예제 #1
0
파일: rwmutex.go 프로젝트: yhtsnda/go
// Unlock 为 rw 的写入将其解锁。
// 若 rw 并没有为写入而锁定,调用 Unlock 就会引发一个运行时错误。
//
// As with Mutexes, a locked RWMutex is not associated with a particular
// goroutine.  One goroutine may RLock (Lock) an RWMutex and then
// arrange for another goroutine to RUnlock (Unlock) it.
// 正如 Mutex 一样,已锁定的 RWMutex 并不与特定的Go程相关联。一个Go程可
// RLock(Lock)一个 RWMutex,然后安排其它Go程来 RUnlock(Unlock)它。
func (rw *RWMutex) Unlock() {
	if race.Enabled {
		_ = rw.w.state
		race.Release(unsafe.Pointer(&rw.readerSem))
		race.Release(unsafe.Pointer(&rw.writerSem))
		race.Disable()
	}

	// Announce to readers there is no active writer.
	// 通知读取器现在没有活动的写入器。
	r := atomic.AddInt32(&rw.readerCount, rwmutexMaxReaders)
	if r >= rwmutexMaxReaders {
		race.Enable()
		panic("sync: Unlock of unlocked RWMutex")
	}
	// Unblock blocked readers, if any.
	// 若有,就 Unblock 已锁定的读取器。
	for i := 0; i < int(r); i++ {
		runtime_Semrelease(&rw.readerSem)
	}
	// Allow other writers to proceed.
	// 允许其它写入器继续。
	rw.w.Unlock()
	if race.Enabled {
		race.Enable()
	}
}
예제 #2
0
파일: mutex.go 프로젝트: RajibTheKing/gcc
// Unlock unlocks m.
// It is a run-time error if m is not locked on entry to Unlock.
//
// A locked Mutex is not associated with a particular goroutine.
// It is allowed for one goroutine to lock a Mutex and then
// arrange for another goroutine to unlock it.
func (m *Mutex) Unlock() {
	if race.Enabled {
		_ = m.state
		race.Release(unsafe.Pointer(m))
	}

	// Fast path: drop lock bit.
	new := atomic.AddInt32(&m.state, -mutexLocked)
	if (new+mutexLocked)&mutexLocked == 0 {
		panic("sync: unlock of unlocked mutex")
	}

	old := new
	for {
		// If there are no waiters or a goroutine has already
		// been woken or grabbed the lock, no need to wake anyone.
		if old>>mutexWaiterShift == 0 || old&(mutexLocked|mutexWoken) != 0 {
			return
		}
		// Grab the right to wake someone.
		new = (old - 1<<mutexWaiterShift) | mutexWoken
		if atomic.CompareAndSwapInt32(&m.state, old, new) {
			runtime_Semrelease(&m.sema)
			return
		}
		old = m.state
	}
}
예제 #3
0
파일: rwmutex.go 프로젝트: achanda/go
// Unlock unlocks rw for writing. It is a run-time error if rw is
// not locked for writing on entry to Unlock.
//
// As with Mutexes, a locked RWMutex is not associated with a particular
// goroutine. One goroutine may RLock (Lock) an RWMutex and then
// arrange for another goroutine to RUnlock (Unlock) it.
func (rw *RWMutex) Unlock() {
	if race.Enabled {
		_ = rw.w.state
		race.Release(unsafe.Pointer(&rw.readerSem))
		race.Release(unsafe.Pointer(&rw.writerSem))
		race.Disable()
	}

	// Announce to readers there is no active writer.
	r := atomic.AddInt32(&rw.readerCount, rwmutexMaxReaders)
	if r >= rwmutexMaxReaders {
		race.Enable()
		throw("sync: Unlock of unlocked RWMutex")
	}
	// Unblock blocked readers, if any.
	for i := 0; i < int(r); i++ {
		runtime_Semrelease(&rw.readerSem)
	}
	// Allow other writers to proceed.
	rw.w.Unlock()
	if race.Enabled {
		race.Enable()
	}
}