Implement arena.<i>.destroy .

Add MALLCTL_ARENAS_DESTROYED for accessing destroyed arena stats as an
analogue to MALLCTL_ARENAS_ALL.

This resolves #382.

Makefile.in

@@ -195,6 +195,10 @@ TESTS_UNIT := \
 	$(srcroot)test/unit/util.c \
 	$(srcroot)test/unit/witness.c \
 	$(srcroot)test/unit/zero.c
+ifeq (@enable_prof@, 1)
+TESTS_UNIT += \
+	$(srcroot)test/unit/arena_reset_prof.c
+endif
 TESTS_INTEGRATION := $(srcroot)test/integration/aligned_alloc.c \
 	$(srcroot)test/integration/allocated.c \
 	$(srcroot)test/integration/extent.c \

doc/jemalloc.xml.in

@@ -426,13 +426,14 @@ for (i = 0; i < nbins; i++) {
       <function>mallctl*()</function> functions internally, so inconsistent
       statistics can be reported if multiple threads use these functions
       simultaneously.  If <option>--enable-stats</option> is specified during
-      configuration, <quote>m</quote> and <quote>a</quote> can be specified to
+      configuration, <quote>m</quote>, <quote>d</quote>, and <quote>a</quote>
-      omit merged arena and per arena statistics, respectively; <quote>b</quote>
+      can be specified to omit merged arena, destroyed merged arena, and per
-      and <quote>l</quote> can be specified to omit per size class statistics
+      arena statistics, respectively; <quote>b</quote> and <quote>l</quote> can
-      for bins and large objects, respectively.  Unrecognized characters are
+      be specified to omit per size class statistics for bins and large objects,
-      silently ignored.  Note that thread caching may prevent some statistics
+      respectively.  Unrecognized characters are silently ignored.  Note that
-      from being completely up to date, since extra locking would be required to
+      thread caching may prevent some statistics from being completely up to
-      merge counters that track thread cache operations.</para>
+      date, since extra locking would be required to merge counters that track
+      thread cache operations.</para>
 
       <para>The <function>malloc_usable_size()</function> function
       returns the usable size of the allocation pointed to by
@@ -687,18 +688,21 @@ for (i = 0; i < nbins; i++) {
   <refsect1 id="mallctl_namespace">
     <title>MALLCTL NAMESPACE</title>
     <para>The following names are defined in the namespace accessible via the
-    <function>mallctl*()</function> functions.  Value types are
+    <function>mallctl*()</function> functions.  Value types are specified in
-    specified in parentheses, their readable/writable statuses are encoded as
+    parentheses, their readable/writable statuses are encoded as
     <literal>rw</literal>, <literal>r-</literal>, <literal>-w</literal>, or
     <literal>--</literal>, and required build configuration flags follow, if
     any.  A name element encoded as <literal>&lt;i&gt;</literal> or
     <literal>&lt;j&gt;</literal> indicates an integer component, where the
     integer varies from 0 to some upper value that must be determined via
     introspection.  In the case of <mallctl>stats.arenas.&lt;i&gt;.*</mallctl>
-    and <mallctl>arena.&lt;i&gt;.{purge,decay,dss}</mallctl>,
+    and <mallctl>arena.&lt;i&gt;.{initialized,purge,decay,dss}</mallctl>,
     <literal>&lt;i&gt;</literal> equal to
     <constant>MALLCTL_ARENAS_ALL</constant> can be used to operate on all arenas
-    or access the summation of statistics from all arenas.  This constant can be
+    or access the summation of statistics from all arenas; similarly
+    <literal>&lt;i&gt;</literal> equal to
+    <constant>MALLCTL_ARENAS_DESTROYED</constant> can be used to access the
+    summation of statistics from all destroyed arenas.  These constants can be
     utilized either via <function>mallctlnametomib()</function> followed by
     <function>mallctlbymib()</function>, or via code such as the following:
     <programlisting language="C"><![CDATA[
@@ -707,9 +711,9 @@ for (i = 0; i < nbins; i++) {
 
 mallctl("arena." STRINGIFY(MALLCTL_ARENAS_ALL) ".decay",
     NULL, NULL, NULL, 0);]]></programlisting>
-    Take special note of the
+    Take special note of the <link
-    <link linkend="epoch"><mallctl>epoch</mallctl></link> mallctl, which
+    linkend="epoch"><mallctl>epoch</mallctl></link> mallctl, which controls
-    controls refreshing of cached dynamic statistics.</para>
+    refreshing of cached dynamic statistics.</para>
 
     <variablelist>
       <varlistentry id="version">
@@ -1478,6 +1482,25 @@ malloc_conf = "xmalloc:true";]]></programlisting>
         beforehand.</para></listitem>
       </varlistentry>
 
+      <varlistentry id="arena.i.destroy">
+        <term>
+          <mallctl>arena.&lt;i&gt;.destroy</mallctl>
+          (<type>void</type>)
+          <literal>--</literal>
+        </term>
+        <listitem><para>Destroy the arena.  Discard all of the arena's extant
+        allocations using the same mechanism as for <link
+        linkend="arena.i.reset"><mallctl>arena.&lt;i&gt;.reset</mallctl></link>
+        (with all the same constraints and side effects), merge the arena stats
+        into those accessible at arena index
+        <constant>MALLCTL_ARENAS_DESTROYED</constant>, and then completely
+        discard all metadata associated with the arena.  Future calls to <link
+        linkend="arenas.create"><mallctl>arenas.create</mallctl></link> may
+        recycle the arena index.  Destruction will fail if any threads are
+        currently associated with the arena as a result of calls to <link
+        linkend="thread.arena"><mallctl>thread.arena</mallctl></link>.</para></listitem>
+      </varlistentry>
+
       <varlistentry id="arena.i.dss">
         <term>
           <mallctl>arena.&lt;i&gt;.dss</mallctl>

include/jemalloc/internal/arena.h

@@ -290,6 +290,7 @@ bool	arena_decay_time_set(tsdn_t *tsdn, arena_t *arena, ssize_t decay_time);
 void	arena_purge(tsdn_t *tsdn, arena_t *arena, bool all);
 void	arena_maybe_purge(tsdn_t *tsdn, arena_t *arena);
 void	arena_reset(tsd_t *tsd, arena_t *arena);
+void	arena_destroy(tsd_t *tsd, arena_t *arena);
 void	arena_tcache_fill_small(tsdn_t *tsdn, arena_t *arena,
     tcache_bin_t *tbin, szind_t binind, uint64_t prof_accumbytes);
 void	arena_alloc_junk_small(void *ptr, const arena_bin_info_t *bin_info,

