33 lines
879 B
Go
33 lines
879 B
Go
// Copyright 2017 The Netstack Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// +build !race
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// +build !amd64
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package sleep
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import "sync/atomic"
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// commitSleep signals to wakers that the given g is now sleeping. Wakers can
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// then fetch it and wake it.
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//
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// The commit may fail if wakers have been asserted after our last check, in
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// which case they will have set s.waitingG to zero.
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//
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// It is written in assembly because it is called from g0, so it doesn't have
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// a race context.
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func commitSleep(g uintptr, waitingG *uintptr) bool {
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for {
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// Check if the wait was aborted.
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if atomic.LoadUintptr(waitingG) == 0 {
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return false
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}
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// Try to store the G so that wakers know who to wake.
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if atomic.CompareAndSwapUintptr(waitingG, preparingG, g) {
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return true
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}
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}
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}
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