+++ /dev/null
-/*
- * Copyright (C) 2012 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. AND ITS 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 APPLE INC. OR ITS 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 BlockAllocator_h
-#define BlockAllocator_h
-
-#include "GCActivityCallback.h"
-#include "HeapBlock.h"
-#include "Region.h"
-#include <condition_variable>
-#include <wtf/DoublyLinkedList.h>
-#include <wtf/Forward.h>
-#include <wtf/PageAllocationAligned.h>
-#include <wtf/TCSpinLock.h>
-#include <wtf/Threading.h>
-
-namespace JSC {
-
-class BlockAllocator;
-class CodeBlock;
-class CopiedBlock;
-class CopyWorkListSegment;
-template <typename T> class GCArraySegment;
-class HandleBlock;
-class JSCell;
-class VM;
-class MarkedBlock;
-class WeakBlock;
-
-// Simple allocator to reduce VM cost by holding onto blocks of memory for
-// short periods of time and then freeing them on a secondary thread.
-
-class BlockAllocator {
-public:
- BlockAllocator();
- ~BlockAllocator();
-
- template <typename T> DeadBlock* allocate();
- DeadBlock* allocateCustomSize(size_t blockSize, size_t blockAlignment);
- template <typename T> void deallocate(T*);
- template <typename T> void deallocateCustomSize(T*);
-
- JS_EXPORT_PRIVATE void releaseFreeRegions();
-
-private:
- void waitForDuration(std::chrono::milliseconds);
-
- friend ThreadIdentifier createBlockFreeingThread(BlockAllocator*);
- void blockFreeingThreadMain();
- static void blockFreeingThreadStartFunc(void* heap);
-
- struct RegionSet {
- RegionSet(size_t blockSize)
- : m_numberOfPartialRegions(0)
- , m_blockSize(blockSize)
- {
- }
-
- bool isEmpty() const
- {
- return m_fullRegions.isEmpty() && m_partialRegions.isEmpty();
- }
-
- DoublyLinkedList<Region> m_fullRegions;
- DoublyLinkedList<Region> m_partialRegions;
- size_t m_numberOfPartialRegions;
- size_t m_blockSize;
- };
-
- DeadBlock* tryAllocateFromRegion(RegionSet&, DoublyLinkedList<Region>&, size_t&);
-
- bool allRegionSetsAreEmpty() const;
-
- template <typename T> RegionSet& regionSetFor();
-
- SuperRegion m_superRegion;
- RegionSet m_copiedRegionSet;
- RegionSet m_markedRegionSet;
- // WeakBlocks and GCArraySegments use the same RegionSet since they're the same size.
- RegionSet m_fourKBBlockRegionSet;
- RegionSet m_workListRegionSet;
-
- DoublyLinkedList<Region> m_emptyRegions;
- size_t m_numberOfEmptyRegions;
-
- bool m_isCurrentlyAllocating;
- bool m_blockFreeingThreadShouldQuit;
- SpinLock m_regionLock;
- std::mutex m_emptyRegionConditionMutex;
- std::condition_variable m_emptyRegionCondition;
- ThreadIdentifier m_blockFreeingThread;
-};
-
-inline DeadBlock* BlockAllocator::tryAllocateFromRegion(RegionSet& set, DoublyLinkedList<Region>& regions, size_t& numberOfRegions)
-{
- if (numberOfRegions) {
- ASSERT(!regions.isEmpty());
- Region* region = regions.head();
- ASSERT(!region->isFull());
-
- if (region->isEmpty()) {
- ASSERT(region == m_emptyRegions.head());
- m_numberOfEmptyRegions--;
- set.m_numberOfPartialRegions++;
- region = m_emptyRegions.removeHead()->reset(set.m_blockSize);
- set.m_partialRegions.push(region);
- }
-
- DeadBlock* block = region->allocate();
-
- if (region->isFull()) {
- set.m_numberOfPartialRegions--;
