77 lines
2.5 KiB
C
77 lines
2.5 KiB
C
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#ifndef nsMemoryPressure_h__
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#define nsMemoryPressure_h__
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#include "nscore.h"
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enum MemoryPressureState
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{
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/*
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* No memory pressure.
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*/
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MemPressure_None = 0,
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/*
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* New memory pressure deteced.
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*
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* On a new memory pressure, we stop everything to start cleaning
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* aggresively the memory used, in order to free as much memory as
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* possible.
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*/
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MemPressure_New,
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/*
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* Repeated memory pressure.
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*
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* A repeated memory pressure implies to clean softly recent allocations.
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* It is supposed to happen after a new memory pressure which already
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* cleaned aggressivley. So there is no need to damage the reactivity of
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* Gecko by stopping the world again.
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*
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* In case of conflict with an new memory pressue, the new memory pressure
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* takes precedence over an ongoing memory pressure. The reason being
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* that if no events are processed between 2 notifications (new followed
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* by ongoing, or ongoing followed by a new) we want to be as aggresive as
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* possible on the clean-up of the memory. After all, we are trying to
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* keep Gecko alive as long as possible.
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*/
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MemPressure_Ongoing
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};
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/**
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* Return and erase the latest state of the memory pressure event set by any of
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* the corresponding dispatch function.
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*/
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MemoryPressureState
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NS_GetPendingMemoryPressure();
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/**
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* This function causes the main thread to fire a memory pressure event
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* before processing the next event, but if there are no events pending in
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* the main thread's event queue, the memory pressure event would not be
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* dispatched until one is enqueued. It is infallible and does not allocate
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* any memory.
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*
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* You may call this function from any thread.
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*/
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void
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NS_DispatchEventualMemoryPressure(MemoryPressureState aState);
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/**
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* This function causes the main thread to fire a memory pressure event
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* before processing the next event. We wake up the main thread by adding a
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* dummy event to its event loop, so, unlike with
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* NS_DispatchEventualMemoryPressure, this memory-pressure event is always
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* fired relatively quickly, even if the event loop is otherwise empty.
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*
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* You may call this function from any thread.
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*/
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nsresult
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NS_DispatchMemoryPressure(MemoryPressureState aState);
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#endif // nsMemoryPressure_h__
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