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// Copyright 2013 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
//go:build plan9
package runtime
import "runtime/internal/atomic"
var netpollInited uint32
var netpollWaiters uint32
var netpollStubLock mutex
var netpollNote note
// netpollBroken, protected by netpollBrokenLock, avoids a double notewakeup.
var netpollBrokenLock mutex
var netpollBroken bool
func netpollGenericInit() {
atomic.Store(&netpollInited, 1)
}
func netpollBreak() {
lock(&netpollBrokenLock)
broken := netpollBroken
netpollBroken = true
if !broken {
notewakeup(&netpollNote)
}
unlock(&netpollBrokenLock)
}
// Polls for ready network connections.
// Returns list of goroutines that become runnable.
func netpoll(delay int64) gList {
// Implementation for platforms that do not support
// integrated network poller.
if delay != 0 {
// This lock ensures that only one goroutine tries to use
// the note. It should normally be completely uncontended.
lock(&netpollStubLock)
lock(&netpollBrokenLock)
noteclear(&netpollNote)
netpollBroken = false
unlock(&netpollBrokenLock)
notetsleep(&netpollNote, delay)
unlock(&netpollStubLock)
// Guard against starvation in case the lock is contended
// (eg when running TestNetpollBreak).
osyield()
}
return gList{}
}
func netpollinited() bool {
return atomic.Load(&netpollInited) != 0
}
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