include/jemalloc/internal/ctl.h

@@ -32,7 +32,10 @@ struct ctl_indexed_node_s {
 };
 
 struct ctl_arena_stats_s {
+	unsigned		arena_ind;
 	bool			initialized;
+	ql_elm(ctl_arena_stats_t)	destroyed_link;
+
 	unsigned		nthreads;
 	const char		*dss;
 	ssize_t			decay_time;
@@ -62,7 +65,14 @@ struct ctl_stats_s {
 	size_t			mapped;
 	size_t			retained;
 	unsigned		narenas;
-	ctl_arena_stats_t	*arenas[1 << MALLOCX_ARENA_BITS];
+	ql_head(ctl_arena_stats_t)	destroyed;
+	/*
+	 * Element 0 contains merged stats for extant arenas (accessed via
+	 * MALLCTL_ARENAS_ALL), element 1 contains merged stats for destroyed
+	 * arenas (accessed via MALLCTL_ARENAS_DESTROYED), and the remaining
+	 * MALLOCX_ARENA_MAX+1 elements correspond to arenas.
+	 */
+	ctl_arena_stats_t	*arenas[MALLOCX_ARENA_MAX + 3];
 };
 
 #endif /* JEMALLOC_H_STRUCTS */

include/jemalloc/internal/extent.h

@@ -125,6 +125,8 @@ extent_t	*extent_alloc_wrapper(tsdn_t *tsdn, arena_t *arena,
 void	extent_dalloc_gap(tsdn_t *tsdn, arena_t *arena, extent_t *extent);
 void	extent_dalloc_cache(tsdn_t *tsdn, arena_t *arena,
     extent_hooks_t **r_extent_hooks, extent_t *extent);
+bool	extent_dalloc_wrapper_try(tsdn_t *tsdn, arena_t *arena,
+    extent_hooks_t **r_extent_hooks, extent_t *extent);
 void	extent_dalloc_wrapper(tsdn_t *tsdn, arena_t *arena,
     extent_hooks_t **r_extent_hooks, extent_t *extent);
 bool	extent_commit_wrapper(tsdn_t *tsdn, arena_t *arena,

include/jemalloc/internal/jemalloc_internal.h.in

@@ -215,6 +215,7 @@ typedef unsigned szind_t;
 #define	MALLOCX_TCACHE_SHIFT	8
 #define	MALLOCX_ARENA_MASK \
     (((1 << MALLOCX_ARENA_BITS) - 1) << MALLOCX_ARENA_SHIFT)
+/* NB: Arena index bias decreases the maximum number of arenas by 1. */
 #define	MALLOCX_ARENA_MAX	((1 << MALLOCX_ARENA_BITS) - 2)
 #define	MALLOCX_TCACHE_MASK \
     (((1 << MALLOCX_TCACHE_BITS) - 1) << MALLOCX_TCACHE_SHIFT)
@@ -470,6 +471,7 @@ void	a0dalloc(void *ptr);
 void	*bootstrap_malloc(size_t size);
 void	*bootstrap_calloc(size_t num, size_t size);
 void	bootstrap_free(void *ptr);
+void	arena_set(unsigned ind, arena_t *arena);
 unsigned	narenas_total_get(void);
 arena_t	*arena_init(tsdn_t *tsdn, unsigned ind, extent_hooks_t *extent_hooks);
 arena_tdata_t	*arena_tdata_get_hard(tsd_t *tsd, unsigned ind);

include/jemalloc/internal/private_symbols.txt

@@ -21,6 +21,7 @@ arena_decay_time_default_get
 arena_decay_time_default_set
 arena_decay_time_get
 arena_decay_time_set
+arena_destroy
 arena_dss_prec_get
 arena_dss_prec_set
 arena_extent_alloc_large
@@ -67,6 +68,7 @@ arena_ralloc_no_move
 arena_reset
 arena_salloc
 arena_sdalloc
+arena_set
 arena_slab_regind
 arena_stats_merge
 arena_tcache_fill_small
@@ -164,6 +166,7 @@ extent_dalloc_cache
 extent_dalloc_gap
 extent_dalloc_mmap
 extent_dalloc_wrapper
+extent_dalloc_wrapper_try
 extent_decommit_wrapper
 extent_dss_boot
 extent_dss_mergeable

include/jemalloc/jemalloc_macros.h.in

@@ -44,6 +44,11 @@
  *       0);
  */
 #define	MALLCTL_ARENAS_ALL	4096
+/*
+ * Use as arena index in "stats.arenas.<i>.*" mallctl interfaces to select
+ * destroyed arenas.
+ */
+#define	MALLCTL_ARENAS_DESTROYED	4097
 
 #if defined(__cplusplus) && defined(JEMALLOC_USE_CXX_THROW)
 #  define JEMALLOC_CXX_THROW throw()

src/arena.c

@@ -903,6 +903,72 @@ arena_reset(tsd_t *tsd, arena_t *arena)
 	malloc_mutex_unlock(tsd_tsdn(tsd), &arena->lock);
 }
 
