /* |
| * It would be nice to assert that if its DMU metadata (level > |
| * 0 || it's the dnode file), then it must be syncing context. |
| * But we don't know that information at this level. |
| */ |
| |
| mutex_enter(&buf->b_evict_lock); |
| |
| ASSERT(HDR_HAS_L1HDR(hdr)); |
| |
| /* |
| * We don't grab the hash lock prior to this check, because if |
| * the buffer's header is in the arc_anon state, it won't be |
| * linked into the hash table. |
| */ |
| if (hdr->b_l1hdr.b_state == arc_anon) { |
| mutex_exit(&buf->b_evict_lock); |
| ASSERT(!HDR_IO_IN_PROGRESS(hdr)); |
| ASSERT(!HDR_IN_HASH_TABLE(hdr)); |
| ASSERT(!HDR_HAS_L2HDR(hdr)); |
| ASSERT(HDR_EMPTY(hdr)); |
| |
| ASSERT3U(hdr->b_l1hdr.b_bufcnt, ==, 1); |
| ASSERT3S(zfs_refcount_count(&hdr->b_l1hdr.b_refcnt), ==, 1); |
| ASSERT(!list_link_active(&hdr->b_l1hdr.b_arc_node)); |
| |
| hdr->b_l1hdr.b_arc_access = 0; |
| |
| /* |
| * If the buf is being overridden then it may already |
| * have a hdr that is not empty. |
| */ |
| buf_discard_identity(hdr); |
| arc_buf_thaw(buf); |
| |
| return; |
| } |
| |
| kmutex_t *hash_lock = HDR_LOCK(hdr); |
| mutex_enter(hash_lock); |
| |
| /* |
| * This assignment is only valid as long as the hash_lock is |
| * held, we must be careful not to reference state or the |
| * b_state field after dropping the lock. |
| */ |
| arc_state_t *state = hdr->b_l1hdr.b_state; |
| ASSERT3P(hash_lock, ==, HDR_LOCK(hdr)); |
| ASSERT3P(state, !=, arc_anon); |
| |
| /* this buffer is not on any list */ |
| ASSERT3S(zfs_refcount_count(&hdr->b_l1hdr.b_refcnt), >, 0); |
| |
| if (HDR_HAS_L2HDR(hdr)) { |
| mutex_enter(&hdr->b_l2hdr.b_dev->l2ad_mtx); |
| |
| /* |
| * We have to recheck this conditional again now that |
| * we're holding the l2ad_mtx to prevent a race with |
| * another thread which might be concurrently calling |
| * l2arc_evict(). In that case, l2arc_evict() might have |
| * destroyed the header's L2 portion as we were waiting |
| * to acquire the l2ad_mtx. |
| */ |
| if (HDR_HAS_L2HDR(hdr)) |
| arc_hdr_l2hdr_destroy(hdr); |
| |
| mutex_exit(&hdr->b_l2hdr.b_dev->l2ad_mtx); |
| } |
| |
| /* |
| * Do we have more than one buf? |
| */ |
| if (hdr->b_l1hdr.b_bufcnt > 1) { |
| arc_buf_hdr_t *nhdr; |
| uint64_t spa = hdr->b_spa; |
| uint64_t psize = HDR_GET_PSIZE(hdr); |
| uint64_t lsize = HDR_GET_LSIZE(hdr); |
| boolean_t protected = HDR_PROTECTED(hdr); |
| enum zio_compress compress = arc_hdr_get_compress(hdr); |
| arc_buf_contents_t type = arc_buf_type(hdr); |
| VERIFY3U(hdr->b_type, ==, type); |
| |
| ASSERT(hdr->b_l1hdr.b_buf != buf || buf->b_next != NULL); |
| (void) remove_reference(hdr, hash_lock, tag); |
| |
| if (arc_buf_is_shared(buf) && !ARC_BUF_COMPRESSED(buf)) { |
| ASSERT3P(hdr->b_l1hdr.b_buf, !=, buf); |
| ASSERT(ARC_BUF_LAST(buf)); |
| } |
| |
| /* |
| * Pull the data off of this hdr and attach it to |
| * a new anonymous hdr. Also find the last buffer |
| * in the hdr's buffer list. |
| */ |
| arc_buf_t *lastbuf = arc_buf_remove(hdr, buf); |
| ASSERT3P(lastbuf, !=, NULL); |
| |
| /* |
| * If the current arc_buf_t and the hdr are sharing their data |
| * buffer, then we must stop sharing that block. |
| */ |
| if (arc_buf_is_shared(buf)) { |
| ASSERT3P(hdr->b_l1hdr.b_buf, !=, buf); |
| VERIFY(!arc_buf_is_shared(lastbuf)); |
| |
| /* |
| * First, sever the block sharing relationship between |
| * buf and the arc_buf_hdr_t. |
| */ |
| arc_unshare_buf(hdr, buf); |
| |
| /* |
| * Now we need to recreate the hdr's b_pabd. Since we |
| * have lastbuf handy, we try to share with it, but if |
| * we can't then we allocate a new b_pabd and copy the |
| * data from buf into it. |
| */ |
| if (arc_can_share(hdr, lastbuf)) { |
| arc_share_buf(hdr, lastbuf); |
| } else { |
| arc_hdr_alloc_abd(hdr, ARC_HDR_DO_ADAPT); |
| abd_copy_from_buf(hdr->b_l1hdr.b_pabd, |
| buf->b_data, psize); |
| } |
| VERIFY3P(lastbuf->b_data, !=, NULL); |
| } else if (HDR_SHARED_DATA(hdr)) { |
| /* |
| * Uncompressed shared buffers are always at the end |
| * of the list. Compressed buffers don't have the |
| * same requirements. This makes it hard to |
| * simply assert that the lastbuf is shared so |
| * we rely on the hdr's compression flags to determine |
| * if we have a compressed, shared buffer. |
| */ |
| ASSERT(arc_buf_is_shared(lastbuf) || |
| arc_hdr_get_compress(hdr) != ZIO_COMPRESS_OFF); |
| ASSERT(!ARC_BUF_SHARED(buf)); |
| } |
| |
| ASSERT(hdr->b_l1hdr.b_pabd != NULL || HDR_HAS_RABD(hdr)); |
| ASSERT3P(state, !=, arc_l2c_only); |
| |
| (void) zfs_refcount_remove_many(&state->arcs_size, |
| arc_buf_size(buf), buf); |
| |
| if (zfs_refcount_is_zero(&hdr->b_l1hdr.b_refcnt)) { |
| ASSERT3P(state, !=, arc_l2c_only); |
| (void) zfs_refcount_remove_many( |
| &state->arcs_esize[type], |
| arc_buf_size(buf), buf); |
| } |
| |
| hdr->b_l1hdr.b_bufcnt -= 1; |
| if (ARC_BUF_ENCRYPTED(buf)) |
| hdr->b_crypt_hdr.b_ebufcnt -= 1; |
| |
| arc_cksum_verify(buf); |
| arc_buf_unwatch(buf); |
| |
| /* if this is the last uncompressed buf free the checksum */ |
| if (!arc_hdr_has_uncompressed_buf(hdr)) |
| arc_cksum_free(hdr); |
| |
| mutex_exit(hash_lock); |
| |
| /* |
| * Allocate a new hdr. The new hdr will contain a b_pabd |
| * buffer which will be freed in arc_write(). |
| */ |
| nhdr = arc_hdr_alloc(spa, psize, lsize, protected, |
| compress, type, HDR_HAS_RABD(hdr)); |
| ASSERT3P(nhdr->b_l1hdr.b_buf, ==, NULL); |
| ASSERT0(nhdr->b_l1hdr.b_bufcnt); |
| ASSERT0(zfs_refcount_count(&nhdr->b_l1hdr.b_refcnt)); |
| VERIFY3U(nhdr->b_type, ==, type); |
| ASSERT(!HDR_SHARED_DATA(nhdr)); |
| |
| nhdr->b_l1hdr.b_buf = buf; |
| nhdr->b_l1hdr.b_bufcnt = 1; |
| if (ARC_BUF_ENCRYPTED(buf)) |
| nhdr->b_crypt_hdr.b_ebufcnt = 1; |
| nhdr->b_l1hdr.b_mru_hits = 0; |
| nhdr->b_l1hdr.b_mru_ghost_hits = 0; |
| nhdr->b_l1hdr.b_mfu_hits = 0; |
| nhdr->b_l1hdr.b_mfu_ghost_hits = 0; |
| nhdr->b_l1hdr.b_l2_hits = 0; |
| (void) zfs_refcount_add(&nhdr->b_l1hdr.b_refcnt, tag); |
| buf->b_hdr = nhdr; |
| |
| mutex_exit(&buf->b_evict_lock); |
| (void) zfs_refcount_add_many(&arc_anon->arcs_size, |
| arc_buf_size(buf), buf); |
| } else { |
| mutex_exit(&buf->b_evict_lock); |
| ASSERT(zfs_refcount_count(&hdr->b_l1hdr.b_refcnt) == 1); |
| /* protected by hash lock, or hdr is on arc_anon */ |
| ASSERT(!multilist_link_active(&hdr->b_l1hdr.b_arc_node)); |
| ASSERT(!HDR_IO_IN_PROGRESS(hdr)); |
| hdr->b_l1hdr.b_mru_hits = 0; |
| hdr->b_l1hdr.b_mru_ghost_hits = 0; |
| hdr->b_l1hdr.b_mfu_hits = 0; |
| hdr->b_l1hdr.b_mfu_ghost_hits = 0; |
| hdr->b_l1hdr.b_l2_hits = 0; |
| arc_change_state(arc_anon, hdr, hash_lock); |
| hdr->b_l1hdr.b_arc_access = 0; |
| |
| mutex_exit(hash_lock); |
| buf_discard_identity(hdr); |
| arc_buf_thaw(buf); |
| } |
| } |
| |
| int |
| arc_released(arc_buf_t *buf) |
| { |
| int released; |
| |
| mutex_enter(&buf->b_evict_lock); |
| released = (buf->b_data != NULL && |
| buf->b_hdr->b_l1hdr.b_state == arc_anon); |
| mutex_exit(&buf->b_evict_lock); |
| return (released); |
| } |
| |
| #ifdef ZFS_DEBUG |
| int |
| arc_referenced(arc_buf_t *buf) |
| { |
| int referenced; |
| |
| mutex_enter(&buf->b_evict_lock); |
| referenced = (zfs_refcount_count(&buf->b_hdr->b_l1hdr.b_refcnt)); |
| mutex_exit(&buf->b_evict_lock); |
| return (referenced); |
| } |
| #endif |
| |
| static void |
| arc_write_ready(zio_t *zio) |
| { |
| arc_write_callback_t *callback = zio->io_private; |
| arc_buf_t *buf = callback->awcb_buf; |
| arc_buf_hdr_t *hdr = buf->b_hdr; |
| blkptr_t *bp = zio->io_bp; |
| uint64_t psize = BP_IS_HOLE(bp) ? 0 : BP_GET_PSIZE(bp); |
| fstrans_cookie_t cookie = spl_fstrans_mark(); |
| |
| ASSERT(HDR_HAS_L1HDR(hdr)); |
| ASSERT(!zfs_refcount_is_zero(&buf->b_hdr->b_l1hdr.b_refcnt)); |
| ASSERT(hdr->b_l1hdr.b_bufcnt > 0); |
| |
| /* |
| * If we're reexecuting this zio because the pool suspended, then |
| * cleanup any state that was previously set the first time the |
| * callback was invoked. |
| */ |
| if (zio->io_flags & ZIO_FLAG_REEXECUTED) { |
| arc_cksum_free(hdr); |
| arc_buf_unwatch(buf); |
| if (hdr->b_l1hdr.b_pabd != NULL) { |
| if (arc_buf_is_shared(buf)) { |
| arc_unshare_buf(hdr, buf); |
| } else { |
| arc_hdr_free_abd(hdr, B_FALSE); |
| } |
| } |
| |
| if (HDR_HAS_RABD(hdr)) |
| arc_hdr_free_abd(hdr, B_TRUE); |
| } |
| ASSERT3P(hdr->b_l1hdr.b_pabd, ==, NULL); |
| ASSERT(!HDR_HAS_RABD(hdr)); |
| ASSERT(!HDR_SHARED_DATA(hdr)); |
| ASSERT(!arc_buf_is_shared(buf)); |
| |
| callback->awcb_ready(zio, buf, callback->awcb_private); |
| |
| if (HDR_IO_IN_PROGRESS(hdr)) |
| ASSERT(zio->io_flags & ZIO_FLAG_REEXECUTED); |
| |
| arc_hdr_set_flags(hdr, ARC_FLAG_IO_IN_PROGRESS); |
| |
| if (BP_IS_PROTECTED(bp) != !!HDR_PROTECTED(hdr)) |
| hdr = arc_hdr_realloc_crypt(hdr, BP_IS_PROTECTED(bp)); |
| |
| if (BP_IS_PROTECTED(bp)) { |
| /* ZIL blocks are written through zio_rewrite */ |
| ASSERT3U(BP_GET_TYPE(bp), !=, DMU_OT_INTENT_LOG); |
| ASSERT(HDR_PROTECTED(hdr)); |
| |
| if (BP_SHOULD_BYTESWAP(bp)) { |
| if (BP_GET_LEVEL(bp) > 0) { |
| hdr->b_l1hdr.b_byteswap = DMU_BSWAP_UINT64; |
| } else { |
| hdr->b_l1hdr.b_byteswap = |
| DMU_OT_BYTESWAP(BP_GET_TYPE(bp)); |
| } |
| } else { |
| hdr->b_l1hdr.b_byteswap = DMU_BSWAP_NUMFUNCS; |
| } |
| |
| hdr->b_crypt_hdr.b_ot = BP_GET_TYPE(bp); |
| hdr->b_crypt_hdr.b_dsobj = zio->io_bookmark.zb_objset; |
| zio_crypt_decode_params_bp(bp, hdr->b_crypt_hdr.b_salt, |
| hdr->b_crypt_hdr.b_iv); |
| zio_crypt_decode_mac_bp(bp, hdr->b_crypt_hdr.b_mac); |
| } |
| |
| /* |
| * If this block was written for raw encryption but the zio layer |
| * ended up only authenticating it, adjust the buffer flags now. |
| */ |
| if (BP_IS_AUTHENTICATED(bp) && ARC_BUF_ENCRYPTED(buf)) { |
| arc_hdr_set_flags(hdr, ARC_FLAG_NOAUTH); |
| buf->b_flags &= ~ARC_BUF_FLAG_ENCRYPTED; |
| if (BP_GET_COMPRESS(bp) == ZIO_COMPRESS_OFF) |
| buf->b_flags &= ~ARC_BUF_FLAG_COMPRESSED; |
| } else if (BP_IS_HOLE(bp) && ARC_BUF_ENCRYPTED(buf)) { |
| buf->b_flags &= ~ARC_BUF_FLAG_ENCRYPTED; |
| buf->b_flags &= ~ARC_BUF_FLAG_COMPRESSED; |
| } |
| |
| /* this must be done after the buffer flags are adjusted */ |
| arc_cksum_compute(buf); |
| |
| enum zio_compress compress; |
| if (BP_IS_HOLE(bp) || BP_IS_EMBEDDED(bp)) { |
| compress = ZIO_COMPRESS_OFF; |
| } else { |
| ASSERT3U(HDR_GET_LSIZE(hdr), ==, BP_GET_LSIZE(bp)); |
| compress = BP_GET_COMPRESS(bp); |
| } |
| HDR_SET_PSIZE(hdr, psize); |
| arc_hdr_set_compress(hdr, compress); |
| |
| if (zio->io_error != 0 || psize == 0) |
| goto out; |
| |
| /* |
| * Fill the hdr with data. If the buffer is encrypted we have no choice |
| * but to copy the data into b_radb. If the hdr is compressed, the data |
| * we want is available from the zio, otherwise we can take it from |
| * the buf. |
| * |
| * We might be able to share the buf's data with the hdr here. However, |
| * doing so would cause the ARC to be full of linear ABDs if we write a |
| * lot of shareable data. As a compromise, we check whether scattered |
| * ABDs are allowed, and assume that if they are then the user wants |
| * the ARC to be primarily filled with them regardless of the data being |
| * written. Therefore, if they're allowed then we allocate one and copy |
| * the data into it; otherwise, we share the data directly if we can. |
| */ |
