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comparison: xpcom/threads/nsMemoryPressure.h
xpcom/threads/nsMemoryPressure.h
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- TOR_BUG_9701
- changeset 15
- b8a032363ba2
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| -1:000000000000 | 0:7cbb09fcd864 |
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| 1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ | |
| 2 /* vim:set ts=2 sw=2 sts=2 et cindent: */ | |
| 3 /* This Source Code Form is subject to the terms of the Mozilla Public | |
| 4 * License, v. 2.0. If a copy of the MPL was not distributed with this | |
| 5 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ | |
| 6 | |
| 7 #ifndef nsMemoryPressure_h__ | |
| 8 #define nsMemoryPressure_h__ | |
| 9 | |
| 10 #include "nscore.h" | |
| 11 | |
| 12 enum MemoryPressureState { | |
| 13 /* | |
| 14 * No memory pressure. | |
| 15 */ | |
| 16 MemPressure_None = 0, | |
| 17 | |
| 18 /* | |
| 19 * New memory pressure deteced. | |
| 20 * | |
| 21 * On a new memory pressure, we stop everything to start cleaning | |
| 22 * aggresively the memory used, in order to free as much memory as | |
| 23 * possible. | |
| 24 */ | |
| 25 MemPressure_New, | |
| 26 | |
| 27 /* | |
| 28 * Repeated memory pressure. | |
| 29 * | |
| 30 * A repeated memory pressure implies to clean softly recent allocations. | |
| 31 * It is supposed to happen after a new memory pressure which already | |
| 32 * cleaned aggressivley. So there is no need to damage the reactivity of | |
| 33 * Gecko by stopping the world again. | |
| 34 * | |
| 35 * In case of conflict with an new memory pressue, the new memory pressure | |
| 36 * takes precedence over an ongoing memory pressure. The reason being | |
| 37 * that if no events are processed between 2 notifications (new followed | |
| 38 * by ongoing, or ongoing followed by a new) we want to be as aggresive as | |
| 39 * possible on the clean-up of the memory. After all, we are trying to | |
| 40 * keep Gecko alive as long as possible. | |
| 41 */ | |
| 42 MemPressure_Ongoing | |
| 43 }; | |
| 44 | |
| 45 /** | |
| 46 * Return and erase the latest state of the memory pressure event set by any of | |
| 47 * the corresponding dispatch function. | |
| 48 */ | |
| 49 MemoryPressureState | |
| 50 NS_GetPendingMemoryPressure(); | |
| 51 | |
| 52 /** | |
| 53 * This function causes the main thread to fire a memory pressure event | |
| 54 * before processing the next event, but if there are no events pending in | |
| 55 * the main thread's event queue, the memory pressure event would not be | |
| 56 * dispatched until one is enqueued. It is infallible and does not allocate | |
| 57 * any memory. | |
| 58 * | |
| 59 * You may call this function from any thread. | |
| 60 */ | |
| 61 void | |
| 62 NS_DispatchEventualMemoryPressure(MemoryPressureState state); | |
| 63 | |
| 64 /** | |
| 65 * This function causes the main thread to fire a memory pressure event | |
| 66 * before processing the next event. We wake up the main thread by adding a | |
| 67 * dummy event to its event loop, so, unlike with | |
| 68 * NS_DispatchEventualMemoryPressure, this memory-pressure event is always | |
| 69 * fired relatively quickly, even if the event loop is otherwise empty. | |
| 70 * | |
| 71 * You may call this function from any thread. | |
| 72 */ | |
| 73 nsresult | |
| 74 NS_DispatchMemoryPressure(MemoryPressureState state); | |
| 75 | |
| 76 #endif // nsMemoryPressure_h__ |
