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heap.cc
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// Copyright 2012 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "src/v8.h"
#include "src/accessors.h"
#include "src/api.h"
#include "src/base/bits.h"
#include "src/base/once.h"
#include "src/base/utils/random-number-generator.h"
#include "src/bootstrapper.h"
#include "src/codegen.h"
#include "src/compilation-cache.h"
#include "src/conversions.h"
#include "src/cpu-profiler.h"
#include "src/debug.h"
#include "src/deoptimizer.h"
#include "src/global-handles.h"
#include "src/heap/gc-idle-time-handler.h"
#include "src/heap/incremental-marking.h"
#include "src/heap/mark-compact.h"
#include "src/heap/objects-visiting-inl.h"
#include "src/heap/objects-visiting.h"
#include "src/heap/store-buffer.h"
#include "src/heap-profiler.h"
#include "src/isolate-inl.h"
#include "src/natives.h"
#include "src/runtime-profiler.h"
#include "src/scopeinfo.h"
#include "src/serialize.h"
#include "src/snapshot.h"
#include "src/utils.h"
#include "src/v8threads.h"
#include "src/vm-state-inl.h"
#if V8_TARGET_ARCH_ARM && !V8_INTERPRETED_REGEXP
#include "src/regexp-macro-assembler.h" // NOLINT
#include "src/arm/regexp-macro-assembler-arm.h" // NOLINT
#endif
#if V8_TARGET_ARCH_MIPS && !V8_INTERPRETED_REGEXP
#include "src/regexp-macro-assembler.h" // NOLINT
#include "src/mips/regexp-macro-assembler-mips.h" // NOLINT
#endif
#if V8_TARGET_ARCH_MIPS64 && !V8_INTERPRETED_REGEXP
#include "src/regexp-macro-assembler.h"
#include "src/mips64/regexp-macro-assembler-mips64.h"
#endif
namespace v8 {
namespace internal {
Heap::Heap()
: amount_of_external_allocated_memory_(0),
amount_of_external_allocated_memory_at_last_global_gc_(0),
isolate_(NULL),
code_range_size_(0),
// semispace_size_ should be a power of 2 and old_generation_size_ should
// be a multiple of Page::kPageSize.
reserved_semispace_size_(8 * (kPointerSize / 4) * MB),
max_semi_space_size_(8 * (kPointerSize / 4) * MB),
initial_semispace_size_(Page::kPageSize),
target_semispace_size_(Page::kPageSize),
max_old_generation_size_(700ul * (kPointerSize / 4) * MB),
initial_old_generation_size_(max_old_generation_size_ / 2),
old_generation_size_configured_(false),
max_executable_size_(256ul * (kPointerSize / 4) * MB),
// Variables set based on semispace_size_ and old_generation_size_ in
// ConfigureHeap.
// Will be 4 * reserved_semispace_size_ to ensure that young
// generation can be aligned to its size.
maximum_committed_(0),
survived_since_last_expansion_(0),
survived_last_scavenge_(0),
sweep_generation_(0),
always_allocate_scope_depth_(0),
contexts_disposed_(0),
global_ic_age_(0),
flush_monomorphic_ics_(false),
scan_on_scavenge_pages_(0),
new_space_(this),
old_pointer_space_(NULL),
old_data_space_(NULL),
code_space_(NULL),
map_space_(NULL),
cell_space_(NULL),
property_cell_space_(NULL),
lo_space_(NULL),
gc_state_(NOT_IN_GC),
gc_post_processing_depth_(0),
allocations_count_(0),
raw_allocations_hash_(0),
dump_allocations_hash_countdown_(FLAG_dump_allocations_digest_at_alloc),
ms_count_(0),
gc_count_(0),
remembered_unmapped_pages_index_(0),
unflattened_strings_length_(0),
#ifdef DEBUG
allocation_timeout_(0),
#endif // DEBUG
old_generation_allocation_limit_(initial_old_generation_size_),
old_gen_exhausted_(false),
inline_allocation_disabled_(false),
store_buffer_rebuilder_(store_buffer()),
hidden_string_(NULL),
gc_safe_size_of_old_object_(NULL),
total_regexp_code_generated_(0),
tracer_(this),
high_survival_rate_period_length_(0),
promoted_objects_size_(0),
promotion_ratio_(0),
semi_space_copied_object_size_(0),
previous_semi_space_copied_object_size_(0),
semi_space_copied_rate_(0),
nodes_died_in_new_space_(0),
nodes_copied_in_new_space_(0),
nodes_promoted_(0),
maximum_size_scavenges_(0),
max_gc_pause_(0.0),
total_gc_time_ms_(0.0),
max_alive_after_gc_(0),
min_in_mutator_(kMaxInt),
marking_time_(0.0),
sweeping_time_(0.0),
last_idle_notification_time_(0.0),
mark_compact_collector_(this),
store_buffer_(this),
marking_(this),
incremental_marking_(this),
gc_count_at_last_idle_gc_(0),
full_codegen_bytes_generated_(0),
crankshaft_codegen_bytes_generated_(0),
gcs_since_last_deopt_(0),
#ifdef VERIFY_HEAP
no_weak_object_verification_scope_depth_(0),
#endif
allocation_sites_scratchpad_length_(0),
promotion_queue_(this),
configured_(false),
external_string_table_(this),
chunks_queued_for_free_(NULL),
gc_callbacks_depth_(0),
deserialization_complete_(false) {
// Allow build-time customization of the max semispace size. Building
// V8 with snapshots and a non-default max semispace size is much
// easier if you can define it as part of the build environment.
