src/hotspot/share/nmt/nmtUsage.cpp

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#include "memory/arena.hpp"
#include "nmt/mallocTracker.hpp"
#include "nmt/memoryFileTracker.hpp"
#include "nmt/memTracker.hpp"
#include "nmt/nmtCommon.hpp"
#include "nmt/nmtUsage.hpp"
#include "nmt/threadStackTracker.hpp"
#include "nmt/virtualMemoryTracker.hpp"

// Enabled all options for snapshot.
const NMTUsageOptions NMTUsage::OptionsAll = { true, true, true };
// Skip expensive thread stacks when refreshing usage.
const NMTUsageOptions NMTUsage::OptionsNoTS = { false, true, true };

NMTUsage::NMTUsage(NMTUsageOptions options) :
    _malloc_by_type(),
    _malloc_total(),
    _vm_by_type(),
    _vm_total(),
    _usage_options(options) { }

void NMTUsage::walk_thread_stacks() {
  // Snapping the thread stacks involves walking the areas to figure out how
  // much memory had been committed if they are backed by virtual memory. This
  // needs to happen before we take the snapshot of the virtual memory since it
  // will update this information.
  VirtualMemoryTracker::snapshot_thread_stacks();
}

void NMTUsage::update_malloc_usage() {
  MallocMemorySnapshot* ms;
  // Lock needed to keep values in sync, total area size
  // is deducted from mtChunk in the end to give correct values.
  {
    ChunkPoolLocker lock;
    ms = MallocMemorySummary::as_snapshot();
  }

  size_t total_arena_size = 0;
  for (int i = 0; i < mt_number_of_tags; i++) {
    MemTag mem_tag = NMTUtil::index_to_tag(i);
    const MallocMemory* mm = ms->by_tag(mem_tag);
    _malloc_by_type[i] = mm->malloc_size() + mm->arena_size();
    total_arena_size +=  mm->arena_size();
  }

  // Total malloc size.
  _malloc_total = ms->total();

  // Adjustment due to mtChunk double counting.
  _malloc_by_type[NMTUtil::tag_to_index(mtChunk)] -= total_arena_size;
  _malloc_total -= total_arena_size;

  // Adjust mtNMT to include malloc overhead.
  _malloc_by_type[NMTUtil::tag_to_index(mtNMT)] += ms->malloc_overhead();
}

void NMTUsage::update_vm_usage() {
  const VirtualMemorySnapshot* vms = VirtualMemorySummary::as_snapshot();

  // Reset total to allow recalculation.
  _vm_total.committed = 0;
  _vm_total.reserved = 0;
  for (int i = 0; i < mt_number_of_tags; i++) {
    MemTag mem_tag = NMTUtil::index_to_tag(i);
    const VirtualMemory* vm = vms->by_tag(mem_tag);

    _vm_by_type[i].reserved = vm->reserved();
    _vm_by_type[i].committed = vm->committed();
    _vm_total.reserved += vm->reserved();
    _vm_total.committed += vm->committed();
  }

  { // MemoryFileTracker addition
    using MFT = MemoryFileTracker::Instance;
    MemTracker::NmtVirtualMemoryLocker nvml;
    MFT::iterate_summary([&](MemTag tag, const VirtualMemory* vm) {
      int i = NMTUtil::tag_to_index(tag);
      _vm_by_type[i].committed += vm->committed();
      _vm_total.committed += vm->committed();
    });
  }
}

void NMTUsage::refresh() {
  if (_usage_options.include_malloc) {
    update_malloc_usage();
  }

  if (_usage_options.include_vm) {
    // Thread stacks only makes sense if virtual memory
    // is also included. It must be executed before the
    // over all usage is calculated.
    if (_usage_options.update_thread_stacks) {
      walk_thread_stacks();
    }
    update_vm_usage();
  }
}

size_t NMTUsage::total_reserved() const {
  return _malloc_total + _vm_total.reserved;
}

size_t NMTUsage::total_committed() const {
  return _malloc_total + _vm_total.committed;
}

size_t NMTUsage::reserved(MemTag mem_tag) const {
  int index = NMTUtil::tag_to_index(mem_tag);
  return _malloc_by_type[index] + _vm_by_type[index].reserved;
}

size_t NMTUsage::committed(MemTag mem_tag) const {
  int index = NMTUtil::tag_to_index(mem_tag);
  return _malloc_by_type[index] + _vm_by_type[index].committed;
}