2019-04-29 21:25:05 +00:00
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// Copyright 2018 The gVisor Authors.
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2018-07-09 21:03:03 +00:00
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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2018-04-27 17:37:02 +00:00
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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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