blob: bb2d1212fa5f01a1c348ed973a42420d0e2e3c06 [file] [log] [blame]
// Copyright (c) 2016 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.
#include "content/browser/memory/memory_monitor.h"
namespace base {
struct SystemMemoryInfoKB;
} // namespace base
namespace content {
// A memory monitor for the Windows platform. After much experimentation this
// class uses a very simple heuristic to anticipate paging (critical memory
// pressure). When the amount of memory available dips below a provided
// threshold, it is assumed that paging is inevitable.
class CONTENT_EXPORT MemoryMonitorWin : public MemoryMonitor {
// Default constants governing the amount of free memory that the memory
// manager attempts to maintain.
static const int kLargeMemoryThresholdMB;
static const int kSmallMemoryTargetFreeMB;
static const int kLargeMemoryTargetFreeMB;
MemoryMonitorWin(MemoryMonitorDelegate* delegate, int target_free_mb);
~MemoryMonitorWin() override {}
// MemoryMonitor:
int GetFreeMemoryUntilCriticalMB() override;
// Returns the current free memory target.
int target_free_mb() const { return target_free_mb_; }
// Factory function. Automatically sizes |target_free_mb| based on the
// system.
static std::unique_ptr<MemoryMonitorWin> Create(
MemoryMonitorDelegate* delegate);
// Determines if the system is in large memory mode. Exposed so that this
// function can be tested.
static bool IsLargeMemory(MemoryMonitorDelegate* delegate);
// Determines the default target free MB value. Exposed so that this function
// can be tested.
static int GetTargetFreeMB(MemoryMonitorDelegate* delegate);
// The delegate to be used for retrieving system memory information. Used as a
// testing seam.
MemoryMonitorDelegate* delegate_;
// The amount of memory that the memory manager (MM) attempts to keep in a
// free state. When less than this amount of physical memory is free, it is
// assumed that the MM will start paging things out.
int target_free_mb_;
// A delegate that wraps functions used by MemoryMonitorWin. Used as a testing
// seam.
class CONTENT_EXPORT MemoryMonitorWinDelegate {
MemoryMonitorWinDelegate() {}
virtual ~MemoryMonitorWinDelegate() {}
// Returns system memory information.
virtual void GetSystemMemoryInfo(base::SystemMemoryInfoKB* mem_info) = 0;
} // namespace content