+static void
+arena_destroy_retained(tsdn_t *tsdn, arena_t *arena)
+{
+	extent_hooks_t *extent_hooks = extent_hooks_get(arena);
+	size_t i;
+
+	/*
+	 * Iterate over the retained extents and blindly attempt to deallocate
+	 * them.  This gives the extent allocator underlying the extent hooks an
+	 * opportunity to unmap all retained memory without having to keep its
+	 * own metadata structures, but if deallocation fails, that is the
+	 * application's decision/problem.  In practice, retained extents are
+	 * leaked here if !config_munmap unless the application provided custom
+	 * extent hooks, so best practice to either enable munmap (and avoid dss
+	 * for arenas to be destroyed), or provide custom extent hooks that
+	 * either unmap retained extents or track them for later use.
+	 */
+	for (i = 0; i < sizeof(arena->extents_retained)/sizeof(extent_heap_t);
+	    i++) {
+		extent_heap_t *extents = &arena->extents_retained[i];
+		extent_t *extent;
+
+		while ((extent = extent_heap_remove_first(extents)) != NULL) {
+			extent_dalloc_wrapper_try(tsdn, arena, &extent_hooks,
+			    extent);
+		}
+	}
+}
+
+void
+arena_destroy(tsd_t *tsd, arena_t *arena)
+{
+
+	assert(base_ind_get(arena->base) >= narenas_auto);
+	assert(arena_nthreads_get(arena, false) == 0);
+	assert(arena_nthreads_get(arena, true) == 0);
+
+	/*
+	 * No allocations have occurred since arena_reset() was called.
+	 * Furthermore, the caller (arena_i_destroy_ctl()) purged all cached
+	 * extents, so only retained extents may remain.
+	 */
+	assert(arena->ndirty == 0);
+
+	/* Attempt to deallocate retained memory. */
+	arena_destroy_retained(tsd_tsdn(tsd), arena);
+
+	/*
+	 * Remove the arena pointer from the arenas array.  We rely on the fact
+	 * that there is no way for the application to get a dirty read from the
+	 * arenas array unless there is an inherent race in the application
+	 * involving access of an arena being concurrently destroyed.  The
+	 * application must synchronize knowledge of the arena's validity, so as
+	 * long as we use an atomic write to update the arenas array, the
+	 * application will get a clean read any time after it synchronizes
+	 * knowledge that the arena is no longer valid.
+	 */
+	arena_set(base_ind_get(arena->base), NULL);
+
+	/*
+	 * Destroy the base allocator, which manages all metadata ever mapped by
+	 * this arena.
+	 */
+	base_delete(arena->base);
+}
+
 static extent_t *
 arena_slab_alloc_hard(tsdn_t *tsdn, arena_t *arena,
     extent_hooks_t **r_extent_hooks, const arena_bin_info_t *bin_info)

src/ctl.c

@@ -48,18 +48,6 @@ static int	n##_ctl(tsd_t *tsd, const size_t *mib, size_t miblen,	\
 static const ctl_named_node_t	*n##_index(tsdn_t *tsdn,		\
     const size_t *mib, size_t miblen, size_t i);
 
-static void	ctl_arena_clear(ctl_arena_stats_t *astats);
-static void	ctl_arena_stats_amerge(tsdn_t *tsdn, ctl_arena_stats_t *cstats,
-    arena_t *arena);
-static void	ctl_arena_stats_smerge(ctl_arena_stats_t *sstats,
-    ctl_arena_stats_t *astats);
-static void	ctl_arena_refresh(tsdn_t *tsdn, arena_t *arena, unsigned i);
-static bool	ctl_grow(tsdn_t *tsdn, extent_hooks_t *extent_hooks);
-static void	ctl_refresh(tsdn_t *tsdn);
-static bool	ctl_init(tsdn_t *tsdn);
-static int	ctl_lookup(tsdn_t *tsdn, const char *name,
-    ctl_node_t const **nodesp, size_t *mibp, size_t *depthp);
-
 CTL_PROTO(version)
 CTL_PROTO(epoch)
 CTL_PROTO(thread_tcache_enabled)
@@ -113,6 +101,7 @@ CTL_PROTO(arena_i_initialized)
 CTL_PROTO(arena_i_purge)
 CTL_PROTO(arena_i_decay)
 CTL_PROTO(arena_i_reset)
+CTL_PROTO(arena_i_destroy)
 CTL_PROTO(arena_i_dss)
 CTL_PROTO(arena_i_decay_time)
 CTL_PROTO(arena_i_extent_hooks)
@@ -274,6 +263,7 @@ static const ctl_named_node_t arena_i_node[] = {
 	{NAME("purge"),		CTL(arena_i_purge)},
 	{NAME("decay"),		CTL(arena_i_decay)},
 	{NAME("reset"),		CTL(arena_i_reset)},
+	{NAME("destroy"),	CTL(arena_i_destroy)},
 	{NAME("dss"),		CTL(arena_i_dss)},
 	{NAME("decay_time"),	CTL(arena_i_decay_time)},
 	{NAME("extent_hooks"),	CTL(arena_i_extent_hooks)}
@@ -452,6 +442,9 @@ stats_arenas_i2a_impl(size_t i, bool compat, bool validate)
 	case MALLCTL_ARENAS_ALL:
 		a = 0;
 		break;
+	case MALLCTL_ARENAS_DESTROYED:
+		a = 1;
+		break;
 	default:
 		if (compat && i == ctl_stats->narenas) {
 			/*
@@ -471,7 +464,7 @@ stats_arenas_i2a_impl(size_t i, bool compat, bool validate)
 			 */
 			assert(i < ctl_stats->narenas || (!validate && i ==
 			    ctl_stats->narenas));
-			a = (unsigned)i + 1;
+			a = (unsigned)i + 2;
 		}
 		break;
 	}
@@ -479,6 +472,13 @@ stats_arenas_i2a_impl(size_t i, bool compat, bool validate)
 	return (a);
 }
 
+static unsigned
+stats_arenas_i2a(size_t i)
+{
+
+	return (stats_arenas_i2a_impl(i, true, false));
+}
+
 static ctl_arena_stats_t *
 stats_arenas_i_impl(tsdn_t *tsdn, size_t i, bool compat, bool init)
 {
@@ -492,10 +492,13 @@ stats_arenas_i_impl(tsdn_t *tsdn, size_t i, bool compat, bool init)
 		    sizeof(ctl_arena_stats_t), QUANTUM);
 		if (ret == NULL)
 			return (NULL);
+		ret->arena_ind = (unsigned)i;
 		ctl_stats->arenas[stats_arenas_i2a_impl(i, compat, false)] =
 		    ret;
 	}
 
+	assert(ret == NULL || stats_arenas_i2a(ret->arena_ind) ==
+	    stats_arenas_i2a(i));
 	return (ret);
 }
 
@@ -553,92 +556,130 @@ ctl_arena_stats_amerge(tsdn_t *tsdn, ctl_arena_stats_t *cstats, arena_t *arena)
 }
 
 static void
-ctl_arena_stats_smerge(ctl_arena_stats_t *sstats, ctl_arena_stats_t *astats)
+ctl_arena_stats_sdmerge(ctl_arena_stats_t *sdstats, ctl_arena_stats_t *astats,
+    bool destroyed)
 {
 	unsigned i;
 
