components/memory_pressure/direct_memory_pressure_calculator.h

   1 // Copyright 2015 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef COMPONENTS_MEMORY_PRESSURE_DIRECT_MEMORY_PRESSURE_CALCULATOR_H_
   6 #define COMPONENTS_MEMORY_PRESSURE_DIRECT_MEMORY_PRESSURE_CALCULATOR_H_
   7
   8 #include "components/memory_pressure/memory_pressure_calculator.h"
   9
  10 #include "base/process/process_metrics.h"
  11
  12 namespace memory_pressure {
  13
  14 #if defined(MEMORY_PRESSURE_IS_POLLING)
  15
  16 // OS-specific implementation of MemoryPressureCalculator. This is only defined
  17 // and used on platforms that do not have native memory pressure signals
  18 // (ChromeOS, Linux, Windows). OSes that do have native signals simply hook into
  19 // the appropriate subsystem (Android, Mac OS X).
  20 class DirectMemoryPressureCalculator : public MemoryPressureCalculator {
  21  public:
  22 #if defined(OS_WIN)
  23   // Exposed for unittesting. See .cc file for detailed discussion of these
  24   // constants.
  25   static const int kLargeMemoryThresholdMb;
  26   static const int kSmallMemoryDefaultModerateThresholdMb;
  27   static const int kSmallMemoryDefaultCriticalThresholdMb;
  28   static const int kLargeMemoryDefaultModerateThresholdMb;
  29   static const int kLargeMemoryDefaultCriticalThresholdMb;
  30 #endif
  31
  32   // Default constructor. Will choose thresholds automatically based on the
  33   // actual amount of system memory installed.
  34   DirectMemoryPressureCalculator();
  35
  36   // Constructor with explicit memory thresholds. These represent the amount of
  37   // free memory below which the applicable memory pressure state applies.
  38   DirectMemoryPressureCalculator(int moderate_threshold_mb,
  39                                  int critical_threshold_mb);
  40
  41   ~DirectMemoryPressureCalculator() override {}
  42
  43   // Calculates the current pressure level.
  44   MemoryPressureLevel CalculateCurrentPressureLevel() override;
  45
  46 #if defined(OS_WIN)
  47   int moderate_threshold_mb() const { return moderate_threshold_mb_; }
  48   int critical_threshold_mb() const { return critical_threshold_mb_; }
  49 #endif
  50
  51  private:
  52   friend class TestDirectMemoryPressureCalculator;
  53
  54   // Gets system memory status. This is virtual as a unittesting hook and by
  55   // default this invokes base::GetSystemMemoryInfo.
  56   virtual bool GetSystemMemoryInfo(base::SystemMemoryInfoKB* mem_info) const;
  57
  58 #if defined(OS_WIN)
  59   // Uses GetSystemMemoryInfo to automatically infer appropriate values for
  60   // moderate_threshold_mb_ and critical_threshold_mb_.
  61   void InferThresholds();
  62
  63   // Threshold amounts of available memory that trigger pressure levels. See
  64   // memory_pressure_monitor_win.cc for a discussion of reasonable values for
  65   // these.
  66   int moderate_threshold_mb_;
  67   int critical_threshold_mb_;
  68 #endif
  69
  70   DISALLOW_COPY_AND_ASSIGN(DirectMemoryPressureCalculator);
  71 };
  72
  73 #endif  // defined(MEMORY_PRESSURE_IS_POLLING)
  74
  75 }  // namespace memory_pressure
  76
  77 #endif  // COMPONENTS_MEMORY_PRESSURE_DIRECT_MEMORY_PRESSURE_CALCULATOR_H_