- set.m_fullRegions.push(set.m_partialRegions.removeHead());
- }
-
- return block;
- }
- return 0;
-}
-
-template<typename T>
-inline DeadBlock* BlockAllocator::allocate()
-{
- RegionSet& set = regionSetFor<T>();
- DeadBlock* block;
- m_isCurrentlyAllocating = true;
- {
- SpinLockHolder locker(&m_regionLock);
- if ((block = tryAllocateFromRegion(set, set.m_partialRegions, set.m_numberOfPartialRegions)))
- return block;
- if ((block = tryAllocateFromRegion(set, m_emptyRegions, m_numberOfEmptyRegions)))
- return block;
- }
-
- Region* newRegion = Region::create(&m_superRegion, T::blockSize);
-
- SpinLockHolder locker(&m_regionLock);
- m_emptyRegions.push(newRegion);
- m_numberOfEmptyRegions++;
- block = tryAllocateFromRegion(set, m_emptyRegions, m_numberOfEmptyRegions);
- ASSERT(block);
- return block;
-}
-
-inline DeadBlock* BlockAllocator::allocateCustomSize(size_t blockSize, size_t blockAlignment)
-{
- size_t realSize = WTF::roundUpToMultipleOf(blockAlignment, blockSize);
- Region* newRegion = Region::createCustomSize(&m_superRegion, realSize, blockAlignment);
- DeadBlock* block = newRegion->allocate();
- ASSERT(block);
- return block;
-}
-
-template<typename T>
-inline void BlockAllocator::deallocate(T* block)
-{
- RegionSet& set = regionSetFor<T>();
- bool shouldWakeBlockFreeingThread = false;
- {
- SpinLockHolder locker(&m_regionLock);
- Region* region = block->region();
- ASSERT(!region->isEmpty());
- if (region->isFull())
- set.m_fullRegions.remove(region);
- else {
- set.m_partialRegions.remove(region);
- set.m_numberOfPartialRegions--;
- }
-
- region->deallocate(block);
-
- if (region->isEmpty()) {
- m_emptyRegions.push(region);
- shouldWakeBlockFreeingThread = !m_numberOfEmptyRegions;
- m_numberOfEmptyRegions++;
- } else {
- set.m_partialRegions.push(region);
- set.m_numberOfPartialRegions++;
- }
- }
-
- if (shouldWakeBlockFreeingThread) {
- std::lock_guard<std::mutex> lock(m_emptyRegionConditionMutex);
- m_emptyRegionCondition.notify_one();
- }
-
- if (!m_blockFreeingThread)
- releaseFreeRegions();
-}
-
-template<typename T>
-inline void BlockAllocator::deallocateCustomSize(T* block)
-{
- Region* region = block->region();
- ASSERT(region->isCustomSize());
- region->deallocate(block);
- region->destroy();
-}
-
-#define REGION_SET_FOR(blockType, set) \
- template <> \
- inline BlockAllocator::RegionSet& BlockAllocator::regionSetFor<blockType>() \
- { \
- return set; \
- } \
- template <> \
- inline BlockAllocator::RegionSet& BlockAllocator::regionSetFor<HeapBlock<blockType>>() \
- { \
- return set; \
- } \
-
-REGION_SET_FOR(MarkedBlock, m_markedRegionSet);
-REGION_SET_FOR(CopiedBlock, m_copiedRegionSet);
-REGION_SET_FOR(WeakBlock, m_fourKBBlockRegionSet);
-REGION_SET_FOR(GCArraySegment<const JSCell*>, m_fourKBBlockRegionSet);
-REGION_SET_FOR(GCArraySegment<CodeBlock*>, m_fourKBBlockRegionSet);
-REGION_SET_FOR(CopyWorkListSegment, m_workListRegionSet);
-REGION_SET_FOR(HandleBlock, m_fourKBBlockRegionSet);
-
-#undef REGION_SET_FOR
-
-template <typename T>
-inline BlockAllocator::RegionSet& BlockAllocator::regionSetFor()
-{
- RELEASE_ASSERT_NOT_REACHED();
- return *(RegionSet*)0;
-}
-
-} // namespace JSC
-
-#endif // BlockAllocator_h
projects / apple / javascriptcore.git / blobdiff