-	sstats->nthreads += astats->nthreads;
+	if (!destroyed) {
-	sstats->pactive += astats->pactive;
+		sdstats->nthreads += astats->nthreads;
-	sstats->pdirty += astats->pdirty;
+		sdstats->pactive += astats->pactive;
+		sdstats->pdirty += astats->pdirty;
+	} else {
+		assert(astats->nthreads == 0);
+		assert(astats->pactive == 0);
+		assert(astats->pdirty == 0);
+	}
 
 	if (config_stats) {
-		sstats->astats.mapped += astats->astats.mapped;
+		if (!destroyed) {
-		sstats->astats.retained += astats->astats.retained;
+			sdstats->astats.mapped += astats->astats.mapped;
-		sstats->astats.npurge += astats->astats.npurge;
+			sdstats->astats.retained += astats->astats.retained;
-		sstats->astats.nmadvise += astats->astats.nmadvise;
+		}
-		sstats->astats.purged += astats->astats.purged;
+		sdstats->astats.npurge += astats->astats.npurge;
+		sdstats->astats.nmadvise += astats->astats.nmadvise;
+		sdstats->astats.purged += astats->astats.purged;
 
-		sstats->astats.base += astats->astats.base;
+		if (!destroyed) {
-		sstats->astats.internal += astats->astats.internal;
+			sdstats->astats.base += astats->astats.base;
-		sstats->astats.resident += astats->astats.resident;
+			sdstats->astats.internal += astats->astats.internal;
+			sdstats->astats.resident += astats->astats.resident;
+		} else
+			assert(astats->astats.internal == 0);
 
-		sstats->allocated_small += astats->allocated_small;
+		if (!destroyed)
-		sstats->nmalloc_small += astats->nmalloc_small;
+			sdstats->allocated_small += astats->allocated_small;
-		sstats->ndalloc_small += astats->ndalloc_small;
+		else
-		sstats->nrequests_small += astats->nrequests_small;
+			assert(astats->allocated_small == 0);
+		sdstats->nmalloc_small += astats->nmalloc_small;
+		sdstats->ndalloc_small += astats->ndalloc_small;
+		sdstats->nrequests_small += astats->nrequests_small;
 
-		sstats->astats.allocated_large +=
+		if (!destroyed) {
+			sdstats->astats.allocated_large +=
 			    astats->astats.allocated_large;
-		sstats->astats.nmalloc_large += astats->astats.nmalloc_large;
+		} else
-		sstats->astats.ndalloc_large += astats->astats.ndalloc_large;
+			assert(astats->astats.allocated_large == 0);
-		sstats->astats.nrequests_large +=
+		sdstats->astats.nmalloc_large += astats->astats.nmalloc_large;
+		sdstats->astats.ndalloc_large += astats->astats.ndalloc_large;
+		sdstats->astats.nrequests_large +=
 		    astats->astats.nrequests_large;
 
 		for (i = 0; i < NBINS; i++) {
-			sstats->bstats[i].nmalloc += astats->bstats[i].nmalloc;
+			sdstats->bstats[i].nmalloc += astats->bstats[i].nmalloc;
-			sstats->bstats[i].ndalloc += astats->bstats[i].ndalloc;
+			sdstats->bstats[i].ndalloc += astats->bstats[i].ndalloc;
-			sstats->bstats[i].nrequests +=
+			sdstats->bstats[i].nrequests +=
 			    astats->bstats[i].nrequests;
-			sstats->bstats[i].curregs += astats->bstats[i].curregs;
+			if (!destroyed) {
+				sdstats->bstats[i].curregs +=
+				    astats->bstats[i].curregs;
+			} else
+				assert(astats->bstats[i].curregs == 0);
 			if (config_tcache) {
-				sstats->bstats[i].nfills +=
+				sdstats->bstats[i].nfills +=
 				    astats->bstats[i].nfills;
-				sstats->bstats[i].nflushes +=
+				sdstats->bstats[i].nflushes +=
 				    astats->bstats[i].nflushes;
 			}
-			sstats->bstats[i].nslabs += astats->bstats[i].nslabs;
+			sdstats->bstats[i].nslabs += astats->bstats[i].nslabs;
-			sstats->bstats[i].reslabs += astats->bstats[i].reslabs;
+			sdstats->bstats[i].reslabs += astats->bstats[i].reslabs;
-			sstats->bstats[i].curslabs +=
+			if (!destroyed) {
+				sdstats->bstats[i].curslabs +=
 				    astats->bstats[i].curslabs;
+			} else
+				assert(astats->bstats[i].curslabs == 0);
 		}
 
 		for (i = 0; i < NSIZES - NBINS; i++) {
-			sstats->lstats[i].nmalloc += astats->lstats[i].nmalloc;
+			sdstats->lstats[i].nmalloc += astats->lstats[i].nmalloc;
-			sstats->lstats[i].ndalloc += astats->lstats[i].ndalloc;
+			sdstats->lstats[i].ndalloc += astats->lstats[i].ndalloc;
-			sstats->lstats[i].nrequests +=
+			sdstats->lstats[i].nrequests +=
 			    astats->lstats[i].nrequests;
-			sstats->lstats[i].curlextents +=
+			if (!destroyed) {
+				sdstats->lstats[i].curlextents +=
 				    astats->lstats[i].curlextents;
+			} else
+				assert(astats->lstats[i].curlextents == 0);
 		}
 	}
 }
 
 static void
-ctl_arena_refresh(tsdn_t *tsdn, arena_t *arena, unsigned i)
+ctl_arena_refresh(tsdn_t *tsdn, arena_t *arena, ctl_arena_stats_t *sdstats,
+    unsigned i, bool destroyed)
 {
 	ctl_arena_stats_t *astats = stats_arenas_i(i);
-	ctl_arena_stats_t *sstats = stats_arenas_i(MALLCTL_ARENAS_ALL);
 
 	ctl_arena_clear(astats);
 	ctl_arena_stats_amerge(tsdn, astats, arena);
 	/* Merge into sum stats as well. */
-	ctl_arena_stats_smerge(sstats, astats);
+	ctl_arena_stats_sdmerge(sdstats, astats, destroyed);
 }
 
-static bool
+static unsigned
-ctl_grow(tsdn_t *tsdn, extent_hooks_t *extent_hooks)
+ctl_arena_init(tsdn_t *tsdn, extent_hooks_t *extent_hooks)
 {
+	unsigned arena_ind;
+	ctl_arena_stats_t *astats;
+
+	if ((astats = ql_last(&ctl_stats->destroyed, destroyed_link)) != NULL) {
+		ql_remove(&ctl_stats->destroyed, astats, destroyed_link);
+		arena_ind = astats->arena_ind;
+	} else
+		arena_ind = ctl_stats->narenas;
 
 	/* Trigger stats allocation. */
-	if (stats_arenas_i_impl(tsdn, ctl_stats->narenas, false, true) == NULL)
+	if (stats_arenas_i_impl(tsdn, arena_ind, false, true) == NULL)
-		return (true);
+		return (UINT_MAX);
 
