Add arena-specific and selective dss allocation.

Add the "arenas.extend" mallctl, so that it is possible to create new arenas that are outside the set that jemalloc automatically multiplexes threads onto. Add the ALLOCM_ARENA() flag for {,r,d}allocm(), so that it is possible to explicitly allocate from a particular arena. Add the "opt.dss" mallctl, which controls the default precedence of dss allocation relative to mmap allocation. Add the "arena.<i>.dss" mallctl, which makes it possible to set the default dss precedence on a per arena or global basis. Add the "arena.<i>.purge" mallctl, which obsoletes "arenas.purge". Add the "stats.arenas.<i>.dss" mallctl.
2026-07-23 13:13:06 +00:00 · 2012-10-11 13:53:15 -07:00
parent d0ffd8ed4f
commit 609ae595f0
23 changed files with 911 additions and 246 deletions
--- a/src/ctl.c
+++ b/src/ctl.c
@@ -48,8 +48,8 @@ static int	n##_ctl(const size_t *mib, size_t miblen, void *oldp,	\
    size_t *oldlenp, void *newp, size_t newlen);

 #define	INDEX_PROTO(n)							\
-const ctl_named_node_t	*n##_index(const size_t *mib, size_t miblen,	\
-    size_t i);
+static const ctl_named_node_t	*n##_index(const size_t *mib,		\
+    size_t miblen, size_t i);

 static bool	ctl_arena_init(ctl_arena_stats_t *astats);
 static void	ctl_arena_clear(ctl_arena_stats_t *astats);
@@ -58,6 +58,7 @@ static void	ctl_arena_stats_amerge(ctl_arena_stats_t *cstats,
 static void	ctl_arena_stats_smerge(ctl_arena_stats_t *sstats,
    ctl_arena_stats_t *astats);
 static void	ctl_arena_refresh(arena_t *arena, unsigned i);
+static bool	ctl_grow(void);
 static void	ctl_refresh(void);
 static bool	ctl_init(void);
 static int	ctl_lookup(const char *name, ctl_node_t const **nodesp,
@@ -88,6 +89,7 @@ CTL_PROTO(config_utrace)
 CTL_PROTO(config_valgrind)
 CTL_PROTO(config_xmalloc)
 CTL_PROTO(opt_abort)
+CTL_PROTO(opt_dss)
 CTL_PROTO(opt_lg_chunk)
 CTL_PROTO(opt_narenas)
 CTL_PROTO(opt_lg_dirty_mult)
@@ -110,6 +112,10 @@ CTL_PROTO(opt_prof_gdump)
 CTL_PROTO(opt_prof_final)
 CTL_PROTO(opt_prof_leak)
 CTL_PROTO(opt_prof_accum)
+CTL_PROTO(arena_i_purge)
+static int	arena_purge(unsigned arena_ind);
+CTL_PROTO(arena_i_dss)
+INDEX_PROTO(arena_i)
 CTL_PROTO(arenas_bin_i_size)
 CTL_PROTO(arenas_bin_i_nregs)
 CTL_PROTO(arenas_bin_i_run_size)
@@ -125,6 +131,7 @@ CTL_PROTO(arenas_nbins)
 CTL_PROTO(arenas_nhbins)
 CTL_PROTO(arenas_nlruns)
 CTL_PROTO(arenas_purge)
+CTL_PROTO(arenas_extend)
 CTL_PROTO(prof_active)
 CTL_PROTO(prof_dump)
 CTL_PROTO(prof_interval)
@@ -158,6 +165,7 @@ CTL_PROTO(stats_arenas_i_lruns_j_nrequests)
 CTL_PROTO(stats_arenas_i_lruns_j_curruns)
 INDEX_PROTO(stats_arenas_i_lruns_j)
 CTL_PROTO(stats_arenas_i_nthreads)
+CTL_PROTO(stats_arenas_i_dss)
 CTL_PROTO(stats_arenas_i_pactive)
 CTL_PROTO(stats_arenas_i_pdirty)
 CTL_PROTO(stats_arenas_i_mapped)
@@ -223,6 +231,7 @@ static const ctl_named_node_t	config_node[] = {