| if (ARC_BUF_ENCRYPTED(buf)) { |
| ASSERT3U(psize, >, 0); |
| ASSERT(ARC_BUF_COMPRESSED(buf)); |
| arc_hdr_alloc_abd(hdr, ARC_HDR_DO_ADAPT|ARC_HDR_ALLOC_RDATA); |
| abd_copy(hdr->b_crypt_hdr.b_rabd, zio->io_abd, psize); |
| } else if (zfs_abd_scatter_enabled || !arc_can_share(hdr, buf)) { |
| /* |
| * Ideally, we would always copy the io_abd into b_pabd, but the |
| * user may have disabled compressed ARC, thus we must check the |
| * hdr's compression setting rather than the io_bp's. |
| */ |
| if (BP_IS_ENCRYPTED(bp)) { |
| ASSERT3U(psize, >, 0); |
| arc_hdr_alloc_abd(hdr, |
| ARC_HDR_DO_ADAPT|ARC_HDR_ALLOC_RDATA); |
| abd_copy(hdr->b_crypt_hdr.b_rabd, zio->io_abd, psize); |
| } else if (arc_hdr_get_compress(hdr) != ZIO_COMPRESS_OFF && |
| !ARC_BUF_COMPRESSED(buf)) { |
| ASSERT3U(psize, >, 0); |
| arc_hdr_alloc_abd(hdr, ARC_HDR_DO_ADAPT); |
| abd_copy(hdr->b_l1hdr.b_pabd, zio->io_abd, psize); |
| } else { |
| ASSERT3U(zio->io_orig_size, ==, arc_hdr_size(hdr)); |
| arc_hdr_alloc_abd(hdr, ARC_HDR_DO_ADAPT); |
| abd_copy_from_buf(hdr->b_l1hdr.b_pabd, buf->b_data, |
| arc_buf_size(buf)); |
| } |
| } else { |
| ASSERT3P(buf->b_data, ==, abd_to_buf(zio->io_orig_abd)); |
| ASSERT3U(zio->io_orig_size, ==, arc_buf_size(buf)); |
| ASSERT3U(hdr->b_l1hdr.b_bufcnt, ==, 1); |
| |
| arc_share_buf(hdr, buf); |
| } |
| |
| out: |
| arc_hdr_verify(hdr, bp); |
| spl_fstrans_unmark(cookie); |
| } |
| |
| static void |
| arc_write_children_ready(zio_t *zio) |
| { |
| arc_write_callback_t *callback = zio->io_private; |
| arc_buf_t *buf = callback->awcb_buf; |
| |
| callback->awcb_children_ready(zio, buf, callback->awcb_private); |
| } |
| |
| /* |
| * The SPA calls this callback for each physical write that happens on behalf |
| * of a logical write. See the comment in dbuf_write_physdone() for details. |
| */ |
| static void |
| arc_write_physdone(zio_t *zio) |
| { |
| arc_write_callback_t *cb = zio->io_private; |
| if (cb->awcb_physdone != NULL) |
| cb->awcb_physdone(zio, cb->awcb_buf, cb->awcb_private); |
| } |
| |
| static void |
| arc_write_done(zio_t *zio) |
| { |
| arc_write_callback_t *callback = zio->io_private; |
| arc_buf_t *buf = callback->awcb_buf; |
| arc_buf_hdr_t *hdr = buf->b_hdr; |
| |
| ASSERT3P(hdr->b_l1hdr.b_acb, ==, NULL); |
| |
| if (zio->io_error == 0) { |
| arc_hdr_verify(hdr, zio->io_bp); |
| |
| if (BP_IS_HOLE(zio->io_bp) || BP_IS_EMBEDDED(zio->io_bp)) { |
| buf_discard_identity(hdr); |
| } else { |
| hdr->b_dva = *BP_IDENTITY(zio->io_bp); |
| hdr->b_birth = BP_PHYSICAL_BIRTH(zio->io_bp); |
| } |
| } else { |
| ASSERT(HDR_EMPTY(hdr)); |
| } |
| |
| /* |
| * If the block to be written was all-zero or compressed enough to be |
| * embedded in the BP, no write was performed so there will be no |
| * dva/birth/checksum. The buffer must therefore remain anonymous |
| * (and uncached). |
| */ |
| if (!HDR_EMPTY(hdr)) { |
| arc_buf_hdr_t *exists; |
| kmutex_t *hash_lock; |
| |
| ASSERT3U(zio->io_error, ==, 0); |
| |
| arc_cksum_verify(buf); |
| |
| exists = buf_hash_insert(hdr, &hash_lock); |
| if (exists != NULL) { |
| /* |
| * This can only happen if we overwrite for |
| * sync-to-convergence, because we remove |
| * buffers from the hash table when we arc_free(). |
| */ |
| if (zio->io_flags & ZIO_FLAG_IO_REWRITE) { |
| if (!BP_EQUAL(&zio->io_bp_orig, zio->io_bp)) |
| panic("bad overwrite, hdr=%p exists=%p", |
| (void *)hdr, (void *)exists); |
| ASSERT(zfs_refcount_is_zero( |
| &exists->b_l1hdr.b_refcnt)); |
| arc_change_state(arc_anon, exists, hash_lock); |
| arc_hdr_destroy(exists); |
| mutex_exit(hash_lock); |
| exists = buf_hash_insert(hdr, &hash_lock); |
| ASSERT3P(exists, ==, NULL); |
| } else if (zio->io_flags & ZIO_FLAG_NOPWRITE) { |
| /* nopwrite */ |
| ASSERT(zio->io_prop.zp_nopwrite); |
| if (!BP_EQUAL(&zio->io_bp_orig, zio->io_bp)) |
| panic("bad nopwrite, hdr=%p exists=%p", |
| (void *)hdr, (void *)exists); |
| } else { |
| /* Dedup */ |
| ASSERT(hdr->b_l1hdr.b_bufcnt == 1); |
| ASSERT(hdr->b_l1hdr.b_state == arc_anon); |
| ASSERT(BP_GET_DEDUP(zio->io_bp)); |
| ASSERT(BP_GET_LEVEL(zio->io_bp) == 0); |
| } |
| } |
| arc_hdr_clear_flags(hdr, ARC_FLAG_IO_IN_PROGRESS); |
| /* if it's not anon, we are doing a scrub */ |
| if (exists == NULL && hdr->b_l1hdr.b_state == arc_anon) |
| arc_access(hdr, hash_lock); |
| mutex_exit(hash_lock); |
| } else { |
| arc_hdr_clear_flags(hdr, ARC_FLAG_IO_IN_PROGRESS); |
| } |
| |
| ASSERT(!zfs_refcount_is_zero(&hdr->b_l1hdr.b_refcnt)); |
| callback->awcb_done(zio, buf, callback->awcb_private); |
| |
| abd_put(zio->io_abd); |
| kmem_free(callback, sizeof (arc_write_callback_t)); |
| } |
| |
| zio_t * |
| arc_write(zio_t *pio, spa_t *spa, uint64_t txg, |
| blkptr_t *bp, arc_buf_t *buf, boolean_t l2arc, |
| const zio_prop_t *zp, arc_write_done_func_t *ready, |
| arc_write_done_func_t *children_ready, arc_write_done_func_t *physdone, |
| arc_write_done_func_t *done, void *private, zio_priority_t priority, |
| int zio_flags, const zbookmark_phys_t *zb) |
| { |
| arc_buf_hdr_t *hdr = buf->b_hdr; |
| arc_write_callback_t *callback; |
| zio_t *zio; |
| zio_prop_t localprop = *zp; |
| |
| ASSERT3P(ready, !=, NULL); |
| ASSERT3P(done, !=, NULL); |
| ASSERT(!HDR_IO_ERROR(hdr)); |
| ASSERT(!HDR_IO_IN_PROGRESS(hdr)); |
| ASSERT3P(hdr->b_l1hdr.b_acb, ==, NULL); |
| ASSERT3U(hdr->b_l1hdr.b_bufcnt, >, 0); |
| if (l2arc) |
| arc_hdr_set_flags(hdr, ARC_FLAG_L2CACHE); |
| |
| if (ARC_BUF_ENCRYPTED(buf)) { |
| ASSERT(ARC_BUF_COMPRESSED(buf)); |
| localprop.zp_encrypt = B_TRUE; |
| localprop.zp_compress = HDR_GET_COMPRESS(hdr); |
| localprop.zp_byteorder = |
| (hdr->b_l1hdr.b_byteswap == DMU_BSWAP_NUMFUNCS) ? |
| ZFS_HOST_BYTEORDER : !ZFS_HOST_BYTEORDER; |
| bcopy(hdr->b_crypt_hdr.b_salt, localprop.zp_salt, |
| ZIO_DATA_SALT_LEN); |
| bcopy(hdr->b_crypt_hdr.b_iv, localprop.zp_iv, |
| ZIO_DATA_IV_LEN); |
| bcopy(hdr->b_crypt_hdr.b_mac, localprop.zp_mac, |
| ZIO_DATA_MAC_LEN); |
| if (DMU_OT_IS_ENCRYPTED(localprop.zp_type)) { |
| localprop.zp_nopwrite = B_FALSE; |
| localprop.zp_copies = |
| MIN(localprop.zp_copies, SPA_DVAS_PER_BP - 1); |
| } |
| zio_flags |= ZIO_FLAG_RAW; |
| } else if (ARC_BUF_COMPRESSED(buf)) { |
| ASSERT3U(HDR_GET_LSIZE(hdr), !=, arc_buf_size(buf)); |
| localprop.zp_compress = HDR_GET_COMPRESS(hdr); |
| zio_flags |= ZIO_FLAG_RAW_COMPRESS; |
| } |
| callback = kmem_zalloc(sizeof (arc_write_callback_t), KM_SLEEP); |
| callback->awcb_ready = ready; |
| callback->awcb_children_ready = children_ready; |
| callback->awcb_physdone = physdone; |
| callback->awcb_done = done; |
| callback->awcb_private = private; |
| callback->awcb_buf = buf; |
| |
| /* |
| * The hdr's b_pabd is now stale, free it now. A new data block |
| * will be allocated when the zio pipeline calls arc_write_ready(). |
| */ |
| if (hdr->b_l1hdr.b_pabd != NULL) { |
| /* |
| * If the buf is currently sharing the data block with |
| * the hdr then we need to break that relationship here. |
| * The hdr will remain with a NULL data pointer and the |
| * buf will take sole ownership of the block. |
| */ |
| if (arc_buf_is_shared(buf)) { |
| arc_unshare_buf(hdr, buf); |
| } else { |
| arc_hdr_free_abd(hdr, B_FALSE); |
| } |
| VERIFY3P(buf->b_data, !=, NULL); |
| } |
| |
| if (HDR_HAS_RABD(hdr)) |
| arc_hdr_free_abd(hdr, B_TRUE); |
| |
| if (!(zio_flags & ZIO_FLAG_RAW)) |
| arc_hdr_set_compress(hdr, ZIO_COMPRESS_OFF); |
| |
| ASSERT(!arc_buf_is_shared(buf)); |
| ASSERT3P(hdr->b_l1hdr.b_pabd, ==, NULL); |
| |
| zio = zio_write(pio, spa, txg, bp, |
| abd_get_from_buf(buf->b_data, HDR_GET_LSIZE(hdr)), |
| HDR_GET_LSIZE(hdr), arc_buf_size(buf), &localprop, arc_write_ready, |
| (children_ready != NULL) ? arc_write_children_ready : NULL, |
| arc_write_physdone, arc_write_done, callback, |
| priority, zio_flags, zb); |
| |
| return (zio); |
| } |
| |
| static int |
| arc_memory_throttle(spa_t *spa, uint64_t reserve, uint64_t txg) |
| { |
| #ifdef _KERNEL |
| uint64_t available_memory = arc_free_memory(); |
| |
| #if defined(_ILP32) |
| available_memory = |
| MIN(available_memory, vmem_size(heap_arena, VMEM_FREE)); |
| #endif |
| |
| if (available_memory > arc_all_memory() * arc_lotsfree_percent / 100) |
| return (0); |
| |
| if (txg > spa->spa_lowmem_last_txg) { |
| spa->spa_lowmem_last_txg = txg; |
| spa->spa_lowmem_page_load = 0; |
| } |
| /* |
| * If we are in pageout, we know that memory is already tight, |
| * the arc is already going to be evicting, so we just want to |
| * continue to let page writes occur as quickly as possible. |
| */ |
| if (current_is_kswapd()) { |
| if (spa->spa_lowmem_page_load > |
| MAX(arc_sys_free / 4, available_memory) / 4) { |
| DMU_TX_STAT_BUMP(dmu_tx_memory_reclaim); |
| return (SET_ERROR(ERESTART)); |
| } |
| /* Note: reserve is inflated, so we deflate */ |
| atomic_add_64(&spa->spa_lowmem_page_load, reserve / 8); |
| return (0); |
| } else if (spa->spa_lowmem_page_load > 0 && arc_reclaim_needed()) { |
| /* memory is low, delay before restarting */ |
| ARCSTAT_INCR(arcstat_memory_throttle_count, 1); |
| DMU_TX_STAT_BUMP(dmu_tx_memory_reclaim); |
| return (SET_ERROR(EAGAIN)); |
| } |
| spa->spa_lowmem_page_load = 0; |
| #endif /* _KERNEL */ |
| return (0); |
| } |
| |
| void |
| arc_tempreserve_clear(uint64_t reserve) |
| { |
| atomic_add_64(&arc_tempreserve, -reserve); |
| ASSERT((int64_t)arc_tempreserve >= 0); |
| } |
| |
| int |
| arc_tempreserve_space(spa_t *spa, uint64_t reserve, uint64_t txg) |
| { |
| int error; |
| uint64_t anon_size; |
| |
| if (!arc_no_grow && |
| reserve > arc_c/4 && |
| reserve * 4 > (2ULL << SPA_MAXBLOCKSHIFT)) |
| arc_c = MIN(arc_c_max, reserve * 4); |
| |
| /* |
| * Throttle when the calculated memory footprint for the TXG |
| * exceeds the target ARC size. |
| */ |
| if (reserve > arc_c) { |
| DMU_TX_STAT_BUMP(dmu_tx_memory_reserve); |
| return (SET_ERROR(ERESTART)); |
| } |
| |
| /* |
| * Don't count loaned bufs as in flight dirty data to prevent long |
| * network delays from blocking transactions that are ready to be |
| * assigned to a txg. |
| */ |
| |
| /* assert that it has not wrapped around */ |
| ASSERT3S(atomic_add_64_nv(&arc_loaned_bytes, 0), >=, 0); |
| |
| anon_size = MAX((int64_t)(zfs_refcount_count(&arc_anon->arcs_size) - |
| arc_loaned_bytes), 0); |
| |
| /* |
| * Writes will, almost always, require additional memory allocations |
| * in order to compress/encrypt/etc the data. We therefore need to |
| * make sure that there is sufficient available memory for this. |
| */ |
| error = arc_memory_throttle(spa, reserve, txg); |
| if (error != 0) |
| return (error); |
| |
| /* |
| * Throttle writes when the amount of dirty data in the cache |
| * gets too large. We try to keep the cache less than half full |
| * of dirty blocks so that our sync times don't grow too large. |
| * |
| * In the case of one pool being built on another pool, we want |
| * to make sure we don't end up throttling the lower (backing) |
| * pool when the upper pool is the majority contributor to dirty |
| * data. To insure we make forward progress during throttling, we |
| * also check the current pool's net dirty data and only throttle |
| * if it exceeds zfs_arc_pool_dirty_percent of the anonymous dirty |
| * data in the cache. |
| * |