 	/* Initialize new arena. */
-	if (arena_init(tsdn, ctl_stats->narenas, extent_hooks) == NULL)
+	if (arena_init(tsdn, arena_ind, extent_hooks) == NULL)
-		return (true);
+		return (UINT_MAX);
+
+	if (arena_ind == ctl_stats->narenas)
 		ctl_stats->narenas++;
 
-	return (false);
+	return (arena_ind);
 }
 
 static void
@@ -663,7 +704,7 @@ ctl_refresh(tsdn_t *tsdn)
 
 		astats->initialized = initialized;
 		if (initialized)
-			ctl_arena_refresh(tsdn, tarenas[i], i);
+			ctl_arena_refresh(tsdn, tarenas[i], sstats, i, false);
 	}
 
 	if (config_stats) {
@@ -687,7 +728,7 @@ ctl_init(tsdn_t *tsdn)
 
 	malloc_mutex_lock(tsdn, &ctl_mtx);
 	if (!ctl_initialized) {
-		ctl_arena_stats_t *sstats;
+		ctl_arena_stats_t *sstats, *dstats;
 		unsigned i;
 
 		/*
@@ -715,6 +756,19 @@ ctl_init(tsdn_t *tsdn)
 		}
 		sstats->initialized = true;
 
+		if ((dstats = stats_arenas_i_impl(tsdn,
+		    MALLCTL_ARENAS_DESTROYED, false, true)) == NULL) {
+			ret = true;
+			goto label_return;
+		}
+		ctl_arena_clear(dstats);
+		/*
+		 * Don't toggle stats for MALLCTL_ARENAS_DESTROYED to
+		 * initialized until an arena is actually destroyed, so that
+		 * arena.<i>.initialized can be used to query whether the stats
+		 * are relevant.
+		 */
+
 		ctl_stats->narenas = narenas_total_get();
 		for (i = 0; i < ctl_stats->narenas; i++) {
 			if (stats_arenas_i_impl(tsdn, i, false, true) == NULL) {
@@ -723,7 +777,7 @@ ctl_init(tsdn_t *tsdn)
 			}
 		}
 
-		ctl_stats->epoch = 0;
+		ql_new(&ctl_stats->destroyed);
 		ctl_refresh(tsdn);
 		ctl_initialized = true;
 	}
@@ -1562,6 +1616,33 @@ label_return:
 	return (ret);
 }
 
+static int
+arena_i_reset_destroy_helper(tsd_t *tsd, const size_t *mib, size_t miblen,
+    void *oldp, size_t *oldlenp, void *newp, size_t newlen, unsigned *arena_ind,
+    arena_t **arena)
+{
+	int ret;
+
+	READONLY();
+	WRITEONLY();
+	MIB_UNSIGNED(*arena_ind, 1);
+
+	if (*arena_ind < narenas_auto) {
+		ret = EFAULT;
+		goto label_return;
+	}
+
+	*arena = arena_get(tsd_tsdn(tsd), *arena_ind, false);
+	if (*arena == NULL) {
+		ret = EFAULT;
+		goto label_return;
+	}
+
+	ret = 0;
+label_return:
+	return (ret);
+}
+
 static int
 arena_i_reset_ctl(tsd_t *tsd, const size_t *mib, size_t miblen, void *oldp,
     size_t *oldlenp, void *newp, size_t newlen)
@@ -1570,26 +1651,51 @@ arena_i_reset_ctl(tsd_t *tsd, const size_t *mib, size_t miblen, void *oldp,
 	unsigned arena_ind;
 	arena_t *arena;
 
-	READONLY();
+	ret = arena_i_reset_destroy_helper(tsd, mib, miblen, oldp, oldlenp,
-	WRITEONLY();
+	    newp, newlen, &arena_ind, &arena);
-	MIB_UNSIGNED(arena_ind, 1);
+	if (ret != 0)
+		return (ret);
 
-	if (config_debug) {
+	arena_reset(tsd, arena);
-		malloc_mutex_lock(tsd_tsdn(tsd), &ctl_mtx);
-		assert(arena_ind < ctl_stats->narenas);
-		malloc_mutex_unlock(tsd_tsdn(tsd), &ctl_mtx);
-	}
-	assert(arena_ind >= opt_narenas);
 
-	arena = arena_get(tsd_tsdn(tsd), arena_ind, false);
+	return (ret);
-	if (arena == NULL) {
+}
+
+static int
+arena_i_destroy_ctl(tsd_t *tsd, const size_t *mib, size_t miblen, void *oldp,
+    size_t *oldlenp, void *newp, size_t newlen)
+{
+	int ret;
+	unsigned arena_ind;
+	arena_t *arena;
+	ctl_arena_stats_t *dstats, *astats;
+
+	ret = arena_i_reset_destroy_helper(tsd, mib, miblen, oldp, oldlenp,
+	    newp, newlen, &arena_ind, &arena);
+	if (ret != 0)
+		goto label_return;
+
+	if (arena_nthreads_get(arena, false) != 0 || arena_nthreads_get(arena,
+	    true) != 0) {
 		ret = EFAULT;
 		goto label_return;
 	}
 
+	/* Merge stats after resetting and purging arena. */
 	arena_reset(tsd, arena);
+	arena_purge(tsd_tsdn(tsd), arena, true);
+	dstats = stats_arenas_i(MALLCTL_ARENAS_DESTROYED);
+	dstats->initialized = true;
+	ctl_arena_refresh(tsd_tsdn(tsd), arena, dstats, arena_ind, true);
+	/* Destroy arena. */
+	arena_destroy(tsd, arena);
+	astats = stats_arenas_i(arena_ind);
+	astats->initialized = false;
+	/* Record arena index for later recycling via arenas.create. */
+	ql_elm_new(astats, destroyed_link);
+	ql_tail_insert(&ctl_stats->destroyed, astats, destroyed_link);
 
