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/*
* Copyright (C) 2010-2018 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.
* 3. Neither the name of Apple Inc. ("Apple") nor the names of
* its contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY APPLE 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 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.
*/
#include "config.h"
#include "GCActivityCallback.h"
#include "HeapInlines.h"
#include "VM.h"
namespace JSC {
bool GCActivityCallback::s_shouldCreateGCTimer = true;
const double timerSlop = 2.0; // Fudge factor to avoid performance cost of resetting timer.
GCActivityCallback::GCActivityCallback(JSC::Heap& heap, Synchronousness synchronousness)
: GCActivityCallback(heap.vm(), synchronousness)
{
}
GCActivityCallback::GCActivityCallback(VM& vm, Synchronousness synchronousness)
: Base(vm)
, m_synchronousness(synchronousness)
{
}
GCActivityCallback::~GCActivityCallback() = default;
void GCActivityCallback::doWork(VM& vm)
{
if (!isEnabled())
return;
ASSERT(vm.currentThreadIsHoldingAPILock());
JSC::Heap& heap = vm.heap;
if (heap.isDeferred()) {
scheduleTimer(0_s);
return;
}
doCollection(vm);
}
void GCActivityCallback::scheduleTimer(Seconds newDelay)
{
if (newDelay * timerSlop > m_delay)
return;
Seconds delta = m_delay - newDelay;
m_delay = newDelay;
if (auto timeUntilFire = this->timeUntilFire())
newDelay = *timeUntilFire - delta;
setTimeUntilFire(newDelay);
}
void GCActivityCallback::didAllocate(JSC::Heap& heap, size_t bytes)
{
// The first byte allocated in an allocation cycle will report 0 bytes to didAllocate.
// We pretend it's one byte so that we don't ignore this allocation entirely.
if (!bytes)
bytes = 1;
double bytesExpectedToReclaim = static_cast<double>(bytes) * deathRate(heap);
Seconds newDelay = lastGCLength(heap) / gcTimeSlice(bytesExpectedToReclaim);
scheduleTimer(newDelay);
}
void GCActivityCallback::willCollect()
{
cancel();
}
void GCActivityCallback::cancel()
{
m_delay = s_decade;
cancelTimer();
}
}
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