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