X works with go -race under wrk load

blob.go

@@ -36,6 +36,9 @@ type AuthCacheEntry struct {
 	// FIXME we need to lock the entry only to "correctly" update Nhit on
 	// read side but we can tolerate some looses in Nhit and update it
 	// without mutex or atomic. Only -race complains...
+	// (we could use atomic.Value for atomic cache entry updates from
+	//  refresher withot need for locks on readers side, but the need to do
+	//  .Nhit++ on readers side ruins that)
 	sync.Mutex
 
 	AuthReply
@@ -55,10 +58,12 @@ type AuthCache struct {
 	cached	map[string]*AuthCacheEntry
 }
 
-var authCache = AuthCache{}	// XXX make map ?
+var authCache = AuthCache{cached: make(map[string]*AuthCacheEntry)}
 
 // XXX u should not be in args?
 func (c *AuthCache) VerifyDownloadAccess(u *upstream, project string) AuthReply {
+	var authReply AuthReply
+
 	// first try to read from cache in parallel with other readers
 	c.mu.RLock()
 	auth := c.cached[project]
@@ -67,7 +72,6 @@ func (c *AuthCache) VerifyDownloadAccess(u *upstream, project string) AuthReply
 have_entry:
 	// entry in cache - use it
 	if auth != nil {
-//have_entry:
 		<-auth.ready // make sure it is ready
 
 		auth.Lock()
@@ -76,6 +80,7 @@ have_entry:
 		//	project,
 		//	time.Since(time.Unix(auth.Tauth, 0)),
 		//	auth.Nhit)
+		authReply = auth.AuthReply
 		auth.Unlock()
 
 	// no entry - relock the cache in exclusive mode, create empty entry,
@@ -100,6 +105,8 @@ have_entry:
 		auth.Tauth = time.Now().Unix()
 		auth.Nhit = 0
 
+		authReply = auth.AuthReply
+
 		// broadcast to other goroutines this entry is ready
 		close(auth.ready)
 
@@ -107,12 +114,12 @@ have_entry:
 		go c.refreshEntry(auth, u, project)
 	}
 
-	return auth.AuthReply
+	return authReply
 }
 
 
 // Time period for refreshing / removing unused entires in authCache
-const authCacheRefresh = 10 * time.Second	// XXX 30
+const authCacheRefresh = 5 * time.Second	// XXX 30
 
 // Goroutine to refresh auth cache entry periodically while it is used.
 // if the entry is detected to be not used - remove it from cache and stop refreshing.