hal/windows/WindowsProcessPriority.cpp

   1 /* This Source Code Form is subject to the terms of the Mozilla Public
   2  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
   3  * You can obtain one at http://mozilla.org/MPL/2.0/. */
   4
   5 #include "Hal.h"
   6 #include "HalLog.h"
   7 #include "nsWindowsHelpers.h"  // for nsAutoHandle and nsModuleHandle
   8 #include "mozilla/StaticPrefs_dom.h"
   9
  10 #include <windows.h>
  11
  12 using namespace mozilla::hal;
  13
  14 namespace mozilla {
  15 namespace hal_impl {
  16
  17 void SetProcessPriority(int aPid, ProcessPriority aPriority) {
  18   HAL_LOG("WindowsProcessPriority - SetProcessPriority(%d, %s)\n", aPid,
  19           ProcessPriorityToString(aPriority));
  20
  21   nsAutoHandle processHandle(
  22       ::OpenProcess(PROCESS_SET_INFORMATION, FALSE, aPid));
  23   if (processHandle) {
  24     DWORD priority = NORMAL_PRIORITY_CLASS;
  25     if (aPriority == PROCESS_PRIORITY_BACKGROUND) {
  26       priority = IDLE_PRIORITY_CLASS;
  27     } else if (aPriority == PROCESS_PRIORITY_BACKGROUND_PERCEIVABLE) {
  28       priority = BELOW_NORMAL_PRIORITY_CLASS;
  29     }
  30
  31     if (::SetPriorityClass(processHandle, priority)) {
  32       HAL_LOG("WindowsProcessPriority - priority set to %d for pid %d\n",
  33               aPriority, aPid);
  34     }
  35
  36     // Set the process into or out of EcoQoS.
  37     static bool alreadyInitialized = false;
  38     static decltype(::SetProcessInformation)* setProcessInformation = nullptr;
  39     if (!alreadyInitialized) {
  40       if (aPriority == PROCESS_PRIORITY_PARENT_PROCESS ||
  41           !StaticPrefs::dom_ipc_processPriorityManager_backgroundUsesEcoQoS()) {
  42         return;
  43       }
  44
  45       alreadyInitialized = true;
  46       // SetProcessInformation only exists on Windows 8 and later.
  47       nsModuleHandle module(LoadLibrary(L"Kernel32.dll"));
  48       if (module) {
  49         setProcessInformation =
  50             (decltype(::SetProcessInformation)*)GetProcAddress(
  51                 module, "SetProcessInformation");
  52       }
  53     }
  54     if (!setProcessInformation) {
  55       return;
  56     }
  57
  58     PROCESS_POWER_THROTTLING_STATE PowerThrottling;
  59     RtlZeroMemory(&PowerThrottling, sizeof(PowerThrottling));
  60     PowerThrottling.Version = PROCESS_POWER_THROTTLING_CURRENT_VERSION;
  61     PowerThrottling.ControlMask = PROCESS_POWER_THROTTLING_EXECUTION_SPEED;
  62     PowerThrottling.StateMask =
  63         (aPriority == PROCESS_PRIORITY_BACKGROUND) &&
  64                 StaticPrefs::
  65                     dom_ipc_processPriorityManager_backgroundUsesEcoQoS()
  66             ? PROCESS_POWER_THROTTLING_EXECUTION_SPEED
  67             : 0;
  68     if (setProcessInformation(processHandle, ProcessPowerThrottling,
  69                               &PowerThrottling, sizeof(PowerThrottling))) {
  70       HAL_LOG("SetProcessInformation(%d, %s)\n", aPid,
  71               aPriority == PROCESS_PRIORITY_BACKGROUND ? "eco" : "normal");
  72     } else {
  73       HAL_LOG("SetProcessInformation failed for %d\n", aPid);
  74     }
  75   }
  76 }
  77
  78 }  // namespace hal_impl
  79 }  // namespace mozilla