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authorMatt A. Tobin <mattatobin@localhost.localdomain>2018-02-02 04:16:08 -0500
committerMatt A. Tobin <mattatobin@localhost.localdomain>2018-02-02 04:16:08 -0500
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tree10027f336435511475e392454359edea8e25895d /xpcom/threads/nsMemoryPressure.h
parent49ee0794b5d912db1f95dce6eb52d781dc210db5 (diff)
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Add m-esr52 at 52.6.0
Diffstat (limited to 'xpcom/threads/nsMemoryPressure.h')
-rw-r--r--xpcom/threads/nsMemoryPressure.h77
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diff --git a/xpcom/threads/nsMemoryPressure.h b/xpcom/threads/nsMemoryPressure.h
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+/* -*- 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"
+
+enum MemoryPressureState
+{
+ /*
+ * No memory pressure.
+ */
+ MemPressure_None = 0,
+
+ /*
+ * 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.
+ */
+ MemPressure_New,
+
+ /*
+ * 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.
+ */
+ MemPressure_Ongoing
+};
+
+/**
+ * Return and erase the latest state of the memory pressure event set by any of
+ * the corresponding dispatch function.
+ */
+MemoryPressureState
+NS_GetPendingMemoryPressure();
+
+/**
+ * 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_DispatchEventualMemoryPressure(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_DispatchEventualMemoryPressure, 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_DispatchMemoryPressure(MemoryPressureState aState);
+
+#endif // nsMemoryPressure_h__