#if defined(V8_MAX_SEMISPACE_SIZE)
max_semi_space_size_ = reserved_semispace_size_ = V8_MAX_SEMISPACE_SIZE;
#endif
// Ensure old_generation_size_ is a multiple of kPageSize.
DCHECK(MB >= Page::kPageSize);
memset(roots_, 0, sizeof(roots_[0]) * kRootListLength);
set_native_contexts_list(NULL);
set_array_buffers_list(Smi::FromInt(0));
set_allocation_sites_list(Smi::FromInt(0));
set_encountered_weak_collections(Smi::FromInt(0));
set_encountered_weak_cells(Smi::FromInt(0));
// Put a dummy entry in the remembered pages so we can find the list the
// minidump even if there are no real unmapped pages.
RememberUnmappedPage(NULL, false);
ClearObjectStats(true);
}
intptr_t Heap::Capacity() {
if (!HasBeenSetUp()) return 0;
return new_space_.Capacity() + old_pointer_space_->Capacity() +
old_data_space_->Capacity() + code_space_->Capacity() +
map_space_->Capacity() + cell_space_->Capacity() +
property_cell_space_->Capacity();
}
intptr_t Heap::CommittedMemory() {
if (!HasBeenSetUp()) return 0;
return new_space_.CommittedMemory() + old_pointer_space_->CommittedMemory() +
old_data_space_->CommittedMemory() + code_space_->CommittedMemory() +
map_space_->CommittedMemory() + cell_space_->CommittedMemory() +
property_cell_space_->CommittedMemory() + lo_space_->Size();
}
size_t Heap::CommittedPhysicalMemory() {
if (!HasBeenSetUp()) return 0;
return new_space_.CommittedPhysicalMemory() +
old_pointer_space_->CommittedPhysicalMemory() +
old_data_space_->CommittedPhysicalMemory() +
code_space_->CommittedPhysicalMemory() +
map_space_->CommittedPhysicalMemory() +
cell_space_->CommittedPhysicalMemory() +
property_cell_space_->CommittedPhysicalMemory() +
lo_space_->CommittedPhysicalMemory();
}
intptr_t Heap::CommittedMemoryExecutable() {
if (!HasBeenSetUp()) return 0;
return isolate()->memory_allocator()->SizeExecutable();
}
void Heap::UpdateMaximumCommitted() {
if (!HasBeenSetUp()) return;
intptr_t current_committed_memory = CommittedMemory();
if (current_committed_memory > maximum_committed_) {
maximum_committed_ = current_committed_memory;
}
}
intptr_t Heap::Available() {
if (!HasBeenSetUp()) return 0;
return new_space_.Available() + old_pointer_space_->Available() +
old_data_space_->Available() + code_space_->Available() +
map_space_->Available() + cell_space_->Available() +
property_cell_space_->Available();
}
bool Heap::HasBeenSetUp() {
return old_pointer_space_ != NULL && old_data_space_ != NULL &&
code_space_ != NULL && map_space_ != NULL && cell_space_ != NULL &&
property_cell_space_ != NULL && lo_space_ != NULL;
}
int Heap::GcSafeSizeOfOldObject(HeapObject* object) {
if (IntrusiveMarking::IsMarked(object)) {
return IntrusiveMarking::SizeOfMarkedObject(object);
}
return object->SizeFromMap(object->map());
}
GarbageCollector Heap::SelectGarbageCollector(AllocationSpace space,
const char** reason) {
// Is global GC requested?
if (space != NEW_SPACE) {
isolate_->counters()->gc_compactor_caused_by_request()->Increment();
*reason = "GC in old space requested";
return MARK_COMPACTOR;
}
if (FLAG_gc_global || (FLAG_stress_compaction && (gc_count_ & 1) != 0)) {
*reason = "GC in old space forced by flags";
return MARK_COMPACTOR;
}
// Is enough data promoted to justify a global GC?
if (OldGenerationAllocationLimitReached()) {
isolate_->counters()->gc_compactor_caused_by_promoted_data()->Increment();
*reason = "promotion limit reached";
return MARK_COMPACTOR;
}
// Have allocation in OLD and LO failed?
if (old_gen_exhausted_) {
isolate_->counters()
->gc_compactor_caused_by_oldspace_exhaustion()
->Increment();
*reason = "old generations exhausted";
return MARK_COMPACTOR;
}
// Is there enough space left in OLD to guarantee that a scavenge can
// succeed?
