| /*****************************************************************************\ |
| * locks.c - semaphore functions for slurmctld |
| ***************************************************************************** |
| * Copyright (C) 2002-2007 The Regents of the University of California. |
| * Copyright (C) 2008-2009 Lawrence Livermore National Security. |
| * Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER). |
| * Written by Morris Jette <jette@llnl.gov>, Randy Sanchez <rsancez@llnl.gov> |
| * CODE-OCEC-09-009. All rights reserved. |
| * |
| * This file is part of SLURM, a resource management program. |
| * For details, see <https://computing.llnl.gov/linux/slurm/>. |
| * Please also read the included file: DISCLAIMER. |
| * |
| * SLURM is free software; you can redistribute it and/or modify it under |
| * the terms of the GNU General Public License as published by the Free |
| * Software Foundation; either version 2 of the License, or (at your option) |
| * any later version. |
| * |
| * In addition, as a special exception, the copyright holders give permission |
| * to link the code of portions of this program with the OpenSSL library under |
| * certain conditions as described in each individual source file, and |
| * distribute linked combinations including the two. You must obey the GNU |
| * General Public License in all respects for all of the code used other than |
| * OpenSSL. If you modify file(s) with this exception, you may extend this |
| * exception to your version of the file(s), but you are not obligated to do |
| * so. If you do not wish to do so, delete this exception statement from your |
| * version. If you delete this exception statement from all source files in |
| * the program, then also delete it here. |
| * |
| * SLURM is distributed in the hope that it will be useful, but WITHOUT ANY |
| * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS |
| * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more |
| * details. |
| * |
| * You should have received a copy of the GNU General Public License along |
| * with SLURM; if not, write to the Free Software Foundation, Inc., |
| * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. |
| \*****************************************************************************/ |
| |
| #ifdef HAVE_CONFIG_H |
| # include "config.h" |
| #endif |
| |
| #ifdef WITH_PTHREADS |
| # include <pthread.h> |
| #endif |
| |
| #include <errno.h> |
| #include <string.h> |
| #include <sys/types.h> |
| |
| #include "src/slurmctld/locks.h" |
| #include "src/slurmctld/slurmctld.h" |
| |
| static pthread_mutex_t locks_mutex = PTHREAD_MUTEX_INITIALIZER; |
| static pthread_cond_t locks_cond = PTHREAD_COND_INITIALIZER; |
| static pthread_mutex_t state_mutex = PTHREAD_MUTEX_INITIALIZER; |
| |
| static slurmctld_lock_flags_t slurmctld_locks; |
| static int kill_thread = 0; |
| |
| static bool _wr_rdlock(lock_datatype_t datatype, bool wait_lock); |
| static void _wr_rdunlock(lock_datatype_t datatype); |
| static bool _wr_wrlock(lock_datatype_t datatype, bool wait_lock); |
| static void _wr_wrunlock(lock_datatype_t datatype); |
| |
| /* init_locks - create locks used for slurmctld data structure access |
| * control */ |
| void init_locks(void) |
| { |
| /* just clear all semaphores */ |
