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/*
* Copyright (C) 2009, 2015 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 "ExecutableAllocator.h"
#include "JSCInlines.h"
#if ENABLE(EXECUTABLE_ALLOCATOR_FIXED)
#include "CodeProfiling.h"
#include "ExecutableAllocationFuzz.h"
#include <wtf/MetaAllocator.h>
#include <wtf/PageReservation.h>
#if OS(DARWIN)
#include <sys/mman.h>
#endif
using namespace WTF;
namespace JSC {
uintptr_t startOfFixedExecutableMemoryPool;
class FixedVMPoolExecutableAllocator : public MetaAllocator {
WTF_MAKE_FAST_ALLOCATED;
public:
FixedVMPoolExecutableAllocator()
: MetaAllocator(jitAllocationGranule) // round up all allocations to 32 bytes
{
size_t reservationSize;
if (Options::jitMemoryReservationSize())
reservationSize = Options::jitMemoryReservationSize();
else
reservationSize = fixedExecutableMemoryPoolSize;
reservationSize = roundUpToMultipleOf(pageSize(), reservationSize);
m_reservation = PageReservation::reserveWithGuardPages(reservationSize, OSAllocator::JSJITCodePages, EXECUTABLE_POOL_WRITABLE, true);
if (m_reservation) {
ASSERT(m_reservation.size() == reservationSize);
addFreshFreeSpace(m_reservation.base(), m_reservation.size());
startOfFixedExecutableMemoryPool = reinterpret_cast<uintptr_t>(m_reservation.base());
}
}
virtual ~FixedVMPoolExecutableAllocator();
protected:
virtual void* allocateNewSpace(size_t&) override
{
// We're operating in a fixed pool, so new allocation is always prohibited.
return 0;
}
virtual void notifyNeedPage(void* page) override
{
#if USE(MADV_FREE_FOR_JIT_MEMORY)
UNUSED_PARAM(page);
#else
m_reservation.commit(page, pageSize());
#endif
}
virtual void notifyPageIsFree(void* page) override
{
#if USE(MADV_FREE_FOR_JIT_MEMORY)
for (;;) {
int result = madvise(page, pageSize(), MADV_FREE);
if (!result)
return;
ASSERT(result == -1);
if (errno != EAGAIN) {
RELEASE_ASSERT_NOT_REACHED(); // In debug mode, this should be a hard failure.
break; // In release mode, we should just ignore the error - not returning memory to the OS is better than crashing, especially since we _will_ be able to reuse the memory internally anyway.
}
}
#else
m_reservation.decommit(page, pageSize());
#endif
}
private:
PageReservation m_reservation;
};
static FixedVMPoolExecutableAllocator* allocator;
void ExecutableAllocator::initializeAllocator()
{
ASSERT(!allocator);
allocator = new FixedVMPoolExecutableAllocator();
CodeProfiling::notifyAllocator(allocator);
}
ExecutableAllocator::ExecutableAllocator(VM&)
{
ASSERT(allocator);
}
ExecutableAllocator::~ExecutableAllocator()
{
}
FixedVMPoolExecutableAllocator::~FixedVMPoolExecutableAllocator()
{
m_reservation.deallocate();
}
bool ExecutableAllocator::isValid() const
{
return !!allocator->bytesReserved();
}
bool ExecutableAllocator::underMemoryPressure()
{
MetaAllocator::Statistics statistics = allocator->currentStatistics();
return statistics.bytesAllocated > statistics.bytesReserved / 2;
}
double ExecutableAllocator::memoryPressureMultiplier(size_t addedMemoryUsage)
{
MetaAllocator::Statistics statistics = allocator->currentStatistics();
ASSERT(statistics.bytesAllocated <= statistics.bytesReserved);
size_t bytesAllocated = statistics.bytesAllocated + addedMemoryUsage;
size_t bytesAvailable = static_cast<size_t>(
statistics.bytesReserved * (1 - executablePoolReservationFraction));
if (bytesAllocated >= bytesAvailable)
bytesAllocated = bytesAvailable;
double result = 1.0;
size_t divisor = bytesAvailable - bytesAllocated;
if (divisor)
result = static_cast<double>(bytesAvailable) / divisor;
if (result < 1.0)
result = 1.0;
return result;
}
RefPtr<ExecutableMemoryHandle> ExecutableAllocator::allocate(VM&, size_t sizeInBytes, void* ownerUID, JITCompilationEffort effort)
{
if (effort != JITCompilationCanFail && Options::reportMustSucceedExecutableAllocations()) {
dataLog("Allocating ", sizeInBytes, " bytes of executable memory with JITCompilationMustSucceed.\n");
WTFReportBacktrace();
}
if (effort == JITCompilationCanFail
&& doExecutableAllocationFuzzingIfEnabled() == PretendToFailExecutableAllocation)
return nullptr;
if (effort == JITCompilationCanFail) {
// Don't allow allocations if we are down to reserve.
MetaAllocator::Statistics statistics = allocator->currentStatistics();
size_t bytesAllocated = statistics.bytesAllocated + sizeInBytes;
size_t bytesAvailable = static_cast<size_t>(
statistics.bytesReserved * (1 - executablePoolReservationFraction));
if (bytesAllocated > bytesAvailable)
return nullptr;
}
RefPtr<ExecutableMemoryHandle> result = allocator->allocate(sizeInBytes, ownerUID);
if (!result) {
if (effort != JITCompilationCanFail) {
dataLog("Ran out of executable memory while allocating ", sizeInBytes, " bytes.\n");
CRASH();
}
return nullptr;
}
return result;
}
bool ExecutableAllocator::isValidExecutableMemory(const LockHolder& locker, void* address)
{
return allocator->isInAllocatedMemory(locker, address);
}
Lock& ExecutableAllocator::getLock() const
{
return allocator->getLock();
}
size_t ExecutableAllocator::committedByteCount()
{
return allocator->bytesCommitted();
}
#if ENABLE(META_ALLOCATOR_PROFILE)
void ExecutableAllocator::dumpProfile()
{
allocator->dumpProfile();
}
#endif
}
#endif // ENABLE(EXECUTABLE_ALLOCATOR_FIXED)
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