From 5f8de423f190bbb79a62f804151bc24824fa32d8 Mon Sep 17 00:00:00 2001 From: "Matt A. Tobin" Date: Fri, 2 Feb 2018 04:16:08 -0500 Subject: Add m-esr52 at 52.6.0 --- dom/ipc/ProcessPriorityManager.h | 84 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 84 insertions(+) create mode 100644 dom/ipc/ProcessPriorityManager.h (limited to 'dom/ipc/ProcessPriorityManager.h') diff --git a/dom/ipc/ProcessPriorityManager.h b/dom/ipc/ProcessPriorityManager.h new file mode 100644 index 000000000..5e02c9c32 --- /dev/null +++ b/dom/ipc/ProcessPriorityManager.h @@ -0,0 +1,84 @@ +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ +/* vim: set ts=8 sts=2 et sw=2 tw=80: */ +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this file, + * You can obtain one at http://mozilla.org/MPL/2.0/. */ + +#ifndef mozilla_ProcessPriorityManager_h_ +#define mozilla_ProcessPriorityManager_h_ + +#include "mozilla/HalTypes.h" + +namespace mozilla { +namespace dom { +class ContentParent; +} // namespace dom + +/** + * This class sets the priority of subprocesses in response to explicit + * requests and events in the system. + * + * A process's priority changes e.g. when it goes into the background via + * mozbrowser's setVisible(false). Process priority affects CPU scheduling and + * also which processes get killed when we run out of memory. + * + * After you call Initialize(), the only thing you probably have to do is call + * SetProcessPriority on processes immediately after creating them in order to + * set their initial priority. The ProcessPriorityManager takes care of the + * rest. + */ +class ProcessPriorityManager final +{ +public: + /** + * Initialize the ProcessPriorityManager machinery, causing the + * ProcessPriorityManager to actively manage the priorities of all + * subprocesses. You should call this before creating any subprocesses. + * + * You should also call this function even if you're in a child process, + * since it will initialize ProcessPriorityManagerChild. + */ + static void Init(); + + /** + * Set the process priority of a given ContentParent's process. + * + * Note that because this method takes a ContentParent*, you can only set the + * priority of your subprocesses. In fact, because we don't support nested + * content processes (bug 761935), you can only call this method from the + * main process. + * + * It probably only makes sense to call this function immediately after a + * process is created. At this point, the process priority manager doesn't + * have enough context about the processs to know what its priority should + * be. + * + * Eventually whatever priority you set here can and probably will be + * overwritten by the process priority manager. + */ + static void SetProcessPriority(dom::ContentParent* aContentParent, + hal::ProcessPriority aPriority); + + /** + * Returns true iff this process's priority is FOREGROUND*. + * + * Note that because process priorities are set in the main process, it's + * possible for this method to return a stale value. So be careful about + * what you use this for. + */ + static bool CurrentProcessIsForeground(); + + /** + * Returns true if one or more processes with FOREGROUND_HIGH priority are + * present, false otherwise. + */ + static bool AnyProcessHasHighPriority(); + +private: + ProcessPriorityManager(); + DISALLOW_EVIL_CONSTRUCTORS(ProcessPriorityManager); +}; + +} // namespace mozilla + +#endif -- cgit v1.2.3