| * Note: if two requests come in concurrently, we might let them |
| * both succeed, when one of them should fail. Not a huge deal. |
| */ |
| uint64_t total_dirty = reserve + arc_tempreserve + anon_size; |
| uint64_t spa_dirty_anon = spa_dirty_data(spa); |
| |
| if (total_dirty > arc_c * zfs_arc_dirty_limit_percent / 100 && |
| anon_size > arc_c * zfs_arc_anon_limit_percent / 100 && |
| spa_dirty_anon > anon_size * zfs_arc_pool_dirty_percent / 100) { |
| #ifdef ZFS_DEBUG |
| uint64_t meta_esize = zfs_refcount_count( |
| &arc_anon->arcs_esize[ARC_BUFC_METADATA]); |
| uint64_t data_esize = |
| zfs_refcount_count(&arc_anon->arcs_esize[ARC_BUFC_DATA]); |
| dprintf("failing, arc_tempreserve=%lluK anon_meta=%lluK " |
| "anon_data=%lluK tempreserve=%lluK arc_c=%lluK\n", |
| arc_tempreserve >> 10, meta_esize >> 10, |
| data_esize >> 10, reserve >> 10, arc_c >> 10); |
| #endif |
| DMU_TX_STAT_BUMP(dmu_tx_dirty_throttle); |
| return (SET_ERROR(ERESTART)); |
| } |
| atomic_add_64(&arc_tempreserve, reserve); |
| return (0); |
| } |
| |
| static void |
| arc_kstat_update_state(arc_state_t *state, kstat_named_t *size, |
| kstat_named_t *evict_data, kstat_named_t *evict_metadata) |
| { |
| size->value.ui64 = zfs_refcount_count(&state->arcs_size); |
| evict_data->value.ui64 = |
| zfs_refcount_count(&state->arcs_esize[ARC_BUFC_DATA]); |
| evict_metadata->value.ui64 = |
| zfs_refcount_count(&state->arcs_esize[ARC_BUFC_METADATA]); |
| } |
| |
| static int |
| arc_kstat_update(kstat_t *ksp, int rw) |
| { |
| arc_stats_t *as = ksp->ks_data; |
| |
| if (rw == KSTAT_WRITE) { |
| return (SET_ERROR(EACCES)); |
| } else { |
| arc_kstat_update_state(arc_anon, |
| &as->arcstat_anon_size, |
| &as->arcstat_anon_evictable_data, |
| &as->arcstat_anon_evictable_metadata); |
| arc_kstat_update_state(arc_mru, |
| &as->arcstat_mru_size, |
| &as->arcstat_mru_evictable_data, |
| &as->arcstat_mru_evictable_metadata); |
| arc_kstat_update_state(arc_mru_ghost, |
| &as->arcstat_mru_ghost_size, |
| &as->arcstat_mru_ghost_evictable_data, |
| &as->arcstat_mru_ghost_evictable_metadata); |
| arc_kstat_update_state(arc_mfu, |
| &as->arcstat_mfu_size, |
| &as->arcstat_mfu_evictable_data, |
| &as->arcstat_mfu_evictable_metadata); |
| arc_kstat_update_state(arc_mfu_ghost, |
| &as->arcstat_mfu_ghost_size, |
| &as->arcstat_mfu_ghost_evictable_data, |
| &as->arcstat_mfu_ghost_evictable_metadata); |
| |
| ARCSTAT(arcstat_size) = aggsum_value(&arc_size); |
| ARCSTAT(arcstat_meta_used) = aggsum_value(&arc_meta_used); |
| ARCSTAT(arcstat_data_size) = aggsum_value(&astat_data_size); |
| ARCSTAT(arcstat_metadata_size) = |
| aggsum_value(&astat_metadata_size); |
| ARCSTAT(arcstat_hdr_size) = aggsum_value(&astat_hdr_size); |
| ARCSTAT(arcstat_l2_hdr_size) = aggsum_value(&astat_l2_hdr_size); |
| ARCSTAT(arcstat_dbuf_size) = aggsum_value(&astat_dbuf_size); |
| ARCSTAT(arcstat_dnode_size) = aggsum_value(&astat_dnode_size); |
| ARCSTAT(arcstat_bonus_size) = aggsum_value(&astat_bonus_size); |
| |
| as->arcstat_memory_all_bytes.value.ui64 = |
| arc_all_memory(); |
| as->arcstat_memory_free_bytes.value.ui64 = |
| arc_free_memory(); |
| as->arcstat_memory_available_bytes.value.i64 = |
| arc_available_memory(); |
| } |
| |
| return (0); |
| } |
| |
| /* |
| * This function *must* return indices evenly distributed between all |
| * sublists of the multilist. This is needed due to how the ARC eviction |
| * code is laid out; arc_evict_state() assumes ARC buffers are evenly |
| * distributed between all sublists and uses this assumption when |
| * deciding which sublist to evict from and how much to evict from it. |
| */ |
| unsigned int |
| arc_state_multilist_index_func(multilist_t *ml, void *obj) |
| { |
| arc_buf_hdr_t *hdr = obj; |
| |
| /* |
| * We rely on b_dva to generate evenly distributed index |
| * numbers using buf_hash below. So, as an added precaution, |
| * let's make sure we never add empty buffers to the arc lists. |
| */ |
| ASSERT(!HDR_EMPTY(hdr)); |
| |
| /* |
| * The assumption here, is the hash value for a given |
| * arc_buf_hdr_t will remain constant throughout its lifetime |
| * (i.e. its b_spa, b_dva, and b_birth fields don't change). |
| * Thus, we don't need to store the header's sublist index |
| * on insertion, as this index can be recalculated on removal. |
| * |
| * Also, the low order bits of the hash value are thought to be |
| * distributed evenly. Otherwise, in the case that the multilist |
| * has a power of two number of sublists, each sublists' usage |
| * would not be evenly distributed. |
| */ |
| return (buf_hash(hdr->b_spa, &hdr->b_dva, hdr->b_birth) % |
| multilist_get_num_sublists(ml)); |
| } |
| |
| /* |
| * Called during module initialization and periodically thereafter to |
| * apply reasonable changes to the exposed performance tunings. Can also be |
| * called explicitly by param_set_arc_*() functions when ARC tunables are |
| * updated manually. Non-zero zfs_* values which differ from the currently set |
| * values will be applied. |
| */ |
| static void |
| arc_tuning_update(void) |
| { |
| uint64_t allmem = arc_all_memory(); |
| unsigned long limit; |
| |
| /* Valid range: 64M - <all physical memory> */ |
| if ((zfs_arc_max) && (zfs_arc_max != arc_c_max) && |
| (zfs_arc_max >= 64 << 20) && (zfs_arc_max < allmem) && |
| (zfs_arc_max > arc_c_min)) { |
| arc_c_max = zfs_arc_max; |
| arc_c = arc_c_max; |
| arc_p = (arc_c >> 1); |
| if (arc_meta_limit > arc_c_max) |
| arc_meta_limit = arc_c_max; |
| if (arc_dnode_limit > arc_meta_limit) |
| arc_dnode_limit = arc_meta_limit; |
| } |
| |
| /* Valid range: 32M - <arc_c_max> */ |
| if ((zfs_arc_min) && (zfs_arc_min != arc_c_min) && |
| (zfs_arc_min >= 2ULL << SPA_MAXBLOCKSHIFT) && |
| (zfs_arc_min <= arc_c_max)) { |
| arc_c_min = zfs_arc_min; |
| arc_c = MAX(arc_c, arc_c_min); |
| } |
| |
| /* Valid range: 16M - <arc_c_max> */ |
| if ((zfs_arc_meta_min) && (zfs_arc_meta_min != arc_meta_min) && |
| (zfs_arc_meta_min >= 1ULL << SPA_MAXBLOCKSHIFT) && |
| (zfs_arc_meta_min <= arc_c_max)) { |
| arc_meta_min = zfs_arc_meta_min; |
| if (arc_meta_limit < arc_meta_min) |
| arc_meta_limit = arc_meta_min; |
| if (arc_dnode_limit < arc_meta_min) |
| arc_dnode_limit = arc_meta_min; |
| } |
| |
| /* Valid range: <arc_meta_min> - <arc_c_max> */ |
| limit = zfs_arc_meta_limit ? zfs_arc_meta_limit : |
| MIN(zfs_arc_meta_limit_percent, 100) * arc_c_max / 100; |
| if ((limit != arc_meta_limit) && |
| (limit >= arc_meta_min) && |
| (limit <= arc_c_max)) |
| arc_meta_limit = limit; |
| |
| /* Valid range: <arc_meta_min> - <arc_meta_limit> */ |
| limit = zfs_arc_dnode_limit ? zfs_arc_dnode_limit : |
| MIN(zfs_arc_dnode_limit_percent, 100) * arc_meta_limit / 100; |
| if ((limit != arc_dnode_limit) && |
| (limit >= arc_meta_min) && |
| (limit <= arc_meta_limit)) |
| arc_dnode_limit = limit; |
| |
| /* Valid range: 1 - N */ |
| if (zfs_arc_grow_retry) |
| arc_grow_retry = zfs_arc_grow_retry; |
| |
| /* Valid range: 1 - N */ |
| if (zfs_arc_shrink_shift) { |
| arc_shrink_shift = zfs_arc_shrink_shift; |
| arc_no_grow_shift = MIN(arc_no_grow_shift, arc_shrink_shift -1); |
| } |
| |
| /* Valid range: 1 - N */ |
| if (zfs_arc_p_min_shift) |
| arc_p_min_shift = zfs_arc_p_min_shift; |
| |
| /* Valid range: 1 - N ms */ |
| if (zfs_arc_min_prefetch_ms) |
| arc_min_prefetch_ms = zfs_arc_min_prefetch_ms; |
| |
| /* Valid range: 1 - N ms */ |
| if (zfs_arc_min_prescient_prefetch_ms) { |
| arc_min_prescient_prefetch_ms = |
| zfs_arc_min_prescient_prefetch_ms; |
| } |
| |
| /* Valid range: 0 - 100 */ |
| if ((zfs_arc_lotsfree_percent >= 0) && |
| (zfs_arc_lotsfree_percent <= 100)) |
| arc_lotsfree_percent = zfs_arc_lotsfree_percent; |
| |
| /* Valid range: 0 - <all physical memory> */ |
| if ((zfs_arc_sys_free) && (zfs_arc_sys_free != arc_sys_free)) |
| arc_sys_free = MIN(MAX(zfs_arc_sys_free, 0), allmem); |
| |
| } |
| |
| static void |
| arc_state_init(void) |
| { |
| arc_anon = &ARC_anon; |
| arc_mru = &ARC_mru; |
| arc_mru_ghost = &ARC_mru_ghost; |
| arc_mfu = &ARC_mfu; |
| arc_mfu_ghost = &ARC_mfu_ghost; |
| arc_l2c_only = &ARC_l2c_only; |
| |
| arc_mru->arcs_list[ARC_BUFC_METADATA] = |
| multilist_create(sizeof (arc_buf_hdr_t), |
| offsetof(arc_buf_hdr_t, b_l1hdr.b_arc_node), |
| arc_state_multilist_index_func); |
| arc_mru->arcs_list[ARC_BUFC_DATA] = |
| multilist_create(sizeof (arc_buf_hdr_t), |
| offsetof(arc_buf_hdr_t, b_l1hdr.b_arc_node), |
| arc_state_multilist_index_func); |
| arc_mru_ghost->arcs_list[ARC_BUFC_METADATA] = |
| multilist_create(sizeof (arc_buf_hdr_t), |
| offsetof(arc_buf_hdr_t, b_l1hdr.b_arc_node), |
| arc_state_multilist_index_func); |
| arc_mru_ghost->arcs_list[ARC_BUFC_DATA] = |
| multilist_create(sizeof (arc_buf_hdr_t), |
| offsetof(arc_buf_hdr_t, b_l1hdr.b_arc_node), |
| arc_state_multilist_index_func); |
| arc_mfu->arcs_list[ARC_BUFC_METADATA] = |
| multilist_create(sizeof (arc_buf_hdr_t), |
| offsetof(arc_buf_hdr_t, b_l1hdr.b_arc_node), |
| arc_state_multilist_index_func); |
| arc_mfu->arcs_list[ARC_BUFC_DATA] = |
| multilist_create(sizeof (arc_buf_hdr_t), |
| offsetof(arc_buf_hdr_t, b_l1hdr.b_arc_node), |
| arc_state_multilist_index_func); |
| arc_mfu_ghost->arcs_list[ARC_BUFC_METADATA] = |
| multilist_create(sizeof (arc_buf_hdr_t), |
| offsetof(arc_buf_hdr_t, b_l1hdr.b_arc_node), |
| arc_state_multilist_index_func); |
| arc_mfu_ghost->arcs_list[ARC_BUFC_DATA] = |
| multilist_create(sizeof (arc_buf_hdr_t), |
| offsetof(arc_buf_hdr_t, b_l1hdr.b_arc_node), |
| arc_state_multilist_index_func); |
| arc_l2c_only->arcs_list[ARC_BUFC_METADATA] = |
| multilist_create(sizeof (arc_buf_hdr_t), |
| offsetof(arc_buf_hdr_t, b_l1hdr.b_arc_node), |
| arc_state_multilist_index_func); |
| arc_l2c_only->arcs_list[ARC_BUFC_DATA] = |
| multilist_create(sizeof (arc_buf_hdr_t), |
| offsetof(arc_buf_hdr_t, b_l1hdr.b_arc_node), |
| arc_state_multilist_index_func); |
| |
| zfs_refcount_create(&arc_anon->arcs_esize[ARC_BUFC_METADATA]); |
| zfs_refcount_create(&arc_anon->arcs_esize[ARC_BUFC_DATA]); |
| zfs_refcount_create(&arc_mru->arcs_esize[ARC_BUFC_METADATA]); |
| zfs_refcount_create(&arc_mru->arcs_esize[ARC_BUFC_DATA]); |
| zfs_refcount_create(&arc_mru_ghost->arcs_esize[ARC_BUFC_METADATA]); |
| zfs_refcount_create(&arc_mru_ghost->arcs_esize[ARC_BUFC_DATA]); |
| zfs_refcount_create(&arc_mfu->arcs_esize[ARC_BUFC_METADATA]); |
| zfs_refcount_create(&arc_mfu->arcs_esize[ARC_BUFC_DATA]); |
| zfs_refcount_create(&arc_mfu_ghost->arcs_esize[ARC_BUFC_METADATA]); |
| zfs_refcount_create(&arc_mfu_ghost->arcs_esize[ARC_BUFC_DATA]); |
| zfs_refcount_create(&arc_l2c_only->arcs_esize[ARC_BUFC_METADATA]); |
| zfs_refcount_create(&arc_l2c_only->arcs_esize[ARC_BUFC_DATA]); |
| |
| zfs_refcount_create(&arc_anon->arcs_size); |
| zfs_refcount_create(&arc_mru->arcs_size); |
| zfs_refcount_create(&arc_mru_ghost->arcs_size); |
| zfs_refcount_create(&arc_mfu->arcs_size); |
| zfs_refcount_create(&arc_mfu_ghost->arcs_size); |
| zfs_refcount_create(&arc_l2c_only->arcs_size); |
| |
| aggsum_init(&arc_meta_used, 0); |
| aggsum_init(&arc_size, 0); |
| aggsum_init(&astat_data_size, 0); |
| aggsum_init(&astat_metadata_size, 0); |
| aggsum_init(&astat_hdr_size, 0); |
| aggsum_init(&astat_l2_hdr_size, 0); |
| aggsum_init(&astat_bonus_size, 0); |
