MemoryPressureHandlerUnix.cpp [plain text]
#include "config.h"
#include <wtf/MemoryPressureHandler.h>
#include <malloc.h>
#include <unistd.h>
#include <wtf/MainThread.h>
#include <wtf/MemoryFootprint.h>
#include <wtf/text/WTFString.h>
#if OS(LINUX)
#include <wtf/linux/CurrentProcessMemoryStatus.h>
#elif OS(FREEBSD)
#include <sys/sysctl.h>
#include <sys/types.h>
#include <sys/user.h>
#endif
#define LOG_CHANNEL_PREFIX Log
namespace WTF {
static const Seconds s_minimumHoldOffTime { 5_s };
static const Seconds s_maximumHoldOffTime { 30_s };
static const size_t s_minimumBytesFreedToUseMinimumHoldOffTime = 1 * MB;
static const unsigned s_holdOffMultiplier = 20;
void MemoryPressureHandler::triggerMemoryPressureEvent(bool isCritical)
{
if (!m_installed)
return;
if (ReliefLogger::loggingEnabled())
LOG(MemoryPressure, "Got memory pressure notification (%s)", isCritical ? "critical" : "non-critical");
setUnderMemoryPressure(true);
if (isMainThread())
respondToMemoryPressure(isCritical ? Critical::Yes : Critical::No);
else
RunLoop::main().dispatch([this, isCritical] {
respondToMemoryPressure(isCritical ? Critical::Yes : Critical::No);
});
if (ReliefLogger::loggingEnabled() && isUnderMemoryPressure())
LOG(MemoryPressure, "System is no longer under memory pressure.");
setUnderMemoryPressure(false);
}
void MemoryPressureHandler::install()
{
if (m_installed || m_holdOffTimer.isActive())
return;
m_installed = true;
}
void MemoryPressureHandler::uninstall()
{
if (!m_installed)
return;
m_holdOffTimer.stop();
m_installed = false;
}
void MemoryPressureHandler::holdOffTimerFired()
{
install();
}
void MemoryPressureHandler::holdOff(Seconds seconds)
{
m_holdOffTimer.startOneShot(seconds);
}
static size_t processMemoryUsage()
{
#if OS(LINUX)
ProcessMemoryStatus memoryStatus;
currentProcessMemoryStatus(memoryStatus);
return (memoryStatus.resident - memoryStatus.shared);
#elif OS(FREEBSD)
static size_t pageSize = sysconf(_SC_PAGE_SIZE);
struct kinfo_proc info;
size_t infolen = sizeof(info);
int mib[4];
mib[0] = CTL_KERN;
mib[1] = KERN_PROC;
mib[2] = KERN_PROC_PID;
mib[3] = getpid();
if (sysctl(mib, 4, &info, &infolen, nullptr, 0))
return 0;
return static_cast<size_t>(info.ki_rssize - info.ki_tsize) * pageSize;
#else
#error "Missing a platform specific way of determining the memory usage"
#endif
}
void MemoryPressureHandler::respondToMemoryPressure(Critical critical, Synchronous synchronous)
{
uninstall();
MonotonicTime startTime = MonotonicTime::now();
int64_t processMemory = processMemoryUsage();
releaseMemory(critical, synchronous);
int64_t bytesFreed = processMemory - processMemoryUsage();
Seconds holdOffTime = s_maximumHoldOffTime;
if (bytesFreed > 0 && static_cast<size_t>(bytesFreed) >= s_minimumBytesFreedToUseMinimumHoldOffTime)
holdOffTime = (MonotonicTime::now() - startTime) * s_holdOffMultiplier;
holdOff(std::max(holdOffTime, s_minimumHoldOffTime));
}
void MemoryPressureHandler::platformReleaseMemory(Critical)
{
#if HAVE(MALLOC_TRIM)
malloc_trim(0);
#endif
}
Optional<MemoryPressureHandler::ReliefLogger::MemoryUsage> MemoryPressureHandler::ReliefLogger::platformMemoryUsage()
{
return MemoryUsage {processMemoryUsage(), memoryFootprint()};
}
}