release-19.1: util/log: ensure that secondary loggers do not l…

pkg/util/log/clog.go

@@ -484,7 +484,7 @@ func formatHeader(
 		cp = nil
 	}
 
-	buf := logging.getBuffer()
+	buf := getBuffer()
 	if line < 0 {
 		line = 0 // not a real line number, but acceptable to someDigits
 	}
@@ -700,13 +700,6 @@ type loggingT struct {
 	// Level flag for output to files.
 	fileThreshold Severity
 
-	// freeList is a list of byte buffers, maintained under freeListMu.
-	freeList *buffer
-	// freeListMu maintains the free list. It is separate from the main mutex
-	// so buffers can be grabbed and printed to without holding the main lock,
-	// for better parallelization.
-	freeListMu syncutil.Mutex
-
 	// mu protects the remaining elements of this structure and is
 	// used to synchronize logging.
 	mu syncutil.Mutex
@@ -746,6 +739,12 @@ type loggingT struct {
 	clusterID string
 }
 
+var freeList struct {
+	syncutil.Mutex
+	// head is the head of a list of byte buffers, maintained under the mutex.
+	head *buffer
+}
+
 // buffer holds a byte Buffer for reuse. The zero value is ready for use.
 type buffer struct {
 	bytes.Buffer
@@ -796,13 +795,13 @@ func (l *loggingT) setVState(verbosity level, filter []modulePat, setFilter bool
 }
 
 // getBuffer returns a new, ready-to-use buffer.
-func (l *loggingT) getBuffer() *buffer {
-	l.freeListMu.Lock()
-	b := l.freeList
+func getBuffer() *buffer {
+	freeList.Lock()
+	b := freeList.head
 	if b != nil {
-		l.freeList = b.next
+		freeList.head = b.next
 	}
-	l.freeListMu.Unlock()
+	freeList.Unlock()
 	if b == nil {
 		b = new(buffer)
 	} else {
@@ -813,15 +812,15 @@ func (l *loggingT) getBuffer() *buffer {
 }
 
 // putBuffer returns a buffer to the free list.
-func (l *loggingT) putBuffer(b *buffer) {
+func putBuffer(b *buffer) {
 	if b.Len() >= 256 {
 		// Let big buffers die a natural death.
 		return
 	}
-	l.freeListMu.Lock()
-	b.next = l.freeList
-	l.freeList = b
-	l.freeListMu.Unlock()
+	freeList.Lock()
+	b.next = freeList.head
+	freeList.head = b
+	freeList.Unlock()
 }
 
 // ensureFile ensures that l.file is set and valid.
@@ -942,10 +941,11 @@ func (l *loggingT) outputLogEntry(s Severity, file string, line int, msg string)
 		if err := l.writeToFile(data); err != nil {
 			l.exitLocked(err)
 			l.mu.Unlock()
+			putBuffer(buf)
 			return
 		}
 
-		l.putBuffer(buf)
+		putBuffer(buf)
 	}
 	// Flush and exit on fatal logging.
 	if s == Severity_FATAL {
@@ -991,10 +991,11 @@ func (l *loggingT) printPanicToFile(r interface{}) {
 
 func (l *loggingT) outputToStderr(entry Entry, stacks []byte) {
 	buf := l.processForStderr(entry, stacks)
-	if _, err := OrigStderr.Write(buf.Bytes()); err != nil {
+	_, err := OrigStderr.Write(buf.Bytes())
+	putBuffer(buf)
+	if err != nil {
 		l.exitLocked(err)
 	}
-	l.putBuffer(buf)
 }
 
 // processForStderr formats a log entry for output to standard error.
@@ -1157,11 +1158,11 @@ func (sb *syncBuffer) rotateFile(now time.Time) error {
 		}, nil, nil)
 		var n int
 		n, err = sb.file.Write(buf.Bytes())
+		putBuffer(buf)
 		sb.nbytes += int64(n)
 		if err != nil {
 			return err
 		}
-		logging.putBuffer(buf)
 	}
 
 	select {

pkg/util/log/clog_test.go

@@ -146,7 +146,7 @@ func TestEntryDecoder(t *testing.T) {
 		buf := formatHeader(s, now, gid, file, line, nil)
 		buf.WriteString(msg)
 		buf.WriteString("\n")
-		defer logging.putBuffer(buf)
+		defer putBuffer(buf)
 		return buf.String()
 	}
 
@@ -724,7 +724,7 @@ func TestExitOnFullDisk(t *testing.T) {
 func BenchmarkHeader(b *testing.B) {
 	for i := 0; i < b.N; i++ {
 		buf := formatHeader(Severity_INFO, timeutil.Now(), 200, "file.go", 100, nil)
-		logging.putBuffer(buf)
+		putBuffer(buf)
 	}
 }
 

pkg/util/log/log.go

@@ -259,7 +259,7 @@ func MakeEntry(s Severity, t int64, file string, line int, msg string) Entry {
 // Format writes the log entry to the specified writer.
 func (e Entry) Format(w io.Writer) error {
 	buf := formatLogEntry(e, nil, nil)
-	defer logging.putBuffer(buf)
+	defer putBuffer(buf)
 	_, err := w.Write(buf.Bytes())
 	return err
 }