Merge branch 'dev'

Tweak chunk purge order to purge unfragmented chunks from high to low
memory.  This facilitates dirty run reuse.

ChangeLog

@@ -6,6 +6,21 @@ found in the git revision history:
     http://www.canonware.com/cgi-bin/gitweb.cgi?p=jemalloc.git
     git://canonware.com/jemalloc.git
 
+* 3.2.0 (November 9, 2012)
+
+  In addition to a couple of bug fixes, this version modifies page run
+  allocation and dirty page purging algorithms in order to better control
+  page-level virtual memory fragmentation.
+
+  Incompatible changes:
+  - Change the "opt.lg_dirty_mult" default from 5 to 3 (32:1 to 8:1).
+
+  Bug fixes:
+  - Fix dss/mmap allocation precedence code to use recyclable mmap memory only
+    after primary dss allocation fails.
+  - Fix deadlock in the "arenas.purge" mallctl.  This regression was introduced
+    in 3.1.0 by the addition of the "arena.<i>.purge" mallctl.
+
 * 3.1.0 (October 16, 2012)
 
   New features:

doc/jemalloc.xml.in

@@ -833,7 +833,7 @@ for (i = 0; i < nbins; i++) {
         <manvolnum>2</manvolnum></citerefentry> or a similar system call.  This
         provides the kernel with sufficient information to recycle dirty pages
         if physical memory becomes scarce and the pages remain unused.  The
-        default minimum ratio is 32:1 (2^5:1); an option value of -1 will
+        default minimum ratio is 8:1 (2^3:1); an option value of -1 will
         disable dirty page purging.</para></listitem>
       </varlistentry>
 
@@ -1512,7 +1512,9 @@ malloc_conf = "xmalloc:true";]]></programlisting>
         application.  This is a multiple of the page size, and greater than or
         equal to <link
         linkend="stats.allocated"><mallctl>stats.allocated</mallctl></link>.
-        </para></listitem>
+        This does not include <link linkend="stats.arenas.i.pdirty">
+        <mallctl>stats.arenas.&lt;i&gt;.pdirty</mallctl></link> and pages
+        entirely devoted to allocator metadata.</para></listitem>
       </varlistentry>
 
       <varlistentry>
@@ -1628,7 +1630,7 @@ malloc_conf = "xmalloc:true";]]></programlisting>
         <listitem><para>Number of pages in active runs.</para></listitem>
       </varlistentry>
 
-      <varlistentry>
+      <varlistentry id="stats.arenas.i.pdirty">
         <term>
           <mallctl>stats.arenas.&lt;i&gt;.pdirty</mallctl>
           (<type>size_t</type>)

include/jemalloc/internal/arena.h

@@ -38,10 +38,10 @@
  *
  *   (nactive >> opt_lg_dirty_mult) >= ndirty
  *
- * So, supposing that opt_lg_dirty_mult is 5, there can be no less than 32
- * times as many active pages as dirty pages.
+ * So, supposing that opt_lg_dirty_mult is 3, there can be no less than 8 times
+ * as many active pages as dirty pages.
  */
-#define	LG_DIRTY_MULT_DEFAULT	5
+#define	LG_DIRTY_MULT_DEFAULT	3
 
 typedef struct arena_chunk_map_s arena_chunk_map_t;
 typedef struct arena_chunk_s arena_chunk_t;
@@ -69,7 +69,7 @@ struct arena_chunk_map_s {
 		/*
 		 * Linkage for run trees.  There are two disjoint uses:
 		 *
-		 * 1) arena_t's runs_avail_{clean,dirty} trees.
+		 * 1) arena_t's runs_avail tree.
 		 * 2) arena_run_t conceptually uses this linkage for in-use
 		 *    non-full runs, rather than directly embedding linkage.
 		 */
@@ -162,20 +162,24 @@ typedef rb_tree(arena_chunk_map_t) arena_run_tree_t;
 /* Arena chunk header. */
 struct arena_chunk_s {
 	/* Arena that owns the chunk. */
-	arena_t		*arena;
+	arena_t			*arena;
 
-	/* Linkage for the arena's chunks_dirty list. */
-	ql_elm(arena_chunk_t) link_dirty;
-
-	/*
-	 * True if the chunk is currently in the chunks_dirty list, due to
-	 * having at some point contained one or more dirty pages.  Removal
-	 * from chunks_dirty is lazy, so (dirtied && ndirty == 0) is possible.
-	 */
-	bool		dirtied;
+	/* Linkage for tree of arena chunks that contain dirty runs. */
+	rb_node(arena_chunk_t)	dirty_link;
 
