chrome/browser/performance_manager/mechanisms/userspace_swap_chromeos.h

// Copyright 2020 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 CHROME_BROWSER_PERFORMANCE_MANAGER_MECHANISMS_USERSPACE_SWAP_CHROMEOS_H_
#define CHROME_BROWSER_PERFORMANCE_MANAGER_MECHANISMS_USERSPACE_SWAP_CHROMEOS_H_

#include "base/macros.h"
#include "chromeos/memory/userspace_swap/userspace_swap.mojom.h"
#include "mojo/public/cpp/bindings/pending_receiver.h"

namespace performance_manager {

class ProcessNode;

namespace mechanism {
namespace userspace_swap {

// NOTE: All of the following methods MUST be called from the PM sequence.

// The policy must query the mechanism IsEligibleToSwap because the mechanism
// knows things that the policy doesn't related to the swap file and
// userfaultfd, this method will return false if an unexpected event that
// prevents swapping occurred.
bool IsEligibleToSwap(const ProcessNode* process_node);

// Swap a |process_node|.
void SwapProcessNode(const ProcessNode* process_node);

// Returns the number of bytes available on the device which is backing the swap
// files.
uint64_t GetSwapDeviceFreeSpaceBytes();

// Returns the number of bytes currently in use by the swap file for
// |process_node|.
uint64_t GetProcessNodeSwapFileUsageBytes(const ProcessNode* process_node);

// Returns the number of bytes that this process node has had reclaimed. Reclaim
// refers to physical memory which were swapped.
uint64_t GetProcessNodeReclaimedBytes(const ProcessNode* process_node);

// Returns the total number of bytes currently in use across all swap files.
uint64_t GetTotalSwapFileUsageBytes();

// Returns the total number of bytes which have been reclaimed.
uint64_t GetTotalReclaimedBytes();

class UserspaceSwapInitializationImpl
    : public ::userspace_swap::mojom::UserspaceSwapInitialization {
 public:
  explicit UserspaceSwapInitializationImpl(int render_process_host_id);
  ~UserspaceSwapInitializationImpl() override;

  static bool UserspaceSwapSupportedAndEnabled();
  static void Create(
      int render_process_host_id,
      mojo::PendingReceiver<
          ::userspace_swap::mojom::UserspaceSwapInitialization> receiver);

  // UserspaceSwapInitialization impl:
  void TransferUserfaultFD(uint64_t error,
                           mojo::PlatformHandle uffd_handle,
                           TransferUserfaultFDCallback cb) override;

 private:
  int render_process_host_id_ = 0;
  bool received_transfer_cb_ = false;

  DISALLOW_COPY_AND_ASSIGN(UserspaceSwapInitializationImpl);
};

}  // namespace userspace_swap
}  // namespace mechanism
}  // namespace performance_manager

#endif  // CHROME_BROWSER_PERFORMANCE_MANAGER_MECHANISMS_USERSPACE_SWAP_CHROMEOS_H_