-	ret = 0;
+	assert(ret == 0);
 label_return:
 	return (ret);
 }
@@ -1733,10 +1839,17 @@ arena_i_index(tsdn_t *tsdn, const size_t *mib, size_t miblen, size_t i)
 	const ctl_named_node_t *ret;
 
 	malloc_mutex_lock(tsdn, &ctl_mtx);
-	if (i > ctl_stats->narenas && i != MALLCTL_ARENAS_ALL) {
+	switch (i) {
+	case MALLCTL_ARENAS_ALL:
+	case MALLCTL_ARENAS_DESTROYED:
+		break;
+	default:
+		if (i > ctl_stats->narenas) {
 			ret = NULL;
 			goto label_return;
 		}
+		break;
+	}
 
 	ret = super_arena_i_node;
 label_return:
@@ -1828,18 +1941,18 @@ arenas_create_ctl(tsd_t *tsd, const size_t *mib, size_t miblen, void *oldp,
 {
 	int ret;
 	extent_hooks_t *extent_hooks;
-	unsigned narenas;
+	unsigned arena_ind;
 
 	malloc_mutex_lock(tsd_tsdn(tsd), &ctl_mtx);
 
 	extent_hooks = (extent_hooks_t *)&extent_hooks_default;
 	WRITE(extent_hooks, extent_hooks_t *);
-	if (ctl_grow(tsd_tsdn(tsd), extent_hooks)) {
+	if ((arena_ind = ctl_arena_init(tsd_tsdn(tsd), extent_hooks)) ==
+	    UINT_MAX) {
 		ret = EAGAIN;
 		goto label_return;
 	}
-	narenas = ctl_stats->narenas - 1;
+	READ(arena_ind, unsigned);
-	READ(narenas, unsigned);
 
 	ret = 0;
 label_return:

src/extent.c

@@ -1039,11 +1039,11 @@ extent_dalloc_default(extent_hooks_t *extent_hooks, void *addr, size_t size,
 	return (extent_dalloc_default_impl(addr, size));
 }
 
-void
+bool
-extent_dalloc_wrapper(tsdn_t *tsdn, arena_t *arena,
+extent_dalloc_wrapper_try(tsdn_t *tsdn, arena_t *arena,
     extent_hooks_t **r_extent_hooks, extent_t *extent)
 {
-	bool err, zeroed;
+	bool err;
 
 	assert(extent_base_get(extent) != NULL);
 	assert(extent_size_get(extent) != 0);
@@ -1067,10 +1067,21 @@ extent_dalloc_wrapper(tsdn_t *tsdn, arena_t *arena,
 		    extent_committed_get(extent), arena_ind_get(arena)));
 	}
 
-	if (!err) {
+	if (!err)
 		extent_dalloc(tsdn, arena, extent);
+
+	return (err);
+}
+
+void
+extent_dalloc_wrapper(tsdn_t *tsdn, arena_t *arena,
+    extent_hooks_t **r_extent_hooks, extent_t *extent)
+{
+	bool zeroed;
+
+	if (!extent_dalloc_wrapper_try(tsdn, arena, r_extent_hooks, extent))
 		return;
-	}
+
 	extent_reregister(tsdn, extent);
 	/* Try to decommit; purge if that fails. */
 	if (!extent_committed_get(extent))

src/jemalloc.c

@@ -375,7 +375,7 @@ bootstrap_free(void *ptr)
 	a0idalloc(iealloc(NULL, ptr), ptr, false);
 }
 
-static void
+void
 arena_set(unsigned ind, arena_t *arena)
 {
 

src/stats.c

@@ -772,7 +772,8 @@ stats_general_print(void (*write_cb)(void *, const char *), void *cbopaque,
 
 static void
 stats_print_helper(void (*write_cb)(void *, const char *), void *cbopaque,
-    bool json, bool merged, bool unmerged, bool bins, bool large)
+    bool json, bool merged, bool destroyed, bool unmerged, bool bins,
+    bool large)
 {
 	size_t allocated, active, metadata, resident, mapped, retained;
 
@@ -808,7 +809,7 @@ stats_print_helper(void (*write_cb)(void *, const char *), void *cbopaque,
 		    allocated, active, metadata, resident, mapped, retained);
 	}
 
-	if (merged || unmerged) {
+	if (merged || destroyed || unmerged) {
 		unsigned narenas;
 
 		if (json) {
@@ -822,6 +823,7 @@ stats_print_helper(void (*write_cb)(void *, const char *), void *cbopaque,
 			size_t miblen = sizeof(mib) / sizeof(size_t);
 			size_t sz;
 			VARIABLE_ARRAY(bool, initialized, narenas);
+			bool destroyed_initialized;
 			unsigned i, j, ninitialized;
 
 			xmallctlnametomib("arena.0.initialized", mib, &miblen);
@@ -833,6 +835,10 @@ stats_print_helper(void (*write_cb)(void *, const char *), void *cbopaque,
 				if (initialized[i])
 					ninitialized++;
 			}
+			mib[1] = MALLCTL_ARENAS_DESTROYED;
+			sz = sizeof(bool);
+			xmallctlbymib(mib, miblen, &destroyed_initialized, &sz,
+			    NULL, 0);
 
 			/* Merged stats. */
 			if (merged && (ninitialized > 1 || !unmerged)) {
@@ -853,6 +859,25 @@ stats_print_helper(void (*write_cb)(void *, const char *), void *cbopaque,
 				}
 			}
 
+			/* Destroyed stats. */
+			if (destroyed_initialized && destroyed) {
+				/* Print destroyed arena stats. */
+				if (json) {
+					malloc_cprintf(write_cb, cbopaque,
+					    "\t\t\t\"destroyed\": {\n");
+				} else {
+					malloc_cprintf(write_cb, cbopaque,
+					    "\nDestroyed arenas stats:\n");
+				}
+				stats_arena_print(write_cb, cbopaque, json,
+				    MALLCTL_ARENAS_DESTROYED, bins, large);
+				if (json) {
+					malloc_cprintf(write_cb, cbopaque,
+					    "\t\t\t}%s\n", (ninitialized > 1) ?
+					    "," : "");
+				}
+			}
+
 			/* Unmerged stats. */
 			for (i = j = 0; i < narenas; i++) {
 				if (initialized[i]) {
@@ -895,6 +920,7 @@ stats_print(void (*write_cb)(void *, const char *), void *cbopaque,
 	bool json = false;
 	bool general = true;
 	bool merged = config_stats;
+	bool destroyed = config_stats;
 	bool unmerged = config_stats;
 	bool bins = true;
 	bool large = true;
@@ -935,6 +961,9 @@ stats_print(void (*write_cb)(void *, const char *), void *cbopaque,
 			case 'm':
 				merged = false;
 				break;
+			case 'd':
+				destroyed = false;
+				break;
 			case 'a':
 				unmerged = false;
 				break;
@@ -963,8 +992,8 @@ stats_print(void (*write_cb)(void *, const char *), void *cbopaque,
 		stats_general_print(write_cb, cbopaque, json, more);
 	}
 	if (config_stats) {
-		stats_print_helper(write_cb, cbopaque, json, merged, unmerged,
+		stats_print_helper(write_cb, cbopaque, json, merged, destroyed,
-		    bins, large);
+		    unmerged, bins, large);
 	}
 
 	if (json) {

test/unit/arena_reset.c

@@ -1,9 +1,9 @@
+#ifndef ARENA_RESET_PROF_C_
 #include "test/jemalloc_test.h"
-
-#ifdef JEMALLOC_PROF
-const char *malloc_conf = "prof:true,lg_prof_sample:0";
 #endif
 