 static const ctl_named_node_t opt_node[] = {
 	{NAME("abort"),			CTL(opt_abort)},
+	{NAME("dss"),			CTL(opt_dss)},
 	{NAME("lg_chunk"),		CTL(opt_lg_chunk)},
 	{NAME("narenas"),		CTL(opt_narenas)},
 	{NAME("lg_dirty_mult"),		CTL(opt_lg_dirty_mult)},
@@ -247,6 +256,18 @@ static const ctl_named_node_t opt_node[] = {
 	{NAME("prof_accum"),		CTL(opt_prof_accum)}
 };

+static const ctl_named_node_t arena_i_node[] = {
+	{NAME("purge"),			CTL(arena_i_purge)},
+	{NAME("dss"),			CTL(arena_i_dss)}
+};
+static const ctl_named_node_t super_arena_i_node[] = {
+	{NAME(""),			CHILD(named, arena_i)}
+};
+
+static const ctl_indexed_node_t arena_node[] = {
+	{INDEX(arena_i)}
+};
+
 static const ctl_named_node_t arenas_bin_i_node[] = {
 	{NAME("size"),			CTL(arenas_bin_i_size)},
 	{NAME("nregs"),			CTL(arenas_bin_i_nregs)},
@@ -282,7 +303,8 @@ static const ctl_named_node_t arenas_node[] = {
 	{NAME("bin"),			CHILD(indexed, arenas_bin)},
 	{NAME("nlruns"),		CTL(arenas_nlruns)},
 	{NAME("lrun"),			CHILD(indexed, arenas_lrun)},
-	{NAME("purge"),			CTL(arenas_purge)}
+	{NAME("purge"),			CTL(arenas_purge)},
+	{NAME("extend"),		CTL(arenas_extend)}
 };

 static const ctl_named_node_t	prof_node[] = {
@@ -352,6 +374,7 @@ static const ctl_indexed_node_t stats_arenas_i_lruns_node[] = {

 static const ctl_named_node_t stats_arenas_i_node[] = {
 	{NAME("nthreads"),		CTL(stats_arenas_i_nthreads)},
+	{NAME("dss"),			CTL(stats_arenas_i_dss)},
 	{NAME("pactive"),		CTL(stats_arenas_i_pactive)},
 	{NAME("pdirty"),		CTL(stats_arenas_i_pdirty)},
 	{NAME("mapped"),		CTL(stats_arenas_i_mapped)},
@@ -387,6 +410,7 @@ static const ctl_named_node_t	root_node[] = {
 	{NAME("thread"),	CHILD(named, thread)},
 	{NAME("config"),	CHILD(named, config)},
 	{NAME("opt"),		CHILD(named, opt)},
+	{NAME("arena"),		CHILD(indexed, arena)},
 	{NAME("arenas"),	CHILD(named, arenas)},
 	{NAME("prof"),		CHILD(named, prof)},
 	{NAME("stats"),		CHILD(named, stats)}
@@ -420,6 +444,7 @@ static void
 ctl_arena_clear(ctl_arena_stats_t *astats)
 {

+	astats->dss = dss_prec_names[dss_prec_limit];
 	astats->pactive = 0;
 	astats->pdirty = 0;
 	if (config_stats) {
@@ -439,8 +464,8 @@ ctl_arena_stats_amerge(ctl_arena_stats_t *cstats, arena_t *arena)
 {
 	unsigned i;

-	arena_stats_merge(arena, &cstats->pactive, &cstats->pdirty,
-	    &cstats->astats, cstats->bstats, cstats->lstats);
+	arena_stats_merge(arena, &cstats->dss, &cstats->pactive,
+	    &cstats->pdirty, &cstats->astats, cstats->bstats, cstats->lstats);

 	for (i = 0; i < NBINS; i++) {
 		cstats->allocated_small += cstats->bstats[i].allocated;
@@ -500,7 +525,7 @@ static void
 ctl_arena_refresh(arena_t *arena, unsigned i)
 {
 	ctl_arena_stats_t *astats = &ctl_stats.arenas[i];
-	ctl_arena_stats_t *sstats = &ctl_stats.arenas[narenas];
+	ctl_arena_stats_t *sstats = &ctl_stats.arenas[ctl_stats.narenas];

 	ctl_arena_clear(astats);