 	/* Number of dirty pages. */
-	size_t		ndirty;
+	size_t			ndirty;
+
+	/* Number of available runs. */
+	size_t			nruns_avail;
+
+	/*
+	 * Number of available run adjacencies.  Clean and dirty available runs
+	 * are not coalesced, which causes virtual memory fragmentation.  The
+	 * ratio of (nruns_avail-nruns_adjac):nruns_adjac is used for tracking
+	 * this fragmentation.
+	 * */
+	size_t			nruns_adjac;
 
 	/*
 	 * Map of pages within chunk that keeps track of free/large/small.  The
@@ -183,7 +187,7 @@ struct arena_chunk_s {
 	 * need to be tracked in the map.  This omission saves a header page
 	 * for common chunk sizes (e.g. 4 MiB).
 	 */
-	arena_chunk_map_t map[1]; /* Dynamically sized. */
+	arena_chunk_map_t	map[1]; /* Dynamically sized. */
 };
 typedef rb_tree(arena_chunk_t) arena_chunk_tree_t;
 
@@ -333,8 +337,8 @@ struct arena_s {
 
 	dss_prec_t		dss_prec;
 
-	/* List of dirty-page-containing chunks this arena manages. */
-	ql_head(arena_chunk_t)	chunks_dirty;
+	/* Tree of dirty-page-containing chunks this arena manages. */
+	arena_chunk_tree_t	chunks_dirty;
 
 	/*
 	 * In order to avoid rapid chunk allocation/deallocation when an arena
@@ -369,18 +373,9 @@ struct arena_s {
 
 	/*
 	 * Size/address-ordered trees of this arena's available runs.  The trees
-	 * are used for first-best-fit run allocation.  The dirty tree contains
-	 * runs with dirty pages (i.e. very likely to have been touched and
-	 * therefore have associated physical pages), whereas the clean tree
-	 * contains runs with pages that either have no associated physical
-	 * pages, or have pages that the kernel may recycle at any time due to
-	 * previous madvise(2) calls.  The dirty tree is used in preference to
-	 * the clean tree for allocations, because using dirty pages reduces
-	 * the amount of dirty purging necessary to keep the active:dirty page
-	 * ratio below the purge threshold.
+	 * are used for first-best-fit run allocation.
 	 */
-	arena_avail_tree_t	runs_avail_clean;
-	arena_avail_tree_t	runs_avail_dirty;
+	arena_avail_tree_t	runs_avail;
 
 	/* bins is used to store trees of free regions. */
 	arena_bin_t		bins[NBINS];

src/arena.c

@@ -40,6 +40,12 @@ const uint8_t	small_size2bin[] = {
 /******************************************************************************/
 /* Function prototypes for non-inline static functions. */
 
+static void	arena_avail_insert(arena_t *arena, arena_chunk_t *chunk,
+    size_t pageind, size_t npages, bool maybe_adjac_pred,
+    bool maybe_adjac_succ);
+static void	arena_avail_remove(arena_t *arena, arena_chunk_t *chunk,
+    size_t pageind, size_t npages, bool maybe_adjac_pred,
+    bool maybe_adjac_succ);
 static void	arena_run_split(arena_t *arena, arena_run_t *run, size_t size,
     bool large, size_t binind, bool zero);
 static arena_chunk_t *arena_chunk_alloc(arena_t *arena);
@@ -48,8 +54,11 @@ static arena_run_t	*arena_run_alloc_helper(arena_t *arena, size_t size,
     bool large, size_t binind, bool zero);
 static arena_run_t *arena_run_alloc(arena_t *arena, size_t size, bool large,
     size_t binind, bool zero);
+static arena_chunk_t	*chunks_dirty_iter_cb(arena_chunk_tree_t *tree,
+    arena_chunk_t *chunk, void *arg);
 static void	arena_purge(arena_t *arena, bool all);
-static void	arena_run_dalloc(arena_t *arena, arena_run_t *run, bool dirty);
+static void	arena_run_dalloc(arena_t *arena, arena_run_t *run, bool dirty,
+    bool cleaned);
 static void	arena_run_trim_head(arena_t *arena, arena_chunk_t *chunk,
     arena_run_t *run, size_t oldsize, size_t newsize);
 static void	arena_run_trim_tail(arena_t *arena, arena_chunk_t *chunk,
@@ -101,9 +110,6 @@ arena_avail_comp(arena_chunk_map_t *a, arena_chunk_map_t *b)
 	size_t a_size = a->bits & ~PAGE_MASK;
 	size_t b_size = b->bits & ~PAGE_MASK;
 