| aggsum_init(&astat_dnode_size, 0); |
| aggsum_init(&astat_dbuf_size, 0); |
| |
| arc_anon->arcs_state = ARC_STATE_ANON; |
| arc_mru->arcs_state = ARC_STATE_MRU; |
| arc_mru_ghost->arcs_state = ARC_STATE_MRU_GHOST; |
| arc_mfu->arcs_state = ARC_STATE_MFU; |
| arc_mfu_ghost->arcs_state = ARC_STATE_MFU_GHOST; |
| arc_l2c_only->arcs_state = ARC_STATE_L2C_ONLY; |
| } |
| |
| static void |
| arc_state_fini(void) |
| { |
| zfs_refcount_destroy(&arc_anon->arcs_esize[ARC_BUFC_METADATA]); |
| zfs_refcount_destroy(&arc_anon->arcs_esize[ARC_BUFC_DATA]); |
| zfs_refcount_destroy(&arc_mru->arcs_esize[ARC_BUFC_METADATA]); |
| zfs_refcount_destroy(&arc_mru->arcs_esize[ARC_BUFC_DATA]); |
| zfs_refcount_destroy(&arc_mru_ghost->arcs_esize[ARC_BUFC_METADATA]); |
| zfs_refcount_destroy(&arc_mru_ghost->arcs_esize[ARC_BUFC_DATA]); |
| zfs_refcount_destroy(&arc_mfu->arcs_esize[ARC_BUFC_METADATA]); |
| zfs_refcount_destroy(&arc_mfu->arcs_esize[ARC_BUFC_DATA]); |
| zfs_refcount_destroy(&arc_mfu_ghost->arcs_esize[ARC_BUFC_METADATA]); |
| zfs_refcount_destroy(&arc_mfu_ghost->arcs_esize[ARC_BUFC_DATA]); |
| zfs_refcount_destroy(&arc_l2c_only->arcs_esize[ARC_BUFC_METADATA]); |
| zfs_refcount_destroy(&arc_l2c_only->arcs_esize[ARC_BUFC_DATA]); |
| |
| zfs_refcount_destroy(&arc_anon->arcs_size); |
| zfs_refcount_destroy(&arc_mru->arcs_size); |
| zfs_refcount_destroy(&arc_mru_ghost->arcs_size); |
| zfs_refcount_destroy(&arc_mfu->arcs_size); |
| zfs_refcount_destroy(&arc_mfu_ghost->arcs_size); |
| zfs_refcount_destroy(&arc_l2c_only->arcs_size); |
| |
| multilist_destroy(arc_mru->arcs_list[ARC_BUFC_METADATA]); |
| multilist_destroy(arc_mru_ghost->arcs_list[ARC_BUFC_METADATA]); |
| multilist_destroy(arc_mfu->arcs_list[ARC_BUFC_METADATA]); |
| multilist_destroy(arc_mfu_ghost->arcs_list[ARC_BUFC_METADATA]); |
| multilist_destroy(arc_mru->arcs_list[ARC_BUFC_DATA]); |
| multilist_destroy(arc_mru_ghost->arcs_list[ARC_BUFC_DATA]); |
| multilist_destroy(arc_mfu->arcs_list[ARC_BUFC_DATA]); |
| multilist_destroy(arc_mfu_ghost->arcs_list[ARC_BUFC_DATA]); |
| multilist_destroy(arc_l2c_only->arcs_list[ARC_BUFC_METADATA]); |
| multilist_destroy(arc_l2c_only->arcs_list[ARC_BUFC_DATA]); |
| |
| aggsum_fini(&arc_meta_used); |
| aggsum_fini(&arc_size); |
| aggsum_fini(&astat_data_size); |
| aggsum_fini(&astat_metadata_size); |
| aggsum_fini(&astat_hdr_size); |
| aggsum_fini(&astat_l2_hdr_size); |
| aggsum_fini(&astat_bonus_size); |
| aggsum_fini(&astat_dnode_size); |
| aggsum_fini(&astat_dbuf_size); |
| } |
| |
| uint64_t |
| arc_target_bytes(void) |
| { |
| return (arc_c); |
| } |
| |
| void |
| arc_init(void) |
| { |
| uint64_t percent, allmem = arc_all_memory(); |
| mutex_init(&arc_adjust_lock, NULL, MUTEX_DEFAULT, NULL); |
| cv_init(&arc_adjust_waiters_cv, NULL, CV_DEFAULT, NULL); |
| |
| arc_min_prefetch_ms = 1000; |
| arc_min_prescient_prefetch_ms = 6000; |
| |
| #ifdef _KERNEL |
| /* |
| * Register a shrinker to support synchronous (direct) memory |
| * reclaim from the arc. This is done to prevent kswapd from |
| * swapping out pages when it is preferable to shrink the arc. |
| */ |
| spl_register_shrinker(&arc_shrinker); |
| |
| /* Set to 1/64 of all memory or a minimum of 512K */ |
| arc_sys_free = MAX(allmem / 64, (512 * 1024)); |
| arc_need_free = 0; |
| #endif |
| |
| /* Set max to 1/2 of all memory */ |
| arc_c_max = allmem / 2; |
| |
| #ifdef _KERNEL |
| /* Set min cache to 1/32 of all memory, or 32MB, whichever is more */ |
| arc_c_min = MAX(allmem / 32, 2ULL << SPA_MAXBLOCKSHIFT); |
| #else |
| /* |
| * In userland, there's only the memory pressure that we artificially |
| * create (see arc_available_memory()). Don't let arc_c get too |
| * small, because it can cause transactions to be larger than |
| * arc_c, causing arc_tempreserve_space() to fail. |
| */ |
| arc_c_min = MAX(arc_c_max / 2, 2ULL << SPA_MAXBLOCKSHIFT); |
| #endif |
| |
| arc_c = arc_c_max; |
| arc_p = (arc_c >> 1); |
| |
| /* Set min to 1/2 of arc_c_min */ |
| arc_meta_min = 1ULL << SPA_MAXBLOCKSHIFT; |
| /* Initialize maximum observed usage to zero */ |
| arc_meta_max = 0; |
| /* |
| * Set arc_meta_limit to a percent of arc_c_max with a floor of |
| * arc_meta_min, and a ceiling of arc_c_max. |
| */ |
| percent = MIN(zfs_arc_meta_limit_percent, 100); |
| arc_meta_limit = MAX(arc_meta_min, (percent * arc_c_max) / 100); |
| percent = MIN(zfs_arc_dnode_limit_percent, 100); |
| arc_dnode_limit = (percent * arc_meta_limit) / 100; |
| |
| /* Apply user specified tunings */ |
| arc_tuning_update(); |
| |
| /* if kmem_flags are set, lets try to use less memory */ |
| if (kmem_debugging()) |
| arc_c = arc_c / 2; |
| if (arc_c < arc_c_min) |
| arc_c = arc_c_min; |
| |
| arc_state_init(); |
| |
| /* |
| * The arc must be "uninitialized", so that hdr_recl() (which is |
| * registered by buf_init()) will not access arc_reap_zthr before |
| * it is created. |
| */ |
| ASSERT(!arc_initialized); |
| buf_init(); |
| |
| list_create(&arc_prune_list, sizeof (arc_prune_t), |
| offsetof(arc_prune_t, p_node)); |
| mutex_init(&arc_prune_mtx, NULL, MUTEX_DEFAULT, NULL); |
| |
| arc_prune_taskq = taskq_create("arc_prune", boot_ncpus, defclsyspri, |
| boot_ncpus, INT_MAX, TASKQ_PREPOPULATE | TASKQ_DYNAMIC); |
| |
| arc_ksp = kstat_create("zfs", 0, "arcstats", "misc", KSTAT_TYPE_NAMED, |
| sizeof (arc_stats) / sizeof (kstat_named_t), KSTAT_FLAG_VIRTUAL); |
| |
| if (arc_ksp != NULL) { |
| arc_ksp->ks_data = &arc_stats; |
| arc_ksp->ks_update = arc_kstat_update; |
| kstat_install(arc_ksp); |
| } |
| |
| arc_adjust_zthr = zthr_create(arc_adjust_cb_check, |
| arc_adjust_cb, NULL); |
| arc_reap_zthr = zthr_create_timer(arc_reap_cb_check, |
| arc_reap_cb, NULL, SEC2NSEC(1)); |
| |
| arc_initialized = B_TRUE; |
| arc_warm = B_FALSE; |
| |
| /* |
| * Calculate maximum amount of dirty data per pool. |
| * |
| * If it has been set by a module parameter, take that. |
| * Otherwise, use a percentage of physical memory defined by |
| * zfs_dirty_data_max_percent (default 10%) with a cap at |
| * zfs_dirty_data_max_max (default 4G or 25% of physical memory). |
| */ |
| if (zfs_dirty_data_max_max == 0) |
| zfs_dirty_data_max_max = MIN(4ULL * 1024 * 1024 * 1024, |
| allmem * zfs_dirty_data_max_max_percent / 100); |
| |
| if (zfs_dirty_data_max == 0) { |
| zfs_dirty_data_max = allmem * |
| zfs_dirty_data_max_percent / 100; |
| zfs_dirty_data_max = MIN(zfs_dirty_data_max, |
| zfs_dirty_data_max_max); |
| } |
| } |
| |
| void |
| arc_fini(void) |
| { |
| arc_prune_t *p; |
| |
| #ifdef _KERNEL |
| spl_unregister_shrinker(&arc_shrinker); |
| #endif /* _KERNEL */ |
| |
| /* Use B_TRUE to ensure *all* buffers are evicted */ |
| arc_flush(NULL, B_TRUE); |
| |
| arc_initialized = B_FALSE; |
| |
| if (arc_ksp != NULL) { |
| kstat_delete(arc_ksp); |
| arc_ksp = NULL; |
| } |
| |
| taskq_wait(arc_prune_taskq); |
| taskq_destroy(arc_prune_taskq); |
| |
| mutex_enter(&arc_prune_mtx); |
| while ((p = list_head(&arc_prune_list)) != NULL) { |
| list_remove(&arc_prune_list, p); |
| zfs_refcount_remove(&p->p_refcnt, &arc_prune_list); |
| zfs_refcount_destroy(&p->p_refcnt); |
| kmem_free(p, sizeof (*p)); |
| } |
| mutex_exit(&arc_prune_mtx); |
| |
| list_destroy(&arc_prune_list); |
| mutex_destroy(&arc_prune_mtx); |
| |
| (void) zthr_cancel(arc_adjust_zthr); |
| (void) zthr_cancel(arc_reap_zthr); |
| |
| mutex_destroy(&arc_adjust_lock); |
| cv_destroy(&arc_adjust_waiters_cv); |
| |
| /* |
| * buf_fini() must proceed arc_state_fini() because buf_fin() may |
| * trigger the release of kmem magazines, which can callback to |
| * arc_space_return() which accesses aggsums freed in act_state_fini(). |
| */ |
| buf_fini(); |
| arc_state_fini(); |
| |
| /* |
| * We destroy the zthrs after all the ARC state has been |
| * torn down to avoid the case of them receiving any |
| * wakeup() signals after they are destroyed. |
| */ |
| zthr_destroy(arc_adjust_zthr); |
| zthr_destroy(arc_reap_zthr); |
| |
| ASSERT0(arc_loaned_bytes); |
| } |
| |
| /* |
| * Level 2 ARC |
| * |
| * The level 2 ARC (L2ARC) is a cache layer in-between main memory and disk. |
| * It uses dedicated storage devices to hold cached data, which are populated |
| * using large infrequent writes. The main role of this cache is to boost |
| * the performance of random read workloads. The intended L2ARC devices |
| * include short-stroked disks, solid state disks, and other media with |
| * substantially faster read latency than disk. |
| * |
| * +-----------------------+ |
| * | ARC | |
| * +-----------------------+ |
| * | ^ ^ |
| * | | | |
| * l2arc_feed_thread() arc_read() |
| * | | | |
| * | l2arc read | |
| * V | | |
| * +---------------+ | |
| * | L2ARC | | |
| * +---------------+ | |
| * | ^ | |
| * l2arc_write() | | |
| * | | | |
| * V | | |
| * +-------+ +-------+ |
| * | vdev | | vdev | |
| * | cache | | cache | |
| * +-------+ +-------+ |
| * +=========+ .-----. |
| * : L2ARC : |-_____-| |
| * : devices : | Disks | |
| * +=========+ `-_____-' |
| * |
| * Read requests are satisfied from the following sources, in order: |
| * |
| * 1) ARC |
| * 2) vdev cache of L2ARC devices |
| * 3) L2ARC devices |
| * 4) vdev cache of disks |
| * 5) disks |
| * |
| * Some L2ARC device types exhibit extremely slow write performance. |
| * To accommodate for this there are some significant differences between |
| * the L2ARC and traditional cache design: |
| * |
| * 1. There is no eviction path from the ARC to the L2ARC. Evictions from |
| * the ARC behave as usual, freeing buffers and placing headers on ghost |
| * lists. The ARC does not send buffers to the L2ARC during eviction as |
| * this would add inflated write latencies for all ARC memory pressure. |
| * |
| * 2. The L2ARC attempts to cache data from the ARC before it is evicted. |
| * It does this by periodically scanning buffers from the eviction-end of |
| * the MFU and MRU ARC lists, copying them to the L2ARC devices if they are |
| * not already there. It scans until a headroom of buffers is satisfied, |
| * which itself is a buffer for ARC eviction. If a compressible buffer is |
| * found during scanning and selected for writing to an L2ARC device, we |
| * temporarily boost scanning headroom during the next scan cycle to make |
| * sure we adapt to compression effects (which might significantly reduce |
| * the data volume we write to L2ARC). The thread that does this is |
| * l2arc_feed_thread(), illustrated below; example sizes are included to |
| * provide a better sense of ratio than this diagram: |
| * |
| * head --> tail |
| * +---------------------+----------+ |
| * ARC_mfu |:::::#:::::::::::::::|o#o###o###|-->. # already on L2ARC |
| * +---------------------+----------+ | o L2ARC eligible |
| * ARC_mru |:#:::::::::::::::::::|#o#ooo####|-->| : ARC buffer |
| * +---------------------+----------+ | |
| * 15.9 Gbytes ^ 32 Mbytes | |
| * headroom | |
| * l2arc_feed_thread() |
| * | |
| * l2arc write hand <--[oooo]--' |
| * | 8 Mbyte |
| * | write max |
| * V |
| * +==============================+ |
| * L2ARC dev |####|#|###|###| |####| ... | |
| * +==============================+ |
| * 32 Gbytes |
| * |
| * 3. If an ARC buffer is copied to the L2ARC but then hit instead of |
