92 lines
2.2 KiB
Go
92 lines
2.2 KiB
Go
/*
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Copyright 2015 The Kubernetes Authors All rights reserved.
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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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http://www.apache.org/licenses/LICENSE-2.0
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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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*/
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package util
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import (
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"os"
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"sync"
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"time"
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"github.com/golang/glog"
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)
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type Lockable interface {
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Lock()
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Unlock()
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}
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type rwMutexToLockableAdapter struct {
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rw *sync.RWMutex
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}
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func (r *rwMutexToLockableAdapter) Lock() {
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r.rw.RLock()
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}
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func (r *rwMutexToLockableAdapter) Unlock() {
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r.rw.RUnlock()
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}
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type deadlockDetector struct {
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name string
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lock Lockable
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maxLockPeriod time.Duration
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clock Clock
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}
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// DeadlockWatchdogReadLock creates a watchdog on read/write mutex. If the mutex can not be acquired
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// for read access within 'maxLockPeriod', the program exits via glog.Exitf() or os.Exit() if that fails
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// 'name' is a semantic name that is useful for the user and is printed on exit.
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func DeadlockWatchdogReadLock(lock *sync.RWMutex, name string, maxLockPeriod time.Duration) {
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DeadlockWatchdog(&rwMutexToLockableAdapter{lock}, name, maxLockPeriod)
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}
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func DeadlockWatchdog(lock Lockable, name string, maxLockPeriod time.Duration) {
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detector := &deadlockDetector{
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lock: lock,
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name: name,
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clock: RealClock{},
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}
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go detector.run()
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}
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func (d *deadlockDetector) run() {
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for {
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ch := make(chan bool, 1)
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go func() {
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d.lock.Lock()
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d.lock.Unlock()
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ch <- true
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}()
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select {
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case <-time.After(d.maxLockPeriod):
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go func() {
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defer func() {
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// Let's just be extra sure we die, even if Exitf panics
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glog.Errorf("Failed to Exitf for %s, dying anyway", d.name)
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os.Exit(2)
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}()
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glog.Exitf("Deadlock on %s, exiting", d.name)
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}()
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case <-ch:
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glog.V(6).Infof("%s is not deadlocked", d.name)
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}
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time.Sleep(d.maxLockPeriod / 2)
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}
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}
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