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Diffstat (limited to 'widget/gonk/GonkMemoryPressureMonitoring.cpp')
| -rw-r--r-- | widget/gonk/GonkMemoryPressureMonitoring.cpp | 359 |
1 files changed, 0 insertions, 359 deletions
diff --git a/widget/gonk/GonkMemoryPressureMonitoring.cpp b/widget/gonk/GonkMemoryPressureMonitoring.cpp deleted file mode 100644 index 0fafb37cf..000000000 --- a/widget/gonk/GonkMemoryPressureMonitoring.cpp +++ /dev/null @@ -1,359 +0,0 @@ -/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ -/* vim: set ts=2 et sw=2 tw=80: */ -/* This Source Code Form is subject to the terms of the Mozilla Public - * License, v. 2.0. If a copy of the MPL was not distributed with this - * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ - -#include <android/log.h> -#include <errno.h> -#include <fcntl.h> -#include <poll.h> -#include <sys/sysinfo.h> - -#include "GonkMemoryPressureMonitoring.h" -#include "mozilla/ArrayUtils.h" -#include "mozilla/FileUtils.h" -#include "mozilla/Monitor.h" -#include "mozilla/Preferences.h" -#include "mozilla/ProcessPriorityManager.h" -#include "mozilla/Services.h" -#include "nsIObserver.h" -#include "nsIObserverService.h" -#include "nsMemoryPressure.h" -#include "nsPrintfCString.h" -#include "nsThreadUtils.h" - -#define LOG(args...) \ - __android_log_print(ANDROID_LOG_INFO, "GonkMemoryPressure" , ## args) - -using namespace mozilla; - -namespace { - -/** - * MemoryPressureWatcher watches sysfs from its own thread to notice when the - * system is under memory pressure. When we observe memory pressure, we use - * MemoryPressureRunnable to notify observers that they should release memory. - * - * When the system is under memory pressure, we don't want to constantly fire - * memory-pressure events. So instead, we try to detect when sysfs indicates - * that we're no longer under memory pressure, and only then start firing events - * again. - * - * (This is a bit problematic because we can't poll() to detect when we're no - * longer under memory pressure; instead we have to periodically read the sysfs - * node. If we remain under memory pressure for a long time, this means we'll - * continue waking up to read from the node for a long time, potentially wasting - * battery life. Hopefully we don't hit this case in practice! We write to - * logcat each time we go around this loop so it's at least noticable.) - * - * Shutting down safely is a bit of a chore. XPCOM won't shut down until all - * threads exit, so we need to exit the Run() method below on shutdown. But our - * thread might be blocked in one of two situations: We might be poll()'ing the - * sysfs node waiting for memory pressure to occur, or we might be asleep - * waiting to read() the sysfs node to see if we're no longer under memory - * pressure. - * - * To let us wake up from the poll(), we poll() not just the sysfs node but also - * a pipe, which we write to on shutdown. To let us wake up from sleeping - * between read()s, we sleep by Wait()'ing on a monitor, which we notify on - * shutdown. - */ -class MemoryPressureWatcher final - : public nsIRunnable - , public nsIObserver -{ -public: - MemoryPressureWatcher() - : mMonitor("MemoryPressureWatcher") - , mLowMemTriggerKB(0) - , mPageSize(0) - , mShuttingDown(false) - , mTriggerFd(-1) - , mShutdownPipeRead(-1) - , mShutdownPipeWrite(-1) - { - } - - NS_DECL_THREADSAFE_ISUPPORTS - - nsresult Init() - { - nsCOMPtr<nsIObserverService> os = services::GetObserverService(); - NS_ENSURE_STATE(os); - - // The observer service holds us alive. - os->AddObserver(this, NS_XPCOM_SHUTDOWN_OBSERVER_ID, /* ownsWeak */ false); - - // Initialize the internal state - mPageSize = sysconf(_SC_PAGESIZE); - ReadPrefs(); - nsresult rv = OpenFiles(); - NS_ENSURE_SUCCESS(rv, rv); - SetLowMemTrigger(mSoftLowMemTriggerKB); - - return NS_OK; - } - - NS_IMETHOD Observe(nsISupports* aSubject, const char* aTopic, - const