| // Copyright 2018 The gVisor Authors. |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| // +build !race |
| // +build !amd64,!arm64 |
| |
| package sleep |
| |
| import "sync/atomic" |
| |
| // commitSleep signals to wakers that the given g is now sleeping. Wakers can |
| // then fetch it and wake it. |
| // |
| // The commit may fail if wakers have been asserted after our last check, in |
| // which case they will have set s.waitingG to zero. |
| // |
| // It is written in assembly because it is called from g0, so it doesn't have |
| // a race context. |
| func commitSleep(g uintptr, waitingG *uintptr) bool { |
| for { |
| // Check if the wait was aborted. |
| if atomic.LoadUintptr(waitingG) == 0 { |
| return false |
| } |
| |
| // Try to store the G so that wakers know who to wake. |
| if atomic.CompareAndSwapUintptr(waitingG, preparingG, g) { |
| return true |
| } |
| } |
| } |