Improve connectDisks() performance (#9203)

cmd/xl-sets.go

@@ -108,23 +108,52 @@ type xlSets struct {
 	mrfUploads map[string]int
 }
 
-// isConnected - checks if the endpoint is connected or not.
-func (s *xlSets) isConnected(endpointStr string) bool {
+func isEndpointConnected(diskMap map[string]StorageAPI, endpoint string) bool {
+	disk := diskMap[endpoint]
+	if disk == nil {
+		return false
+	}
+	return disk.IsOnline()
+}
+
+func (s *xlSets) getOnlineDisksCount() int {
+	s.xlDisksMu.RLock()
+	defer s.xlDisksMu.RUnlock()
+	count := 0
+	for i := 0; i < s.setCount; i++ {
+		for j := 0; j < s.drivesPerSet; j++ {
+			disk := s.xlDisks[i][j]
+			if disk == nil {
+				continue
+			}
+			if !disk.IsOnline() {
+				continue
+			}
+			count++
+		}
+	}
+	return count
+}
+
+func (s *xlSets) getDiskMap() map[string]StorageAPI {
+	diskMap := make(map[string]StorageAPI)
+
 	s.xlDisksMu.RLock()
 	defer s.xlDisksMu.RUnlock()
 
 	for i := 0; i < s.setCount; i++ {
 		for j := 0; j < s.drivesPerSet; j++ {
-			if s.xlDisks[i][j] == nil {
+			disk := s.xlDisks[i][j]
+			if disk == nil {
 				continue
 			}
-			if s.xlDisks[i][j].String() != endpointStr {
+			if !disk.IsOnline() {
 				continue
 			}
-			return s.xlDisks[i][j].IsOnline()
+			diskMap[disk.String()] = disk
 		}
 	}
-	return false
+	return diskMap
 }
 
 // Initializes a new StorageAPI from the endpoint argument, returns
@@ -172,30 +201,11 @@ func findDiskIndex(refFormat, format *formatXLV3) (int, int, error) {
 // connectDisksWithQuorum is same as connectDisks but waits
 // for quorum number of formatted disks to be online in any given sets.
 func (s *xlSets) connectDisksWithQuorum() {
-	var onlineDisks int
-	for onlineDisks < len(s.endpoints)/2 {
-		for i, endpoint := range s.endpoints {
-			if s.isConnected(s.endpointStrings[i]) {
-				continue
+	for {
+		s.connectDisks()
+		if s.getOnlineDisksCount() > len(s.endpoints)/2 {
+			return
 		}
-			disk, format, err := connectEndpoint(endpoint)
-			if err != nil {
-				printEndpointError(endpoint, err)
-				continue
-			}
-			i, j, err := findDiskIndex(s.format, format)
-			if err != nil {
-				// Close the internal connection to avoid connection leaks.
-				disk.Close()
-				printEndpointError(endpoint, err)
-				continue
-			}
-			disk.SetDiskID(format.XL.This)
-			s.xlDisks[i][j] = disk
-			onlineDisks++
-		}
-		// Sleep for a while - so that we don't go into
-		// 100% CPU when half the disks are online.
 		time.Sleep(100 * time.Millisecond)
 	}
 }
@@ -203,33 +213,41 @@ func (s *xlSets) connectDisksWithQuorum() {
 // connectDisks - attempt to connect all the endpoints, loads format
 // and re-arranges the disks in proper position.
 func (s *xlSets) connectDisks() {
+	var wg sync.WaitGroup
+	diskMap := s.getDiskMap()
 	for i, endpoint := range s.endpoints {
-		if s.isConnected(s.endpointStrings[i]) {
+		if isEndpointConnected(diskMap, s.endpointStrings[i]) {
 			continue
 		}
+		wg.Add(1)
+		go func(endpoint Endpoint) {
+			defer wg.Done()
 			disk, format, err := connectEndpoint(endpoint)
 			if err != nil {
 				printEndpointError(endpoint, err)
-			continue
+				return
 			}
 			setIndex, diskIndex, err := findDiskIndex(s.format, format)
 			if err != nil {
 				// Close the internal connection to avoid connection leaks.
 				disk.Close()
 				printEndpointError(endpoint, err)
-			continue
+				return
 			}
 			disk.SetDiskID(format.XL.This)
 			s.xlDisksMu.Lock()
 			s.xlDisks[setIndex][diskIndex] = disk
 			s.xlDisksMu.Unlock()
-
+			go func(setIndex int) {
 				// Send a new disk connect event with a timeout
 				select {
 				case s.disksConnectEvent <- diskConnectInfo{setIndex: setIndex}:
 				case <-time.After(100 * time.Millisecond):
 				}
+			}(setIndex)
+		}(endpoint)
 	}
+	wg.Wait()
 }
 
 // monitorAndConnectEndpoints this is a monitoring loop to keep track of disconnected
@@ -259,8 +277,8 @@ func (s *xlSets) GetLockers(setIndex int) func() []dsync.NetLocker {
 // GetDisks returns a closure for a given set, which provides list of disks per set.
 func (s *xlSets) GetDisks(setIndex int) func() []StorageAPI {
 	return func() []StorageAPI {
-		s.xlDisksMu.Lock()
-		defer s.xlDisksMu.Unlock()
+		s.xlDisksMu.RLock()
+		defer s.xlDisksMu.RUnlock()
 		disks := make([]StorageAPI, s.drivesPerSet)
 		copy(disks, s.xlDisks[setIndex])
 		return disks
@@ -272,13 +290,14 @@ const defaultMonitorConnectEndpointInterval = time.Second * 10 // Set to 10 secs
 // Initialize new set of erasure coded sets.
 func newXLSets(endpoints Endpoints, format *formatXLV3, setCount int, drivesPerSet int) (*xlSets, error) {
 	endpointStrings := make([]string, len(endpoints))
-	for _, endpoint := range endpoints {
+	for i, endpoint := range endpoints {
 		if endpoint.IsLocal {
-			endpointStrings = append(endpointStrings, endpoint.Path)
+			endpointStrings[i] = endpoint.Path
 		} else {
-			endpointStrings = append(endpointStrings, endpoint.String())
+			endpointStrings[i] = endpoint.String()
 		}
 	}
+
 	// Initialize the XL sets instance.
 	s := &xlSets{
 		sets:               make([]*xlObjects, setCount),

cmd/xl-v1-common.go

@@ -24,12 +24,13 @@ import (
 )
 
 // getLoadBalancedDisks - fetches load balanced (sufficiently randomized) disk slice.
-func (xl xlObjects) getLoadBalancedDisks() (disks []StorageAPI) {
+func (xl xlObjects) getLoadBalancedDisks() (newDisks []StorageAPI) {
+	disks := xl.getDisks()
 	// Based on the random shuffling return back randomized disks.
-	for _, i := range hashOrder(UTCNow().String(), len(xl.getDisks())) {
-		disks = append(disks, xl.getDisks()[i-1])
+	for _, i := range hashOrder(UTCNow().String(), len(disks)) {
+		newDisks = append(newDisks, disks[i-1])
 	}
-	return disks
+	return newDisks
 }
 
 // This function does the following check, suppose