char16_t* aData) - { - MOZ_ASSERT(strcmp(aTopic, NS_XPCOM_SHUTDOWN_OBSERVER_ID) == 0); - LOG("Observed XPCOM shutdown."); - - MonitorAutoLock lock(mMonitor); - mShuttingDown = true; - mMonitor.Notify(); - - int rv; - do { - // Write something to the pipe; doesn't matter what. - uint32_t dummy = 0; - rv = write(mShutdownPipeWrite, &dummy, sizeof(dummy)); - } while(rv == -1 && errno == EINTR); - - return NS_OK; - } - - NS_IMETHOD Run() override - { - MOZ_ASSERT(!NS_IsMainThread()); - - int triggerResetTimeout = -1; - bool memoryPressure; - nsresult rv = CheckForMemoryPressure(&memoryPressure); - NS_ENSURE_SUCCESS(rv, rv); - - while (true) { - // Wait for a notification on mTriggerFd or for data to be written to - // mShutdownPipeWrite. (poll(mTriggerFd, POLLPRI) blocks until we're - // under memory pressure or until we time out, the time out is used - // to adjust the trigger level after a memory pressure event.) - struct pollfd pollfds[2]; - pollfds[0].fd = mTriggerFd; - pollfds[0].events = POLLPRI; - pollfds[1].fd = mShutdownPipeRead; - pollfds[1].events = POLLIN; - - int pollRv = MOZ_TEMP_FAILURE_RETRY( - poll(pollfds, ArrayLength(pollfds), triggerResetTimeout) - ); - - if (pollRv == 0) { - // Timed out, adjust the trigger and update the timeout. - triggerResetTimeout = AdjustTrigger(triggerResetTimeout); - continue; - } - - if (pollfds[1].revents) { - // Something was written to our shutdown pipe; we're outta here. - LOG("shutting down (1)"); - return NS_OK; - } - - // If pollfds[1] isn't happening, pollfds[0] ought to be! - if (!(pollfds[0].revents & POLLPRI)) { - LOG("Unexpected revents value after poll(): %d. " - "Shutting down GonkMemoryPressureMonitoring.", pollfds[0].revents); - return NS_ERROR_FAILURE; - } - - // POLLPRI on mTriggerFd indicates that we're in a low-memory situation. - // We could read lowMemFd to double-check, but we've observed that the - // read sometimes completes after the memory-pressure event is over, so - // let's just believe the result of poll(). - rv = DispatchMemoryPressure(MemPressure_New); - NS_ENSURE_SUCCESS(rv, rv); - - // Move to the hard level if we're on the soft one. - if (mLowMemTriggerKB > mHardLowMemTriggerKB) { - SetLowMemTrigger(mHardLowMemTriggerKB); - } - - // Manually check mTriggerFd until we observe that memory pressure is - // over. We won't fire any more low-memory events until we observe that - // we're no longer under pressure. Instead, we fire low-memory-ongoing - // events, which cause processes to keep flushing caches but will not - // trigger expensive GCs and other attempts to save memory that are - // likely futile at this point. - do { - { - MonitorAutoLock lock(mMonitor); - - // We need to check mShuttingDown before we wait here, in order to - // catch a shutdown signal sent after we poll()'ed mShutdownPipeRead - // above but before we started waiting on the monitor. But we don't - // need to check after we wait, because we'll either do another - // iteration of this inner loop, in which case we'll check - // mShuttingDown, or we'll exit this loop and do another iteration - // of the outer loop, in which case we'll check the shutdown pipe. - if (mShuttingDown) { - LOG("shutting down (2)"); - return NS_OK; - } - mMonitor.Wait(PR_MillisecondsToInterval(mPollMS)); - } - - LOG("Checking to see if memory pressure is over."); - rv = CheckForMemoryPressure(&memoryPressure); - NS_ENSURE_SUCCESS(rv, rv); - - if (memoryPressure) { - rv = DispatchMemoryPressure(MemPressure_Ongoing); - NS_ENSURE_SUCCESS(rv, rv); - continue; - } - } while (false); - - if (XRE_IsParentProcess()) { - // The main process will try to adjust the trigger. - triggerResetTimeout = mPollMS * 2; - } - - LOG("Memory pressure is over."); - } - - return NS_OK; - } - -protected: - ~MemoryPressureWatcher() {} - -private: - void ReadPrefs() { - // While we're under memory pressure, we periodically read() - // notify_trigger_active to try and see when we're no longer