| memset((void *) &slurmctld_locks, 0, sizeof(slurmctld_locks)); |
| } |
| |
| /* lock_slurmctld - Issue the required lock requests in a well defined order */ |
| extern void lock_slurmctld(slurmctld_lock_t lock_levels) |
| { |
| if (lock_levels.config == READ_LOCK) |
| (void) _wr_rdlock(CONFIG_LOCK, true); |
| else if (lock_levels.config == WRITE_LOCK) |
| (void) _wr_wrlock(CONFIG_LOCK, true); |
| |
| if (lock_levels.job == READ_LOCK) |
| (void) _wr_rdlock(JOB_LOCK, true); |
| else if (lock_levels.job == WRITE_LOCK) |
| (void) _wr_wrlock(JOB_LOCK, true); |
| |
| if (lock_levels.node == READ_LOCK) |
| (void) _wr_rdlock(NODE_LOCK, true); |
| else if (lock_levels.node == WRITE_LOCK) |
| (void) _wr_wrlock(NODE_LOCK, true); |
| |
| if (lock_levels.partition == READ_LOCK) |
| (void) _wr_rdlock(PART_LOCK, true); |
| else if (lock_levels.partition == WRITE_LOCK) |
| (void) _wr_wrlock(PART_LOCK, true); |
| } |
| |
| /* try_lock_slurmctld - equivalent to lock_slurmctld() except |
| * RET 0 on success or -1 if the locks are currently not available */ |
| extern int try_lock_slurmctld (slurmctld_lock_t lock_levels) |
| { |
| bool success = true; |
| |
| if (lock_levels.config == READ_LOCK) |
| success = _wr_rdlock(CONFIG_LOCK, false); |
| else if (lock_levels.config == WRITE_LOCK) |
| success = _wr_wrlock(CONFIG_LOCK, false); |
| if (!success) |
| return -1; |
| |
| if (lock_levels.job == READ_LOCK) |
| success = _wr_rdlock(JOB_LOCK, false); |
| else if (lock_levels.job == WRITE_LOCK) |
| success = _wr_wrlock(JOB_LOCK, false); |
| if (!success) { |
| if (lock_levels.config == READ_LOCK) |
| _wr_rdunlock(CONFIG_LOCK); |
| else if (lock_levels.config == WRITE_LOCK) |
| _wr_wrunlock(CONFIG_LOCK); |
| return -1; |
| } |
| |
| if (lock_levels.node == READ_LOCK) |
| success = _wr_rdlock(NODE_LOCK, false); |
| else if (lock_levels.node == WRITE_LOCK) |
| success = _wr_wrlock(NODE_LOCK, false); |
| if (!success) { |
| if (lock_levels.job == READ_LOCK) |
| _wr_rdunlock(JOB_LOCK); |
| else if (lock_levels.job == WRITE_LOCK) |
| _wr_wrunlock(JOB_LOCK); |
| if (lock_levels.config == READ_LOCK) |
| _wr_rdunlock(CONFIG_LOCK); |
| else if (lock_levels.config == WRITE_LOCK) |
| _wr_wrunlock(CONFIG_LOCK); |
| return -1; |
| } |
| |
| if (lock_levels.partition == READ_LOCK) |
| success = _wr_rdlock(PART_LOCK, false); |
| else if (lock_levels.partition == WRITE_LOCK) |
| success = _wr_wrlock(PART_LOCK, false); |
| if (!success) { |
| if (lock_levels.node == READ_LOCK) |
| _wr_rdunlock(NODE_LOCK); |
| else if (lock_levels.node == WRITE_LOCK) |
| _wr_wrunlock(NODE_LOCK); |
| if (lock_levels.job == READ_LOCK) |
| _wr_rdunlock(JOB_LOCK); |
| else if (lock_levels.job == WRITE_LOCK) |
| _wr_wrunlock(JOB_LOCK); |
| if (lock_levels.config == READ_LOCK) |
| _wr_rdunlock(CONFIG_LOCK); |
| else if (lock_levels.config == WRITE_LOCK) |
| _wr_wrunlock(CONFIG_LOCK); |
| return -1; |
| } |
| |
| return 0; |
| } |
| |
| /* unlock_slurmctld - Issue the required unlock requests in a well |
| * defined order */ |
| extern void unlock_slurmctld(slurmctld_lock_t lock_levels) |
| { |
| if (lock_levels.partition == READ_LOCK) |
| _wr_rdunlock(PART_LOCK); |
| else if (lock_levels.partition == WRITE_LOCK) |
| _wr_wrunlock(PART_LOCK); |
| |
| if (lock_levels.node == READ_LOCK) |
| _wr_rdunlock(NODE_LOCK); |