+#include "test/extent_hooks.h"
+
 static unsigned
 get_nsizes_impl(const char *cmd)
 {
@@ -79,57 +79,64 @@ vsalloc(tsdn_t *tsdn, const void *ptr)
 	return (isalloc(tsdn, extent, ptr));
 }
 
-TEST_BEGIN(test_arena_reset)
+static unsigned
+do_arena_create(extent_hooks_t *h)
+{
+	unsigned arena_ind;
+	size_t sz = sizeof(unsigned);
+	assert_d_eq(mallctl("arenas.create", (void *)&arena_ind, &sz,
+	    (void *)(h != NULL ? &h : NULL), (h != NULL ? sizeof(h) : 0)), 0,
+	    "Unexpected mallctl() failure");
+	return (arena_ind);
+}
+
+static void
+do_arena_reset_pre(unsigned arena_ind, void ***ptrs, unsigned *nptrs)
 {
 #define	NLARGE	32
-	unsigned arena_ind, nsmall, nlarge, nptrs, i;
+	unsigned nsmall, nlarge, i;
-	size_t sz, miblen;
+	size_t sz;
-	void **ptrs;
 	int flags;
-	size_t mib[3];
 	tsdn_t *tsdn;
 
-	sz = sizeof(unsigned);
-	assert_d_eq(mallctl("arenas.create", (void *)&arena_ind, &sz, NULL, 0),
-	    0, "Unexpected mallctl() failure");
-
 	flags = MALLOCX_ARENA(arena_ind) | MALLOCX_TCACHE_NONE;
 
 	nsmall = get_nsmall();
 	nlarge = get_nlarge() > NLARGE ? NLARGE : get_nlarge();
-	nptrs = nsmall + nlarge;
+	*nptrs = nsmall + nlarge;
-	ptrs = (void **)malloc(nptrs * sizeof(void *));
+	*ptrs = (void **)malloc(*nptrs * sizeof(void *));
-	assert_ptr_not_null(ptrs, "Unexpected malloc() failure");
+	assert_ptr_not_null(*ptrs, "Unexpected malloc() failure");
 
 	/* Allocate objects with a wide range of sizes. */
 	for (i = 0; i < nsmall; i++) {
 		sz = get_small_size(i);
-		ptrs[i] = mallocx(sz, flags);
+		(*ptrs)[i] = mallocx(sz, flags);
-		assert_ptr_not_null(ptrs[i],
+		assert_ptr_not_null((*ptrs)[i],
 		    "Unexpected mallocx(%zu, %#x) failure", sz, flags);
 	}
 	for (i = 0; i < nlarge; i++) {
 		sz = get_large_size(i);
-		ptrs[nsmall + i] = mallocx(sz, flags);
+		(*ptrs)[nsmall + i] = mallocx(sz, flags);
-		assert_ptr_not_null(ptrs[i],
+		assert_ptr_not_null((*ptrs)[i],
 		    "Unexpected mallocx(%zu, %#x) failure", sz, flags);
 	}
 
 	tsdn = tsdn_fetch();
 
 	/* Verify allocations. */
-	for (i = 0; i < nptrs; i++) {
+	for (i = 0; i < *nptrs; i++) {
-		assert_zu_gt(ivsalloc(tsdn, ptrs[i]), 0,
+		assert_zu_gt(ivsalloc(tsdn, (*ptrs)[i]), 0,
 		    "Allocation should have queryable size");
 	}
+}
 
-	/* Reset. */
+static void
-	miblen = sizeof(mib)/sizeof(size_t);
+do_arena_reset_post(void **ptrs, unsigned nptrs)
-	assert_d_eq(mallctlnametomib("arena.0.reset", mib, &miblen), 0,
+{
-	    "Unexpected mallctlnametomib() failure");
+	tsdn_t *tsdn;
-	mib[1] = (size_t)arena_ind;
+	unsigned i;
-	assert_d_eq(mallctlbymib(mib, miblen, NULL, NULL, NULL, 0), 0,
+
-	    "Unexpected mallctlbymib() failure");
+	tsdn = tsdn_fetch();
 
 	/* Verify allocations no longer exist. */
 	for (i = 0; i < nptrs; i++) {
@@ -139,6 +146,193 @@ TEST_BEGIN(test_arena_reset)
 
