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/*
* Copyright (C) 2012-2021 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 "IncrementalSweeper.h"
#include "DeferGCInlines.h"
#include "HeapInlines.h"
#include "MarkedBlock.h"
#include "VM.h"
namespace JSC {
static constexpr Seconds sweepTimeSlice = 10_ms;
static constexpr double sweepTimeTotal = .10;
static constexpr double sweepTimeMultiplier = 1.0 / sweepTimeTotal;
void IncrementalSweeper::scheduleTimer()
{
setTimeUntilFire(sweepTimeSlice * sweepTimeMultiplier);
}
IncrementalSweeper::IncrementalSweeper(Heap* heap)
: Base(heap->vm())
, m_currentDirectory(nullptr)
{
}
void IncrementalSweeper::doWork(VM& vm)
{
doSweep(vm, MonotonicTime::now());
}
void IncrementalSweeper::doSweep(VM& vm, MonotonicTime sweepBeginTime)
{
while (sweepNextBlock(vm)) {
Seconds elapsedTime = MonotonicTime::now() - sweepBeginTime;
if (elapsedTime < sweepTimeSlice)
continue;
scheduleTimer();
return;
}
if (m_shouldFreeFastMallocMemoryAfterSweeping) {
WTF::releaseFastMallocFreeMemory();
m_shouldFreeFastMallocMemoryAfterSweeping = false;
}
cancelTimer();
}
bool IncrementalSweeper::sweepNextBlock(VM& vm)
{
vm.heap.stopIfNecessary();
MarkedBlock::Handle* block = nullptr;
for (; m_currentDirectory; m_currentDirectory = m_currentDirectory->nextDirectory()) {
block = m_currentDirectory->findBlockToSweep();
if (block)
break;
}
if (block) {
DeferGCForAWhile deferGC(vm);
block->sweep(nullptr);
vm.heap.objectSpace().freeOrShrinkBlock(block);
return true;
}
return vm.heap.sweepNextLogicallyEmptyWeakBlock();
}
void IncrementalSweeper::startSweeping(Heap& heap)
{
scheduleTimer();
m_currentDirectory = heap.objectSpace().firstDirectory();
}
void IncrementalSweeper::stopSweeping()
{
m_currentDirectory = nullptr;
cancelTimer();
}
} // namespace JSC