| else if (lock_levels.node == WRITE_LOCK) |
| _wr_wrunlock(NODE_LOCK); |
| |
| if (lock_levels.job == READ_LOCK) |
| _wr_rdunlock(JOB_LOCK); |
| else if (lock_levels.job == WRITE_LOCK) |
| _wr_wrunlock(JOB_LOCK); |
| |
| if (lock_levels.config == READ_LOCK) |
| _wr_rdunlock(CONFIG_LOCK); |
| else if (lock_levels.config == WRITE_LOCK) |
| _wr_wrunlock(CONFIG_LOCK); |
| } |
| |
| /* _wr_rdlock - Issue a read lock on the specified data type */ |
| static bool _wr_rdlock(lock_datatype_t datatype, bool wait_lock) |
| { |
| bool success = true; |
| |
| slurm_mutex_lock(&locks_mutex); |
| while (1) { |
| if ((slurmctld_locks.entity[write_wait_lock(datatype)] == 0) && |
| (slurmctld_locks.entity[write_lock(datatype)] == 0)) { |
| slurmctld_locks.entity[read_lock(datatype)]++; |
| break; |
| } else if (!wait_lock) { |
| success = false; |
| break; |
| } else { /* wait for state change and retry */ |
| pthread_cond_wait(&locks_cond, &locks_mutex); |
| if (kill_thread) |
| pthread_exit(NULL); |
| } |
| } |
| slurm_mutex_unlock(&locks_mutex); |
| return success; |
| } |
| |
| /* _wr_rdunlock - Issue a read unlock on the specified data type */ |
| static void _wr_rdunlock(lock_datatype_t datatype) |
| { |
| slurm_mutex_lock(&locks_mutex); |
| slurmctld_locks.entity[read_lock(datatype)]--; |
| pthread_cond_broadcast(&locks_cond); |
| slurm_mutex_unlock(&locks_mutex); |
| } |
| |
| /* _wr_wrlock - Issue a write lock on the specified data type */ |
| static bool _wr_wrlock(lock_datatype_t datatype, bool wait_lock) |
| { |
| bool success = true; |
| |
| slurm_mutex_lock(&locks_mutex); |
| slurmctld_locks.entity[write_wait_lock(datatype)]++; |
| |
| while (1) { |
| if ((slurmctld_locks.entity[read_lock(datatype)] == 0) && |
| (slurmctld_locks.entity[write_lock(datatype)] == 0)) { |
| slurmctld_locks.entity[write_lock(datatype)]++; |
| slurmctld_locks.entity[write_wait_lock(datatype)]--; |
| break; |
| } else if (!wait_lock) { |
| slurmctld_locks.entity[write_wait_lock(datatype)]--; |
| success = false; |
| break; |
| } else { /* wait for state change and retry */ |
| pthread_cond_wait(&locks_cond, &locks_mutex); |
| if (kill_thread) |
| pthread_exit(NULL); |
| } |
| } |
| slurm_mutex_unlock(&locks_mutex); |
| return success; |
| } |
| |
| /* _wr_wrunlock - Issue a write unlock on the specified data type */ |
| static void _wr_wrunlock(lock_datatype_t datatype) |
| { |
| slurm_mutex_lock(&locks_mutex); |
| slurmctld_locks.entity[write_lock(datatype)]--; |
| pthread_cond_broadcast(&locks_cond); |
| slurm_mutex_unlock(&locks_mutex); |
| } |
| |
| /* get_lock_values - Get the current value of all locks |
| * OUT lock_flags - a copy of the current lock values */ |
| void get_lock_values(slurmctld_lock_flags_t * lock_flags) |
| { |
| xassert(lock_flags); |
| memcpy((void *) lock_flags, (void *) &slurmctld_locks, |
| sizeof(slurmctld_locks)); |
| } |
| |
| /* kill_locked_threads - Kill all threads waiting on semaphores */ |
| extern void kill_locked_threads(void) |
| { |
| kill_thread = 1; |
| pthread_cond_broadcast(&locks_cond); |
| } |
| |
| /* un/lock semaphore used for saving state of slurmctld */ |
| extern void lock_state_files(void) |
| { |
| slurm_mutex_lock(&state_mutex); |
| } |
| extern void unlock_state_files(void) |
| { |
| slurm_mutex_unlock(&state_mutex); |
| } |