//
// Note that MemoryAllocator->MaxAvailable() undercounts the memory available
// for object promotion. It counts only the bytes that the memory
// allocator has not yet allocated from the OS and assigned to any space,
// and does not count available bytes already in the old space or code
// space. Undercounting is safe---we may get an unrequested full GC when
// a scavenge would have succeeded.
if (isolate_->memory_allocator()->MaxAvailable() <= new_space_.Size()) {
isolate_->counters()
->gc_compactor_caused_by_oldspace_exhaustion()
->Increment();
*reason = "scavenge might not succeed";
return MARK_COMPACTOR;
}
// Default
*reason = NULL;
return SCAVENGER;
}
// TODO(1238405): Combine the infrastructure for --heap-stats and
// --log-gc to avoid the complicated preprocessor and flag testing.
void Heap::ReportStatisticsBeforeGC() {
// Heap::ReportHeapStatistics will also log NewSpace statistics when
// compiled --log-gc is set. The following logic is used to avoid
// double logging.
#ifdef DEBUG
if (FLAG_heap_stats || FLAG_log_gc) new_space_.CollectStatistics();
if (FLAG_heap_stats) {
ReportHeapStatistics("Before GC");
} else if (FLAG_log_gc) {
new_space_.ReportStatistics();
}
if (FLAG_heap_stats || FLAG_log_gc) new_space_.ClearHistograms();
#else
if (FLAG_log_gc) {
new_space_.CollectStatistics();
new_space_.ReportStatistics();
new_space_.ClearHistograms();
}
#endif // DEBUG
}
void Heap::PrintShortHeapStatistics() {
if (!FLAG_trace_gc_verbose) return;
PrintPID("Memory allocator, used: %6" V8_PTR_PREFIX
"d KB"
", available: %6" V8_PTR_PREFIX "d KB\n",
isolate_->memory_allocator()->Size() / KB,
isolate_->memory_allocator()->Available() / KB);
PrintPID("New space, used: %6" V8_PTR_PREFIX
"d KB"
", available: %6" V8_PTR_PREFIX
"d KB"
", committed: %6" V8_PTR_PREFIX "d KB\n",
new_space_.Size() / KB, new_space_.Available() / KB,
new_space_.CommittedMemory() / KB);
PrintPID("Old pointers, used: %6" V8_PTR_PREFIX
"d KB"
", available: %6" V8_PTR_PREFIX
"d KB"
", committed: %6" V8_PTR_PREFIX "d KB\n",
old_pointer_space_->SizeOfObjects() / KB,
old_pointer_space_->Available() / KB,
old_pointer_space_->CommittedMemory() / KB);
PrintPID("Old data space, used: %6" V8_PTR_PREFIX
"d KB"
", available: %6" V8_PTR_PREFIX
"d KB"
", committed: %6" V8_PTR_PREFIX "d KB\n",
old_data_space_->SizeOfObjects() / KB,
old_data_space_->Available() / KB,
old_data_space_->CommittedMemory() / KB);
PrintPID("Code space, used: %6" V8_PTR_PREFIX
"d KB"
", available: %6" V8_PTR_PREFIX
"d KB"
", committed: %6" V8_PTR_PREFIX "d KB\n",
code_space_->SizeOfObjects() / KB, code_space_->Available() / KB,
code_space_->CommittedMemory() / KB);
PrintPID("Map space, used: %6" V8_PTR_PREFIX
"d KB"
", available: %6" V8_PTR_PREFIX
"d KB"
", committed: %6" V8_PTR_PREFIX "d KB\n",
map_space_->SizeOfObjects() / KB, map_space_->Available() / KB,
map_space_->CommittedMemory() / KB);
PrintPID("Cell space, used: %6" V8_PTR_PREFIX
"d KB"
", available: %6" V8_PTR_PREFIX
"d KB"
", committed: %6" V8_PTR_PREFIX "d KB\n",
cell_space_->SizeOfObjects() / KB, cell_space_->Available() / KB,
cell_space_->CommittedMemory() / KB);
PrintPID("PropertyCell space, used: %6" V8_PTR_PREFIX
"d KB"
", available: %6" V8_PTR_PREFIX
"d KB"
", committed: %6" V8_PTR_PREFIX "d KB\n",
property_cell_space_->SizeOfObjects() / KB,
property_cell_space_->Available() / KB,
property_cell_space_->CommittedMemory() / KB);
PrintPID("Large object space, used: %6" V8_PTR_PREFIX
"d KB"
", available: %6" V8_PTR_PREFIX
"d KB"
", committed: %6" V8_PTR_PREFIX "d KB\n",
lo_space_->SizeOfObjects() / KB, lo_space_->Available() / KB,
lo_space_->CommittedMemory() / KB);
PrintPID("All spaces, used: %6" V8_PTR_PREFIX
"d KB"
", available: %6" V8_PTR_PREFIX
"d KB"
", committed: %6" V8_PTR_PREFIX "d KB\n",
this->SizeOfObjects() / KB, this->Available() / KB,
this->CommittedMemory() / KB);
PrintPID("External memory reported: %6" V8_PTR_PREFIX "d KB\n",
static_cast<intptr_t>(amount_of_external_allocated_memory_ / KB));
PrintPID("Total time spent in GC : %.1f ms\n", total_gc_time_ms_);
}
// TODO(1238405): Combine the infrastructure for --heap-stats and
// --log-gc to avoid the complicated preprocessor and flag testing.
