Reduce lock contention for simple cases.

# this really should be done with pthread_once, but I've debugged this code.

Reviewed by: arch@

1 files changed, 22 insertions, 16 deletions

diff --git a/lib/libc/stdtime/localtime.c b/lib/libc/stdtime/localtime.c
index 827b140..bbffea5 100644
--- a/lib/libc/stdtime/localtime.c
+++ b/lib/libc/stdtime/localtime.c
@@ -1093,14 +1093,16 @@ const time_t * const	timep;
 	struct tm *p_tm;
 
 	if (__isthreaded != 0) {
-		_pthread_mutex_lock(&localtime_mutex);
 		if (localtime_key < 0) {
-			if (_pthread_key_create(&localtime_key, free) < 0) {
-				_pthread_mutex_unlock(&localtime_mutex);
-				return(NULL);
+			_pthread_mutex_lock(&localtime_mutex);
+			if (localtime_key < 0) {
+				if (_pthread_key_create(&localtime_key, free) < 0) {
+					_pthread_mutex_unlock(&localtime_mutex);
+					return(NULL);
+				}
 			}
+			_pthread_mutex_unlock(&localtime_mutex);
 		}
-		_pthread_mutex_unlock(&localtime_mutex);
 		p_tm = _pthread_getspecific(localtime_key);
 		if (p_tm == NULL) {
 			if ((p_tm = (struct tm *)malloc(sizeof(struct tm)))
@@ -1146,16 +1148,18 @@ const time_t * const	timep;
 const long		offset;
 struct tm * const	tmp;
 {
-	_MUTEX_LOCK(&gmt_mutex);
 	if (!gmt_is_set) {
-		gmt_is_set = TRUE;
+		_MUTEX_LOCK(&gmt_mutex);
+		if (!gmt_is_set) {
 #ifdef ALL_STATE
-		gmtptr = (struct state *) malloc(sizeof *gmtptr);
-		if (gmtptr != NULL)
+			gmtptr = (struct state *) malloc(sizeof *gmtptr);
+			if (gmtptr != NULL)
 #endif /* defined ALL_STATE */
-			gmtload(gmtptr);
+				gmtload(gmtptr);
+			gmt_is_set = TRUE;
+		}
+		_MUTEX_UNLOCK(&gmt_mutex);
 	}
-	_MUTEX_UNLOCK(&gmt_mutex);
 	timesub(timep, offset, gmtptr, tmp);
 #ifdef TM_ZONE
 	/*
@@ -1187,14 +1191,16 @@ const time_t * const	timep;
 	struct tm *p_tm;
 
 	if (__isthreaded != 0) {
-		_pthread_mutex_lock(&gmtime_mutex);
 		if (gmtime_key < 0) {
-			if (_pthread_key_create(&gmtime_key, free) < 0) {
-				_pthread_mutex_unlock(&gmtime_mutex);
-				return(NULL);
+			_pthread_mutex_lock(&gmtime_mutex);
+			if (gmtime_key < 0) {
+				if (_pthread_key_create(&gmtime_key, free) < 0) {
+					_pthread_mutex_unlock(&gmtime_mutex);
+					return(NULL);
+				}
 			}
+			_pthread_mutex_unlock(&gmtime_mutex);
 		}
-		_pthread_mutex_unlock(&gmtime_mutex);
 		/*
 		 * Changed to follow POSIX.1 threads standard, which
 		 * is what BSD currently has.