| * evicted, then the L2ARC has cached a buffer much sooner than it probably |
| * needed to, potentially wasting L2ARC device bandwidth and storage. It is |
| * safe to say that this is an uncommon case, since buffers at the end of |
| * the ARC lists have moved there due to inactivity. |
| * |
| * 4. If the ARC evicts faster than the L2ARC can maintain a headroom, |
| * then the L2ARC simply misses copying some buffers. This serves as a |
| * pressure valve to prevent heavy read workloads from both stalling the ARC |
| * with waits and clogging the L2ARC with writes. This also helps prevent |
| * the potential for the L2ARC to churn if it attempts to cache content too |
| * quickly, such as during backups of the entire pool. |
| * |
| * 5. After system boot and before the ARC has filled main memory, there are |
| * no evictions from the ARC and so the tails of the ARC_mfu and ARC_mru |
| * lists can remain mostly static. Instead of searching from tail of these |
| * lists as pictured, the l2arc_feed_thread() will search from the list heads |
| * for eligible buffers, greatly increasing its chance of finding them. |
| * |
| * The L2ARC device write speed is also boosted during this time so that |
| * the L2ARC warms up faster. Since there have been no ARC evictions yet, |
| * there are no L2ARC reads, and no fear of degrading read performance |
| * through increased writes. |
| * |
| * 6. Writes to the L2ARC devices are grouped and sent in-sequence, so that |
| * the vdev queue can aggregate them into larger and fewer writes. Each |
| * device is written to in a rotor fashion, sweeping writes through |
| * available space then repeating. |
| * |
| * 7. The L2ARC does not store dirty content. It never needs to flush |
| * write buffers back to disk based storage. |
| * |
| * 8. If an ARC buffer is written (and dirtied) which also exists in the |
| * L2ARC, the now stale L2ARC buffer is immediately dropped. |
| * |
| * The performance of the L2ARC can be tweaked by a number of tunables, which |
| * may be necessary for different workloads: |
| * |
| * l2arc_write_max max write bytes per interval |
| * l2arc_write_boost extra write bytes during device warmup |
| * l2arc_noprefetch skip caching prefetched buffers |
| * l2arc_headroom number of max device writes to precache |
| * l2arc_headroom_boost when we find compressed buffers during ARC |
| * scanning, we multiply headroom by this |
| * percentage factor for the next scan cycle, |
| * since more compressed buffers are likely to |
| * be present |
| * l2arc_feed_secs seconds between L2ARC writing |
| * |
| * Tunables may be removed or added as future performance improvements are |
| * integrated, and also may become zpool properties. |
| * |
| * There are three key functions that control how the L2ARC warms up: |
| * |
| * l2arc_write_eligible() check if a buffer is eligible to cache |
| * l2arc_write_size() calculate how much to write |
| * l2arc_write_interval() calculate sleep delay between writes |
| * |
| * These three functions determine what to write, how much, and how quickly |
| * to send writes. |
| */ |
| |
| static boolean_t |
| l2arc_write_eligible(uint64_t spa_guid, arc_buf_hdr_t *hdr) |
| { |
| /* |
| * A buffer is *not* eligible for the L2ARC if it: |
| * 1. belongs to a different spa. |
| * 2. is already cached on the L2ARC. |
| * 3. has an I/O in progress (it may be an incomplete read). |
| * 4. is flagged not eligible (zfs property). |
| */ |
| if (hdr->b_spa != spa_guid || HDR_HAS_L2HDR(hdr) || |
| HDR_IO_IN_PROGRESS(hdr) || !HDR_L2CACHE(hdr)) |
| return (B_FALSE); |
| |
| return (B_TRUE); |
| } |
| |
| static uint64_t |
| l2arc_write_size(void) |
| { |
| uint64_t size; |
| |
| /* |
| * Make sure our globals have meaningful values in case the user |
| * altered them. |
| */ |
| size = l2arc_write_max; |
| if (size == 0) { |
| cmn_err(CE_NOTE, "Bad value for l2arc_write_max, value must " |
| "be greater than zero, resetting it to the default (%d)", |
| L2ARC_WRITE_SIZE); |
| size = l2arc_write_max = L2ARC_WRITE_SIZE; |
| } |
| |
| if (arc_warm == B_FALSE) |
| size += l2arc_write_boost; |
| |
| return (size); |
| |
| } |
| |
| static clock_t |
| l2arc_write_interval(clock_t began, uint64_t wanted, uint64_t wrote) |
| { |
| clock_t interval, next, now; |
| |
| /* |
| * If the ARC lists are busy, increase our write rate; if the |
| * lists are stale, idle back. This is achieved by checking |
| * how much we previously wrote - if it was more than half of |
| * what we wanted, schedule the next write much sooner. |
| */ |
| if (l2arc_feed_again && wrote > (wanted / 2)) |
| interval = (hz * l2arc_feed_min_ms) / 1000; |
| else |
| interval = hz * l2arc_feed_secs; |
| |
| now = ddi_get_lbolt(); |
| next = MAX(now, MIN(now + interval, began + interval)); |
| |
| return (next); |
| } |
| |
| /* |
| * Cycle through L2ARC devices. This is how L2ARC load balances. |
| * If a device is returned, this also returns holding the spa config lock. |
| */ |
| static l2arc_dev_t * |
| l2arc_dev_get_next(void) |
| { |
| l2arc_dev_t *first, *next = NULL; |
| |
| /* |
| * Lock out the removal of spas (spa_namespace_lock), then removal |
| * of cache devices (l2arc_dev_mtx). Once a device has been selected, |
| * both locks will be dropped and a spa config lock held instead. |
| */ |
| mutex_enter(&spa_namespace_lock); |
| mutex_enter(&l2arc_dev_mtx); |
| |
| /* if there are no vdevs, there is nothing to do */ |
| if (l2arc_ndev == 0) |
| goto out; |
| |
| first = NULL; |
| next = l2arc_dev_last; |
| do { |
| /* loop around the list looking for a non-faulted vdev */ |
| if (next == NULL) { |
| next = list_head(l2arc_dev_list); |
| } else { |
| next = list_next(l2arc_dev_list, next); |
| if (next == NULL) |
| next = list_head(l2arc_dev_list); |
| } |
| |
| /* if we have come back to the start, bail out */ |
| if (first == NULL) |
| first = next; |
| else if (next == first) |
| break; |
| |
| } while (vdev_is_dead(next->l2ad_vdev)); |
| |
| /* if we were unable to find any usable vdevs, return NULL */ |
| if (vdev_is_dead(next->l2ad_vdev)) |
| next = NULL; |
| |
| l2arc_dev_last = next; |
| |
| out: |
| mutex_exit(&l2arc_dev_mtx); |
| |
| /* |
| * Grab the config lock to prevent the 'next' device from being |
| * removed while we are writing to it. |
| */ |
| if (next != NULL) |
| spa_config_enter(next->l2ad_spa, SCL_L2ARC, next, RW_READER); |
| mutex_exit(&spa_namespace_lock); |
| |
| return (next); |
| } |
| |
| /* |
| * Free buffers that were tagged for destruction. |
| */ |
| static void |
| l2arc_do_free_on_write(void) |
| { |
| list_t *buflist; |
| l2arc_data_free_t *df, *df_prev; |
| |
| mutex_enter(&l2arc_free_on_write_mtx); |
| buflist = l2arc_free_on_write; |
| |
| for (df = list_tail(buflist); df; df = df_prev) { |
| df_prev = list_prev(buflist, df); |
| ASSERT3P(df->l2df_abd, !=, NULL); |
| abd_free(df->l2df_abd); |
| list_remove(buflist, df); |
| kmem_free(df, sizeof (l2arc_data_free_t)); |
| } |
| |
| mutex_exit(&l2arc_free_on_write_mtx); |
| } |
| |
| /* |
| * A write to a cache device has completed. Update all headers to allow |
| * reads from these buffers to begin. |
| */ |
| static void |
| l2arc_write_done(zio_t *zio) |
| { |
| l2arc_write_callback_t *cb; |
| l2arc_dev_t *dev; |
| list_t *buflist; |
| arc_buf_hdr_t *head, *hdr, *hdr_prev; |
| kmutex_t *hash_lock; |
| int64_t bytes_dropped = 0; |
| |
| cb = zio->io_private; |
| ASSERT3P(cb, !=, NULL); |
| dev = cb->l2wcb_dev; |
| ASSERT3P(dev, !=, NULL); |
| head = cb->l2wcb_head; |
| ASSERT3P(head, !=, NULL); |
| buflist = &dev->l2ad_buflist; |
| ASSERT3P(buflist, !=, NULL); |
| DTRACE_PROBE2(l2arc__iodone, zio_t *, zio, |
| l2arc_write_callback_t *, cb); |
| |
| if (zio->io_error != 0) |
| ARCSTAT_BUMP(arcstat_l2_writes_error); |
| |
| /* |
| * All writes completed, or an error was hit. |
| */ |
| top: |
| mutex_enter(&dev->l2ad_mtx); |
| for (hdr = list_prev(buflist, head); hdr; hdr = hdr_prev) { |
| hdr_prev = list_prev(buflist, hdr); |
| |
| hash_lock = HDR_LOCK(hdr); |
| |
| /* |
| * We cannot use mutex_enter or else we can deadlock |
| * with l2arc_write_buffers (due to swapping the order |
| * the hash lock and l2ad_mtx are taken). |
| */ |
| if (!mutex_tryenter(hash_lock)) { |
| /* |
| * Missed the hash lock. We must retry so we |
| * don't leave the ARC_FLAG_L2_WRITING bit set. |
| */ |
| ARCSTAT_BUMP(arcstat_l2_writes_lock_retry); |
| |
| /* |
| * We don't want to rescan the headers we've |
| * already marked as having been written out, so |
| * we reinsert the head node so we can pick up |
| * where we left off. |
| */ |
| list_remove(buflist, head); |
| list_insert_after(buflist, hdr, head); |
| |
| mutex_exit(&dev->l2ad_mtx); |
| |
| /* |
| * We wait for the hash lock to become available |
| * to try and prevent busy waiting, and increase |
| * the chance we'll be able to acquire the lock |
| * the next time around. |
| */ |
| mutex_enter(hash_lock); |
| mutex_exit(hash_lock); |
| goto top; |
| } |
| |
| /* |
| * We could not have been moved into the arc_l2c_only |
| * state while in-flight due to our ARC_FLAG_L2_WRITING |
| * bit being set. Let's just ensure that's being enforced. |
| */ |
| ASSERT(HDR_HAS_L1HDR(hdr)); |
| |
| /* |
| * Skipped - drop L2ARC entry and mark the header as no |
| * longer L2 eligibile. |
| */ |
| if (zio->io_error != 0) { |
| /* |
| * Error - drop L2ARC entry. |
| */ |
| list_remove(buflist, hdr); |
| arc_hdr_clear_flags(hdr, ARC_FLAG_HAS_L2HDR); |
| |
| uint64_t psize = HDR_GET_PSIZE(hdr); |
| ARCSTAT_INCR(arcstat_l2_psize, -psize); |
| ARCSTAT_INCR(arcstat_l2_lsize, -HDR_GET_LSIZE(hdr)); |
| |
| bytes_dropped += |
| vdev_psize_to_asize(dev->l2ad_vdev, psize); |
| (void) zfs_refcount_remove_many(&dev->l2ad_alloc, |
| arc_hdr_size(hdr), hdr); |
| } |
| |
| /* |
| * Allow ARC to begin reads and ghost list evictions to |
| * this L2ARC entry. |
| */ |
| arc_hdr_clear_flags(hdr, ARC_FLAG_L2_WRITING); |
| |
| mutex_exit(hash_lock); |
| } |
| |
| atomic_inc_64(&l2arc_writes_done); |
| list_remove(buflist, head); |
| ASSERT(!HDR_HAS_L1HDR(head)); |
| kmem_cache_free(hdr_l2only_cache, head); |
| mutex_exit(&dev->l2ad_mtx); |
| |
| vdev_space_update(dev->l2ad_vdev, -bytes_dropped, 0, 0); |
| |
| l2arc_do_free_on_write(); |
| |
| kmem_free(cb, sizeof (l2arc_write_callback_t)); |
| } |
| |
| static int |
| l2arc_untransform(zio_t *zio, l2arc_read_callback_t *cb) |
| { |
| int ret; |
| spa_t *spa = zio->io_spa; |
| arc_buf_hdr_t *hdr = cb->l2rcb_hdr; |
| blkptr_t *bp = zio->io_bp; |
| uint8_t salt[ZIO_DATA_SALT_LEN]; |
| uint8_t iv[ZIO_DATA_IV_LEN]; |
| uint8_t mac[ZIO_DATA_MAC_LEN]; |
| boolean_t no_crypt = B_FALSE; |
| |
| /* |
| * ZIL data is never be written to the L2ARC, so we don't need |
| * special handling for its unique MAC storage. |
| */ |
| ASSERT3U(BP_GET_TYPE(bp), !=, DMU_OT_INTENT_LOG); |
| ASSERT(MUTEX_HELD(HDR_LOCK(hdr))); |
| ASSERT3P(hdr->b_l1hdr.b_pabd, !=, NULL); |
| |
| /* |
| * If the data was encrypted, decrypt it now. Note that |
| * we must check the bp here and not the hdr, since the |
| * hdr does not have its encryption parameters updated |
| * until arc_read_done(). |
| */ |
| if (BP_IS_ENCRYPTED(bp)) { |
| abd_t *eabd = arc_get_data_abd(hdr, arc_hdr_size(hdr), hdr, |