void Heap::ReportStatisticsAfterGC() {
// Similar to the before GC, we use some complicated logic to ensure that
// NewSpace statistics are logged exactly once when --log-gc is turned on.
#if defined(DEBUG)
if (FLAG_heap_stats) {
new_space_.CollectStatistics();
ReportHeapStatistics("After GC");
} else if (FLAG_log_gc) {
new_space_.ReportStatistics();
}
#else
if (FLAG_log_gc) new_space_.ReportStatistics();
#endif // DEBUG
}
void Heap::GarbageCollectionPrologue() {
{
AllowHeapAllocation for_the_first_part_of_prologue;
ClearJSFunctionResultCaches();
gc_count_++;
unflattened_strings_length_ = 0;
if (FLAG_flush_code && FLAG_flush_code_incrementally) {
mark_compact_collector()->EnableCodeFlushing(true);
}
#ifdef VERIFY_HEAP
if (FLAG_verify_heap) {
Verify();
}
#endif
}
// Reset GC statistics.
promoted_objects_size_ = 0;
previous_semi_space_copied_object_size_ = semi_space_copied_object_size_;
semi_space_copied_object_size_ = 0;
nodes_died_in_new_space_ = 0;
nodes_copied_in_new_space_ = 0;
nodes_promoted_ = 0;
UpdateMaximumCommitted();
#ifdef DEBUG
DCHECK(!AllowHeapAllocation::IsAllowed() && gc_state_ == NOT_IN_GC);
if (FLAG_gc_verbose) Print();
ReportStatisticsBeforeGC();
#endif // DEBUG
store_buffer()->GCPrologue();
if (isolate()->concurrent_osr_enabled()) {
isolate()->optimizing_compiler_thread()->AgeBufferedOsrJobs();
}
if (new_space_.IsAtMaximumCapacity()) {
maximum_size_scavenges_++;
} else {
maximum_size_scavenges_ = 0;
}
CheckNewSpaceExpansionCriteria();
}
intptr_t Heap::SizeOfObjects() {
intptr_t total = 0;
AllSpaces spaces(this);
for (Space* space = spaces.next(); space != NULL; space = spaces.next()) {
total += space->SizeOfObjects();
}
return total;
}
void Heap::ClearAllICsByKind(Code::Kind kind) {
HeapObjectIterator it(code_space());
for (Object* object = it.Next(); object != NULL; object = it.Next()) {
Code* code = Code::cast(object);
Code::Kind current_kind = code->kind();
if (current_kind == Code::FUNCTION ||
current_kind == Code::OPTIMIZED_FUNCTION) {
code->ClearInlineCaches(kind);
}
}
}
void Heap::RepairFreeListsAfterBoot() {
PagedSpaces spaces(this);
for (PagedSpace* space = spaces.next(); space != NULL;
space = spaces.next()) {
space->RepairFreeListsAfterBoot();
}
}
void Heap::ProcessPretenuringFeedback() {
if (FLAG_allocation_site_pretenuring) {
int tenure_decisions = 0;
int dont_tenure_decisions = 0;
int allocation_mementos_found = 0;
int allocation_sites = 0;
int active_allocation_sites = 0;
// If the scratchpad overflowed, we have to iterate over the allocation
// sites list.