 	free(ptrs);
 }
+
+static void
+do_arena_reset_destroy(const char *name, unsigned arena_ind)
+{
+	size_t mib[3];
+	size_t miblen;
+
+	miblen = sizeof(mib)/sizeof(size_t);
+	assert_d_eq(mallctlnametomib(name, mib, &miblen), 0,
+	    "Unexpected mallctlnametomib() failure");
+	mib[1] = (size_t)arena_ind;
+	assert_d_eq(mallctlbymib(mib, miblen, NULL, NULL, NULL, 0), 0,
+	    "Unexpected mallctlbymib() failure");
+}
+
+static void
+do_arena_reset(unsigned arena_ind)
+{
+
+	do_arena_reset_destroy("arena.0.reset", arena_ind);
+}
+
+static void
+do_arena_destroy(unsigned arena_ind)
+{
+
+	do_arena_reset_destroy("arena.0.destroy", arena_ind);
+}
+
+TEST_BEGIN(test_arena_reset)
+{
+	unsigned arena_ind;
+	void **ptrs;
+	unsigned nptrs;
+
+	arena_ind = do_arena_create(NULL);
+	do_arena_reset_pre(arena_ind, &ptrs, &nptrs);
+	do_arena_reset(arena_ind);
+	do_arena_reset_post(ptrs, nptrs);
+}
+TEST_END
+
+static bool
+arena_i_initialized(unsigned arena_ind, bool refresh)
+{
+	bool initialized;
+	size_t mib[3];
+	size_t miblen, sz;
+
+	if (refresh) {
+		uint64_t epoch = 1;
+		assert_d_eq(mallctl("epoch", NULL, NULL, (void *)&epoch,
+		    sizeof(epoch)), 0, "Unexpected mallctl() failure");
+	}
+
+	miblen = sizeof(mib)/sizeof(size_t);
+	assert_d_eq(mallctlnametomib("arena.0.initialized", mib, &miblen), 0,
+	    "Unexpected mallctlnametomib() failure");
+	mib[1] = (size_t)arena_ind;
+	sz = sizeof(initialized);
+	assert_d_eq(mallctlbymib(mib, miblen, (void *)&initialized, &sz, NULL,
+	    0), 0, "Unexpected mallctlbymib() failure");
+
+	return (initialized);
+}
+
+TEST_BEGIN(test_arena_destroy_initial)
+{
+
+	assert_false(arena_i_initialized(MALLCTL_ARENAS_DESTROYED, false),
+	    "Destroyed arena stats should not be initialized");
+}
+TEST_END
+
+TEST_BEGIN(test_arena_destroy_hooks_default)
+{
+	unsigned arena_ind, arena_ind_another, arena_ind_prev;
+	void **ptrs;
+	unsigned nptrs;
+
+	arena_ind = do_arena_create(NULL);
+	do_arena_reset_pre(arena_ind, &ptrs, &nptrs);
+
+	assert_false(arena_i_initialized(arena_ind, false),
+	    "Arena stats should not be initialized");
+	assert_true(arena_i_initialized(arena_ind, true),
+	    "Arena stats should be initialized");
+
+	/*
+	 * Create another arena before destroying one, to better verify arena
+	 * index reuse.
+	 */
+	arena_ind_another = do_arena_create(NULL);
+
+	do_arena_destroy(arena_ind);
+
+	assert_false(arena_i_initialized(arena_ind, true),
+	    "Arena stats should not be initialized");
+	assert_true(arena_i_initialized(MALLCTL_ARENAS_DESTROYED, false),
+	    "Destroyed arena stats should be initialized");
+
+	do_arena_reset_post(ptrs, nptrs);
+
+	arena_ind_prev = arena_ind;
+	arena_ind = do_arena_create(NULL);
+	do_arena_reset_pre(arena_ind, &ptrs, &nptrs);
+	assert_u_eq(arena_ind, arena_ind_prev,
+	    "Arena index should have been recycled");
+	do_arena_destroy(arena_ind);
+	do_arena_reset_post(ptrs, nptrs);
+
+	do_arena_destroy(arena_ind_another);
+}
+TEST_END
+
+/*
+ * Actually unmap extents, regardless of config_munmap, so that attempts to
+ * access a destroyed arena's memory will segfault.
+ */
+static bool
+extent_dalloc_unmap(extent_hooks_t *extent_hooks, void *addr, size_t size,
+    bool committed, unsigned arena_ind)
+{
+
+	TRACE_HOOK("%s(extent_hooks=%p, addr=%p, size=%zu, committed=%s, "
+	    "arena_ind=%u)\n", __func__, extent_hooks, addr, size, committed ?
+	    "true" : "false", arena_ind);
+	assert_ptr_eq(extent_hooks, &hooks,
+	    "extent_hooks should be same as pointer used to set hooks");
+	assert_ptr_eq(extent_hooks->dalloc, extent_dalloc_unmap,
+	    "Wrong hook function");
+	called_dalloc = true;
+	if (!try_dalloc)
+		return (true);
+	pages_unmap(addr, size);
+	did_dalloc = true;
+	return (false);
+}
+
+static extent_hooks_t hooks_orig;
+
+static extent_hooks_t hooks_unmap = {
+	extent_alloc_hook,
+	extent_dalloc_unmap, /* dalloc */
+	extent_commit_hook,
+	extent_decommit_hook,
+	extent_purge_lazy_hook,
+	extent_purge_forced_hook,
+	extent_split_hook,
+	extent_merge_hook
+};
+
+TEST_BEGIN(test_arena_destroy_hooks_unmap)
+{
+	unsigned arena_ind;
+	void **ptrs;
+	unsigned nptrs;
+
+	extent_hooks_prep();
+	try_decommit = false;
+	memcpy(&hooks_orig, &hooks, sizeof(extent_hooks_t));
+	memcpy(&hooks, &hooks_unmap, sizeof(extent_hooks_t));
+
+	did_alloc = false;
+	arena_ind = do_arena_create(&hooks);
+	do_arena_reset_pre(arena_ind, &ptrs, &nptrs);
+
+	assert_true(did_alloc, "Expected alloc");
+
+	assert_false(arena_i_initialized(arena_ind, false),
+	    "Arena stats should not be initialized");
+	assert_true(arena_i_initialized(arena_ind, true),
+	    "Arena stats should be initialized");
+
+	did_dalloc = false;
+	do_arena_destroy(arena_ind);
+	assert_true(did_dalloc, "Expected dalloc");
+
+	assert_false(arena_i_initialized(arena_ind, true),
+	    "Arena stats should not be initialized");
+	assert_true(arena_i_initialized(MALLCTL_ARENAS_DESTROYED, false),
+	    "Destroyed arena stats should be initialized");
+
+	do_arena_reset_post(ptrs, nptrs);
+
+	memcpy(&hooks, &hooks_orig, sizeof(extent_hooks_t));
+}
 TEST_END
 
 int
@@ -146,5 +340,8 @@ main(void)
 {
 
 	return (test(
-	    test_arena_reset));
+	    test_arena_reset,
+	    test_arena_destroy_initial,
+	    test_arena_destroy_hooks_default,
+	    test_arena_destroy_hooks_unmap));
 }

test/unit/arena_reset_prof.c

@@ -0,0 +1,5 @@
+#include "test/jemalloc_test.h"
+#define	ARENA_RESET_PROF_C_
+
+const char *malloc_conf = "prof:true,lg_prof_sample:0";
+#include "arena_reset.c"

test/unit/mallctl.c

@@ -381,6 +381,15 @@ TEST_BEGIN(test_arena_i_initialized)
 	    "Unexpected mallctl() failure");
 	assert_true(initialized,
 	    "Merged arena statistics should always be initialized");
+
+	/* Equivalent to the above but using mallctl() directly. */
+	sz = sizeof(initialized);
+	assert_d_eq(mallctl(
+	    "arena." STRINGIFY(MALLCTL_ARENAS_ALL) ".initialized",
+	    (void *)&initialized, &sz, NULL, 0), 0,
+	    "Unexpected mallctl() failure");
+	assert_true(initialized,
+	    "Merged arena statistics should always be initialized");
 }
 TEST_END