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| author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 19:33:14 +0000 |
|---|---|---|
| committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 19:33:14 +0000 |
| commit | 36d22d82aa202bb199967e9512281e9a53db42c9 (patch) | |
| tree | 105e8c98ddea1c1e4784a60a5a6410fa416be2de /xpcom/threads/nsMemoryPressure.h | |
| parent | Initial commit. (diff) | |
| download | firefox-esr-36d22d82aa202bb199967e9512281e9a53db42c9.tar.xz firefox-esr-36d22d82aa202bb199967e9512281e9a53db42c9.zip | |
Adding upstream version 115.7.0esr.upstream/115.7.0esr
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'xpcom/threads/nsMemoryPressure.h')
| -rw-r--r-- | xpcom/threads/nsMemoryPressure.h | 77 |
1 files changed, 77 insertions, 0 deletions
diff --git a/xpcom/threads/nsMemoryPressure.h b/xpcom/threads/nsMemoryPressure.h new file mode 100644 index 0000000000..5a68b0bce5 --- /dev/null +++ b/xpcom/threads/nsMemoryPressure.h @@ -0,0 +1,77 @@ +/* -*- 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__ |