@@ -518,11 +543,72 @@ ctl_arena_refresh(arena_t *arena, unsigned i)
 	}
 }

+static bool
+ctl_grow(void)
+{
+	size_t astats_size;
+	ctl_arena_stats_t *astats;
+	arena_t **tarenas;
+
+	/* Extend arena stats and arenas arrays. */
+	astats_size = (ctl_stats.narenas + 2) * sizeof(ctl_arena_stats_t);
+	if (ctl_stats.narenas == narenas_auto) {
+		/* ctl_stats.arenas and arenas came from base_alloc(). */
+		astats = (ctl_arena_stats_t *)imalloc(astats_size);
+		if (astats == NULL)
+			return (true);
+		memcpy(astats, ctl_stats.arenas, (ctl_stats.narenas + 1) *
+		    sizeof(ctl_arena_stats_t));
+
+		tarenas = (arena_t **)imalloc((ctl_stats.narenas + 1) *
+		    sizeof(arena_t *));
+		if (tarenas == NULL) {
+			idalloc(astats);
+			return (true);
+		}
+		memcpy(tarenas, arenas, ctl_stats.narenas * sizeof(arena_t *));
+	} else {
+		astats = (ctl_arena_stats_t *)iralloc(ctl_stats.arenas,
+		    astats_size, 0, 0, false, false);
+		if (astats == NULL)
+			return (true);
+
+		tarenas = (arena_t **)iralloc(arenas, (ctl_stats.narenas + 1) *
+		    sizeof(arena_t *), 0, 0, false, false);
+		if (tarenas == NULL)
+			return (true);
+	}
+	/* Initialize the new astats and arenas elements. */
+	memset(&astats[ctl_stats.narenas + 1], 0, sizeof(ctl_arena_stats_t));
+	if (ctl_arena_init(&astats[ctl_stats.narenas + 1]))
+		return (true);
+	tarenas[ctl_stats.narenas] = NULL;
+	/* Swap merged stats to their new location. */
+	{
+		ctl_arena_stats_t tstats;
+		memcpy(&tstats, &astats[ctl_stats.narenas],
+		    sizeof(ctl_arena_stats_t));
+		memcpy(&astats[ctl_stats.narenas],
+		    &astats[ctl_stats.narenas + 1], sizeof(ctl_arena_stats_t));
+		memcpy(&astats[ctl_stats.narenas + 1], &tstats,
+		    sizeof(ctl_arena_stats_t));
+	}
+	ctl_stats.arenas = astats;
+	ctl_stats.narenas++;
+	malloc_mutex_lock(&arenas_lock);
+	arenas = tarenas;
+	narenas_total++;
+	arenas_extend(narenas_total - 1);
+	malloc_mutex_unlock(&arenas_lock);
+
+	return (false);
+}
+
 static void
 ctl_refresh(void)
 {
 	unsigned i;
-	VARIABLE_ARRAY(arena_t *, tarenas, narenas);
+	VARIABLE_ARRAY(arena_t *, tarenas, ctl_stats.narenas);

 	if (config_stats) {
 		malloc_mutex_lock(&chunks_mtx);
@@ -542,19 +628,19 @@ ctl_refresh(void)
 	 * Clear sum stats, since they will be merged into by
 	 * ctl_arena_refresh().
 	 */
-	ctl_stats.arenas[narenas].nthreads = 0;
-	ctl_arena_clear(&ctl_stats.arenas[narenas]);
+	ctl_stats.arenas[ctl_stats.narenas].nthreads = 0;
+	ctl_arena_clear(&ctl_stats.arenas[ctl_stats.narenas]);

