54 lines
1.6 KiB
C++
54 lines
1.6 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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#include "nsMemoryPressure.h"
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#include "mozilla/Assertions.h"
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#include "mozilla/Atomics.h"
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#include "nsThreadUtils.h"
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using namespace mozilla;
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static Atomic<int32_t, Relaxed> sMemoryPressurePending;
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static_assert(MemPressure_None == 0,
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"Bad static initialization with the default constructor.");
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MemoryPressureState
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NS_GetPendingMemoryPressure()
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{
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int32_t value = sMemoryPressurePending.exchange(MemPressure_None);
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return MemoryPressureState(value);
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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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/*
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* A new memory pressure event erases an ongoing memory pressure, but an
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* existing "new" memory pressure event takes precedence over a new "ongoing"
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* memory pressure event.
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*/
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switch (aState) {
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case MemPressure_None:
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sMemoryPressurePending = MemPressure_None;
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break;
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case MemPressure_New:
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sMemoryPressurePending = MemPressure_New;
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break;
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case MemPressure_Ongoing:
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sMemoryPressurePending.compareExchange(MemPressure_None,
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MemPressure_Ongoing);
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break;
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}
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}
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nsresult
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NS_DispatchMemoryPressure(MemoryPressureState aState)
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{
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NS_DispatchEventualMemoryPressure(aState);
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nsCOMPtr<nsIRunnable> event = new Runnable;
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return NS_DispatchToMainThread(event);
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}
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