Add the "thread.tcache.enabled" mallctl.

src/ctl.c

@@ -39,6 +39,7 @@ static int	ctl_lookup(const char *name, ctl_node_t const **nodesp,
 
 CTL_PROTO(version)
 CTL_PROTO(epoch)
+CTL_PROTO(thread_tcache_enabled)
 CTL_PROTO(thread_tcache_flush)
 CTL_PROTO(thread_arena)
 CTL_PROTO(thread_allocated)
@@ -151,6 +152,7 @@ CTL_PROTO(stats_mapped)
 #define	INDEX(i)	false,	{.indexed = {i##_index}},		NULL
 
 static const ctl_node_t	tcache_node[] = {
+	{NAME("enabled"),	CTL(thread_tcache_enabled)},
 	{NAME("flush"),		CTL(thread_tcache_flush)}
 };
 
@@ -966,25 +968,43 @@ RETURN:
 	return (ret);
 }
 
+static int
+thread_tcache_enabled_ctl(const size_t *mib, size_t miblen, void *oldp,
+    size_t *oldlenp, void *newp, size_t newlen)
+{
+	int ret;
+	bool oldval;
+
+	if (config_tcache == false)
+		return (ENOENT);
+
+	oldval = tcache_enabled_get();
+	if (newp != NULL) {
+		if (newlen != sizeof(bool)) {
+			ret = EINVAL;
+			goto RETURN;
+		}
+		tcache_enabled_set(*(bool *)newp);
+	}
+	READ(oldval, bool);
+
+RETURN:
+	ret = 0;
+	return (ret);
+}
+
 static int
 thread_tcache_flush_ctl(const size_t *mib, size_t miblen, void *oldp,
     size_t *oldlenp, void *newp, size_t newlen)
 {
 	int ret;
-	tcache_t *tcache;
 
 	if (config_tcache == false)
 		return (ENOENT);
 
 	VOID();
 
-	if ((tcache = *tcache_tsd_get()) == NULL) {
-		ret = 0;
-		goto RETURN;
-	}
-	tcache_destroy(tcache);
-	tcache = NULL;
-	tcache_tsd_set(&tcache);
+	tcache_flush();
 
 	ret = 0;
 RETURN:

src/tcache.c

@@ -5,6 +5,7 @@
 /* Data. */
 
 malloc_tsd_data(, tcache, tcache_t *, NULL)
+malloc_tsd_data(, tcache_enabled, tcache_enabled_t, tcache_enabled_default)
 
 bool	opt_tcache = true;
 ssize_t	opt_lg_tcache_max = LG_TCACHE_MAXCLASS_DEFAULT;
@@ -328,25 +329,27 @@ tcache_thread_cleanup(void *arg)
 {
 	tcache_t *tcache = *(tcache_t **)arg;
 
-	if (tcache == (void *)(uintptr_t)1) {
+	if (tcache == TCACHE_STATE_DISABLED) {
+		/* Do nothing. */
+	} else if (tcache == TCACHE_STATE_REINCARNATED) {
+		/*
+		 * Another destructor called an allocator function after this
+		 * destructor was called.  Reset tcache to 1 in order to
+		 * receive another callback.
+		 */
+		tcache = TCACHE_STATE_PURGATORY;
+		tcache_tsd_set(&tcache);
+	} else if (tcache == TCACHE_STATE_PURGATORY) {
 		/*
 		 * The previous time this destructor was called, we set the key
 		 * to 1 so that other destructors wouldn't cause re-creation of
 		 * the tcache.  This time, do nothing, so that the destructor
 		 * will not be called again.
 		 */
-	} else if (tcache == (void *)(uintptr_t)2) {
-		/*
-		 * Another destructor called an allocator function after this
-		 * destructor was called.  Reset tcache to 1 in order to
-		 * receive another callback.
-		 */
-		tcache = (tcache_t *)(uintptr_t)1;
-		tcache_tsd_set(&tcache);
 	} else if (tcache != NULL) {
-		assert(tcache != (void *)(uintptr_t)1);
+		assert(tcache != TCACHE_STATE_PURGATORY);
 		tcache_destroy(tcache);
-		tcache = (tcache_t *)(uintptr_t)1;
+		tcache = TCACHE_STATE_PURGATORY;
 		tcache_tsd_set(&tcache);
 	}
 }
@@ -428,7 +431,7 @@ tcache_boot1(void)
 {
 
 	if (opt_tcache) {
-		if (tcache_tsd_boot())
+		if (tcache_tsd_boot() || tcache_enabled_tsd_boot())
 			return (true);
 	}