// TODO(hpayer): We iterate over the whole list of allocation sites when
// we grew to the maximum semi-space size to deopt maybe tenured
// allocation sites. We could hold the maybe tenured allocation sites
// in a seperate data structure if this is a performance problem.
bool deopt_maybe_tenured = DeoptMaybeTenuredAllocationSites();
bool use_scratchpad =
allocation_sites_scratchpad_length_ < kAllocationSiteScratchpadSize &&
!deopt_maybe_tenured;
int i = 0;
Object* list_element = allocation_sites_list();
bool trigger_deoptimization = false;
bool maximum_size_scavenge = MaximumSizeScavenge();
while (use_scratchpad ? i < allocation_sites_scratchpad_length_
: list_element->IsAllocationSite()) {
AllocationSite* site =
use_scratchpad
? AllocationSite::cast(allocation_sites_scratchpad()->get(i))
: AllocationSite::cast(list_element);
allocation_mementos_found += site->memento_found_count();
if (site->memento_found_count() > 0) {
active_allocation_sites++;
if (site->DigestPretenuringFeedback(maximum_size_scavenge)) {
trigger_deoptimization = true;
}
if (site->GetPretenureMode() == TENURED) {
tenure_decisions++;
} else {
dont_tenure_decisions++;
}
allocation_sites++;
}
if (deopt_maybe_tenured && site->IsMaybeTenure()) {
site->set_deopt_dependent_code(true);
trigger_deoptimization = true;
}
if (use_scratchpad) {
i++;
} else {
list_element = site->weak_next();
}
}
if (trigger_deoptimization) {
isolate_->stack_guard()->RequestDeoptMarkedAllocationSites();
}
FlushAllocationSitesScratchpad();
if (FLAG_trace_pretenuring_statistics &&
(allocation_mementos_found > 0 || tenure_decisions > 0 ||
dont_tenure_decisions > 0)) {
PrintF(
"GC: (mode, #visited allocation sites, #active allocation sites, "
"#mementos, #tenure decisions, #donttenure decisions) "
"(%s, %d, %d, %d, %d, %d)\n",
use_scratchpad ? "use scratchpad" : "use list", allocation_sites,
active_allocation_sites, allocation_mementos_found, tenure_decisions,
dont_tenure_decisions);
}
}
}
void Heap::DeoptMarkedAllocationSites() {
// TODO(hpayer): If iterating over the allocation sites list becomes a
// performance issue, use a cache heap data structure instead (similar to the
// allocation sites scratchpad).
Object* list_element = allocation_sites_list();
while (list_element->IsAllocationSite()) {
AllocationSite* site = AllocationSite::cast(list_element);
if (site->deopt_dependent_code()) {
site->dependent_code()->MarkCodeForDeoptimization(
isolate_, DependentCode::kAllocationSiteTenuringChangedGroup);
site->set_deopt_dependent_code(false);
}
list_element = site->weak_next();
}
Deoptimizer::DeoptimizeMarkedCode(isolate_);
}
void Heap::GarbageCollectionEpilogue() {
store_buffer()->GCEpilogue();
// In release mode, we only zap the from space under heap verification.
if (Heap::ShouldZapGarbage()) {
ZapFromSpace();
}
// Process pretenuring feedback and update allocation sites.
ProcessPretenuringFeedback();
#ifdef VERIFY_HEAP
if (FLAG_verify_heap) {
Verify();
}
#endif
AllowHeapAllocation for_the_rest_of_the_epilogue;
#ifdef DEBUG
if (FLAG_print_global_handles) isolate_->global_handles()->Print();
if (FLAG_print_handles) PrintHandles();
if (FLAG_gc_verbose) Print();
if (FLAG_code_stats) ReportCodeStatistics("After GC");
#endif
if (FLAG_deopt_every_n_garbage_collections > 0) {
// TODO(jkummerow/ulan/jarin): This is not safe! We can't assume that
// the topmost optimized frame can be deoptimized safely, because it
// might not have a lazy bailout point right after its current PC.
