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[heap] Move ActiveSystemPages out of page header

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ActiveSystemPages uses std::bitset internally for convenience. Our
MemoryChunk fields implicitly assume that all fields only require
system pointer alignment.

However MSVC on 32-bit uses uint64_t internally to implement
std::bitset. Because of this ActiveSystemPages needs 8-bytes alignment
on 32-bit architectures. We can solve this by moving
ActiveSystemPages out of the page header and storing it in the
malloc()'ed heap.

Bug: v8:13716
Change-Id: Iecb17372d065c612bbdbca7d854c76d3256bc01d
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/4223005
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Auto-Submit: Dominik Inführ <dinfuehr@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/main@{#85681}
This commit is contained in:
Dominik Inführ 2023-02-06 12:57:26 +01:00 committed by V8 LUCI CQ
parent ee93bc8035
commit 95b7d03067
4 changed files with 14 additions and 11 deletions
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6
src/heap/memory-chunk-layout.h
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@ -39,11 +39,7 @@ class V8_EXPORT_PRIVATE MemoryChunkLayout {
public:
static constexpr int kNumSets = NUMBER_OF_REMEMBERED_SET_TYPES;
static constexpr int kNumTypes = ExternalBackingStoreType::kNumTypes;
#if V8_CC_MSVC && V8_TARGET_ARCH_IA32
static constexpr int kMemoryChunkAlignment = 8;
#else
static constexpr int kMemoryChunkAlignment = sizeof(size_t);
#endif // V8_CC_MSVC && V8_TARGET_ARCH_IA32
#define FIELD(Type, Name) \
k##Name##Offset, k##Name##End = k##Name##Offset + sizeof(Type) - 1
enum Header {
@ -73,7 +69,7 @@ class V8_EXPORT_PRIVATE MemoryChunkLayout {
FIELD(FreeListCategory**, Categories),
FIELD(CodeObjectRegistry*, CodeObjectRegistry),
FIELD(PossiblyEmptyBuckets, PossiblyEmptyBuckets),
FIELD(ActiveSystemPages, ActiveSystemPages),
FIELD(ActiveSystemPages*, ActiveSystemPages),
#ifdef V8_ENABLE_INNER_POINTER_RESOLUTION_OSB
FIELD(ObjectStartBitmap, ObjectStartBitmap),
#endif // V8_ENABLE_INNER_POINTER_RESOLUTION_OSB

15
src/heap/memory-chunk.cc
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@ -182,11 +182,13 @@ MemoryChunk::MemoryChunk(Heap* heap, BaseSpace* space, size_t chunk_size,
possibly_empty_buckets_.Initialize();
if (page_size == PageSize::kRegular) {
active_system_pages_.Init(MemoryChunkLayout::kMemoryChunkHeaderSize,
MemoryAllocator::GetCommitPageSizeBits(), size());
active_system_pages_ = new ActiveSystemPages;
active_system_pages_->Init(MemoryChunkLayout::kMemoryChunkHeaderSize,
MemoryAllocator::GetCommitPageSizeBits(),
size());
} else {
// We do not track active system pages for large pages.
active_system_pages_.Clear();
active_system_pages_ = nullptr;
}
// All pages of a shared heap need to be marked with this flag.
@ -202,7 +204,7 @@ MemoryChunk::MemoryChunk(Heap* heap, BaseSpace* space, size_t chunk_size,
size_t MemoryChunk::CommittedPhysicalMemory() const {
if (!base::OS::HasLazyCommits() || IsLargePage()) return size();
return active_system_pages_.Size(MemoryAllocator::GetCommitPageSizeBits());
return active_system_pages_->Size(MemoryAllocator::GetCommitPageSizeBits());
}
void MemoryChunk::SetOldGenerationPageFlags(bool is_marking) {
@ -245,6 +247,11 @@ void MemoryChunk::ReleaseAllocatedMemoryNeededForWritableChunk() {
code_object_registry_ = nullptr;
}
if (active_system_pages_ != nullptr) {
delete active_system_pages_;
active_system_pages_ = nullptr;
}
possibly_empty_buckets_.Release();
ReleaseSlotSet<OLD_TO_NEW>();
ReleaseSlotSet<OLD_TO_OLD>();

2
src/heap/memory-chunk.h
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@ -297,7 +297,7 @@ class MemoryChunk : public BasicMemoryChunk {
PossiblyEmptyBuckets possibly_empty_buckets_;
ActiveSystemPages active_system_pages_;
ActiveSystemPages* active_system_pages_;
#ifdef V8_ENABLE_INNER_POINTER_RESOLUTION_OSB
ObjectStartBitmap object_start_bitmap_;

2
src/heap/spaces.h
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@ -315,7 +315,7 @@ class Page : public MemoryChunk {
void AllocateFreeListCategories();
void ReleaseFreeListCategories();
ActiveSystemPages* active_system_pages() { return &active_system_pages_; }
ActiveSystemPages* active_system_pages() { return active_system_pages_; }
template <RememberedSetType remembered_set>
void ClearTypedSlotsInFreeMemory(const TypedSlotSet::FreeRangesMap& ranges) {