MemoryPressureHandlerCocoa.mm [plain text]
/*
* Copyright (C) 2011-2017 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 <wtf/MemoryPressureHandler.h>
#import <mach/mach.h>
#import <mach/task_info.h>
#import <malloc/malloc.h>
#import <notify.h>
#import <wtf/spi/darwin/DispatchSPI.h>
#define ENABLE_FMW_FOOTPRINT_COMPARISON 0
extern "C" void cache_simulate_memory_warning_event(uint64_t);
namespace WTF {
void MemoryPressureHandler::platformReleaseMemory(Critical critical)
{
if (critical == Critical::Yes && (!isUnderMemoryPressure() || m_isSimulatingMemoryPressure)) {
// libcache listens to OS memory notifications, but for process suspension
// or memory pressure simulation, we need to prod it manually:
cache_simulate_memory_warning_event(DISPATCH_MEMORYPRESSURE_CRITICAL);
}
}
static dispatch_source_t memoryPressureEventSource = nullptr;
static dispatch_source_t timerEventSource = nullptr;
static int notifyTokens[3];
// 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 Seconds s_minimumHoldOffTime { 5_s };
#if !PLATFORM(IOS_FAMILY)
static const unsigned s_holdOffMultiplier = 20;
#endif
void MemoryPressureHandler::install()
{
if (m_installed || timerEventSource)
return;
dispatch_async(m_dispatchQueue, ^{
#if PLATFORM(IOS_FAMILY)
auto memoryStatusFlags = DISPATCH_MEMORYPRESSURE_NORMAL | DISPATCH_MEMORYPRESSURE_WARN | DISPATCH_MEMORYPRESSURE_CRITICAL | DISPATCH_MEMORYPRESSURE_PROC_LIMIT_WARN | DISPATCH_MEMORYPRESSURE_PROC_LIMIT_CRITICAL;
#else // PLATFORM(MAC)
auto memoryStatusFlags = DISPATCH_MEMORYPRESSURE_CRITICAL;
#endif
memoryPressureEventSource = dispatch_source_create(DISPATCH_SOURCE_TYPE_MEMORYPRESSURE, 0, memoryStatusFlags, m_dispatchQueue);
dispatch_source_set_event_handler(memoryPressureEventSource, ^{
auto status = dispatch_source_get_data(memoryPressureEventSource);
#if PLATFORM(IOS_FAMILY)
switch (status) {
// VM pressure events.
case DISPATCH_MEMORYPRESSURE_NORMAL:
setUnderMemoryPressure(false);
break;
case DISPATCH_MEMORYPRESSURE_WARN:
setUnderMemoryPressure(false);
respondToMemoryPressure(Critical::No);
break;
case DISPATCH_MEMORYPRESSURE_CRITICAL:
setUnderMemoryPressure(true);
respondToMemoryPressure(Critical::Yes);
break;
// Process memory limit events.
case DISPATCH_MEMORYPRESSURE_PROC_LIMIT_WARN:
respondToMemoryPressure(Critical::No);
break;
case DISPATCH_MEMORYPRESSURE_PROC_LIMIT_CRITICAL:
respondToMemoryPressure(Critical::Yes);
break;
}
#else // PLATFORM(MAC)
respondToMemoryPressure(Critical::Yes);
#endif
if (m_shouldLogMemoryMemoryPressureEvents)
WTFLogAlways("Received memory pressure event %lu vm pressure %d", status, isUnderMemoryPressure());
});
dispatch_resume(memoryPressureEventSource);
});
// Allow simulation of memory pressure with "notifyutil -p org.WebKit.lowMemory"
notify_register_dispatch("org.WebKit.lowMemory", ¬ifyTokens[0], m_dispatchQueue, ^(int) {
#if ENABLE(FMW_FOOTPRINT_COMPARISON)
auto footprintBefore = pagesPerVMTag();
#endif
beginSimulatedMemoryPressure();
WTF::releaseFastMallocFreeMemory();
malloc_zone_pressure_relief(nullptr, 0);
#if ENABLE(FMW_FOOTPRINT_COMPARISON)
auto footprintAfter = pagesPerVMTag();
logFootprintComparison(footprintBefore, footprintAfter);
#endif
dispatch_async(m_dispatchQueue, ^{
endSimulatedMemoryPressure();
});
});
notify_register_dispatch("org.WebKit.lowMemory.begin", ¬ifyTokens[1], m_dispatchQueue, ^(int) {
beginSimulatedMemoryPressure();
});
notify_register_dispatch("org.WebKit.lowMemory.end", ¬ifyTokens[2], m_dispatchQueue, ^(int) {
endSimulatedMemoryPressure();
});
m_installed = true;
}
void MemoryPressureHandler::uninstall()
{
if (!m_installed)
return;
dispatch_async(m_dispatchQueue, ^{
if (memoryPressureEventSource) {
dispatch_source_cancel(memoryPressureEventSource);
memoryPressureEventSource = nullptr;
}
if (timerEventSource) {
dispatch_source_cancel(timerEventSource);
timerEventSource = nullptr;
}
});
m_installed = false;
for (auto& token : notifyTokens)
notify_cancel(token);
}
void MemoryPressureHandler::holdOff(Seconds seconds)
{
dispatch_async(m_dispatchQueue, ^{
timerEventSource = dispatch_source_create(DISPATCH_SOURCE_TYPE_TIMER, 0, 0, m_dispatchQueue);
if (timerEventSource) {
dispatch_set_context(timerEventSource, this);
// FIXME: The final argument `s_minimumHoldOffTime.seconds()` seems wrong.
// https://bugs.webkit.org/show_bug.cgi?id=183277
dispatch_source_set_timer(timerEventSource, dispatch_time(DISPATCH_TIME_NOW, seconds.seconds() * NSEC_PER_SEC), DISPATCH_TIME_FOREVER, s_minimumHoldOffTime.seconds());
dispatch_source_set_event_handler(timerEventSource, ^{
if (timerEventSource) {
dispatch_source_cancel(timerEventSource);
timerEventSource = nullptr;
}
MemoryPressureHandler::singleton().install();
});
dispatch_resume(timerEventSource);
}
});
}
void MemoryPressureHandler::respondToMemoryPressure(Critical critical, Synchronous synchronous)
{
#if !PLATFORM(IOS_FAMILY)
uninstall();
MonotonicTime startTime = MonotonicTime::now();
#endif
releaseMemory(critical, synchronous);
#if !PLATFORM(IOS_FAMILY)
Seconds holdOffTime = (MonotonicTime::now() - startTime) * s_holdOffMultiplier;
holdOff(std::max(holdOffTime, s_minimumHoldOffTime));
#endif
}
Optional<MemoryPressureHandler::ReliefLogger::MemoryUsage> MemoryPressureHandler::ReliefLogger::platformMemoryUsage()
{
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 WTF::nullopt;
return MemoryUsage {static_cast<size_t>(vmInfo.internal), static_cast<size_t>(vmInfo.phys_footprint)};
}
} // namespace WTF