if (++gcs_since_last_deopt_ == FLAG_deopt_every_n_garbage_collections) {
Deoptimizer::DeoptimizeAll(isolate());
gcs_since_last_deopt_ = 0;
}
}
UpdateMaximumCommitted();
isolate_->counters()->alive_after_last_gc()->Set(
static_cast<int>(SizeOfObjects()));
isolate_->counters()->string_table_capacity()->Set(
string_table()->Capacity());
isolate_->counters()->number_of_symbols()->Set(
string_table()->NumberOfElements());
if (full_codegen_bytes_generated_ + crankshaft_codegen_bytes_generated_ > 0) {
isolate_->counters()->codegen_fraction_crankshaft()->AddSample(
static_cast<int>((crankshaft_codegen_bytes_generated_ * 100.0) /
(crankshaft_codegen_bytes_generated_ +
full_codegen_bytes_generated_)));
}
if (CommittedMemory() > 0) {
isolate_->counters()->external_fragmentation_total()->AddSample(
static_cast<int>(100 - (SizeOfObjects() * 100.0) / CommittedMemory()));
isolate_->counters()->heap_fraction_new_space()->AddSample(static_cast<int>(
(new_space()->CommittedMemory() * 100.0) / CommittedMemory()));
isolate_->counters()->heap_fraction_old_pointer_space()->AddSample(
static_cast<int>((old_pointer_space()->CommittedMemory() * 100.0) /
CommittedMemory()));
isolate_->counters()->heap_fraction_old_data_space()->AddSample(
static_cast<int>((old_data_space()->CommittedMemory() * 100.0) /
CommittedMemory()));
isolate_->counters()->heap_fraction_code_space()->AddSample(
static_cast<int>((code_space()->CommittedMemory() * 100.0) /
CommittedMemory()));
isolate_->counters()->heap_fraction_map_space()->AddSample(static_cast<int>(
(map_space()->CommittedMemory() * 100.0) / CommittedMemory()));
isolate_->counters()->heap_fraction_cell_space()->AddSample(
static_cast<int>((cell_space()->CommittedMemory() * 100.0) /
CommittedMemory()));
isolate_->counters()->heap_fraction_property_cell_space()->AddSample(
static_cast<int>((property_cell_space()->CommittedMemory() * 100.0) /
CommittedMemory()));
isolate_->counters()->heap_fraction_lo_space()->AddSample(static_cast<int>(
(lo_space()->CommittedMemory() * 100.0) / CommittedMemory()));
isolate_->counters()->heap_sample_total_committed()->AddSample(
static_cast<int>(CommittedMemory() / KB));
isolate_->counters()->heap_sample_total_used()->AddSample(
static_cast<int>(SizeOfObjects() / KB));
isolate_->counters()->heap_sample_map_space_committed()->AddSample(
static_cast<int>(map_space()->CommittedMemory() / KB));
isolate_->counters()->heap_sample_cell_space_committed()->AddSample(
static_cast<int>(cell_space()->CommittedMemory() / KB));
isolate_->counters()
->heap_sample_property_cell_space_committed()
->AddSample(
static_cast<int>(property_cell_space()->CommittedMemory() / KB));
isolate_->counters()->heap_sample_code_space_committed()->AddSample(
static_cast<int>(code_space()->CommittedMemory() / KB));
isolate_->counters()->heap_sample_maximum_committed()->AddSample(
static_cast<int>(MaximumCommittedMemory() / KB));
}
#define UPDATE_COUNTERS_FOR_SPACE(space) \
isolate_->counters()->space##_bytes_available()->Set( \
static_cast<int>(space()->Available())); \
isolate_->counters()->space##_bytes_committed()->Set( \
static_cast<int>(space()->CommittedMemory())); \
isolate_->counters()->space##_bytes_used()->Set( \
static_cast<int>(space()->SizeOfObjects()));
#define UPDATE_FRAGMENTATION_FOR_SPACE(space) \
if (space()->CommittedMemory() > 0) { \
isolate_->counters()->external_fragmentation_##space()->AddSample( \
static_cast<int>(100 - \
(space()->SizeOfObjects() * 100.0) / \
space()->CommittedMemory())); \
}
#define UPDATE_COUNTERS_AND_FRAGMENTATION_FOR_SPACE(space) \
UPDATE_COUNTERS_FOR_SPACE(space) \
UPDATE_FRAGMENTATION_FOR_SPACE(space)
UPDATE_COUNTERS_FOR_SPACE(new_space)
UPDATE_COUNTERS_AND_FRAGMENTATION_FOR_SPACE(old_pointer_space)
UPDATE_COUNTERS_AND_FRAGMENTATION_FOR_SPACE(old_data_space)
UPDATE_COUNTERS_AND_FRAGMENTATION_FOR_SPACE(code_space)
UPDATE_COUNTERS_AND_FRAGMENTATION_FOR_SPACE(map_space)
UPDATE_COUNTERS_AND_FRAGMENTATION_FOR_SPACE(cell_space)
UPDATE_COUNTERS_AND_FRAGMENTATION_FOR_SPACE(property_cell_space)
UPDATE_COUNTERS_AND_FRAGMENTATION_FOR_SPACE(lo_space)
#undef UPDATE_COUNTERS_FOR_SPACE
#undef UPDATE_FRAGMENTATION_FOR_SPACE
#undef UPDATE_COUNTERS_AND_FRAGMENTATION_FOR_SPACE
#ifdef DEBUG
ReportStatisticsAfterGC();
#endif // DEBUG
// Remember the last top pointer so that we can later find out
// whether we allocated in new space since the last GC.
