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      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
     66