 	malloc_mutex_lock(&arenas_lock);
-	memcpy(tarenas, arenas, sizeof(arena_t *) * narenas);
-	for (i = 0; i < narenas; i++) {
+	memcpy(tarenas, arenas, sizeof(arena_t *) * ctl_stats.narenas);
+	for (i = 0; i < ctl_stats.narenas; i++) {
 		if (arenas[i] != NULL)
 			ctl_stats.arenas[i].nthreads = arenas[i]->nthreads;
 		else
 			ctl_stats.arenas[i].nthreads = 0;
 	}
 	malloc_mutex_unlock(&arenas_lock);
-	for (i = 0; i < narenas; i++) {
+	for (i = 0; i < ctl_stats.narenas; i++) {
 		bool initialized = (tarenas[i] != NULL);

 		ctl_stats.arenas[i].initialized = initialized;
@@ -563,11 +649,13 @@ ctl_refresh(void)
 	}

 	if (config_stats) {
-		ctl_stats.allocated = ctl_stats.arenas[narenas].allocated_small
-		    + ctl_stats.arenas[narenas].astats.allocated_large
+		ctl_stats.allocated =
+		    ctl_stats.arenas[ctl_stats.narenas].allocated_small
+		    + ctl_stats.arenas[ctl_stats.narenas].astats.allocated_large
+		    + ctl_stats.huge.allocated;
+		ctl_stats.active =
+		    (ctl_stats.arenas[ctl_stats.narenas].pactive << LG_PAGE)
 		    + ctl_stats.huge.allocated;
-		ctl_stats.active = (ctl_stats.arenas[narenas].pactive <<
-		    LG_PAGE) + ctl_stats.huge.allocated;
 		ctl_stats.mapped = (ctl_stats.chunks.current << opt_lg_chunk);
 	}

@@ -585,13 +673,15 @@ ctl_init(void)
 		 * Allocate space for one extra arena stats element, which
 		 * contains summed stats across all arenas.
 		 */
+		assert(narenas_auto == narenas_total_get());
+		ctl_stats.narenas = narenas_auto;
 		ctl_stats.arenas = (ctl_arena_stats_t *)base_alloc(
-		    (narenas + 1) * sizeof(ctl_arena_stats_t));
+		    (ctl_stats.narenas + 1) * sizeof(ctl_arena_stats_t));
 		if (ctl_stats.arenas == NULL) {
 			ret = true;
 			goto label_return;
 		}
-		memset(ctl_stats.arenas, 0, (narenas + 1) *
+		memset(ctl_stats.arenas, 0, (ctl_stats.narenas + 1) *
 		    sizeof(ctl_arena_stats_t));

 		/*
@@ -601,14 +691,14 @@ ctl_init(void)
 		 */
 		if (config_stats) {
 			unsigned i;
-			for (i = 0; i <= narenas; i++) {
+			for (i = 0; i <= ctl_stats.narenas; i++) {
 				if (ctl_arena_init(&ctl_stats.arenas[i])) {
 					ret = true;
 					goto label_return;
 				}
 			}
 		}
-		ctl_stats.arenas[narenas].initialized = true;
+		ctl_stats.arenas[ctl_stats.narenas].initialized = true;

 		ctl_epoch = 0;
 		ctl_refresh();
@@ -1084,13 +1174,14 @@ thread_arena_ctl(const size_t *mib, size_t miblen, void *oldp, size_t *oldlenp,
 	int ret;
 	unsigned newind, oldind;

+	malloc_mutex_lock(&ctl_mtx);
 	newind = oldind = choose_arena(NULL)->ind;
 	WRITE(newind, unsigned);
 	READ(oldind, unsigned);
 	if (newind != oldind) {
 		arena_t *arena;

-		if (newind >= narenas) {
+		if (newind >= ctl_stats.narenas) {
 			/* New arena index is out of range. */
 			ret = EFAULT;
 			goto label_return;
@@ -1123,6 +1214,7 @@ thread_arena_ctl(const size_t *mib, size_t miblen, void *oldp, size_t *oldlenp,

 	ret = 0;
 label_return:
+	malloc_mutex_unlock(&ctl_mtx);
 	return (ret);
 }

@@ -1156,6 +1248,7 @@ CTL_RO_BOOL_CONFIG_GEN(config_xmalloc)
 /******************************************************************************/