new_space_top_after_last_gc_ = new_space()->top();
}
void Heap::CollectAllGarbage(int flags, const char* gc_reason,
const v8::GCCallbackFlags gc_callback_flags) {
// Since we are ignoring the return value, the exact choice of space does
// not matter, so long as we do not specify NEW_SPACE, which would not
// cause a full GC.
mark_compact_collector_.SetFlags(flags);
CollectGarbage(OLD_POINTER_SPACE, gc_reason, gc_callback_flags);
mark_compact_collector_.SetFlags(kNoGCFlags);
}
void Heap::CollectAllAvailableGarbage(const char* gc_reason) {
// Since we are ignoring the return value, the exact choice of space does
// not matter, so long as we do not specify NEW_SPACE, which would not
// cause a full GC.
// Major GC would invoke weak handle callbacks on weakly reachable
// handles, but won't collect weakly reachable objects until next
// major GC. Therefore if we collect aggressively and weak handle callback
// has been invoked, we rerun major GC to release objects which become
// garbage.
// Note: as weak callbacks can execute arbitrary code, we cannot
// hope that eventually there will be no weak callbacks invocations.
// Therefore stop recollecting after several attempts.
if (isolate()->concurrent_recompilation_enabled()) {
// The optimizing compiler may be unnecessarily holding on to memory.
DisallowHeapAllocation no_recursive_gc;
isolate()->optimizing_compiler_thread()->Flush();
}
mark_compact_collector()->SetFlags(kMakeHeapIterableMask |
kReduceMemoryFootprintMask);
isolate_->compilation_cache()->Clear();
const int kMaxNumberOfAttempts = 7;
const int kMinNumberOfAttempts = 2;
for (int attempt = 0; attempt < kMaxNumberOfAttempts; attempt++) {
if (!CollectGarbage(MARK_COMPACTOR, gc_reason, NULL) &&
attempt + 1 >= kMinNumberOfAttempts) {
break;
}
}
mark_compact_collector()->SetFlags(kNoGCFlags);
new_space_.Shrink();
UncommitFromSpace();
}
void Heap::EnsureFillerObjectAtTop() {
// There may be an allocation memento behind every object in new space.
// If we evacuate a not full new space or if we are on the last page of
// the new space, then there may be uninitialized memory behind the top
// pointer of the new space page. We store a filler object there to
// identify the unused space.
Address from_top = new_space_.top();
Address from_limit = new_space_.limit();
if (from_top < from_limit) {
int remaining_in_page = static_cast<int>(from_limit - from_top);
CreateFillerObjectAt(from_top, remaining_in_page);
}
}
bool Heap::CollectGarbage(GarbageCollector collector, const char* gc_reason,
const char* collector_reason,
const v8::GCCallbackFlags gc_callback_flags) {
// The VM is in the GC state until exiting this function.
VMState<GC> state(isolate_);
#ifdef DEBUG
// Reset the allocation timeout to the GC interval, but make sure to
// allow at least a few allocations after a collection. The reason
// for this is that we have a lot of allocation sequences and we
// assume that a garbage collection will allow the subsequent
// allocation attempts to go through.
allocation_timeout_ = Max(6, FLAG_gc_interval);
#endif
EnsureFillerObjectAtTop();
if (collector == SCAVENGER && !incremental_marking()->IsStopped()) {
if (FLAG_trace_incremental_marking) {
PrintF("[IncrementalMarking] Scavenge during marking.\n");
}
}
if (collector == MARK_COMPACTOR &&
!mark_compact_collector()->abort_incremental_marking() &&
!incremental_marking()->IsStopped() &&
!incremental_marking()->should_hurry() &&
FLAG_incremental_marking_steps) {
// Make progress in incremental marking.
const intptr_t kStepSizeWhenDelayedByScavenge = 1 * MB;
incremental_marking()->Step(kStepSizeWhenDelayedByScavenge,
IncrementalMarking::NO_GC_VIA_STACK_GUARD);
if (!incremental_marking()->IsComplete() && !FLAG_gc_global) {
if (FLAG_trace_incremental_marking) {
PrintF("[IncrementalMarking] Delaying MarkSweep.\n");
}
collector = SCAVENGER;
collector_reason = "incremental marking delaying mark-sweep";
}
}
bool next_gc_likely_to_collect_more = false;
{
tracer()->Start(collector, gc_reason, collector_reason);
DCHECK(AllowHeapAllocation::IsAllowed());
DisallowHeapAllocation no_allocation_during_gc;
GarbageCollectionPrologue();
{
HistogramTimerScope histogram_timer_scope(
(collector == SCAVENGER) ? isolate_->counters()->gc_scavenger()
: isolate_->counters()->gc_compactor());
next_gc_likely_to_collect_more =
PerformGarbageCollection(collector, gc_callback_flags);
}
GarbageCollectionEpilogue();
tracer()->Stop(collector);
}
// Start incremental marking for the next cycle. The heap snapshot
// generator needs incremental marking to stay off after it aborted.
