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/*
* Copyright (C) 2011 Apple Inc. All Rights Reserved.
* Copyright (C) 2014 Raspberry Pi Foundation. 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.
*/
#ifndef MemoryPressureHandler_h
#define MemoryPressureHandler_h
#include <atomic>
#include <ctime>
#include <functional>
#include <wtf/FastMalloc.h>
#include <wtf/Forward.h>
#if PLATFORM(IOS)
#include <wtf/Lock.h>
#include <wtf/ThreadingPrimitives.h>
#elif OS(LINUX)
#include "Timer.h"
#endif
namespace WebCore {
#if PLATFORM(IOS)
enum MemoryPressureReason {
MemoryPressureReasonNone = 0 << 0,
MemoryPressureReasonVMPressure = 1 << 0,
MemoryPressureReasonVMStatus = 1 << 1,
};
#endif
enum class Critical { No, Yes };
enum class Synchronous { No, Yes };
typedef std::function<void(Critical, Synchronous)> LowMemoryHandler;
class MemoryPressureHandler {
WTF_MAKE_FAST_ALLOCATED;
friend class WTF::NeverDestroyed<MemoryPressureHandler>;
public:
WEBCORE_EXPORT static MemoryPressureHandler& singleton();
WEBCORE_EXPORT void install();
void setLowMemoryHandler(LowMemoryHandler handler)
{
ASSERT(!m_installed);
m_lowMemoryHandler = handler;
}
bool isUnderMemoryPressure() const { return m_underMemoryPressure; }
void setUnderMemoryPressure(bool b) { m_underMemoryPressure = b; }
#if PLATFORM(IOS)
// FIXME: Can we share more of this with OpenSource?
WEBCORE_EXPORT void installMemoryReleaseBlock(void (^releaseMemoryBlock)(), bool clearPressureOnMemoryRelease = true);
WEBCORE_EXPORT void setReceivedMemoryPressure(MemoryPressureReason);
WEBCORE_EXPORT void clearMemoryPressure();
WEBCORE_EXPORT bool shouldWaitForMemoryClearMessage();
void respondToMemoryPressureIfNeeded();
#elif OS(LINUX)
static void waitForMemoryPressureEvent(void*);
#endif
class ReliefLogger {
public:
explicit ReliefLogger(const char *log)
: m_logString(log)
, m_initialMemory(s_loggingEnabled ? platformMemoryUsage() : 0)
{
}
~ReliefLogger()
{
if (s_loggingEnabled)
platformLog();
}
const char* logString() const { return m_logString; }
static void setLoggingEnabled(bool enabled) { s_loggingEnabled = enabled; }
static bool loggingEnabled() { return s_loggingEnabled; }
private:
size_t platformMemoryUsage();
void platformLog();
const char* m_logString;
size_t m_initialMemory;
WEBCORE_EXPORT static bool s_loggingEnabled;
};
WEBCORE_EXPORT void releaseMemory(Critical, Synchronous = Synchronous::No);
private:
void releaseNoncriticalMemory();
void releaseCriticalMemory(Synchronous);
void uninstall();
void holdOff(unsigned);
MemoryPressureHandler();
~MemoryPressureHandler() = delete;
void respondToMemoryPressure(Critical, Synchronous = Synchronous::No);
void platformReleaseMemory(Critical);
bool m_installed;
time_t m_lastRespondTime;
LowMemoryHandler m_lowMemoryHandler;
std::atomic<bool> m_underMemoryPressure;
#if PLATFORM(IOS)
uint32_t m_memoryPressureReason;
bool m_clearPressureOnMemoryRelease;
void (^m_releaseMemoryBlock)();
CFRunLoopObserverRef m_observer;
Lock m_observerMutex;
#elif OS(LINUX)
int m_eventFD;
int m_pressureLevelFD;
WTF::ThreadIdentifier m_threadID;
Timer m_holdOffTimer;
void holdOffTimerFired();
void logErrorAndCloseFDs(const char* error);
#endif
};
} // namespace WebCore
#endif // MemoryPressureHandler_h
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