 CTL_RO_NL_GEN(opt_abort, opt_abort, bool)
+CTL_RO_NL_GEN(opt_dss, opt_dss, const char *)
 CTL_RO_NL_GEN(opt_lg_chunk, opt_lg_chunk, size_t)
 CTL_RO_NL_GEN(opt_narenas, opt_narenas, size_t)
 CTL_RO_NL_GEN(opt_lg_dirty_mult, opt_lg_dirty_mult, ssize_t)
@@ -1179,12 +1272,126 @@ CTL_RO_NL_CGEN(config_prof, opt_prof_final, opt_prof_final, bool)
 CTL_RO_NL_CGEN(config_prof, opt_prof_leak, opt_prof_leak, bool)
 CTL_RO_NL_CGEN(config_prof, opt_prof_accum, opt_prof_accum, bool)

+/******************************************************************************/
+
+static int
+arena_purge(unsigned arena_ind)
+{
+	int ret;
+
+	malloc_mutex_lock(&ctl_mtx);
+	{
+		VARIABLE_ARRAY(arena_t *, tarenas, ctl_stats.narenas);
+
+		malloc_mutex_lock(&arenas_lock);
+		memcpy(tarenas, arenas, sizeof(arena_t *) * ctl_stats.narenas);
+		malloc_mutex_unlock(&arenas_lock);
+
+		if (arena_ind == ctl_stats.narenas) {
+			unsigned i;
+			for (i = 0; i < ctl_stats.narenas; i++) {
+				if (tarenas[i] != NULL)
+					arena_purge_all(tarenas[i]);
+			}
+		} else {
+			assert(arena_ind < ctl_stats.narenas);
+			if (tarenas[arena_ind] != NULL)
+				arena_purge_all(tarenas[arena_ind]);
+		}
+	}
+
+	ret = 0;
+	malloc_mutex_unlock(&ctl_mtx);
+	return (ret);
+}
+
+static int
+arena_i_purge_ctl(const size_t *mib, size_t miblen, void *oldp, size_t *oldlenp,
+    void *newp, size_t newlen)
+{
+	int ret;
+
+	READONLY();
+	WRITEONLY();
+	ret = arena_purge(mib[1]);
+
+label_return:
+	return (ret);
+}
+
+static int
+arena_i_dss_ctl(const size_t *mib, size_t miblen, void *oldp, size_t *oldlenp,
+    void *newp, size_t newlen)
+{
+	int ret, i;
+	bool match, err;
+	const char *dss;
+	unsigned arena_ind = mib[1];
+	dss_prec_t dss_prec_old = dss_prec_limit;
+	dss_prec_t dss_prec = dss_prec_limit;
+
+	WRITE(dss, const char *);
+	match = false;
+	for (i = 0; i < dss_prec_limit; i++) {
+		if (strcmp(dss_prec_names[i], dss) == 0) {
+			dss_prec = i;
+			match = true;
+			break;
+		}
+	}
+	if (match == false) {
+		ret = EINVAL;
+		goto label_return;
+	}
+
+	if (arena_ind < ctl_stats.narenas) {
+		arena_t *arena = arenas[arena_ind];
+		if (arena != NULL) {
+			dss_prec_old = arena_dss_prec_get(arena);
+			arena_dss_prec_set(arena, dss_prec);
+			err = false;
+		} else
+			err = true;
+	} else {
+		dss_prec_old = chunk_dss_prec_get();
+		err = chunk_dss_prec_set(dss_prec);
+	}
+	dss = dss_prec_names[dss_prec_old];
+	READ(dss, const char *);
+	if (err) {
+		ret = EFAULT;
+		goto label_return;
+	}
+
+	ret = 0;
+label_return:
+	return (ret);
+}
+
+static const ctl_named_node_t *
+arena_i_index(const size_t *mib, size_t miblen, size_t i)
+{
+	const ctl_named_node_t * ret;
+
+	malloc_mutex_lock(&ctl_mtx);
+	if (i > ctl_stats.narenas) {
+		ret = NULL;
+		goto label_return;
+	}
+
+	ret = super_arena_i_node;
+label_return:
+	malloc_mutex_unlock(&ctl_mtx);
+	return (ret);
+}
+
+
 /******************************************************************************/