if (!mark_compact_collector()->abort_incremental_marking() &&
WorthActivatingIncrementalMarking()) {
incremental_marking()->Start();
}
return next_gc_likely_to_collect_more;
}
int Heap::NotifyContextDisposed(bool dependant_context) {
if (!dependant_context) {
tracer()->ResetSurvivalEvents();
old_generation_size_configured_ = false;
}
if (isolate()->concurrent_recompilation_enabled()) {
// Flush the queued recompilation tasks.
isolate()->optimizing_compiler_thread()->Flush();
}
flush_monomorphic_ics_ = true;
AgeInlineCaches();
tracer()->AddContextDisposalTime(base::OS::TimeCurrentMillis());
return ++contexts_disposed_;
}
void Heap::MoveElements(FixedArray* array, int dst_index, int src_index,
int len) {
if (len == 0) return;
DCHECK(array->map() != fixed_cow_array_map());
Object** dst_objects = array->data_start() + dst_index;
MemMove(dst_objects, array->data_start() + src_index, len * kPointerSize);
if (!InNewSpace(array)) {
for (int i = 0; i < len; i++) {
// TODO(hpayer): check store buffer for entries
if (InNewSpace(dst_objects[i])) {
RecordWrite(array->address(), array->OffsetOfElementAt(dst_index + i));
}
}
}
incremental_marking()->RecordWrites(array);
}
#ifdef VERIFY_HEAP
// Helper class for verifying the string table.
class StringTableVerifier : public ObjectVisitor {
public:
void VisitPointers(Object** start, Object** end) {
// Visit all HeapObject pointers in [start, end).
for (Object** p = start; p < end; p++) {
if ((*p)->IsHeapObject()) {
// Check that the string is actually internalized.
CHECK((*p)->IsTheHole() || (*p)->IsUndefined() ||
(*p)->IsInternalizedString());
}
}
}
};
static void VerifyStringTable(Heap* heap) {
StringTableVerifier verifier;
heap->string_table()->IterateElements(&verifier);
}
#endif // VERIFY_HEAP
static bool AbortIncrementalMarkingAndCollectGarbage(
Heap* heap, AllocationSpace space, const char* gc_reason = NULL) {
heap->mark_compact_collector()->SetFlags(Heap::kAbortIncrementalMarkingMask);
bool result = heap->CollectGarbage(space, gc_reason);
heap->mark_compact_collector()->SetFlags(Heap::kNoGCFlags);
return result;
}
bool Heap::ReserveSpace(Reservation* reservations) {
bool gc_performed = true;
int counter = 0;
static const int kThreshold = 20;
while (gc_performed && counter++ < kThreshold) {
gc_performed = false;
for (int space = NEW_SPACE; space < Serializer::kNumberOfSpaces; space++) {
Reservation* reservation = &reservations[space];
DCHECK_LE(1, reservation->length());
if (reservation->at(0).size == 0) continue;
bool perform_gc = false;
if (space == LO_SPACE) {
DCHECK_EQ(1, reservation->length());
perform_gc = !lo_space()->CanAllocateSize(reservation->at(0).size);
} else {
for (auto& chunk : *reservation) {
AllocationResult allocation;
int size = chunk.size;
DCHECK_LE(size, MemoryAllocator::PageAreaSize(
static_cast<AllocationSpace>(space)));
if (space == NEW_SPACE) {
allocation = new_space()->AllocateRaw(size);
} else {
allocation = paged_space(space)->AllocateRaw(size);
}
FreeListNode* node;
if (allocation.To(&node)) {
// Mark with a free list node, in case we have a GC before
// deserializing.
node->set_size(this, size);
DCHECK(space < Serializer::kNumberOfPreallocatedSpaces);
chunk.start = node->address();
chunk.end = node->address() + size;
} else {
perform_gc = true;
break;
}
}
}
if (perform_gc) {
if (space == NEW_SPACE) {
Heap::CollectGarbage(NEW_SPACE,
"failed to reserve space in the new space");
} else {
AbortIncrementalMarkingAndCollectGarbage(
this, static_cast<AllocationSpace>(space),
"failed to reserve space in paged or large object space");
}
gc_performed = true;
break; // Abort for-loop over spaces and retry.
}
}
}
return !gc_performed;
}
void Heap::EnsureFromSpaceIsCommitted() {
if (new_space_.CommitFromSpaceIfNeeded()) return;
// Committing memory to from space failed.
// Memory is exhausted and we will die.
V8::FatalProcessOutOfMemory("Committing semi space failed.");
}