xpcom/threads/nsMemoryPressure.h@b8a032363ba2 (annotated)
xpcom/threads/nsMemoryPressure.h
Thu, 22 Jan 2015 13:21:57 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Thu, 22 Jan 2015 13:21:57 +0100
- branch
- TOR_BUG_9701
- changeset 15
- b8a032363ba2
- permissions
- -rw-r--r--
Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6
| michael@0 | 1 | /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ |
| michael@0 | 2 | /* vim:set ts=2 sw=2 sts=2 et cindent: */ |
| michael@0 | 3 | /* This Source Code Form is subject to the terms of the Mozilla Public |
| michael@0 | 4 | * License, v. 2.0. If a copy of the MPL was not distributed with this |
| michael@0 | 5 | * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ |
| michael@0 | 6 | |
| michael@0 | 7 | #ifndef nsMemoryPressure_h__ |
| michael@0 | 8 | #define nsMemoryPressure_h__ |
| michael@0 | 9 | |
| michael@0 | 10 | #include "nscore.h" |
| michael@0 | 11 | |
| michael@0 | 12 | enum MemoryPressureState { |
| michael@0 | 13 | /* |
| michael@0 | 14 | * No memory pressure. |
| michael@0 | 15 | */ |
| michael@0 | 16 | MemPressure_None = 0, |
| michael@0 | 17 | |
| michael@0 | 18 | /* |
| michael@0 | 19 | * New memory pressure deteced. |
| michael@0 | 20 | * |
| michael@0 | 21 | * On a new memory pressure, we stop everything to start cleaning |
| michael@0 | 22 | * aggresively the memory used, in order to free as much memory as |
| michael@0 | 23 | * possible. |
| michael@0 | 24 | */ |
| michael@0 | 25 | MemPressure_New, |
| michael@0 | 26 | |
| michael@0 | 27 | /* |
| michael@0 | 28 | * Repeated memory pressure. |
| michael@0 | 29 | * |
| michael@0 | 30 | * A repeated memory pressure implies to clean softly recent allocations. |
| michael@0 | 31 | * It is supposed to happen after a new memory pressure which already |
| michael@0 | 32 | * cleaned aggressivley. So there is no need to damage the reactivity of |
| michael@0 | 33 | * Gecko by stopping the world again. |
| michael@0 | 34 | * |
| michael@0 | 35 | * In case of conflict with an new memory pressue, the new memory pressure |
| michael@0 | 36 | * takes precedence over an ongoing memory pressure. The reason being |
| michael@0 | 37 | * that if no events are processed between 2 notifications (new followed |
| michael@0 | 38 | * by ongoing, or ongoing followed by a new) we want to be as aggresive as |
| michael@0 | 39 | * possible on the clean-up of the memory. After all, we are trying to |
| michael@0 | 40 | * keep Gecko alive as long as possible. |
| michael@0 | 41 | */ |
| michael@0 | 42 | MemPressure_Ongoing |
| michael@0 | 43 | }; |
| michael@0 | 44 | |
| michael@0 | 45 | /** |
| michael@0 | 46 | * Return and erase the latest state of the memory pressure event set by any of |
| michael@0 | 47 | * the corresponding dispatch function. |
| michael@0 | 48 | */ |
| michael@0 | 49 | MemoryPressureState |
| michael@0 | 50 | NS_GetPendingMemoryPressure(); |
| michael@0 | 51 | |
| michael@0 | 52 | /** |
| michael@0 | 53 | * This function causes the main thread to fire a memory pressure event |
| michael@0 | 54 | * before processing the next event, but if there are no events pending in |
| michael@0 | 55 | * the main thread's event queue, the memory pressure event would not be |
| michael@0 | 56 | * dispatched until one is enqueued. It is infallible and does not allocate |
| michael@0 | 57 | * any memory. |
| michael@0 | 58 | * |
| michael@0 | 59 | * You may call this function from any thread. |
| michael@0 | 60 | */ |
| michael@0 | 61 | void |
| michael@0 | 62 | NS_DispatchEventualMemoryPressure(MemoryPressureState state); |
| michael@0 | 63 | |
| michael@0 | 64 | /** |
| michael@0 | 65 | * This function causes the main thread to fire a memory pressure event |
| michael@0 | 66 | * before processing the next event. We wake up the main thread by adding a |
| michael@0 | 67 | * dummy event to its event loop, so, unlike with |
| michael@0 | 68 | * NS_DispatchEventualMemoryPressure, this memory-pressure event is always |
| michael@0 | 69 | * fired relatively quickly, even if the event loop is otherwise empty. |
| michael@0 | 70 | * |
| michael@0 | 71 | * You may call this function from any thread. |
| michael@0 | 72 | */ |
| michael@0 | 73 | nsresult |
| michael@0 | 74 | NS_DispatchMemoryPressure(MemoryPressureState state); |
| michael@0 | 75 | |
| michael@0 | 76 | #endif // nsMemoryPressure_h__ |