 CTL_RO_NL_GEN(arenas_bin_i_size, arena_bin_info[mib[2]].reg_size, size_t)
 CTL_RO_NL_GEN(arenas_bin_i_nregs, arena_bin_info[mib[2]].nregs, uint32_t)
 CTL_RO_NL_GEN(arenas_bin_i_run_size, arena_bin_info[mib[2]].run_size, size_t)
-const ctl_named_node_t *
+static const ctl_named_node_t *
 arenas_bin_i_index(const size_t *mib, size_t miblen, size_t i)
 {

@@ -1194,7 +1401,7 @@ arenas_bin_i_index(const size_t *mib, size_t miblen, size_t i)
 }

 CTL_RO_NL_GEN(arenas_lrun_i_size, ((mib[2]+1) << LG_PAGE), size_t)
-const ctl_named_node_t *
+static const ctl_named_node_t *
 arenas_lrun_i_index(const size_t *mib, size_t miblen, size_t i)
 {

@@ -1203,7 +1410,27 @@ arenas_lrun_i_index(const size_t *mib, size_t miblen, size_t i)
 	return (super_arenas_lrun_i_node);
 }

-CTL_RO_NL_GEN(arenas_narenas, narenas, unsigned)
+static int
+arenas_narenas_ctl(const size_t *mib, size_t miblen, void *oldp,
+    size_t *oldlenp, void *newp, size_t newlen)
+{
+	int ret;
+	unsigned narenas;
+
+	malloc_mutex_lock(&ctl_mtx);
+	READONLY();
+	if (*oldlenp != sizeof(unsigned)) {
+		ret = EINVAL;
+		goto label_return;
+	}
+	narenas = ctl_stats.narenas;
+	READ(narenas, unsigned);
+
+	ret = 0;
+label_return:
+	malloc_mutex_unlock(&ctl_mtx);
+	return (ret);
+}

 static int
 arenas_initialized_ctl(const size_t *mib, size_t miblen, void *oldp,
@@ -1214,13 +1441,13 @@ arenas_initialized_ctl(const size_t *mib, size_t miblen, void *oldp,

 	malloc_mutex_lock(&ctl_mtx);
 	READONLY();
-	if (*oldlenp != narenas * sizeof(bool)) {
+	if (*oldlenp != ctl_stats.narenas * sizeof(bool)) {
 		ret = EINVAL;
-		nread = (*oldlenp < narenas * sizeof(bool))
-		    ? (*oldlenp / sizeof(bool)) : narenas;
+		nread = (*oldlenp < ctl_stats.narenas * sizeof(bool))
+		    ? (*oldlenp / sizeof(bool)) : ctl_stats.narenas;
 	} else {
 		ret = 0;
-		nread = narenas;
+		nread = ctl_stats.narenas;
 	}

 	for (i = 0; i < nread; i++)
@@ -1243,36 +1470,42 @@ arenas_purge_ctl(const size_t *mib, size_t miblen, void *oldp, size_t *oldlenp,
    void *newp, size_t newlen)
 {
 	int ret;
-	unsigned arena;
+	unsigned arena_ind;

