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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>
#include <wtf/NeverDestroyed.h>
#include <wtf/Optional.h>
#include <wtf/RunLoop.h>
#if PLATFORM(IOS)
#include <wtf/Lock.h>
#include <wtf/ThreadingPrimitives.h>
#endif
#if USE(GLIB)
#include <wtf/glib/GRefPtr.h>
#endif
namespace WebCore {
#if PLATFORM(IOS)
enum MemoryPressureReason {
MemoryPressureReasonNone = 0 << 0,
MemoryPressureReasonVMPressure = 1 << 0,
MemoryPressureReasonVMStatus = 1 << 1,
};
#endif
enum class MemoryUsagePolicy {
Unrestricted, // Allocate as much as you want
Conservative, // Maybe you don't cache every single thing
Strict, // Time to start pinching pennies for real
Panic, // OH GOD WE'RE SINKING, THROW EVERYTHING OVERBOARD
};
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();
WEBCORE_EXPORT void setShouldUsePeriodicMemoryMonitor(bool);
void setMemoryKillCallback(WTF::Function<void()> function) { m_memoryKillCallback = WTFMove(function); }
void setProcessIsEligibleForMemoryKillCallback(WTF::Function<bool()> function) { m_processIsEligibleForMemoryKillCallback = WTFMove(function); }
void setLowMemoryHandler(LowMemoryHandler&& handler)
{
m_lowMemoryHandler = WTFMove(handler);
}
bool isUnderMemoryPressure() const
{
return m_underMemoryPressure
#if PLATFORM(MAC)
|| m_memoryUsagePolicy >= MemoryUsagePolicy::Strict
#endif
|| m_isSimulatingMemoryPressure;
}
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)
void setMemoryPressureMonitorHandle(int fd);
#endif
class ReliefLogger {
public:
explicit ReliefLogger(const char *log)
: m_logString(log)
, m_initialMemory(loggingEnabled() ? platformMemoryUsage() : MemoryUsage { })
{
}
~ReliefLogger()
{
if (loggingEnabled())
logMemoryUsageChange();
}
const char* logString() const { return m_logString; }
static void setLoggingEnabled(bool enabled) { s_loggingEnabled = enabled; }
static bool loggingEnabled()
{
#if RELEASE_LOG_DISABLED
return s_loggingEnabled;
#else
return true;
#endif
}
private:
struct MemoryUsage {
MemoryUsage() = default;
MemoryUsage(size_t resident, size_t physical)
: resident(resident)
, physical(physical)
{
}
size_t resident { 0 };
size_t physical { 0 };
};
std::optional<MemoryUsage> platformMemoryUsage();
void logMemoryUsageChange();
const char* m_logString;
std::optional<MemoryUsage> m_initialMemory;
WEBCORE_EXPORT static bool s_loggingEnabled;
};
WEBCORE_EXPORT void releaseMemory(Critical, Synchronous = Synchronous::No);
WEBCORE_EXPORT void beginSimulatedMemoryPressure();
WEBCORE_EXPORT void endSimulatedMemoryPressure();
private:
void uninstall();
void holdOff(unsigned);
MemoryPressureHandler();
~MemoryPressureHandler() = delete;
void respondToMemoryPressure(Critical, Synchronous = Synchronous::No);
void platformReleaseMemory(Critical);
NO_RETURN_DUE_TO_CRASH void didExceedMemoryLimitAndFailedToRecover();
void measurementTimerFired();
#if OS(LINUX)
class EventFDPoller {
WTF_MAKE_NONCOPYABLE(EventFDPoller); WTF_MAKE_FAST_ALLOCATED;
public:
EventFDPoller(int fd, std::function<void ()>&& notifyHandler);
~EventFDPoller();
private:
void readAndNotify() const;
std::optional<int> m_fd;
std::function<void ()> m_notifyHandler;
#if USE(GLIB)
GRefPtr<GSource> m_source;
#else
ThreadIdentifier m_threadID;
#endif
};
#endif
bool m_installed { false };
LowMemoryHandler m_lowMemoryHandler;
std::atomic<bool> m_underMemoryPressure;
bool m_isSimulatingMemoryPressure { false };
std::unique_ptr<RunLoop::Timer<MemoryPressureHandler>> m_measurementTimer;
MemoryUsagePolicy m_memoryUsagePolicy { MemoryUsagePolicy::Unrestricted };
WTF::Function<void()> m_memoryKillCallback;
WTF::Function<bool()> m_processIsEligibleForMemoryKillCallback;
#if PLATFORM(IOS)
// FIXME: Can we share more of this with OpenSource?
uint32_t m_memoryPressureReason { MemoryPressureReasonNone };
bool m_clearPressureOnMemoryRelease { true };
void (^m_releaseMemoryBlock)() { nullptr };
CFRunLoopObserverRef m_observer { nullptr };
Lock m_observerMutex;
#elif OS(LINUX)
std::optional<int> m_eventFD;
std::optional<int> m_pressureLevelFD;
std::unique_ptr<EventFDPoller> m_eventFDPoller;
RunLoop::Timer<MemoryPressureHandler> m_holdOffTimer;
void holdOffTimerFired();
void logErrorAndCloseFDs(const char* error);
bool tryEnsureEventFD();
#endif
};
} // namespace WebCore
#endif // MemoryPressureHandler_h
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