athena/resource_manager/memory_pressure_notifier.cc

   1 // Copyright (c) 2014 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 #include "athena/resource_manager/memory_pressure_notifier.h"
   6
   7 #include "athena/resource_manager/public/resource_manager_delegate.h"
   8 #include "base/time/time.h"
   9
  10
  11 namespace athena {
  12
  13 MemoryPressureNotifier::MemoryPressureNotifier(
  14     MemoryPressureObserver* listener)
  15       : listener_(listener),
  16         current_pressure_(MemoryPressureObserver::MEMORY_PRESSURE_UNKNOWN) {
  17   StartObserving();
  18 }
  19
  20 MemoryPressureNotifier::~MemoryPressureNotifier() {
  21   StopObserving();
  22 }
  23
  24 void MemoryPressureNotifier::StartObserving() {
  25   int time_in_ms = listener_->GetDelegate()->MemoryPressureIntervalInMS();
  26   timer_.Start(FROM_HERE,
  27                base::TimeDelta::FromMilliseconds(time_in_ms),
  28                base::Bind(&MemoryPressureNotifier::CheckMemoryPressure,
  29                           base::Unretained(this)));
  30 }
  31
  32 void MemoryPressureNotifier::StopObserving() {
  33   // If StartObserving failed, StopObserving will still get called.
  34   timer_.Stop();
  35 }
  36
  37 void MemoryPressureNotifier::CheckMemoryPressure() {
  38   MemoryPressureObserver::MemoryPressure pressure =
  39       GetMemoryPressureLevelFromFillLevel(
  40           listener_->GetDelegate()->GetUsedMemoryInPercent());
  41   if (current_pressure_ != pressure ||
  42       (pressure != MemoryPressureObserver::MEMORY_PRESSURE_LOW &&
  43        pressure != MemoryPressureObserver::MEMORY_PRESSURE_UNKNOWN)) {
  44     // If we are anything worse than |MEMORY_PRESSURE_LOW|, we notify the
  45     // listener.
  46     current_pressure_ = pressure;
  47     listener_->OnMemoryPressure(current_pressure_);
  48   }
  49 }
  50
  51 MemoryPressureObserver::MemoryPressure
  52 MemoryPressureNotifier::GetMemoryPressureLevelFromFillLevel(
  53     int memory_fill_level) {
  54   if (memory_fill_level == 0)
  55     return MemoryPressureObserver::MEMORY_PRESSURE_UNKNOWN;
  56   if (memory_fill_level < 50)
  57     return MemoryPressureObserver::MEMORY_PRESSURE_LOW;
  58   if (memory_fill_level < 75)
  59     return MemoryPressureObserver::MEMORY_PRESSURE_MODERATE;
  60   if (memory_fill_level < 90)
  61     return MemoryPressureObserver::MEMORY_PRESSURE_HIGH;
  62   return MemoryPressureObserver::MEMORY_PRESSURE_CRITICAL;
  63 }
  64
  65 }  // namespace athena