+	malloc_mutex_lock(&ctl_mtx);
 	WRITEONLY();
-	arena = UINT_MAX;
-	WRITE(arena, unsigned);
-	if (newp != NULL && arena >= narenas) {
+	arena_ind = UINT_MAX;
+	WRITE(arena_ind, unsigned);
+	if (newp != NULL && arena_ind >= ctl_stats.narenas)
 		ret = EFAULT;
-		goto label_return;
-	} else {
-		VARIABLE_ARRAY(arena_t *, tarenas, narenas);
-
-		malloc_mutex_lock(&arenas_lock);
-		memcpy(tarenas, arenas, sizeof(arena_t *) * narenas);
-		malloc_mutex_unlock(&arenas_lock);
-
-		if (arena == UINT_MAX) {
-			unsigned i;
-			for (i = 0; i < narenas; i++) {
-				if (tarenas[i] != NULL)
-					arena_purge_all(tarenas[i]);
-			}
-		} else {
-			assert(arena < narenas);
-			if (tarenas[arena] != NULL)
-				arena_purge_all(tarenas[arena]);
-		}
+	else {
+		if (arena_ind == UINT_MAX)
+			arena_ind = ctl_stats.narenas;
+		ret = arena_purge(arena_ind);
 	}

+label_return:
+	malloc_mutex_unlock(&ctl_mtx);
+	return (ret);
+}
+
+static int
+arenas_extend_ctl(const size_t *mib, size_t miblen, void *oldp, size_t *oldlenp,
+    void *newp, size_t newlen)
+{
+	int ret;
+
+	malloc_mutex_lock(&ctl_mtx);
+	READONLY();
+	if (ctl_grow()) {
+		ret = EAGAIN;
+		goto label_return;
+	}
+	READ(ctl_stats.narenas - 1, unsigned);
+
 	ret = 0;
 label_return:
+	malloc_mutex_unlock(&ctl_mtx);
 	return (ret);
 }

@@ -1377,7 +1610,7 @@ CTL_RO_CGEN(config_stats, stats_arenas_i_bins_j_nreruns,
 CTL_RO_CGEN(config_stats, stats_arenas_i_bins_j_curruns,
    ctl_stats.arenas[mib[2]].bstats[mib[4]].curruns, size_t)

-const ctl_named_node_t *
+static const ctl_named_node_t *
 stats_arenas_i_bins_j_index(const size_t *mib, size_t miblen, size_t j)
 {

@@ -1395,7 +1628,7 @@ CTL_RO_CGEN(config_stats, stats_arenas_i_lruns_j_nrequests,
 CTL_RO_CGEN(config_stats, stats_arenas_i_lruns_j_curruns,
    ctl_stats.arenas[mib[2]].lstats[mib[4]].curruns, size_t)

-const ctl_named_node_t *
+static const ctl_named_node_t *
 stats_arenas_i_lruns_j_index(const size_t *mib, size_t miblen, size_t j)
 {

@@ -1405,6 +1638,7 @@ stats_arenas_i_lruns_j_index(const size_t *mib, size_t miblen, size_t j)
 }

 CTL_RO_GEN(stats_arenas_i_nthreads, ctl_stats.arenas[mib[2]].nthreads, unsigned)
+CTL_RO_GEN(stats_arenas_i_dss, ctl_stats.arenas[mib[2]].dss, const char *)
 CTL_RO_GEN(stats_arenas_i_pactive, ctl_stats.arenas[mib[2]].pactive, size_t)
 CTL_RO_GEN(stats_arenas_i_pdirty, ctl_stats.arenas[mib[2]].pdirty, size_t)
 CTL_RO_CGEN(config_stats, stats_arenas_i_mapped,
@@ -1416,13 +1650,13 @@ CTL_RO_CGEN(config_stats, stats_arenas_i_nmadvise,
 CTL_RO_CGEN(config_stats, stats_arenas_i_purged,
    ctl_stats.arenas[mib[2]].astats.purged, uint64_t)

-const ctl_named_node_t *
+static const ctl_named_node_t *
 stats_arenas_i_index(const size_t *mib, size_t miblen, size_t i)
 {
 	const ctl_named_node_t * ret;

 	malloc_mutex_lock(&ctl_mtx);
-	if (ctl_stats.arenas[i].initialized == false) {
+	if (i > ctl_stats.narenas || ctl_stats.arenas[i].initialized == false) {
 		ret = NULL;
 		goto label_return;
 	}