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/*
* Copyright (C) 2012-2019 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. 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.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``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 APPLE INC. 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.
*/
#include "config.h"
#include "BlockDirectory.h"
#include "BlockDirectoryInlines.h"
#include "GCActivityCallback.h"
#include "Heap.h"
#include "IncrementalSweeper.h"
#include "JSCInlines.h"
#include "MarkedBlockInlines.h"
#include "SubspaceInlines.h"
#include "SuperSampler.h"
#include "VM.h"
namespace JSC {
BlockDirectory::BlockDirectory(size_t cellSize)
: m_cellSize(static_cast<unsigned>(cellSize))
{
}
BlockDirectory::~BlockDirectory()
{
auto locker = holdLock(m_localAllocatorsLock);
while (!m_localAllocators.isEmpty())
m_localAllocators.begin()->remove();
}
void BlockDirectory::setSubspace(Subspace* subspace)
{
m_attributes = subspace->attributes();
m_subspace = subspace;
}
bool BlockDirectory::isPagedOut(MonotonicTime deadline)
{
unsigned itersSinceLastTimeCheck = 0;
for (auto* block : m_blocks) {
if (block)
block->block().populatePage();
++itersSinceLastTimeCheck;
if (itersSinceLastTimeCheck >= Heap::s_timeCheckResolution) {
MonotonicTime currentTime = MonotonicTime::now();
if (currentTime > deadline)
return true;
itersSinceLastTimeCheck = 0;
}
}
return false;
}
MarkedBlock::Handle* BlockDirectory::findEmptyBlockToSteal()
{
m_emptyCursor = m_bits.empty().findBit(m_emptyCursor, true);
if (m_emptyCursor >= m_blocks.size())
return nullptr;
return m_blocks[m_emptyCursor];
}
MarkedBlock::Handle* BlockDirectory::findBlockForAllocation(LocalAllocator& allocator)
{
for (;;) {
allocator.m_allocationCursor = (m_bits.canAllocateButNotEmpty() | m_bits.empty()).findBit(allocator.m_allocationCursor, true);
if (allocator.m_allocationCursor >= m_blocks.size())
return nullptr;
size_t blockIndex = allocator.m_allocationCursor++;
MarkedBlock::Handle* result = m_blocks[blockIndex];
setIsCanAllocateButNotEmpty(NoLockingNecessary, blockIndex, false);
return result;
}
}
MarkedBlock::Handle* BlockDirectory::tryAllocateBlock(Heap& heap)
{
SuperSamplerScope superSamplerScope(false);
MarkedBlock::Handle* handle = MarkedBlock::tryCreate(heap, subspace()->alignedMemoryAllocator());
if (!handle)
return nullptr;
markedSpace().didAddBlock(handle);
return handle;
}
void BlockDirectory::addBlock(MarkedBlock::Handle* block)
{
size_t index;
if (m_freeBlockIndices.isEmpty()) {
index = m_blocks.size();
size_t oldCapacity = m_blocks.capacity();
m_blocks.append(block);
if (m_blocks.capacity() != oldCapacity) {
ASSERT(m_bits.numBits() == oldCapacity);
ASSERT(m_blocks.capacity() > oldCapacity);
LockHolder locker(m_bitvectorLock);
subspace()->didResizeBits(m_blocks.capacity());
m_bits.resize(m_blocks.capacity());
}
} else {
index = m_freeBlockIndices.takeLast();
ASSERT(!m_blocks[index]);
m_blocks[index] = block;
}
forEachBitVector(
NoLockingNecessary,
[&](auto vectorRef) {
ASSERT_UNUSED(vectorRef, !vectorRef[index]);
});
// This is the point at which the block learns of its cellSize() and attributes().
block->didAddToDirectory(this, index);
setIsLive(NoLockingNecessary, index, true);
setIsEmpty(NoLockingNecessary, index, true);
}
void BlockDirectory::removeBlock(MarkedBlock::Handle* block)
{
ASSERT(block->directory() == this);
ASSERT(m_blocks[block->index()] == block);
subspace()->didRemoveBlock(block->index());
m_blocks[block->index()] = nullptr;
m_freeBlockIndices.append(block->index());
forEachBitVector(
holdLock(m_bitvectorLock),
[&](auto vectorRef) {
vectorRef[block->index()] = false;
});
block->didRemoveFromDirectory();
}
void BlockDirectory::stopAllocating()
{
if (false)
dataLog(RawPointer(this), ": BlockDirectory::stopAllocating!\n");
m_localAllocators.forEach(
[&] (LocalAllocator* allocator) {
allocator->stopAllocating();
});
}
void BlockDirectory::prepareForAllocation()
{
m_localAllocators.forEach(
[&] (LocalAllocator* allocator) {
allocator->prepareForAllocation();
});
m_unsweptCursor = 0;
m_emptyCursor = 0;
m_bits.eden().clearAll();
if (UNLIKELY(Options::useImmortalObjects())) {
// FIXME: Make this work again.
