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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
*/
/* arena allocation for the frame tree and closely-related objects */
#include "nsPresArena.h"
#include "mozilla/Poison.h"
#include "nsDebug.h"
#include "nsDisplayList.h"
#include "nsPrintfCString.h"
#include "mozilla/ArrayUtils.h"
#include "mozilla/ComputedStyle.h"
#include "mozilla/ComputedStyleInlines.h"
#include "nsWindowSizes.h"
#include <inttypes.h>
using namespace mozilla;
template <size_t ArenaSize, typename ObjectId, size_t ObjectIdCount>
nsPresArena<ArenaSize, ObjectId, ObjectIdCount>::~nsPresArena() {
#if defined(MOZ_HAVE_MEM_CHECKS)
for (FreeList* entry = mFreeLists; entry != ArrayEnd(mFreeLists); ++entry) {
for (void* result : entry->mEntries) {
MOZ_MAKE_MEM_UNDEFINED(result, entry->mEntrySize);
}
entry->mEntries.Clear();
}
#endif
}
template <size_t ArenaSize, typename ObjectId, size_t ObjectIdCount>
void* nsPresArena<ArenaSize, ObjectId, ObjectIdCount>::Allocate(ObjectId aCode,
size_t aSize) {
MOZ_ASSERT(NS_IsMainThread());
MOZ_ASSERT(aSize > 0, "PresArena cannot allocate zero bytes");
MOZ_ASSERT(size_t(aCode) < ArrayLength(mFreeLists));
// We only hand out aligned sizes
aSize = mPool.AlignedSize(aSize);
FreeList* list = &mFreeLists[size_t(aCode)];
nsTArray<void*>::index_type len = list->mEntries.Length();
if (list->mEntrySize == 0) {
MOZ_ASSERT(len == 0, "list with entries but no recorded size");
list->mEntrySize = aSize;
} else {
MOZ_ASSERT(list->mEntrySize == aSize,
"different sizes for same object type code");
}
void* result;
if (len > 0) {
// Remove from the end of the mEntries array to avoid memmoving entries,
// and use SetLengthAndRetainStorage to avoid a lot of malloc/free
// from ShrinkCapacity on smaller sizes. 500 pointers means the malloc size
// for the array is 4096 bytes or more on a 64-bit system. The next smaller
// size is 2048 (with jemalloc), which we consider not worth compacting.
result = list->mEntries.Elements()[len - 1];
if (list->mEntries.Capacity() > 500) {
list->mEntries.RemoveElementAtUnsafe(len - 1);
} else {
list->mEntries.SetLengthAndRetainStorage(len - 1);
}
#if defined(DEBUG)
{
MOZ_MAKE_MEM_DEFINED(result, list->mEntrySize);
char* p = reinterpret_cast<char*>(result);
char* limit = p + list->mEntrySize;
for (; p < limit; p += sizeof(uintptr_t)) {
uintptr_t val = *reinterpret_cast<uintptr_t*>(p);
if (val != mozPoisonValue()) {
MOZ_ReportAssertionFailure(
nsPrintfCString("PresArena: poison overwritten; "
"wanted %.16" PRIx64 " "
"found %.16" PRIx64 " "
"errors in bits %.16" PRIx64 " ",
uint64_t(mozPoisonValue()), uint64_t(val),
uint64_t(mozPoisonValue() ^ val))
.get(),
__FILE__, __LINE__);
MOZ_CRASH();
}
}
}
#endif
MOZ_MAKE_MEM_UNDEFINED(result, list->mEntrySize);
return result;
}
// Allocate a new chunk from the arena
list->mEntriesEverAllocated++;
return mPool.Allocate(aSize);
}
template <size_t ArenaSize, typename ObjectId, size_t ObjectIdCount>
void nsPresArena<ArenaSize, ObjectId, ObjectIdCount>::Free(ObjectId aCode,
void* aPtr) {
MOZ_ASSERT(NS_IsMainThread());
MOZ_ASSERT(size_t(aCode) < ArrayLength(mFreeLists));
// Try to recycle this entry.
FreeList* list = &mFreeLists[size_t(aCode)];
MOZ_ASSERT(list->mEntrySize > 0, "object of this type was never allocated");
mozWritePoison(aPtr, list->mEntrySize);
MOZ_MAKE_MEM_NOACCESS(aPtr, list->mEntrySize);
list->mEntries.AppendElement(aPtr);
}
template <size_t ArenaSize, typename ObjectId, size_t ObjectIdCount>
void nsPresArena<ArenaSize, ObjectId, ObjectIdCount>::AddSizeOfExcludingThis(
nsWindowSizes& aSizes, ArenaKind aKind) const {
// We do a complicated dance here because we want to measure the
// space taken up by the different kinds of objects in the arena,
// but we don't have pointers to those objects. And even if we did,
// we wouldn't be able to use mMallocSizeOf on them, since they were
// allocated out of malloc'd chunks of memory. So we compute the
// size of the arena as known by malloc and we add up the sizes of
// all the objects that we care about. Subtracting these two
// quantities gives us a catch-all "other" number, which includes
// slop in the arena itself as well as the size of objects that
// we've not measured explicitly.
size_t mallocSize = mPool.SizeOfExcludingThis(aSizes.mState.mMallocSizeOf);
size_t totalSizeInFreeLists = 0;
for (const FreeList* entry = mFreeLists; entry != ArrayEnd(mFreeLists);
++entry) {
mallocSize += entry->SizeOfExcludingThis(aSizes.mState.mMallocSizeOf);
// Note that we're not measuring the size of the entries on the free
// list here. The free list knows how many objects we've allocated
// ever (which includes any objects that may be on the FreeList's
// |mEntries| at this point) and we're using that to determine the
// total size of objects allocated with a given ID.
size_t totalSize = entry->mEntrySize * entry->mEntriesEverAllocated;
if (aKind == ArenaKind::PresShell) {
switch (entry - mFreeLists) {
#define PRES_ARENA_OBJECT(name_) \
case eArenaObjectID_##name_: \
aSizes.mArenaSizes.NS_ARENA_SIZES_FIELD(name_) += totalSize; \
break;
#include "nsPresArenaObjectList.h"
#undef PRES_ARENA_OBJECT
default:
MOZ_ASSERT_UNREACHABLE("Unknown arena object type");
}
} else {
MOZ_ASSERT(aKind == ArenaKind::DisplayList);
switch (DisplayListArenaObjectId(entry - mFreeLists)) {
#define DISPLAY_LIST_ARENA_OBJECT(name_) \
case DisplayListArenaObjectId::name_: \
aSizes.mArenaSizes.NS_ARENA_SIZES_FIELD(name_) += totalSize; \
break;
#include "nsDisplayListArenaTypes.h"
#undef DISPLAY_LIST_ARENA_OBJECT
default:
MOZ_ASSERT_UNREACHABLE("Unknown display item arena type");
}
}
totalSizeInFreeLists += totalSize;
}
auto& field = aKind == ArenaKind::PresShell
? aSizes.mLayoutPresShellSize
: aSizes.mLayoutRetainedDisplayListSize;
field += mallocSize - totalSizeInFreeLists;
}
// Explicitly instantiate templates for the used nsPresArena allocator sizes.
// This is needed because nsPresArena definition is split across multiple files.
template class nsPresArena<8192, ArenaObjectID, eArenaObjectID_COUNT>;
template class nsPresArena<32768, DisplayListArenaObjectId,
size_t(DisplayListArenaObjectId::COUNT)>;