| B_TRUE); |
| |
| zio_crypt_decode_params_bp(bp, salt, iv); |
| zio_crypt_decode_mac_bp(bp, mac); |
| |
| ret = spa_do_crypt_abd(B_FALSE, spa, &cb->l2rcb_zb, |
| BP_GET_TYPE(bp), BP_GET_DEDUP(bp), BP_SHOULD_BYTESWAP(bp), |
| salt, iv, mac, HDR_GET_PSIZE(hdr), eabd, |
| hdr->b_l1hdr.b_pabd, &no_crypt); |
| if (ret != 0) { |
| arc_free_data_abd(hdr, eabd, arc_hdr_size(hdr), hdr); |
| goto error; |
| } |
| |
| /* |
| * If we actually performed decryption, replace b_pabd |
| * with the decrypted data. Otherwise we can just throw |
| * our decryption buffer away. |
| */ |
| if (!no_crypt) { |
| arc_free_data_abd(hdr, hdr->b_l1hdr.b_pabd, |
| arc_hdr_size(hdr), hdr); |
| hdr->b_l1hdr.b_pabd = eabd; |
| zio->io_abd = eabd; |
| } else { |
| arc_free_data_abd(hdr, eabd, arc_hdr_size(hdr), hdr); |
| } |
| } |
| |
| /* |
| * If the L2ARC block was compressed, but ARC compression |
| * is disabled we decompress the data into a new buffer and |
| * replace the existing data. |
| */ |
| if (HDR_GET_COMPRESS(hdr) != ZIO_COMPRESS_OFF && |
| !HDR_COMPRESSION_ENABLED(hdr)) { |
| abd_t *cabd = arc_get_data_abd(hdr, arc_hdr_size(hdr), hdr, |
| B_TRUE); |
| void *tmp = abd_borrow_buf(cabd, arc_hdr_size(hdr)); |
| |
| ret = zio_decompress_data(HDR_GET_COMPRESS(hdr), |
| hdr->b_l1hdr.b_pabd, tmp, HDR_GET_PSIZE(hdr), |
| HDR_GET_LSIZE(hdr)); |
| if (ret != 0) { |
| abd_return_buf_copy(cabd, tmp, arc_hdr_size(hdr)); |
| arc_free_data_abd(hdr, cabd, arc_hdr_size(hdr), hdr); |
| goto error; |
| } |
| |
| abd_return_buf_copy(cabd, tmp, arc_hdr_size(hdr)); |
| arc_free_data_abd(hdr, hdr->b_l1hdr.b_pabd, |
| arc_hdr_size(hdr), hdr); |
| hdr->b_l1hdr.b_pabd = cabd; |
| zio->io_abd = cabd; |
| zio->io_size = HDR_GET_LSIZE(hdr); |
| } |
| |
| return (0); |
| |
| error: |
| return (ret); |
| } |
| |
| |
| /* |
| * A read to a cache device completed. Validate buffer contents before |
| * handing over to the regular ARC routines. |
| */ |
| static void |
| l2arc_read_done(zio_t *zio) |
| { |
| int tfm_error = 0; |
| l2arc_read_callback_t *cb = zio->io_private; |
| arc_buf_hdr_t *hdr; |
| kmutex_t *hash_lock; |
| boolean_t valid_cksum; |
| boolean_t using_rdata = (BP_IS_ENCRYPTED(&cb->l2rcb_bp) && |
| (cb->l2rcb_flags & ZIO_FLAG_RAW_ENCRYPT)); |
| |
| ASSERT3P(zio->io_vd, !=, NULL); |
| ASSERT(zio->io_flags & ZIO_FLAG_DONT_PROPAGATE); |
| |
| spa_config_exit(zio->io_spa, SCL_L2ARC, zio->io_vd); |
| |
| ASSERT3P(cb, !=, NULL); |
| hdr = cb->l2rcb_hdr; |
| ASSERT3P(hdr, !=, NULL); |
| |
| hash_lock = HDR_LOCK(hdr); |
| mutex_enter(hash_lock); |
| ASSERT3P(hash_lock, ==, HDR_LOCK(hdr)); |
| |
| /* |
| * If the data was read into a temporary buffer, |
| * move it and free the buffer. |
| */ |
| if (cb->l2rcb_abd != NULL) { |
| ASSERT3U(arc_hdr_size(hdr), <, zio->io_size); |
| if (zio->io_error == 0) { |
| if (using_rdata) { |
| abd_copy(hdr->b_crypt_hdr.b_rabd, |
| cb->l2rcb_abd, arc_hdr_size(hdr)); |
| } else { |
| abd_copy(hdr->b_l1hdr.b_pabd, |
| cb->l2rcb_abd, arc_hdr_size(hdr)); |
| } |
| } |
| |
| /* |
| * The following must be done regardless of whether |
| * there was an error: |
| * - free the temporary buffer |
| * - point zio to the real ARC buffer |
| * - set zio size accordingly |
| * These are required because zio is either re-used for |
| * an I/O of the block in the case of the error |
| * or the zio is passed to arc_read_done() and it |
| * needs real data. |
| */ |
| abd_free(cb->l2rcb_abd); |
| zio->io_size = zio->io_orig_size = arc_hdr_size(hdr); |
| |
| if (using_rdata) { |
| ASSERT(HDR_HAS_RABD(hdr)); |
| zio->io_abd = zio->io_orig_abd = |
| hdr->b_crypt_hdr.b_rabd; |
| } else { |
| ASSERT3P(hdr->b_l1hdr.b_pabd, !=, NULL); |
| zio->io_abd = zio->io_orig_abd = hdr->b_l1hdr.b_pabd; |
| } |
| } |
| |
| ASSERT3P(zio->io_abd, !=, NULL); |
| |
| /* |
| * Check this survived the L2ARC journey. |
| */ |
| ASSERT(zio->io_abd == hdr->b_l1hdr.b_pabd || |
| (HDR_HAS_RABD(hdr) && zio->io_abd == hdr->b_crypt_hdr.b_rabd)); |
| zio->io_bp_copy = cb->l2rcb_bp; /* XXX fix in L2ARC 2.0 */ |
| zio->io_bp = &zio->io_bp_copy; /* XXX fix in L2ARC 2.0 */ |
| |
| valid_cksum = arc_cksum_is_equal(hdr, zio); |
| |
| /* |
| * b_rabd will always match the data as it exists on disk if it is |
| * being used. Therefore if we are reading into b_rabd we do not |
| * attempt to untransform the data. |
| */ |
| if (valid_cksum && !using_rdata) |
| tfm_error = l2arc_untransform(zio, cb); |
| |
| if (valid_cksum && tfm_error == 0 && zio->io_error == 0 && |
| !HDR_L2_EVICTED(hdr)) { |
| mutex_exit(hash_lock); |
| zio->io_private = hdr; |
| arc_read_done(zio); |
| } else { |
| /* |
| * Buffer didn't survive caching. Increment stats and |
| * reissue to the original storage device. |
| */ |
| if (zio->io_error != 0) { |
| ARCSTAT_BUMP(arcstat_l2_io_error); |
| } else { |
| zio->io_error = SET_ERROR(EIO); |
| } |
| if (!valid_cksum || tfm_error != 0) |
| ARCSTAT_BUMP(arcstat_l2_cksum_bad); |
| |
| /* |
| * If there's no waiter, issue an async i/o to the primary |
| * storage now. If there *is* a waiter, the caller must |
| * issue the i/o in a context where it's OK to block. |
| */ |
| if (zio->io_waiter == NULL) { |
| zio_t *pio = zio_unique_parent(zio); |
| void *abd = (using_rdata) ? |
| hdr->b_crypt_hdr.b_rabd : hdr->b_l1hdr.b_pabd; |
| |
| ASSERT(!pio || pio->io_child_type == ZIO_CHILD_LOGICAL); |
| |
| zio = zio_read(pio, zio->io_spa, zio->io_bp, |
| abd, zio->io_size, arc_read_done, |
| hdr, zio->io_priority, cb->l2rcb_flags, |
| &cb->l2rcb_zb); |
| |
| /* |
| * Original ZIO will be freed, so we need to update |
| * ARC header with the new ZIO pointer to be used |
| * by zio_change_priority() in arc_read(). |
| */ |
| for (struct arc_callback *acb = hdr->b_l1hdr.b_acb; |
| acb != NULL; acb = acb->acb_next) |
| acb->acb_zio_head = zio; |
| |
| mutex_exit(hash_lock); |
| zio_nowait(zio); |
| } else { |
| mutex_exit(hash_lock); |
| } |
| } |
| |
| kmem_free(cb, sizeof (l2arc_read_callback_t)); |
| } |
| |
| /* |
| * This is the list priority from which the L2ARC will search for pages to |
| * cache. This is used within loops (0..3) to cycle through lists in the |
| * desired order. This order can have a significant effect on cache |
| * performance. |
| * |
| * Currently the metadata lists are hit first, MFU then MRU, followed by |
| * the data lists. This function returns a locked list, and also returns |
| * the lock pointer. |
| */ |
| static multilist_sublist_t * |
| l2arc_sublist_lock(int list_num) |
| { |
| multilist_t *ml = NULL; |
| unsigned int idx; |
| |
| ASSERT(list_num >= 0 && list_num < L2ARC_FEED_TYPES); |
| |
| switch (list_num) { |
| case 0: |
| ml = arc_mfu->arcs_list[ARC_BUFC_METADATA]; |
| break; |
| case 1: |
| ml = arc_mru->arcs_list[ARC_BUFC_METADATA]; |
| break; |
| case 2: |
| ml = arc_mfu->arcs_list[ARC_BUFC_DATA]; |
| break; |
| case 3: |
| ml = arc_mru->arcs_list[ARC_BUFC_DATA]; |
| break; |
| default: |
| return (NULL); |
| } |
| |
| /* |
| * Return a randomly-selected sublist. This is acceptable |
| * because the caller feeds only a little bit of data for each |
| * call (8MB). Subsequent calls will result in different |
| * sublists being selected. |
| */ |
| idx = multilist_get_random_index(ml); |
| return (multilist_sublist_lock(ml, idx)); |
| } |
| |
| /* |
| * Evict buffers from the device write hand to the distance specified in |
| * bytes. This distance may span populated buffers, it may span nothing. |
| * This is clearing a region on the L2ARC device ready for writing. |
| * If the 'all' boolean is set, every buffer is evicted. |
| */ |
| static void |
| l2arc_evict(l2arc_dev_t *dev, uint64_t distance, boolean_t all) |
| { |
| list_t *buflist; |
| arc_buf_hdr_t *hdr, *hdr_prev; |
| kmutex_t *hash_lock; |
| uint64_t taddr; |
| |
| buflist = &dev->l2ad_buflist; |
| |
| if (!all && dev->l2ad_first) { |
| /* |
| * This is the first sweep through the device. There is |
| * nothing to evict. |
| */ |
| return; |
| } |
| |
| if (dev->l2ad_hand >= (dev->l2ad_end - (2 * distance))) { |
| /* |
| * When nearing the end of the device, evict to the end |
| * before the device write hand jumps to the start. |
| */ |
| taddr = dev->l2ad_end; |
| } else { |
| taddr = dev->l2ad_hand + distance; |
| } |
| DTRACE_PROBE4(l2arc__evict, l2arc_dev_t *, dev, list_t *, buflist, |
| uint64_t, taddr, boolean_t, all); |
| |
| top: |
| mutex_enter(&dev->l2ad_mtx); |
| for (hdr = list_tail(buflist); hdr; hdr = hdr_prev) { |
| hdr_prev = list_prev(buflist, hdr); |
| |
| ASSERT(!HDR_EMPTY(hdr)); |
| hash_lock = HDR_LOCK(hdr); |
| |
| /* |
| * We cannot use mutex_enter or else we can deadlock |
| * with l2arc_write_buffers (due to swapping the order |
| * the hash lock and l2ad_mtx are taken). |
| */ |
| if (!mutex_tryenter(hash_lock)) { |
| /* |
| * Missed the hash lock. Retry. |
| */ |
| ARCSTAT_BUMP(arcstat_l2_evict_lock_retry); |
| mutex_exit(&dev->l2ad_mtx); |
| mutex_enter(hash_lock); |
| mutex_exit(hash_lock); |
| goto top; |
| } |
| |
| /* |
| * A header can't be on this list if it doesn't have L2 header. |
| */ |
| ASSERT(HDR_HAS_L2HDR(hdr)); |
| |
| /* Ensure this header has finished being written. */ |
| ASSERT(!HDR_L2_WRITING(hdr)); |
| ASSERT(!HDR_L2_WRITE_HEAD(hdr)); |
| |
| if (!all && (hdr->b_l2hdr.b_daddr >= taddr || |
| hdr->b_l2hdr.b_daddr < dev->l2ad_hand)) { |
| /* |
| * We've evicted to the target address, |
| * or the end of the device. |
| */ |
| mutex_exit(hash_lock); |
| break; |
| } |
| |
| if (!HDR_HAS_L1HDR(hdr)) { |
| ASSERT(!HDR_L2_READING(hdr)); |
| /* |
| * This doesn't exist in the ARC. Destroy. |
| * arc_hdr_destroy() will call list_remove() |
| * and decrement arcstat_l2_lsize. |
| */ |
| arc_change_state(arc_anon, hdr, hash_lock); |
| arc_hdr_destroy(hdr); |
| } else { |
| ASSERT(hdr->b_l1hdr.b_state != arc_l2c_only); |
| ARCSTAT_BUMP(arcstat_l2_evict_l1cached); |
| /* |
| * Invalidate issued or about to be issued |
| * reads, since we may be about to write |
| * over this location. |
| */ |
| if (HDR_L2_READING(hdr)) { |
| ARCSTAT_BUMP(arcstat_l2_evict_reading); |
| arc_hdr_set_flags(hdr, ARC_FLAG_L2_EVICTED); |
| } |
| |
| arc_hdr_l2hdr_destroy(hdr); |
| } |
| mutex_exit(hash_lock); |
| } |
| mutex_exit(&dev->l2ad_mtx); |
| } |
| |
| /* |
| * Handle any abd transforms that might be required for writing to the L2ARC. |
| * If successful, this function will always return an abd with the data |
| * transformed as it is on disk in a new abd of asize bytes. |
| */ |
| static int |
| l2arc_apply_transforms(spa_t *spa, arc_buf_hdr_t *hdr, uint64_t asize, |
| abd_t **abd_out) |
| { |
| int ret; |
| void *tmp = NULL; |
| abd_t *cabd = NULL, *eabd = NULL, *to_write = hdr->b_l1hdr.b_pabd; |
| enum zio_compress compress = HDR_GET_COMPRESS(hdr); |
| uint64_t psize = HDR_GET_PSIZE(hdr); |
| uint64_t size = arc_hdr_size(hdr); |
| boolean_t ismd = HDR_ISTYPE_METADATA(hdr); |
| boolean_t bswap = (hdr->b_l1hdr.b_byteswap != DMU_BSWAP_NUMFUNCS); |
| dsl_crypto_key_t *dck = NULL; |
| uint8_t mac[ZIO_DATA_MAC_LEN] = { 0 }; |
| boolean_t no_crypt = B_FALSE; |
| |
| ASSERT((HDR_GET_COMPRESS(hdr) != ZIO_COMPRESS_OFF && |
| !HDR_COMPRESSION_ENABLED(hdr)) || |
| HDR_ENCRYPTED(hdr) || HDR_SHARED_DATA(hdr) || psize != asize); |
