Merge pull request #1405 from fishy/atomic-value-last-dial-error

Use atomic.Value instead of lock for ConnPool.lastDialError

internal/pool/pool.go

@@ -62,13 +62,16 @@ type Options struct {
 	IdleCheckFrequency time.Duration
 }
 
+type lastDialErrorWrap struct {
+	err error
+}
+
 type ConnPool struct {
 	opt *Options
 
 	dialErrorsNum uint32 // atomic
 
-	lastDialErrorMu sync.RWMutex
-	lastDialError   error
+	lastDialError atomic.Value
 
 	queue chan struct{}
 
@@ -207,16 +210,15 @@ func (p *ConnPool) tryDial() {
 }
 
 func (p *ConnPool) setLastDialError(err error) {
-	p.lastDialErrorMu.Lock()
-	p.lastDialError = err
-	p.lastDialErrorMu.Unlock()
+	p.lastDialError.Store(&lastDialErrorWrap{err: err})
 }
 
 func (p *ConnPool) getLastDialError() error {
-	p.lastDialErrorMu.RLock()
-	err := p.lastDialError
-	p.lastDialErrorMu.RUnlock()
-	return err
+	err, _ := p.lastDialError.Load().(*lastDialErrorWrap)
+	if err != nil {
+		return err.err
+	}
+	return nil
 }
 
 // Get returns existed connection from the pool or creates a new one.