v8/src/heap-inl.h
antonm@chromium.org 20938fc53c Attempt to collect more garbage before panicking with out of memory.
Currently weak handles retain an object for another GC round (oftem times,
major GC round.)  Instrumenting Chromium shows that navigation leaves
many global objects which are only collected in next go.  Let's
attempt to collect more garbage when approacing OOM condition.

This is a better version of rolled out r5455: now it's correctly
rebuilds object groups between additional GCs.

Review URL: http://codereview.chromium.org/4295004

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@5761 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2010-11-03 13:00:28 +00:00

510 lines
17 KiB
C++

// Copyright 2006-2008 the V8 project authors. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following
// disclaimer in the documentation and/or other materials provided
// with the distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived
// from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#ifndef V8_HEAP_INL_H_
#define V8_HEAP_INL_H_
#include "heap.h"
#include "objects.h"
#include "v8-counters.h"
namespace v8 {
namespace internal {
int Heap::MaxObjectSizeInPagedSpace() {
return Page::kMaxHeapObjectSize;
}
MaybeObject* Heap::AllocateSymbol(Vector<const char> str,
int chars,
uint32_t hash_field) {
unibrow::Utf8InputBuffer<> buffer(str.start(),
static_cast<unsigned>(str.length()));
return AllocateInternalSymbol(&buffer, chars, hash_field);
}
MaybeObject* Heap::CopyFixedArray(FixedArray* src) {
return CopyFixedArrayWithMap(src, src->map());
}
MaybeObject* Heap::AllocateRaw(int size_in_bytes,
AllocationSpace space,
AllocationSpace retry_space) {
ASSERT(allocation_allowed_ && gc_state_ == NOT_IN_GC);
ASSERT(space != NEW_SPACE ||
retry_space == OLD_POINTER_SPACE ||
retry_space == OLD_DATA_SPACE ||
retry_space == LO_SPACE);
#ifdef DEBUG
if (FLAG_gc_interval >= 0 &&
!disallow_allocation_failure_ &&
Heap::allocation_timeout_-- <= 0) {
return Failure::RetryAfterGC(space);
}
Counters::objs_since_last_full.Increment();
Counters::objs_since_last_young.Increment();
#endif
MaybeObject* result;
if (NEW_SPACE == space) {
result = new_space_.AllocateRaw(size_in_bytes);
if (always_allocate() && result->IsFailure()) {
space = retry_space;
} else {
return result;
}
}
if (OLD_POINTER_SPACE == space) {
result = old_pointer_space_->AllocateRaw(size_in_bytes);
} else if (OLD_DATA_SPACE == space) {
result = old_data_space_->AllocateRaw(size_in_bytes);
} else if (CODE_SPACE == space) {
result = code_space_->AllocateRaw(size_in_bytes);
} else if (LO_SPACE == space) {
result = lo_space_->AllocateRaw(size_in_bytes);
} else if (CELL_SPACE == space) {
result = cell_space_->AllocateRaw(size_in_bytes);
} else {
ASSERT(MAP_SPACE == space);
result = map_space_->AllocateRaw(size_in_bytes);
}
if (result->IsFailure()) old_gen_exhausted_ = true;
return result;
}
MaybeObject* Heap::NumberFromInt32(int32_t value) {
if (Smi::IsValid(value)) return Smi::FromInt(value);
// Bypass NumberFromDouble to avoid various redundant checks.
return AllocateHeapNumber(FastI2D(value));
}
MaybeObject* Heap::NumberFromUint32(uint32_t value) {
if ((int32_t)value >= 0 && Smi::IsValid((int32_t)value)) {
return Smi::FromInt((int32_t)value);
}
// Bypass NumberFromDouble to avoid various redundant checks.
return AllocateHeapNumber(FastUI2D(value));
}
void Heap::FinalizeExternalString(String* string) {
ASSERT(string->IsExternalString());
v8::String::ExternalStringResourceBase** resource_addr =
reinterpret_cast<v8::String::ExternalStringResourceBase**>(
reinterpret_cast<byte*>(string) +
ExternalString::kResourceOffset -
kHeapObjectTag);
// Dispose of the C++ object if it has not already been disposed.
if (*resource_addr != NULL) {
(*resource_addr)->Dispose();
}
// Clear the resource pointer in the string.