| ASSERT3U(psize, <=, asize); |
| |
| /* |
| * If this data simply needs its own buffer, we simply allocate it |
| * and copy the data. This may be done to eliminate a dependency on a |
| * shared buffer or to reallocate the buffer to match asize. |
| */ |
| if (HDR_HAS_RABD(hdr) && asize != psize) { |
| ASSERT3U(asize, >=, psize); |
| to_write = abd_alloc_for_io(asize, ismd); |
| abd_copy(to_write, hdr->b_crypt_hdr.b_rabd, psize); |
| if (psize != asize) |
| abd_zero_off(to_write, psize, asize - psize); |
| goto out; |
| } |
| |
| if ((compress == ZIO_COMPRESS_OFF || HDR_COMPRESSION_ENABLED(hdr)) && |
| !HDR_ENCRYPTED(hdr)) { |
| ASSERT3U(size, ==, psize); |
| to_write = abd_alloc_for_io(asize, ismd); |
| abd_copy(to_write, hdr->b_l1hdr.b_pabd, size); |
| if (size != asize) |
| abd_zero_off(to_write, size, asize - size); |
| goto out; |
| } |
| |
| if (compress != ZIO_COMPRESS_OFF && !HDR_COMPRESSION_ENABLED(hdr)) { |
| cabd = abd_alloc_for_io(asize, ismd); |
| tmp = abd_borrow_buf(cabd, asize); |
| |
| psize = zio_compress_data(compress, to_write, tmp, size); |
| ASSERT3U(psize, <=, HDR_GET_PSIZE(hdr)); |
| if (psize < asize) |
| bzero((char *)tmp + psize, asize - psize); |
| psize = HDR_GET_PSIZE(hdr); |
| abd_return_buf_copy(cabd, tmp, asize); |
| to_write = cabd; |
| } |
| |
| if (HDR_ENCRYPTED(hdr)) { |
| eabd = abd_alloc_for_io(asize, ismd); |
| |
| /* |
| * If the dataset was disowned before the buffer |
| * made it to this point, the key to re-encrypt |
| * it won't be available. In this case we simply |
| * won't write the buffer to the L2ARC. |
| */ |
| ret = spa_keystore_lookup_key(spa, hdr->b_crypt_hdr.b_dsobj, |
| FTAG, &dck); |
| if (ret != 0) |
| goto error; |
| |
| ret = zio_do_crypt_abd(B_TRUE, &dck->dck_key, |
| hdr->b_crypt_hdr.b_ot, bswap, hdr->b_crypt_hdr.b_salt, |
| hdr->b_crypt_hdr.b_iv, mac, psize, to_write, eabd, |
| &no_crypt); |
| if (ret != 0) |
| goto error; |
| |
| if (no_crypt) |
| abd_copy(eabd, to_write, psize); |
| |
| if (psize != asize) |
| abd_zero_off(eabd, psize, asize - psize); |
| |
| /* assert that the MAC we got here matches the one we saved */ |
| ASSERT0(bcmp(mac, hdr->b_crypt_hdr.b_mac, ZIO_DATA_MAC_LEN)); |
| spa_keystore_dsl_key_rele(spa, dck, FTAG); |
| |
| if (to_write == cabd) |
| abd_free(cabd); |
| |
| to_write = eabd; |
| } |
| |
| out: |
| ASSERT3P(to_write, !=, hdr->b_l1hdr.b_pabd); |
| *abd_out = to_write; |
| return (0); |
| |
| error: |
| if (dck != NULL) |
| spa_keystore_dsl_key_rele(spa, dck, FTAG); |
| if (cabd != NULL) |
| abd_free(cabd); |
| if (eabd != NULL) |
| abd_free(eabd); |
| |
| *abd_out = NULL; |
| return (ret); |
| } |
| |
| /* |
| * Find and write ARC buffers to the L2ARC device. |
| * |
| * An ARC_FLAG_L2_WRITING flag is set so that the L2ARC buffers are not valid |
| * for reading until they have completed writing. |
| * The headroom_boost is an in-out parameter used to maintain headroom boost |
| * state between calls to this function. |
| * |
| * Returns the number of bytes actually written (which may be smaller than |
| * the delta by which the device hand has changed due to alignment). |
| */ |
| static uint64_t |
| l2arc_write_buffers(spa_t *spa, l2arc_dev_t *dev, uint64_t target_sz) |
| { |
| arc_buf_hdr_t *hdr, *hdr_prev, *head; |
| uint64_t write_asize, write_psize, write_lsize, headroom; |
| boolean_t full; |
| l2arc_write_callback_t *cb; |
| zio_t *pio, *wzio; |
| uint64_t guid = spa_load_guid(spa); |
| |
| ASSERT3P(dev->l2ad_vdev, !=, NULL); |
| |
| pio = NULL; |
| write_lsize = write_asize = write_psize = 0; |
| full = B_FALSE; |
| head = kmem_cache_alloc(hdr_l2only_cache, KM_PUSHPAGE); |
| arc_hdr_set_flags(head, ARC_FLAG_L2_WRITE_HEAD | ARC_FLAG_HAS_L2HDR); |
| |
| /* |
| * Copy buffers for L2ARC writing. |
| */ |
| for (int try = 0; try < L2ARC_FEED_TYPES; try++) { |
| multilist_sublist_t *mls = l2arc_sublist_lock(try); |
| uint64_t passed_sz = 0; |
| |
| VERIFY3P(mls, !=, NULL); |
| |
| /* |
| * L2ARC fast warmup. |
| * |
| * Until the ARC is warm and starts to evict, read from the |
| * head of the ARC lists rather than the tail. |
| */ |
| if (arc_warm == B_FALSE) |
| hdr = multilist_sublist_head(mls); |
| else |
| hdr = multilist_sublist_tail(mls); |
| |
| headroom = target_sz * l2arc_headroom; |
| if (zfs_compressed_arc_enabled) |
| headroom = (headroom * l2arc_headroom_boost) / 100; |
| |
| for (; hdr; hdr = hdr_prev) { |
| kmutex_t *hash_lock; |
| abd_t *to_write = NULL; |
| |
| if (arc_warm == B_FALSE) |
| hdr_prev = multilist_sublist_next(mls, hdr); |
| else |
| hdr_prev = multilist_sublist_prev(mls, hdr); |
| |
| hash_lock = HDR_LOCK(hdr); |
| if (!mutex_tryenter(hash_lock)) { |
| /* |
| * Skip this buffer rather than waiting. |
| */ |
| continue; |
| } |
| |
| passed_sz += HDR_GET_LSIZE(hdr); |
| if (passed_sz > headroom) { |
| /* |
| * Searched too far. |
| */ |
| mutex_exit(hash_lock); |
| break; |
| } |
| |
| if (!l2arc_write_eligible(guid, hdr)) { |
| mutex_exit(hash_lock); |
| continue; |
| } |
| |
| /* |
| * We rely on the L1 portion of the header below, so |
| * it's invalid for this header to have been evicted out |
| * of the ghost cache, prior to being written out. The |
| * ARC_FLAG_L2_WRITING bit ensures this won't happen. |
| */ |
| ASSERT(HDR_HAS_L1HDR(hdr)); |
| |
| ASSERT3U(HDR_GET_PSIZE(hdr), >, 0); |
| ASSERT3U(arc_hdr_size(hdr), >, 0); |
| ASSERT(hdr->b_l1hdr.b_pabd != NULL || |
| HDR_HAS_RABD(hdr)); |
| uint64_t psize = HDR_GET_PSIZE(hdr); |
| uint64_t asize = vdev_psize_to_asize(dev->l2ad_vdev, |
| psize); |
| |
| if ((write_asize + asize) > target_sz) { |
| full = B_TRUE; |
| mutex_exit(hash_lock); |
| break; |
| } |
| |
| /* |
| * We rely on the L1 portion of the header below, so |
| * it's invalid for this header to have been evicted out |
| * of the ghost cache, prior to being written out. The |
| * ARC_FLAG_L2_WRITING bit ensures this won't happen. |
| */ |
| arc_hdr_set_flags(hdr, ARC_FLAG_L2_WRITING); |
| ASSERT(HDR_HAS_L1HDR(hdr)); |
| |
| ASSERT3U(HDR_GET_PSIZE(hdr), >, 0); |
| ASSERT(hdr->b_l1hdr.b_pabd != NULL || |
| HDR_HAS_RABD(hdr)); |
| ASSERT3U(arc_hdr_size(hdr), >, 0); |
| |
| /* |
| * If this header has b_rabd, we can use this since it |
| * must always match the data exactly as it exists on |
| * disk. Otherwise, the L2ARC can normally use the |
| * hdr's data, but if we're sharing data between the |
| * hdr and one of its bufs, L2ARC needs its own copy of |
| * the data so that the ZIO below can't race with the |
| * buf consumer. To ensure that this copy will be |
| * available for the lifetime of the ZIO and be cleaned |
| * up afterwards, we add it to the l2arc_free_on_write |
| * queue. If we need to apply any transforms to the |
| * data (compression, encryption) we will also need the |
| * extra buffer. |
| */ |
| if (HDR_HAS_RABD(hdr) && psize == asize) { |
| to_write = hdr->b_crypt_hdr.b_rabd; |
| } else if ((HDR_COMPRESSION_ENABLED(hdr) || |
| HDR_GET_COMPRESS(hdr) == ZIO_COMPRESS_OFF) && |
| !HDR_ENCRYPTED(hdr) && !HDR_SHARED_DATA(hdr) && |
| psize == asize) { |
| to_write = hdr->b_l1hdr.b_pabd; |
| } else { |
| int ret; |
| arc_buf_contents_t type = arc_buf_type(hdr); |
| |
| ret = l2arc_apply_transforms(spa, hdr, asize, |
| &to_write); |
| if (ret != 0) { |
| arc_hdr_clear_flags(hdr, |
| ARC_FLAG_L2_WRITING); |
| mutex_exit(hash_lock); |
| continue; |
| } |
| |
| l2arc_free_abd_on_write(to_write, asize, type); |
| } |
| |
| if (pio == NULL) { |
| /* |
| * Insert a dummy header on the buflist so |
| * l2arc_write_done() can find where the |
| * write buffers begin without searching. |
| */ |
| mutex_enter(&dev->l2ad_mtx); |
| list_insert_head(&dev->l2ad_buflist, head); |
| mutex_exit(&dev->l2ad_mtx); |
| |
| cb = kmem_alloc( |
| sizeof (l2arc_write_callback_t), KM_SLEEP); |
| cb->l2wcb_dev = dev; |
| cb->l2wcb_head = head; |
| pio = zio_root(spa, l2arc_write_done, cb, |
| ZIO_FLAG_CANFAIL); |
| } |
| |
| hdr->b_l2hdr.b_dev = dev; |
| hdr->b_l2hdr.b_hits = 0; |
| |
| hdr->b_l2hdr.b_daddr = dev->l2ad_hand; |
| arc_hdr_set_flags(hdr, ARC_FLAG_HAS_L2HDR); |
| |
| mutex_enter(&dev->l2ad_mtx); |
| list_insert_head(&dev->l2ad_buflist, hdr); |
| mutex_exit(&dev->l2ad_mtx); |
| |
| (void) zfs_refcount_add_many(&dev->l2ad_alloc, |
| arc_hdr_size(hdr), hdr); |
| |
| wzio = zio_write_phys(pio, dev->l2ad_vdev, |
| hdr->b_l2hdr.b_daddr, asize, to_write, |
| ZIO_CHECKSUM_OFF, NULL, hdr, |
| ZIO_PRIORITY_ASYNC_WRITE, |
| ZIO_FLAG_CANFAIL, B_FALSE); |
| |
| write_lsize += HDR_GET_LSIZE(hdr); |
| DTRACE_PROBE2(l2arc__write, vdev_t *, dev->l2ad_vdev, |
| zio_t *, wzio); |
| |
| write_psize += psize; |
| write_asize += asize; |
| dev->l2ad_hand += asize; |
| vdev_space_update(dev->l2ad_vdev, asize, 0, 0); |
| |
| mutex_exit(hash_lock); |
| |
| (void) zio_nowait(wzio); |
| } |
| |
| multilist_sublist_unlock(mls); |
| |
| if (full == B_TRUE) |
| break; |
| } |
| |
| /* No buffers selected for writing? */ |
| if (pio == NULL) { |
| ASSERT0(write_lsize); |
| ASSERT(!HDR_HAS_L1HDR(head)); |
| kmem_cache_free(hdr_l2only_cache, head); |
| return (0); |
| } |
| |
| ASSERT3U(write_asize, <=, target_sz); |
| ARCSTAT_BUMP(arcstat_l2_writes_sent); |
| ARCSTAT_INCR(arcstat_l2_write_bytes, write_psize); |
| ARCSTAT_INCR(arcstat_l2_lsize, write_lsize); |
| ARCSTAT_INCR(arcstat_l2_psize, write_psize); |
| |
| /* |
| * Bump device hand to the device start if it is approaching the end. |
| * l2arc_evict() will already have evicted ahead for this case. |
| */ |
| if (dev->l2ad_hand >= (dev->l2ad_end - target_sz)) { |
| dev->l2ad_hand = dev->l2ad_start; |
| dev->l2ad_first = B_FALSE; |
| } |
| |
| dev->l2ad_writing = B_TRUE; |
| (void) zio_wait(pio); |
| dev->l2ad_writing = B_FALSE; |
| |
| return (write_asize); |
| } |
| |
| /* |
| * This thread feeds the L2ARC at regular intervals. This is the beating |
| * heart of the L2ARC. |
| */ |
| /* ARGSUSED */ |
| static void |
| l2arc_feed_thread(void *unused) |
| { |
| callb_cpr_t cpr; |
| l2arc_dev_t *dev; |
| spa_t *spa; |
| uint64_t size, wrote; |
| clock_t begin, next = ddi_get_lbolt(); |
| fstrans_cookie_t cookie; |
| |
| CALLB_CPR_INIT(&cpr, &l2arc_feed_thr_lock, callb_generic_cpr, FTAG); |
| |
| mutex_enter(&l2arc_feed_thr_lock); |
| |
| cookie = spl_fstrans_mark(); |
| while (l2arc_thread_exit == 0) { |
| CALLB_CPR_SAFE_BEGIN(&cpr); |
| (void) cv_timedwait_sig(&l2arc_feed_thr_cv, |
| &l2arc_feed_thr_lock, next); |
| CALLB_CPR_SAFE_END(&cpr, &l2arc_feed_thr_lock); |
| next = ddi_get_lbolt() + hz; |
| |
| /* |
| * Quick check for L2ARC devices. |
| */ |
| mutex_enter(&l2arc_dev_mtx); |
| if (l2arc_ndev == 0) { |
| mutex_exit(&l2arc_dev_mtx); |
| continue; |
| } |
| mutex_exit(&l2arc_dev_mtx); |
| begin = ddi_get_lbolt(); |
| |
| /* |
| * This selects the next l2arc device to write to, and in |
| * doing so the next spa to feed from: dev->l2ad_spa. This |
| * will return NULL if there are now no l2arc devices or if |
| * they are all faulted. |
| * |
| * If a device is returned, its spa's config lock is also |
| * held to prevent device removal. l2arc_dev_get_next() |
| * will grab and release l2arc_dev_mtx. |
| */ |
| if ((dev = l2arc_dev_get_next()) == NULL) |
| continue; |
| |
| spa = dev->l2ad_spa; |
