MemoryPressureHandlerCocoa.mm [plain text]
/*
* Copyright (C) 2011-2015 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.
*/
#import "config.h"
#import "MemoryPressureHandler.h"
#import "IOSurfacePool.h"
#import "GCController.h"
#import "JSDOMWindow.h"
#import "JSDOMWindowBase.h"
#import "LayerPool.h"
#import "Logging.h"
#import "WebCoreSystemInterface.h"
#import <mach/mach.h>
#import <mach/task_info.h>
#import <malloc/malloc.h>
#import <notify.h>
#import <wtf/CurrentTime.h>
#if PLATFORM(IOS)
#import "SystemMemory.h"
#import "WebCoreThread.h"
#endif
extern "C" void cache_simulate_memory_warning_event(uint64_t);
extern "C" void _sqlite3_purgeEligiblePagerCacheMemory(void);
namespace WebCore {
void MemoryPressureHandler::platformReleaseMemory(Critical critical)
{
{
ReliefLogger log("Purging SQLite caches");
_sqlite3_purgeEligiblePagerCacheMemory();
}
{
ReliefLogger log("Drain LayerPools");
for (auto& pool : LayerPool::allLayerPools())
pool->drain();
}
#if USE(IOSURFACE)
{
ReliefLogger log("Drain IOSurfacePool");
IOSurfacePool::sharedPool().discardAllSurfaces();
}
#endif
#if PLATFORM(IOS) || __MAC_OS_X_VERSION_MIN_REQUIRED >= 101000
if (critical == Critical::Yes && !isUnderMemoryPressure()) {
// libcache listens to OS memory notifications, but for process suspension
// or memory pressure simulation, we need to prod it manually:
ReliefLogger log("Purging libcache caches");
cache_simulate_memory_warning_event(DISPATCH_MEMORYPRESSURE_CRITICAL);
}
#else
UNUSED_PARAM(critical);
#endif
}
static dispatch_source_t _cache_event_source = 0;
static dispatch_source_t _timer_event_source = 0;
static int _notifyToken;
// Disable memory event reception for a minimum of s_minimumHoldOffTime
// seconds after receiving an event. Don't let events fire any sooner than
// s_holdOffMultiplier times the last cleanup processing time. Effectively
// this is 1 / s_holdOffMultiplier percent of the time.
// These value seems reasonable and testing verifies that it throttles frequent
// low memory events, greatly reducing CPU usage.
static const unsigned s_minimumHoldOffTime = 5;
#if !PLATFORM(IOS)
static const unsigned s_holdOffMultiplier = 20;
#endif
void MemoryPressureHandler::install()
{
if (m_installed || _timer_event_source)
return;
dispatch_async(dispatch_get_main_queue(), ^{
#if PLATFORM(IOS)
_cache_event_source = dispatch_source_create(DISPATCH_SOURCE_TYPE_MEMORYPRESSURE, 0, DISPATCH_MEMORYPRESSURE_NORMAL | DISPATCH_MEMORYPRESSURE_WARN | DISPATCH_MEMORYPRESSURE_CRITICAL, dispatch_get_main_queue());
#elif PLATFORM(MAC)
_cache_event_source = dispatch_source_create(DISPATCH_SOURCE_TYPE_MEMORYPRESSURE, 0, DISPATCH_MEMORYPRESSURE_CRITICAL, dispatch_get_main_queue());
#endif
dispatch_set_context(_cache_event_source, this);
dispatch_source_set_event_handler(_cache_event_source, ^{
bool critical = true;
#if PLATFORM(IOS)
unsigned long status = dispatch_source_get_data(_cache_event_source);
critical = status == DISPATCH_MEMORYPRESSURE_CRITICAL;
auto& memoryPressureHandler = MemoryPressureHandler::singleton();
bool wasCritical = memoryPressureHandler.isUnderMemoryPressure();
memoryPressureHandler.setUnderMemoryPressure(critical);
if (status == DISPATCH_MEMORYPRESSURE_NORMAL) {
if (ReliefLogger::loggingEnabled())
NSLog(@"System is no longer under (%s) memory pressure.", wasCritical ? "critical" : "non-critical");
return;
}
if (ReliefLogger::loggingEnabled())
NSLog(@"Got memory pressure notification (%s)", critical ? "critical" : "non-critical");
#endif
MemoryPressureHandler::singleton().respondToMemoryPressure(critical ? Critical::Yes : Critical::No);
});
dispatch_resume(_cache_event_source);
});
// Allow simulation of memory pressure with "notifyutil -p org.WebKit.lowMemory"
notify_register_dispatch("org.WebKit.lowMemory", &_notifyToken, dispatch_get_main_queue(), ^(int) {
MemoryPressureHandler::singleton().respondToMemoryPressure(Critical::Yes, Synchronous::Yes);
WTF::releaseFastMallocFreeMemory();
malloc_zone_pressure_relief(nullptr, 0);
});
m_installed = true;
}
void MemoryPressureHandler::uninstall()
{
if (!m_installed)
return;
dispatch_async(dispatch_get_main_queue(), ^{
if (_cache_event_source) {
dispatch_source_cancel(_cache_event_source);
dispatch_release(_cache_event_source);
_cache_event_source = 0;
}
if (_timer_event_source) {
dispatch_source_cancel(_timer_event_source);
dispatch_release(_timer_event_source);
_timer_event_source = 0;
}
});
m_installed = false;
notify_cancel(_notifyToken);
}
void MemoryPressureHandler::holdOff(unsigned seconds)
{
dispatch_async(dispatch_get_main_queue(), ^{
_timer_event_source = dispatch_source_create(DISPATCH_SOURCE_TYPE_TIMER, 0, 0, dispatch_get_main_queue());
if (_timer_event_source) {
dispatch_set_context(_timer_event_source, this);
dispatch_source_set_timer(_timer_event_source, dispatch_time(DISPATCH_TIME_NOW, seconds * NSEC_PER_SEC), DISPATCH_TIME_FOREVER, 1 * s_minimumHoldOffTime);
dispatch_source_set_event_handler(_timer_event_source, ^{
if (_timer_event_source) {
dispatch_source_cancel(_timer_event_source);
dispatch_release(_timer_event_source);
_timer_event_source = 0;
}
MemoryPressureHandler::singleton().install();
});
dispatch_resume(_timer_event_source);
}
});
}
void MemoryPressureHandler::respondToMemoryPressure(Critical critical, Synchronous synchronous)
{
#if !PLATFORM(IOS)
uninstall();
double startTime = monotonicallyIncreasingTime();
#endif
m_lowMemoryHandler(critical, synchronous);
#if !PLATFORM(IOS)
unsigned holdOffTime = (monotonicallyIncreasingTime() - startTime) * s_holdOffMultiplier;
holdOff(std::max(holdOffTime, s_minimumHoldOffTime));
#endif
}
size_t MemoryPressureHandler::ReliefLogger::platformMemoryUsage()
{
// Flush free memory back to the OS before every measurement.
