Golang race.ReleaseMerge函数代码示例

// Put adds x to the pool.
func (p *Pool) Put(x interface{}) {
	if x == nil {
		return
	}
	if race.Enabled {
		if fastrand()%4 == 0 {
			// Randomly drop x on floor.
			return
		}
		race.ReleaseMerge(poolRaceAddr(x))
		race.Disable()
	}
	l := p.pin()
	if l.private == nil {
		l.private = x
		x = nil
	}
	runtime_procUnpin()
	if x != nil {
		l.Lock()
		l.shared = append(l.shared, x)
		l.Unlock()
	}
	if race.Enabled {
		race.Enable()
	}
}

func Write(fd int, p []byte) (n int, err error) {
	if race.Enabled {
		race.ReleaseMerge(unsafe.Pointer(&ioSync))
	}
	n, err = write(fd, p)
	if race.Enabled && n > 0 {
		race.ReadRange(unsafe.Pointer(&p[0]), n)
	}
	if msanenabled && n > 0 {
		msanRead(unsafe.Pointer(&p[0]), n)
	}
	return
}

//sys	sendfile(outfd int, infd int, offset *Offset_t, count int) (written int, err error)
//sendfile64(outfd _C_int, infd _C_int, offset *Offset_t, count Size_t) Ssize_t
func Sendfile(outfd int, infd int, offset *int64, count int) (written int, err error) {
	if race.Enabled {
		race.ReleaseMerge(unsafe.Pointer(&ioSync))
	}
	var soff Offset_t
	var psoff *Offset_t
	if offset != nil {
		soff = Offset_t(*offset)
		psoff = &soff
	}
	written, err = sendfile(outfd, infd, psoff, count)
	if offset != nil {
		*offset = int64(soff)
	}
	return
}

func Write(fd Handle, p []byte) (n int, err error) {
	if race.Enabled {
		race.ReleaseMerge(unsafe.Pointer(&ioSync))
	}
	var done uint32
	e := WriteFile(fd, p, &done, nil)
	if e != nil {
		return 0, e
	}
	if race.Enabled && done > 0 {
		race.ReadRange(unsafe.Pointer(&p[0]), int(done))
	}
	if msanenabled && done > 0 {
		msanRead(unsafe.Pointer(&p[0]), int(done))
	}
	return int(done), nil
}

// Add 添加 delta，对于 WaitGroup 的 counter 来说，它可能为负数。
// 若 counter 变为零，在 Wait() 被释放后所有Go程就会阻塞。
// 若 counter 变为负数，Add 就会引发Panic。
//
// 注意，当 counter 为零时，用正整数的 delta 调用它必须发生在调用 Wait 之前。
// 用负整数的 delta 调用它，或在 counter 大于零时开始用正整数的 delta 调用它，
// 那么它可以在任何时候发生。
// 一般来说，这意味着对 Add 的调用应当在该语句创建Go程，或等待其它事件之前执行。
// 具体见 WaitGroup 的示例。
func (wg *WaitGroup) Add(delta int) {
	statep := wg.state()
	if race.Enabled {
		_ = *statep // trigger nil deref early
		if delta < 0 {
			// Synchronize decrements with Wait.
			race.ReleaseMerge(unsafe.Pointer(wg))
		}
		race.Disable()
		defer race.Enable()
	}
	state := atomic.AddUint64(statep, uint64(delta)<<32)
	v := int32(state >> 32)
	w := uint32(state)
	if race.Enabled {
		if delta > 0 && v == int32(delta) {
			// The first increment must be synchronized with Wait.
			// Need to model this as a read, because there can be
			// several concurrent wg.counter transitions from 0.
			race.Read(unsafe.Pointer(&wg.sema))
		}
	}
	if v < 0 {
		panic("sync: negative WaitGroup counter")
	}
	if w != 0 && delta > 0 && v == int32(delta) {
		panic("sync: WaitGroup misuse: Add called concurrently with Wait")
	}
	if v > 0 || w == 0 {
		return
	}
	// This goroutine has set counter to 0 when waiters > 0.
	// Now there can't be concurrent mutations of state:
	// - Adds must not happen concurrently with Wait,
	// - Wait does not increment waiters if it sees counter == 0.
	// Still do a cheap sanity check to detect WaitGroup misuse.
	if *statep != state {
		panic("sync: WaitGroup misuse: Add called concurrently with Wait")
	}
	// Reset waiters count to 0.
	*statep = 0
	for ; w != 0; w-- {
		runtime_Semrelease(&wg.sema)
	}
}

func (fd *netFD) Write(buf []byte) (int, error) {
	if err := fd.writeLock(); err != nil {
		return 0, err
	}
	defer fd.writeUnlock()
	if race.Enabled {
		race.ReleaseMerge(unsafe.Pointer(&ioSync))
	}
	o := &fd.wop
	o.InitBuf(buf)
	n, err := wsrv.ExecIO(o, "WSASend", func(o *operation) error {
		return syscall.WSASend(o.fd.sysfd, &o.buf, 1, &o.qty, 0, &o.o, nil)
	})
	if _, ok := err.(syscall.Errno); ok {
		err = os.NewSyscallError("wsasend", err)
	}
	return n, err
}

// RUnlock undoes a single RLock call;
// it does not affect other simultaneous readers.
// It is a run-time error if rw is not locked for reading
// on entry to RUnlock.
func (rw *RWMutex) RUnlock() {
	if race.Enabled {
		_ = rw.w.state
		race.ReleaseMerge(unsafe.Pointer(&rw.writerSem))
		race.Disable()
	}
	if r := atomic.AddInt32(&rw.readerCount, -1); r < 0 {
		if r+1 == 0 || r+1 == -rwmutexMaxReaders {
			race.Enable()
			panic("sync: RUnlock of unlocked RWMutex")
		}
		// A writer is pending.
		if atomic.AddInt32(&rw.readerWait, -1) == 0 {
			// The last reader unblocks the writer.
			runtime_Semrelease(&rw.writerSem)
		}
	}
	if race.Enabled {
		race.Enable()
	}
}

func (fd *netFD) writeBuffers(buf *Buffers) (int64, error) {
	if len(*buf) == 0 {
		return 0, nil
	}
	if err := fd.writeLock(); err != nil {
		return 0, err
	}
	defer fd.writeUnlock()
	if race.Enabled {
		race.ReleaseMerge(unsafe.Pointer(&ioSync))
	}
	o := &fd.wop
	o.InitBufs(buf)
	n, err := wsrv.ExecIO(o, "WSASend", func(o *operation) error {
		return syscall.WSASend(o.fd.sysfd, &o.bufs[0], uint32(len(*buf)), &o.qty, 0, &o.o, nil)
	})
	o.ClearBufs()
	if _, ok := err.(syscall.Errno); ok {
		err = os.NewSyscallError("wsasend", err)
	}
	testHookDidWritev(n)
	buf.consume(int64(n))
	return int64(n), err
}

func Sendfile(outfd int, infd int, offset *int64, count int) (written int, err error) {
	if race.Enabled {
		race.ReleaseMerge(unsafe.Pointer(&ioSync))
	}
	return sendfile(outfd, infd, offset, count)
}