*resource_addr = NULL;
}
MaybeObject* Heap::AllocateRawMap() {
#ifdef DEBUG
Counters::objs_since_last_full.Increment();
Counters::objs_since_last_young.Increment();
#endif
MaybeObject* result = map_space_->AllocateRaw(Map::kSize);
if (result->IsFailure()) old_gen_exhausted_ = true;
#ifdef DEBUG
if (!result->IsFailure()) {
// Maps have their own alignment.
CHECK((reinterpret_cast<intptr_t>(result) & kMapAlignmentMask) ==
static_cast<intptr_t>(kHeapObjectTag));
}
#endif
return result;
}
MaybeObject* Heap::AllocateRawCell() {
#ifdef DEBUG
Counters::objs_since_last_full.Increment();
Counters::objs_since_last_young.Increment();
#endif
MaybeObject* result = cell_space_->AllocateRaw(JSGlobalPropertyCell::kSize);
if (result->IsFailure()) old_gen_exhausted_ = true;
return result;
}
bool Heap::InNewSpace(Object* object) {
bool result = new_space_.Contains(object);
ASSERT(!result || // Either not in new space
gc_state_ != NOT_IN_GC || // ... or in the middle of GC
InToSpace(object)); // ... or in to-space (where we allocate).
return result;
}
bool Heap::InFromSpace(Object* object) {
return new_space_.FromSpaceContains(object);
}
bool Heap::InToSpace(Object* object) {
return new_space_.ToSpaceContains(object);
}
bool Heap::ShouldBePromoted(Address old_address, int object_size) {
// An object should be promoted if:
// - the object has survived a scavenge operation or
// - to space is already 25% full.
return old_address < new_space_.age_mark()
|| (new_space_.Size() + object_size) >= (new_space_.Capacity() >> 2);
}
void Heap::RecordWrite(Address address, int offset) {
if (new_space_.Contains(address)) return;
ASSERT(!new_space_.FromSpaceContains(address));
SLOW_ASSERT(Contains(address + offset));
Page::FromAddress(address)->MarkRegionDirty(address + offset);
}
void Heap::RecordWrites(Address address, int start, int len) {
if (new_space_.Contains(address)) return;
ASSERT(!new_space_.FromSpaceContains(address));
Page* page = Page::FromAddress(address);
page->SetRegionMarks(page->GetRegionMarks() |
page->GetRegionMaskForSpan(address + start, len * kPointerSize));
}
OldSpace* Heap::TargetSpace(HeapObject* object) {
InstanceType type = object->map()->instance_type();
AllocationSpace space = TargetSpaceId(type);
return (space == OLD_POINTER_SPACE)
? old_pointer_space_
: old_data_space_;
}
AllocationSpace Heap::TargetSpaceId(InstanceType type) {
// Heap numbers and sequential strings are promoted to old data space, all
// other object types are promoted to old pointer space. We do not use
// object->IsHeapNumber() and object->IsSeqString() because we already
// know that object has the heap object tag.
// These objects are never allocated in new space.
ASSERT(type != MAP_TYPE);
ASSERT(type != CODE_TYPE);
ASSERT(type != ODDBALL_TYPE);
ASSERT(type != JS_GLOBAL_PROPERTY_CELL_TYPE);
if (type < FIRST_NONSTRING_TYPE) {
// There are three string representations: sequential strings, cons
// strings, and external strings. Only cons strings contain
// non-map-word pointers to heap objects.
