mirror of
https://github.com/mozilla/gecko-dev.git
synced 2024-12-03 02:25:34 +00:00
b3df452cb8
We had `NS_DispatchMemoryPressure` and `NS_DispatchEventualMemoryPressure` to dispatch a memory-pressure event which took `MemPressure_New` and `MemPressure_Ongoing` to translate into "low-memory" and "low-memory-ongoing" message respectively. With that model, we could end up sending a wrong message if somebody called the API with `MemPressure_Ongoing` without sending `MemPressure_New`. To avoid that, this patch removes `MemPressure_Ongoing` and makes the API decide whether it should dispatch a "new" event or "ongoing" event. Differential Revision: https://phabricator.services.mozilla.com/D119122
78 lines
3.2 KiB
C
78 lines
3.2 KiB
C
/* -*- 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 nsMemoryPressure_h__
|
|
#define nsMemoryPressure_h__
|
|
|
|
#include "nscore.h"
|
|
|
|
/*
|
|
* These pre-defined strings are the topic to pass to the observer
|
|
* service to declare the memory-pressure or lift the memory-pressure.
|
|
*
|
|
* 1. Notify kTopicMemoryPressure with kSubTopicLowMemoryNew
|
|
* New memory pressure deteced
|
|
* On a new memory pressure, we stop everything to start cleaning
|
|
* aggresively the memory used, in order to free as much memory as
|
|
* possible.
|
|
*
|
|
* 2. Notify kTopicMemoryPressure with kSubTopicLowMemoryOngoing
|
|
* Repeated memory pressure.
|
|
* A repeated memory pressure implies to clean softly recent allocations.
|
|
* It is supposed to happen after a new memory pressure which already
|
|
* cleaned aggressivley. So there is no need to damage the reactivity of
|
|
* Gecko by stopping the world again.
|
|
*
|
|
* In case of conflict with an new memory pressue, the new memory pressure
|
|
* takes precedence over an ongoing memory pressure. The reason being
|
|
* that if no events are processed between 2 notifications (new followed
|
|
* by ongoing, or ongoing followed by a new) we want to be as aggresive as
|
|
* possible on the clean-up of the memory. After all, we are trying to
|
|
* keep Gecko alive as long as possible.
|
|
*
|
|
* 3. Notify kTopicMemoryPressureStop with nullptr
|
|
* Memory pressure stopped.
|
|
* We're no longer under acute memory pressure, so we might want to have a
|
|
* chance of (cautiously) re-enabling some things we previously turned off.
|
|
* As above, an already enqueued new memory pressure event takes precedence.
|
|
* The priority ordering between concurrent attempts to queue both stopped
|
|
* and ongoing memory pressure is currently not defined.
|
|
*/
|
|
extern const char* const kTopicMemoryPressure;
|
|
extern const char* const kTopicMemoryPressureStop;
|
|
extern const char16_t* const kSubTopicLowMemoryNew;
|
|
extern const char16_t* const kSubTopicLowMemoryOngoing;
|
|
|
|
enum class MemoryPressureState : uint32_t {
|
|
None, // For internal use. Don't use this value.
|
|
LowMemory,
|
|
NoPressure,
|
|
};
|
|
|
|
/**
|
|
* This function causes the main thread to fire a memory pressure event
|
|
* before processing the next event, but if there are no events pending in
|
|
* the main thread's event queue, the memory pressure event would not be
|
|
* dispatched until one is enqueued. It is infallible and does not allocate
|
|
* any memory.
|
|
*
|
|
* You may call this function from any thread.
|
|
*/
|
|
void NS_NotifyOfEventualMemoryPressure(MemoryPressureState aState);
|
|
|
|
/**
|
|
* This function causes the main thread to fire a memory pressure event
|
|
* before processing the next event. We wake up the main thread by adding a
|
|
* dummy event to its event loop, so, unlike with
|
|
* NS_NotifyOfEventualMemoryPressure, this memory-pressure event is always
|
|
* fired relatively quickly, even if the event loop is otherwise empty.
|
|
*
|
|
* You may call this function from any thread.
|
|
*/
|
|
nsresult NS_NotifyOfMemoryPressure(MemoryPressureState aState);
|
|
|
|
#endif // nsMemoryPressure_h__
|