under memory - // pressure. mPollMS indicates how many milliseconds we wait between those - // read()s. - Preferences::AddUintVarCache(&mPollMS, - "gonk.systemMemoryPressureRecoveryPollMS", /* default */ 5000); - - // We have two values for the notify trigger, a soft one which is triggered - // before we start killing background applications and an hard one which is - // after we've killed background applications but before we start killing - // foreground ones. - Preferences::AddUintVarCache(&mSoftLowMemTriggerKB, - "gonk.notifySoftLowMemUnderKB", /* default */ 43008); - Preferences::AddUintVarCache(&mHardLowMemTriggerKB, - "gonk.notifyHardLowMemUnderKB", /* default */ 14336); - } - - nsresult OpenFiles() { - mTriggerFd = open("/sys/kernel/mm/lowmemkiller/notify_trigger_active", - O_RDONLY | O_CLOEXEC); - NS_ENSURE_STATE(mTriggerFd != -1); - - int pipes[2]; - NS_ENSURE_STATE(!pipe(pipes)); - mShutdownPipeRead = pipes[0]; - mShutdownPipeWrite = pipes[1]; - return NS_OK; - } - - /** - * Set the low memory trigger to the specified value, this can be done by - * the main process alone. - */ - void SetLowMemTrigger(uint32_t aValue) { - if (XRE_IsParentProcess()) { - nsPrintfCString str("%ld", (aValue * 1024) / mPageSize); - if (WriteSysFile("/sys/module/lowmemorykiller/parameters/notify_trigger", - str.get())) { - mLowMemTriggerKB = aValue; - } - } - } - - /** - * Read from the trigger file descriptor and determine whether we're - * currently under memory pressure. - * - * We don't expect this method to block. - */ - nsresult CheckForMemoryPressure(bool* aOut) - { - *aOut = false; - - lseek(mTriggerFd, 0, SEEK_SET); - - char buf[2]; - int nread = MOZ_TEMP_FAILURE_RETRY(read(mTriggerFd, buf, sizeof(buf))); - NS_ENSURE_STATE(nread == 2); - - // The notify_trigger_active sysfs node should contain either "0\n" or - // "1\n". The latter indicates memory pressure. - *aOut = (buf[0] == '1'); - return NS_OK; - } - - int AdjustTrigger(int timeout) - { - if (!XRE_IsParentProcess()) { - return -1; // Only the main process can adjust the trigger. - } - - struct sysinfo info; - int rv = sysinfo(&info); - if (rv < 0) { - return -1; // Without system information we're blind, bail out. - } - - size_t freeMemory = (info.freeram * info.mem_unit) / 1024; - - if (freeMemory > mSoftLowMemTriggerKB) { - SetLowMemTrigger(mSoftLowMemTriggerKB); - return -1; // Trigger adjusted, wait indefinitely. - } - - // Wait again but double the duration, max once per day. - return std::min(86400000, timeout * 2); - } - - /** - * Dispatch the specified memory pressure event unless a high-priority - * process is present. If a high-priority process is present then it's likely - * responding to an urgent event (an incoming call or message for example) so - * avoid wasting CPU time responding to low-memory events. - */ - nsresult DispatchMemoryPressure(MemoryPressureState state) - { - if (ProcessPriorityManager::AnyProcessHasHighPriority()) { - return NS_OK; - } - - return NS_DispatchMemoryPressure(state); - } - - Monitor mMonitor; - uint32_t mPollMS; // Ongoing pressure poll delay - uint32_t mSoftLowMemTriggerKB; // Soft memory pressure level - uint32_t mHardLowMemTriggerKB; // Hard memory pressure level - uint32_t mLowMemTriggerKB; // Current value of the trigger - size_t mPageSize; - bool mShuttingDown; - - ScopedClose mTriggerFd; - ScopedClose mShutdownPipeRead; - ScopedClose mShutdownPipeWrite; -}; - -NS_IMPL_ISUPPORTS(MemoryPressureWatcher, nsIRunnable, nsIObserver); - -} // namespace - -namespace mozilla { - -void -InitGonkMemoryPressureMonitoring() -{ - // memoryPressureWatcher is held alive by the observer service. - RefPtr<MemoryPressureWatcher> memoryPressureWatcher = - new MemoryPressureWatcher(); - NS_ENSURE_SUCCESS_VOID(memoryPressureWatcher->Init()); - - nsCOMPtr<nsIThread> thread; - NS_NewNamedThread("MemoryPressure", getter_AddRefs(thread), - memoryPressureWatcher); -} - -} // namespace mozilla |