return ((type & kStringRepresentationMask) == kConsStringTag)
? OLD_POINTER_SPACE
: OLD_DATA_SPACE;
} else {
return (type <= LAST_DATA_TYPE) ? OLD_DATA_SPACE : OLD_POINTER_SPACE;
}
}
void Heap::CopyBlock(Address dst, Address src, int byte_size) {
ASSERT(IsAligned(byte_size, kPointerSize));
CopyWords(reinterpret_cast<Object**>(dst),
reinterpret_cast<Object**>(src),
byte_size / kPointerSize);
}
void Heap::CopyBlockToOldSpaceAndUpdateRegionMarks(Address dst,
Address src,
int byte_size) {
ASSERT(IsAligned(byte_size, kPointerSize));
Page* page = Page::FromAddress(dst);
uint32_t marks = page->GetRegionMarks();
for (int remaining = byte_size / kPointerSize;
remaining > 0;
remaining--) {
Memory::Object_at(dst) = Memory::Object_at(src);
if (Heap::InNewSpace(Memory::Object_at(dst))) {
marks |= page->GetRegionMaskForAddress(dst);
}
dst += kPointerSize;
src += kPointerSize;
}
page->SetRegionMarks(marks);
}
void Heap::MoveBlock(Address dst, Address src, int byte_size) {
ASSERT(IsAligned(byte_size, kPointerSize));
int size_in_words = byte_size / kPointerSize;
if ((dst < src) || (dst >= (src + size_in_words))) {
ASSERT((dst >= (src + size_in_words)) ||
((OffsetFrom(reinterpret_cast<Address>(src)) -
OffsetFrom(reinterpret_cast<Address>(dst))) >= kPointerSize));
Object** src_slot = reinterpret_cast<Object**>(src);
Object** dst_slot = reinterpret_cast<Object**>(dst);
Object** end_slot = src_slot + size_in_words;
while (src_slot != end_slot) {
*dst_slot++ = *src_slot++;
}
} else {
memmove(dst, src, byte_size);
}
}
void Heap::MoveBlockToOldSpaceAndUpdateRegionMarks(Address dst,
Address src,
int byte_size) {
ASSERT(IsAligned(byte_size, kPointerSize));
ASSERT((dst >= (src + byte_size)) ||
((OffsetFrom(src) - OffsetFrom(dst)) >= kPointerSize));
CopyBlockToOldSpaceAndUpdateRegionMarks(dst, src, byte_size);
}
void Heap::ScavengeObject(HeapObject** p, HeapObject* object) {
ASSERT(InFromSpace(object));
// We use the first word (where the map pointer usually is) of a heap
// object to record the forwarding pointer. A forwarding pointer can
// point to an old space, the code space, or the to space of the new
// generation.
MapWord first_word = object->map_word();
// If the first word is a forwarding address, the object has already been
// copied.
if (first_word.IsForwardingAddress()) {
*p = first_word.ToForwardingAddress();
return;
}
// Call the slow part of scavenge object.
return ScavengeObjectSlow(p, object);
}
bool Heap::CollectGarbage(AllocationSpace space) {
return CollectGarbage(space, SelectGarbageCollector(space));
}
MaybeObject* Heap::PrepareForCompare(String* str) {
// Always flatten small strings and force flattening of long strings
// after we have accumulated a certain amount we failed to flatten.
static const int kMaxAlwaysFlattenLength = 32;
static const int kFlattenLongThreshold = 16*KB;
const int length = str->length();
MaybeObject* obj = str->TryFlatten();
if (length <= kMaxAlwaysFlattenLength ||
unflattened_strings_length_ >= kFlattenLongThreshold) {
return obj;
}
if (obj->IsFailure()) {
unflattened_strings_length_ += length;
}
return str;
}
int Heap::AdjustAmountOfExternalAllocatedMemory(int change_in_bytes) {
ASSERT(HasBeenSetup());
int amount = amount_of_external_allocated_memory_ + change_in_bytes;
if (change_in_bytes >= 0) {
// Avoid overflow.
if (amount > amount_of_external_allocated_memory_) {
amount_of_external_allocated_memory_ = amount;
}
int amount_since_last_global_gc =
amount_of_external_allocated_memory_ -
amount_of_external_allocated_memory_at_last_global_gc_;
if (amount_since_last_global_gc > external_allocation_limit_) {
CollectAllGarbage(false);
}
} else {
// Avoid underflow.
if (amount >= 0) {
amount_of_external_allocated_memory_ = amount;
}
}
ASSERT(amount_of_external_allocated_memory_ >= 0);
return amount_of_external_allocated_memory_;
}
void Heap::SetLastScriptId(Object* last_script_id) {
roots_[kLastScriptIdRootIndex] = last_script_id;
}
#ifdef DEBUG
#define GC_GREEDY_CHECK() \
if (FLAG_gc_greedy) v8::internal::Heap::GarbageCollectionGreedyCheck()
#else
#define GC_GREEDY_CHECK() { }
#endif
// Calls the FUNCTION_CALL function and retries it up to three times
// to guarantee that any allocations performed during the call will
// succeed if there's enough memory.
