Add profiling for the background thread mutex.

include/jemalloc/internal/mutex_externs.h

@@ -10,12 +10,12 @@ extern bool isthreaded;
 #  define isthreaded true
 #endif
 
-bool	malloc_mutex_init(malloc_mutex_t *mutex, const char *name,
+bool malloc_mutex_init(malloc_mutex_t *mutex, const char *name,
     witness_rank_t rank, malloc_mutex_lock_order_t lock_order);
-void	malloc_mutex_prefork(tsdn_t *tsdn, malloc_mutex_t *mutex);
+void malloc_mutex_prefork(tsdn_t *tsdn, malloc_mutex_t *mutex);
-void	malloc_mutex_postfork_parent(tsdn_t *tsdn, malloc_mutex_t *mutex);
+void malloc_mutex_postfork_parent(tsdn_t *tsdn, malloc_mutex_t *mutex);
-void	malloc_mutex_postfork_child(tsdn_t *tsdn, malloc_mutex_t *mutex);
+void malloc_mutex_postfork_child(tsdn_t *tsdn, malloc_mutex_t *mutex);
-bool	malloc_mutex_boot(void);
+bool malloc_mutex_boot(void);
-void	malloc_mutex_prof_data_reset(tsdn_t *tsdn, malloc_mutex_t *mutex);
+void malloc_mutex_prof_data_reset(tsdn_t *tsdn, malloc_mutex_t *mutex);
 
 #endif /* JEMALLOC_INTERNAL_MUTEX_EXTERNS_H */

include/jemalloc/internal/mutex_prof.h

@@ -6,6 +6,7 @@
 #include "jemalloc/internal/tsd_types.h"
 
 #define MUTEX_PROF_GLOBAL_MUTEXES					\
+    OP(background_thread)						\
     OP(ctl)								\
     OP(prof)
 

src/ctl.c

@@ -947,6 +947,15 @@ ctl_refresh(tsdn_t *tsdn) {
 			READ_GLOBAL_MUTEX_PROF_DATA(global_prof_mutex_prof,
 			    bt2gctx_mtx);
 		}
+		if (have_background_thread) {
+			READ_GLOBAL_MUTEX_PROF_DATA(
+			    global_prof_mutex_background_thread,
+			    background_thread_lock);
+		} else {
+			memset(&ctl_stats->mutex_prof_data[
+			    global_prof_mutex_background_thread], 0,
+			    sizeof(mutex_prof_data_t));
+		}
 		/* We own ctl mutex already. */
 		malloc_mutex_prof_read(tsdn,
 		    &ctl_stats->mutex_prof_data[global_prof_mutex_ctl],
@@ -2557,6 +2566,9 @@ stats_mutexes_reset_ctl(tsd_t *tsd, const size_t *mib, size_t miblen,
 
 	/* Global mutexes: ctl and prof. */
 	MUTEX_PROF_RESET(ctl_mtx);
+	if (have_background_thread) {
+		MUTEX_PROF_RESET(background_thread_lock);
+	}
 	if (config_prof && opt_prof) {
 		MUTEX_PROF_RESET(bt2gctx_mtx);
 	}

src/mutex.c

@@ -112,6 +112,8 @@ label_spin_done:
 static void
 mutex_prof_data_init(mutex_prof_data_t *data) {
 	memset(data, 0, sizeof(mutex_prof_data_t));
+	nstime_init(&data->max_wait_time, 0);
+	nstime_init(&data->tot_wait_time, 0);
 	data->prev_owner = NULL;
 }