// https://bugs.webkit.org/show_bug.cgi?id=162296
RELEASE_ASSERT_NOT_REACHED();
}
}
void BlockDirectory::stopAllocatingForGood()
{
if (false)
dataLog(RawPointer(this), ": BlockDirectory::stopAllocatingForGood!\n");
m_localAllocators.forEach(
[&] (LocalAllocator* allocator) {
allocator->stopAllocatingForGood();
});
auto locker = holdLock(m_localAllocatorsLock);
while (!m_localAllocators.isEmpty())
m_localAllocators.begin()->remove();
}
void BlockDirectory::lastChanceToFinalize()
{
forEachBlock(
[&] (MarkedBlock::Handle* block) {
block->lastChanceToFinalize();
});
}
void BlockDirectory::resumeAllocating()
{
m_localAllocators.forEach(
[&] (LocalAllocator* allocator) {
allocator->resumeAllocating();
});
}
void BlockDirectory::beginMarkingForFullCollection()
{
// Mark bits are sticky and so is our summary of mark bits. We only clear these during full
// collections, so if you survived the last collection you will survive the next one so long
// as the next one is eden.
m_bits.markingNotEmpty().clearAll();
m_bits.markingRetired().clearAll();
}
void BlockDirectory::endMarking()
{
m_bits.allocated().clearAll();
// It's surprising and frustrating to comprehend, but the end-of-marking flip does not need to
// know what kind of collection it is. That knowledge is already encoded in the m_markingXYZ
// vectors.
m_bits.empty() = m_bits.live() & ~m_bits.markingNotEmpty();
m_bits.canAllocateButNotEmpty() = m_bits.live() & m_bits.markingNotEmpty() & ~m_bits.markingRetired();
if (needsDestruction()) {
// There are some blocks that we didn't allocate out of in the last cycle, but we swept them. This
// will forget that we did that and we will end up sweeping them again and attempting to call their
// destructors again. That's fine because of zapping. The only time when we cannot forget is when
// we just allocate a block or when we move a block from one size class to another. That doesn't
// happen here.
m_bits.destructible() = m_bits.live();
}
if (false) {
dataLog("Bits for ", m_cellSize, ", ", m_attributes, " after endMarking:\n");
dumpBits(WTF::dataFile());
}
}
void BlockDirectory::snapshotUnsweptForEdenCollection()
{
m_bits.unswept() |= m_bits.eden();
}
void BlockDirectory::snapshotUnsweptForFullCollection()
{
m_bits.unswept() = m_bits.live();
}
MarkedBlock::Handle* BlockDirectory::findBlockToSweep()
{
m_unsweptCursor = m_bits.unswept().findBit(m_unsweptCursor, true);
if (m_unsweptCursor >= m_blocks.size())
return nullptr;
return m_blocks[m_unsweptCursor];
}
void BlockDirectory::sweep()
{
m_bits.unswept().forEachSetBit(
[&] (size_t index) {
MarkedBlock::Handle* block = m_blocks[index];
block->sweep(nullptr);
});
}
void BlockDirectory::shrink()
{
(m_bits.empty() & ~m_bits.destructible()).forEachSetBit(
[&] (size_t index) {
markedSpace().freeBlock(m_blocks[index]);
});
}
void BlockDirectory::assertNoUnswept()
{
if (ASSERT_DISABLED)
return;
if (m_bits.unswept().isEmpty())
return;
dataLog("Assertion failed: unswept not empty in ", *this, ".\n");
dumpBits();
ASSERT_NOT_REACHED();
}
RefPtr<SharedTask<MarkedBlock::Handle*()>> BlockDirectory::parallelNotEmptyBlockSource()
{
class Task : public SharedTask<MarkedBlock::Handle*()> {
public:
Task(BlockDirectory& directory)
: m_directory(directory)
{
}
MarkedBlock::Handle* run() override
{
if (m_done)
return nullptr;
auto locker = holdLock(m_lock);
m_index = m_directory.m_bits.markingNotEmpty().findBit(m_index, true);
if (m_index >= m_directory.m_blocks.size()) {
m_done = true;
return nullptr;
}
return m_directory.m_blocks[m_index++];
}
private:
BlockDirectory& m_directory;
size_t m_index { 0 };
Lock m_lock;
bool m_done { false };
};
return adoptRef(new Task(*this));
}
void BlockDirectory::dump(PrintStream& out) const
{
out.print(RawPointer(this), ":", m_cellSize, "/", m_attributes);
}
void BlockDirectory::dumpBits(PrintStream& out)
{
unsigned maxNameLength = 0;
forEachBitVectorWithName(
NoLockingNecessary,
[&](auto vectorRef, const char* name) {
UNUSED_PARAM(vectorRef);
unsigned length = strlen(name);
maxNameLength = std::max(maxNameLength, length);
});
forEachBitVectorWithName(
NoLockingNecessary,
[&](auto vectorRef, const char* name) {
out.print(" ", name, ": ");
for (unsigned i = maxNameLength - strlen(name); i--;)
out.print(" ");
out.print(vectorRef, "\n");
});
}
MarkedSpace& BlockDirectory::markedSpace() const
{
return m_subspace->space();
}
bool BlockDirectory::isFreeListedCell(const void* target)
{
bool result = false;
m_localAllocators.forEach(
[&] (LocalAllocator* allocator) {
result |= allocator->isFreeListedCell(target);
});
return result;
}
} // namespace JSC