// Warning: Do not use the identifiers __object__, __maybe_object__ or
// __scope__ in a call to this macro.
#define CALL_AND_RETRY(FUNCTION_CALL, RETURN_VALUE, RETURN_EMPTY) \
do { \
GC_GREEDY_CHECK(); \
MaybeObject* __maybe_object__ = FUNCTION_CALL; \
Object* __object__ = NULL; \
if (__maybe_object__->ToObject(&__object__)) RETURN_VALUE; \
if (__maybe_object__->IsOutOfMemory()) { \
v8::internal::V8::FatalProcessOutOfMemory("CALL_AND_RETRY_0", true);\
} \
if (!__maybe_object__->IsRetryAfterGC()) RETURN_EMPTY; \
Heap::CollectGarbage(Failure::cast(__maybe_object__)-> \
allocation_space()); \
__maybe_object__ = FUNCTION_CALL; \
if (__maybe_object__->ToObject(&__object__)) RETURN_VALUE; \
if (__maybe_object__->IsOutOfMemory()) { \
v8::internal::V8::FatalProcessOutOfMemory("CALL_AND_RETRY_1", true);\
} \
if (!__maybe_object__->IsRetryAfterGC()) RETURN_EMPTY; \
Counters::gc_last_resort_from_handles.Increment(); \
Heap::CollectAllAvailableGarbage(); \
{ \
AlwaysAllocateScope __scope__; \
__maybe_object__ = FUNCTION_CALL; \
} \
if (__maybe_object__->ToObject(&__object__)) RETURN_VALUE; \
if (__maybe_object__->IsOutOfMemory() || \
__maybe_object__->IsRetryAfterGC()) { \
/* TODO(1181417): Fix this. */ \
v8::internal::V8::FatalProcessOutOfMemory("CALL_AND_RETRY_2", true);\
} \
RETURN_EMPTY; \
} while (false)
#define CALL_HEAP_FUNCTION(FUNCTION_CALL, TYPE) \
CALL_AND_RETRY(FUNCTION_CALL, \
return Handle<TYPE>(TYPE::cast(__object__)), \
return Handle<TYPE>())
#define CALL_HEAP_FUNCTION_VOID(FUNCTION_CALL) \
CALL_AND_RETRY(FUNCTION_CALL, return, return)
#ifdef DEBUG
inline bool Heap::allow_allocation(bool new_state) {
bool old = allocation_allowed_;
allocation_allowed_ = new_state;
return old;
}
#endif
void ExternalStringTable::AddString(String* string) {
ASSERT(string->IsExternalString());
if (Heap::InNewSpace(string)) {
new_space_strings_.Add(string);
} else {
old_space_strings_.Add(string);
}
}
void ExternalStringTable::Iterate(ObjectVisitor* v) {
if (!new_space_strings_.is_empty()) {
Object** start = &new_space_strings_[0];
v->VisitPointers(start, start + new_space_strings_.length());
}
if (!old_space_strings_.is_empty()) {
Object** start = &old_space_strings_[0];
v->VisitPointers(start, start + old_space_strings_.length());
}
}
// Verify() is inline to avoid ifdef-s around its calls in release
// mode.
void ExternalStringTable::Verify() {
#ifdef DEBUG
for (int i = 0; i < new_space_strings_.length(); ++i) {
ASSERT(Heap::InNewSpace(new_space_strings_[i]));
ASSERT(new_space_strings_[i] != Heap::raw_unchecked_null_value());
}
for (int i = 0; i < old_space_strings_.length(); ++i) {
ASSERT(!Heap::InNewSpace(old_space_strings_[i]));
ASSERT(old_space_strings_[i] != Heap::raw_unchecked_null_value());
}
#endif
}
void ExternalStringTable::AddOldString(String* string) {
ASSERT(string->IsExternalString());
ASSERT(!Heap::InNewSpace(string));
old_space_strings_.Add(string);
}
void ExternalStringTable::ShrinkNewStrings(int position) {
new_space_strings_.Rewind(position);
Verify();
}
} } // namespace v8::internal
#endif // V8_HEAP_INL_H_