| ASSERT3P(spa, !=, NULL); |
| |
| /* |
| * If the pool is read-only then force the feed thread to |
| * sleep a little longer. |
| */ |
| if (!spa_writeable(spa)) { |
| next = ddi_get_lbolt() + 5 * l2arc_feed_secs * hz; |
| spa_config_exit(spa, SCL_L2ARC, dev); |
| continue; |
| } |
| |
| /* |
| * Avoid contributing to memory pressure. |
| */ |
| if (arc_reclaim_needed()) { |
| ARCSTAT_BUMP(arcstat_l2_abort_lowmem); |
| spa_config_exit(spa, SCL_L2ARC, dev); |
| continue; |
| } |
| |
| ARCSTAT_BUMP(arcstat_l2_feeds); |
| |
| size = l2arc_write_size(); |
| |
| /* |
| * Evict L2ARC buffers that will be overwritten. |
| */ |
| l2arc_evict(dev, size, B_FALSE); |
| |
| /* |
| * Write ARC buffers. |
| */ |
| wrote = l2arc_write_buffers(spa, dev, size); |
| |
| /* |
| * Calculate interval between writes. |
| */ |
| next = l2arc_write_interval(begin, size, wrote); |
| spa_config_exit(spa, SCL_L2ARC, dev); |
| } |
| spl_fstrans_unmark(cookie); |
| |
| l2arc_thread_exit = 0; |
| cv_broadcast(&l2arc_feed_thr_cv); |
| CALLB_CPR_EXIT(&cpr); /* drops l2arc_feed_thr_lock */ |
| thread_exit(); |
| } |
| |
| boolean_t |
| l2arc_vdev_present(vdev_t *vd) |
| { |
| l2arc_dev_t *dev; |
| |
| mutex_enter(&l2arc_dev_mtx); |
| for (dev = list_head(l2arc_dev_list); dev != NULL; |
| dev = list_next(l2arc_dev_list, dev)) { |
| if (dev->l2ad_vdev == vd) |
| break; |
| } |
| mutex_exit(&l2arc_dev_mtx); |
| |
| return (dev != NULL); |
| } |
| |
| /* |
| * Add a vdev for use by the L2ARC. By this point the spa has already |
| * validated the vdev and opened it. |
| */ |
| void |
| l2arc_add_vdev(spa_t *spa, vdev_t *vd) |
| { |
| l2arc_dev_t *adddev; |
| |
| ASSERT(!l2arc_vdev_present(vd)); |
| |
| /* |
| * Create a new l2arc device entry. |
| */ |
| adddev = kmem_zalloc(sizeof (l2arc_dev_t), KM_SLEEP); |
| adddev->l2ad_spa = spa; |
| adddev->l2ad_vdev = vd; |
| adddev->l2ad_start = VDEV_LABEL_START_SIZE; |
| adddev->l2ad_end = VDEV_LABEL_START_SIZE + vdev_get_min_asize(vd); |
| adddev->l2ad_hand = adddev->l2ad_start; |
| adddev->l2ad_first = B_TRUE; |
| adddev->l2ad_writing = B_FALSE; |
| list_link_init(&adddev->l2ad_node); |
| |
| mutex_init(&adddev->l2ad_mtx, NULL, MUTEX_DEFAULT, NULL); |
| /* |
| * This is a list of all ARC buffers that are still valid on the |
| * device. |
| */ |
| list_create(&adddev->l2ad_buflist, sizeof (arc_buf_hdr_t), |
| offsetof(arc_buf_hdr_t, b_l2hdr.b_l2node)); |
| |
| vdev_space_update(vd, 0, 0, adddev->l2ad_end - adddev->l2ad_hand); |
| zfs_refcount_create(&adddev->l2ad_alloc); |
| |
| /* |
| * Add device to global list |
| */ |
| mutex_enter(&l2arc_dev_mtx); |
| list_insert_head(l2arc_dev_list, adddev); |
| atomic_inc_64(&l2arc_ndev); |
| mutex_exit(&l2arc_dev_mtx); |
| } |
| |
| /* |
| * Remove a vdev from the L2ARC. |
| */ |
| void |
| l2arc_remove_vdev(vdev_t *vd) |
| { |
| l2arc_dev_t *dev, *nextdev, *remdev = NULL; |
| |
| /* |
| * Find the device by vdev |
| */ |
| mutex_enter(&l2arc_dev_mtx); |
| for (dev = list_head(l2arc_dev_list); dev; dev = nextdev) { |
| nextdev = list_next(l2arc_dev_list, dev); |
| if (vd == dev->l2ad_vdev) { |
| remdev = dev; |
| break; |
| } |
| } |
| ASSERT3P(remdev, !=, NULL); |
| |
| /* |
| * Remove device from global list |
| */ |
| list_remove(l2arc_dev_list, remdev); |
| l2arc_dev_last = NULL; /* may have been invalidated */ |
| atomic_dec_64(&l2arc_ndev); |
| mutex_exit(&l2arc_dev_mtx); |
| |
| /* |
| * Clear all buflists and ARC references. L2ARC device flush. |
| */ |
| l2arc_evict(remdev, 0, B_TRUE); |
| list_destroy(&remdev->l2ad_buflist); |
| mutex_destroy(&remdev->l2ad_mtx); |
| zfs_refcount_destroy(&remdev->l2ad_alloc); |
| kmem_free(remdev, sizeof (l2arc_dev_t)); |
| } |
| |
| void |
| l2arc_init(void) |
| { |
| l2arc_thread_exit = 0; |
| l2arc_ndev = 0; |
| l2arc_writes_sent = 0; |
| l2arc_writes_done = 0; |
| |
| mutex_init(&l2arc_feed_thr_lock, NULL, MUTEX_DEFAULT, NULL); |
| cv_init(&l2arc_feed_thr_cv, NULL, CV_DEFAULT, NULL); |
| mutex_init(&l2arc_dev_mtx, NULL, MUTEX_DEFAULT, NULL); |
| mutex_init(&l2arc_free_on_write_mtx, NULL, MUTEX_DEFAULT, NULL); |
| |
| l2arc_dev_list = &L2ARC_dev_list; |
| l2arc_free_on_write = &L2ARC_free_on_write; |
| list_create(l2arc_dev_list, sizeof (l2arc_dev_t), |
| offsetof(l2arc_dev_t, l2ad_node)); |
| list_create(l2arc_free_on_write, sizeof (l2arc_data_free_t), |
| offsetof(l2arc_data_free_t, l2df_list_node)); |
| } |
| |
| void |
| l2arc_fini(void) |
| { |
| /* |
| * This is called from dmu_fini(), which is called from spa_fini(); |
| * Because of this, we can assume that all l2arc devices have |
| * already been removed when the pools themselves were removed. |
| */ |
| |
| l2arc_do_free_on_write(); |
| |
| mutex_destroy(&l2arc_feed_thr_lock); |
| cv_destroy(&l2arc_feed_thr_cv); |
| mutex_destroy(&l2arc_dev_mtx); |
| mutex_destroy(&l2arc_free_on_write_mtx); |
| |
| list_destroy(l2arc_dev_list); |
| list_destroy(l2arc_free_on_write); |
| } |
| |
| void |
| l2arc_start(void) |
| { |
| if (!(spa_mode_global & FWRITE)) |
| return; |
| |
| (void) thread_create(NULL, 0, l2arc_feed_thread, NULL, 0, &p0, |
| TS_RUN, defclsyspri); |
| } |
| |
| void |
| l2arc_stop(void) |
| { |
| if (!(spa_mode_global & FWRITE)) |
| return; |
| |
| mutex_enter(&l2arc_feed_thr_lock); |
| cv_signal(&l2arc_feed_thr_cv); /* kick thread out of startup */ |
| l2arc_thread_exit = 1; |
| while (l2arc_thread_exit != 0) |
| cv_wait(&l2arc_feed_thr_cv, &l2arc_feed_thr_lock); |
| mutex_exit(&l2arc_feed_thr_lock); |
| } |
| |
| #if defined(_KERNEL) |
| static int |
| param_set_arc_long(const char *buf, zfs_kernel_param_t *kp) |
| { |
| int error; |
| |
| error = param_set_long(buf, kp); |
| if (error < 0) |
| return (SET_ERROR(error)); |
| |
| arc_tuning_update(); |
| |
| return (0); |
| } |
| |
| static int |
| param_set_arc_int(const char *buf, zfs_kernel_param_t *kp) |
| { |
| int error; |
| |
| error = param_set_int(buf, kp); |
| if (error < 0) |
| return (SET_ERROR(error)); |
| |
| arc_tuning_update(); |
| |
| return (0); |
| } |
| |
| |
| EXPORT_SYMBOL(arc_buf_size); |
| EXPORT_SYMBOL(arc_write); |
| EXPORT_SYMBOL(arc_read); |
| EXPORT_SYMBOL(arc_buf_info); |
| EXPORT_SYMBOL(arc_getbuf_func); |
| EXPORT_SYMBOL(arc_add_prune_callback); |
| EXPORT_SYMBOL(arc_remove_prune_callback); |
| |
| /* BEGIN CSTYLED */ |
| module_param_call(zfs_arc_min, param_set_arc_long, param_get_long, |
| &zfs_arc_min, 0644); |
| MODULE_PARM_DESC(zfs_arc_min, "Min arc size"); |
| |
| module_param_call(zfs_arc_max, param_set_arc_long, param_get_long, |
| &zfs_arc_max, 0644); |
| MODULE_PARM_DESC(zfs_arc_max, "Max arc size"); |
| |
| module_param_call(zfs_arc_meta_limit, param_set_arc_long, param_get_long, |
| &zfs_arc_meta_limit, 0644); |
| MODULE_PARM_DESC(zfs_arc_meta_limit, "Meta limit for arc size"); |
| |
| module_param_call(zfs_arc_meta_limit_percent, param_set_arc_long, |
| param_get_long, &zfs_arc_meta_limit_percent, 0644); |
| MODULE_PARM_DESC(zfs_arc_meta_limit_percent, |
| "Percent of arc size for arc meta limit"); |
| |
| module_param_call(zfs_arc_meta_min, param_set_arc_long, param_get_long, |
| &zfs_arc_meta_min, 0644); |
| MODULE_PARM_DESC(zfs_arc_meta_min, "Min arc metadata"); |
| |
| module_param(zfs_arc_meta_prune, int, 0644); |
| MODULE_PARM_DESC(zfs_arc_meta_prune, "Meta objects to scan for prune"); |
| |
| module_param(zfs_arc_meta_adjust_restarts, int, 0644); |
| MODULE_PARM_DESC(zfs_arc_meta_adjust_restarts, |
| "Limit number of restarts in arc_adjust_meta"); |
| |
| module_param(zfs_arc_meta_strategy, int, 0644); |
| MODULE_PARM_DESC(zfs_arc_meta_strategy, "Meta reclaim strategy"); |
| |
| module_param_call(zfs_arc_grow_retry, param_set_arc_int, param_get_int, |
| &zfs_arc_grow_retry, 0644); |
| MODULE_PARM_DESC(zfs_arc_grow_retry, "Seconds before growing arc size"); |
| |
| module_param(zfs_arc_p_dampener_disable, int, 0644); |
| MODULE_PARM_DESC(zfs_arc_p_dampener_disable, "disable arc_p adapt dampener"); |
| |
| module_param_call(zfs_arc_shrink_shift, param_set_arc_int, param_get_int, |
| &zfs_arc_shrink_shift, 0644); |
| MODULE_PARM_DESC(zfs_arc_shrink_shift, "log2(fraction of arc to reclaim)"); |
| |
| module_param(zfs_arc_pc_percent, uint, 0644); |
| MODULE_PARM_DESC(zfs_arc_pc_percent, |
| "Percent of pagecache to reclaim arc to"); |
| |
| module_param_call(zfs_arc_p_min_shift, param_set_arc_int, param_get_int, |
| &zfs_arc_p_min_shift, 0644); |
| MODULE_PARM_DESC(zfs_arc_p_min_shift, "arc_c shift to calc min/max arc_p"); |
| |
| module_param(zfs_arc_average_blocksize, int, 0444); |
| MODULE_PARM_DESC(zfs_arc_average_blocksize, "Target average block size"); |
| |
| module_param(zfs_compressed_arc_enabled, int, 0644); |
| MODULE_PARM_DESC(zfs_compressed_arc_enabled, "Disable compressed arc buffers"); |
| |
| module_param_call(zfs_arc_min_prefetch_ms, param_set_arc_int, param_get_int, |
| &zfs_arc_min_prefetch_ms, 0644); |
| MODULE_PARM_DESC(zfs_arc_min_prefetch_ms, "Min life of prefetch block in ms"); |
| |
| module_param(zfs_arc_min_prescient_prefetch_ms, int, 0644); |
| MODULE_PARM_DESC(zfs_arc_min_prescient_prefetch_ms, |
| "Min life of prescient prefetched block in ms"); |
| |
| module_param(l2arc_write_max, ulong, 0644); |
| MODULE_PARM_DESC(l2arc_write_max, "Max write bytes per interval"); |
| |
| module_param(l2arc_write_boost, ulong, 0644); |
| MODULE_PARM_DESC(l2arc_write_boost, "Extra write bytes during device warmup"); |
| |
| module_param(l2arc_headroom, ulong, 0644); |
| MODULE_PARM_DESC(l2arc_headroom, "Number of max device writes to precache"); |
| |
| module_param(l2arc_headroom_boost, ulong, 0644); |
| MODULE_PARM_DESC(l2arc_headroom_boost, "Compressed l2arc_headroom multiplier"); |
| |
| module_param(l2arc_feed_secs, ulong, 0644); |
| MODULE_PARM_DESC(l2arc_feed_secs, "Seconds between L2ARC writing"); |
| |
| module_param(l2arc_feed_min_ms, ulong, 0644); |
| MODULE_PARM_DESC(l2arc_feed_min_ms, "Min feed interval in milliseconds"); |
| |
| module_param(l2arc_noprefetch, int, 0644); |
| MODULE_PARM_DESC(l2arc_noprefetch, "Skip caching prefetched buffers"); |
| |
| module_param(l2arc_feed_again, int, 0644); |
| MODULE_PARM_DESC(l2arc_feed_again, "Turbo L2ARC warmup"); |
| |
| module_param(l2arc_norw, int, 0644); |
| MODULE_PARM_DESC(l2arc_norw, "No reads during writes"); |
| |
| module_param_call(zfs_arc_lotsfree_percent, param_set_arc_int, param_get_int, |
| &zfs_arc_lotsfree_percent, 0644); |
| MODULE_PARM_DESC(zfs_arc_lotsfree_percent, |
| "System free memory I/O throttle in bytes"); |
| |
| module_param_call(zfs_arc_sys_free, param_set_arc_long, param_get_long, |
| &zfs_arc_sys_free, 0644); |
| MODULE_PARM_DESC(zfs_arc_sys_free, "System free memory target size in bytes"); |
| |
| module_param_call(zfs_arc_dnode_limit, param_set_arc_long, param_get_long, |
| &zfs_arc_dnode_limit, 0644); |
| MODULE_PARM_DESC(zfs_arc_dnode_limit, "Minimum bytes of dnodes in arc"); |
| |
| module_param(zfs_arc_dnode_limit_percent, ulong, 0644); |
| MODULE_PARM_DESC(zfs_arc_dnode_limit_percent, |
| "Percent of ARC meta buffers for dnodes"); |
| |
| module_param(zfs_arc_dnode_reduce_percent, ulong, 0644); |
| MODULE_PARM_DESC(zfs_arc_dnode_reduce_percent, |
| "Percentage of excess dnodes to try to unpin"); |
| /* END CSTYLED */ |
| #endif |