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Diffstat (limited to 'base/memory/memory_pressure_monitor_chromeos.h')
-rw-r--r-- | base/memory/memory_pressure_monitor_chromeos.h | 128 |
1 files changed, 128 insertions, 0 deletions
diff --git a/base/memory/memory_pressure_monitor_chromeos.h b/base/memory/memory_pressure_monitor_chromeos.h new file mode 100644 index 0000000000..563ba85081 --- /dev/null +++ b/base/memory/memory_pressure_monitor_chromeos.h @@ -0,0 +1,128 @@ +// Copyright 2014 The Chromium Authors. All rights reserved. +// Use of this source code is governed by a BSD-style license that can be +// found in the LICENSE file. + +#ifndef BASE_MEMORY_MEMORY_PRESSURE_MONITOR_CHROMEOS_H_ +#define BASE_MEMORY_MEMORY_PRESSURE_MONITOR_CHROMEOS_H_ + +#include "base/base_export.h" +#include "base/files/scoped_file.h" +#include "base/macros.h" +#include "base/memory/memory_pressure_listener.h" +#include "base/memory/memory_pressure_monitor.h" +#include "base/memory/weak_ptr.h" +#include "base/timer/timer.h" + +namespace base { +namespace chromeos { + +class TestMemoryPressureMonitor; + +//////////////////////////////////////////////////////////////////////////////// +// MemoryPressureMonitor +// +// A class to handle the observation of our free memory. It notifies the +// MemoryPressureListener of memory fill level changes, so that it can take +// action to reduce memory resources accordingly. +// +class BASE_EXPORT MemoryPressureMonitor : public base::MemoryPressureMonitor { + public: + using GetUsedMemoryInPercentCallback = int (*)(); + + // There are two memory pressure events: + // MODERATE - which will mainly release caches. + // CRITICAL - which will discard tabs. + // The |MemoryPressureThresholds| enum selects the strategy of firing these + // events: A conservative strategy will keep as much content in memory as + // possible (causing the system to swap to zram) and an aggressive strategy + // will release memory earlier to avoid swapping. + enum MemoryPressureThresholds { + // Use the system default. + THRESHOLD_DEFAULT = 0, + // Try to keep as much content in memory as possible. + THRESHOLD_CONSERVATIVE = 1, + // Discard caches earlier, allowing to keep more tabs in memory. + THRESHOLD_AGGRESSIVE_CACHE_DISCARD = 2, + // Discard tabs earlier, allowing the system to get faster. + THRESHOLD_AGGRESSIVE_TAB_DISCARD = 3, + // Discard caches and tabs earlier to allow the system to be faster. + THRESHOLD_AGGRESSIVE = 4 + }; + + explicit MemoryPressureMonitor(MemoryPressureThresholds thresholds); + ~MemoryPressureMonitor() override; + + // Redo the memory pressure calculation soon and call again if a critical + // memory pressure prevails. Note that this call will trigger an asynchronous + // action which gives the system time to release memory back into the pool. + void ScheduleEarlyCheck(); + + // Get the current memory pressure level. + MemoryPressureListener::MemoryPressureLevel GetCurrentPressureLevel() + override; + void SetDispatchCallback(const DispatchCallback& callback) override; + + // Returns a type-casted version of the current memory pressure monitor. A + // simple wrapper to base::MemoryPressureMonitor::Get. + static MemoryPressureMonitor* Get(); + + private: + friend TestMemoryPressureMonitor; + // Starts observing the memory fill level. + // Calls to StartObserving should always be matched with calls to + // StopObserving. + void StartObserving(); + + // Stop observing the memory fill level. + // May be safely called if StartObserving has not been called. + void StopObserving(); + + // The function which gets periodically called to check any changes in the + // memory pressure. It will report pressure changes as well as continuous + // critical pressure levels. + void CheckMemoryPressure(); + + // The function periodically checks the memory pressure changes and records + // the UMA histogram statistics for the current memory pressure level. + void CheckMemoryPressureAndRecordStatistics(); + + // Get the memory pressure in percent (virtual for testing). + virtual int GetUsedMemoryInPercent(); + + // The current memory pressure. + base::MemoryPressureListener::MemoryPressureLevel + current_memory_pressure_level_; + + // A periodic timer to check for resource pressure changes. This will get + // replaced by a kernel triggered event system (see crbug.com/381196). + base::RepeatingTimer timer_; + + // To slow down the amount of moderate pressure event calls, this counter + // gets used to count the number of events since the last event occured. + int moderate_pressure_repeat_count_; + + // The "Memory.PressureLevel" statistic is recorded every + // 5 seconds, but the timer to report "ChromeOS.MemoryPressureLevel" + // fires every second. This counter is used to allow reporting + // "Memory.PressureLevel" correctly without adding another + // timer. + int seconds_since_reporting_; + + // The thresholds for moderate and critical pressure. + const int moderate_pressure_threshold_percent_; + const int critical_pressure_threshold_percent_; + + // File descriptor used to detect low memory condition. + ScopedFD low_mem_file_; + + DispatchCallback dispatch_callback_; + + base::WeakPtrFactory<MemoryPressureMonitor> weak_ptr_factory_; + + DISALLOW_COPY_AND_ASSIGN(MemoryPressureMonitor); +}; + +} // namespace chromeos +} // namespace base + +#endif // BASE_MEMORY_MEMORY_PRESSURE_MONITOR_CHROMEOS_H_ |