// Note that this code only runs when detailed pressure relief logging is enabled.
WTF::releaseFastMallocFreeMemory();
malloc_zone_pressure_relief(nullptr, 0);
task_vm_info_data_t vmInfo;
mach_msg_type_number_t count = TASK_VM_INFO_COUNT;
kern_return_t err = task_info(mach_task_self(), TASK_VM_INFO, (task_info_t) &vmInfo, &count);
if (err != KERN_SUCCESS)
return static_cast<size_t>(-1);
return static_cast<size_t>(vmInfo.internal);
}
void MemoryPressureHandler::ReliefLogger::platformLog()
{
size_t currentMemory = platformMemoryUsage();
if (currentMemory == static_cast<size_t>(-1) || m_initialMemory == static_cast<size_t>(-1)) {
NSLog(@"%s (Unable to get dirty memory information for process)\n", m_logString);
return;
}
ssize_t memoryDiff = currentMemory - m_initialMemory;
if (memoryDiff < 0)
NSLog(@"Pressure relief: %s: -dirty %ld bytes (from %ld to %ld)\n", m_logString, (memoryDiff * -1), m_initialMemory, currentMemory);
else if (memoryDiff > 0)
NSLog(@"Pressure relief: %s: +dirty %ld bytes (from %ld to %ld)\n", m_logString, memoryDiff, m_initialMemory, currentMemory);
else
NSLog(@"Pressure relief: %s: =dirty (at %ld bytes)\n", m_logString, currentMemory);
}
#if PLATFORM(IOS)
static void respondToMemoryPressureCallback(CFRunLoopObserverRef observer, CFRunLoopActivity /*activity*/, void* /*info*/)
{
MemoryPressureHandler::singleton().respondToMemoryPressureIfNeeded();
CFRunLoopObserverInvalidate(observer);
CFRelease(observer);
}
void MemoryPressureHandler::installMemoryReleaseBlock(void (^releaseMemoryBlock)(), bool clearPressureOnMemoryRelease)
{
if (m_installed)
return;
m_releaseMemoryBlock = Block_copy(releaseMemoryBlock);
m_clearPressureOnMemoryRelease = clearPressureOnMemoryRelease;
m_installed = true;
}
void MemoryPressureHandler::setReceivedMemoryPressure(MemoryPressureReason reason)
{
m_underMemoryPressure = true;
{
MutexLocker locker(m_observerMutex);
if (!m_observer) {
m_observer = CFRunLoopObserverCreate(NULL, kCFRunLoopBeforeWaiting | kCFRunLoopExit, NO /* don't repeat */,
0, WebCore::respondToMemoryPressureCallback, NULL);
CFRunLoopAddObserver(WebThreadRunLoop(), m_observer, kCFRunLoopCommonModes);
CFRunLoopWakeUp(WebThreadRunLoop());
}
m_memoryPressureReason |= reason;
}
}
void MemoryPressureHandler::clearMemoryPressure()
{
m_underMemoryPressure = false;
{
MutexLocker locker(m_observerMutex);
m_memoryPressureReason = MemoryPressureReasonNone;
}
}
bool MemoryPressureHandler::shouldWaitForMemoryClearMessage()
{
MutexLocker locker(m_observerMutex);
return m_memoryPressureReason & MemoryPressureReasonVMStatus;
}
void MemoryPressureHandler::respondToMemoryPressureIfNeeded()
{
ASSERT(WebThreadIsLockedOrDisabled());
{
MutexLocker locker(m_observerMutex);
m_observer = 0;
}
if (isUnderMemoryPressure()) {
ASSERT(m_releaseMemoryBlock);
LOG(MemoryPressure, "Handle memory pressure at %s", __PRETTY_FUNCTION__);
m_releaseMemoryBlock();
if (m_clearPressureOnMemoryRelease)
clearMemoryPressure();
}
}
#endif
} // namespace WebCore