-	assert((a->bits & CHUNK_MAP_KEY) == CHUNK_MAP_KEY || (a->bits &
-	    CHUNK_MAP_DIRTY) == (b->bits & CHUNK_MAP_DIRTY));
-
 	ret = (a_size > b_size) - (a_size < b_size);
 	if (ret == 0) {
 		uintptr_t a_mapelm, b_mapelm;
@@ -129,6 +135,182 @@ arena_avail_comp(arena_chunk_map_t *a, arena_chunk_map_t *b)
 rb_gen(static UNUSED, arena_avail_tree_, arena_avail_tree_t, arena_chunk_map_t,
     u.rb_link, arena_avail_comp)
 
+static inline int
+arena_chunk_dirty_comp(arena_chunk_t *a, arena_chunk_t *b)
+{
+
+	assert(a != NULL);
+	assert(b != NULL);
+
+	/*
+	 * Short-circuit for self comparison.  The following comparison code
+	 * would come to the same result, but at the cost of executing the slow
+	 * path.
+	 */
+	if (a == b)
+		return (0);
+
+	/*
+	 * Order such that chunks with higher fragmentation are "less than"
+	 * those with lower fragmentation -- purging order is from "least" to
+	 * "greatest".  Fragmentation is measured as:
+	 *
+	 *     mean current avail run size
+	 *   --------------------------------
+	 *   mean defragmented avail run size
+	 *
+	 *            navail
+	 *         -----------
+	 *         nruns_avail           nruns_avail-nruns_adjac
+	 * = ========================= = -----------------------
+	 *            navail                  nruns_avail
+	 *    -----------------------
+	 *    nruns_avail-nruns_adjac
+	 *
+	 * The following code multiplies away the denominator prior to
+	 * comparison, in order to avoid division.
+	 *
+	 */
+	{
+		size_t a_val = (a->nruns_avail - a->nruns_adjac) *
+		    b->nruns_avail;
+		size_t b_val = (b->nruns_avail - b->nruns_adjac) *
+		    a->nruns_avail;
+
+		if (a_val < b_val)
+			return (1);
+		if (a_val > b_val)
+			return (-1);
+	}
+	/*
+	 * Break ties by chunk address.  For fragmented chunks, report lower
+	 * addresses as "lower", so that fragmentation reduction happens first
+	 * at lower addresses.  However, use the opposite ordering for
+	 * unfragmented chunks, in order to increase the chances of
+	 * re-allocating dirty runs.
+	 */
+	{
+		uintptr_t a_chunk = (uintptr_t)a;
+		uintptr_t b_chunk = (uintptr_t)b;
+		int ret = ((a_chunk > b_chunk) - (a_chunk < b_chunk));
+		if (a->nruns_adjac == 0) {
+			assert(b->nruns_adjac == 0);
+			ret = -ret;
+		}
+		return (ret);
+	}
+}
+
+/* Generate red-black tree functions. */
+rb_gen(static UNUSED, arena_chunk_dirty_, arena_chunk_tree_t, arena_chunk_t,
+    dirty_link, arena_chunk_dirty_comp)
+
+static inline bool
+arena_avail_adjac_pred(arena_chunk_t *chunk, size_t pageind)
+{
+	bool ret;
+
+	if (pageind-1 < map_bias)
+		ret = false;
+	else {
+		ret = (arena_mapbits_allocated_get(chunk, pageind-1) == 0);
+		assert(ret == false || arena_mapbits_dirty_get(chunk,
+		    pageind-1) != arena_mapbits_dirty_get(chunk, pageind));
+	}
+	return (ret);
+}
+
+static inline bool
+arena_avail_adjac_succ(arena_chunk_t *chunk, size_t pageind, size_t npages)
+{
+	bool ret;
+
+	if (pageind+npages == chunk_npages)
+		ret = false;
+	else {
+		assert(pageind+npages < chunk_npages);
+		ret = (arena_mapbits_allocated_get(chunk, pageind+npages) == 0);
+		assert(ret == false || arena_mapbits_dirty_get(chunk, pageind)
+		    != arena_mapbits_dirty_get(chunk, pageind+npages));
+	}
+	return (ret);
+}
+
+static inline bool
+arena_avail_adjac(arena_chunk_t *chunk, size_t pageind, size_t npages)
+{
+
+	return (arena_avail_adjac_pred(chunk, pageind) ||
+	    arena_avail_adjac_succ(chunk, pageind, npages));
+}
+
+static void
+arena_avail_insert(arena_t *arena, arena_chunk_t *chunk, size_t pageind,
+    size_t npages, bool maybe_adjac_pred, bool maybe_adjac_succ)
+{
+
+	assert(npages == (arena_mapbits_unallocated_size_get(chunk, pageind) >>
+	    LG_PAGE));
+
+	/*
+	 * chunks_dirty is keyed by nruns_{avail,adjac}, so the chunk must be
+	 * removed and reinserted even if the run to be inserted is clean.
+	 */
+	if (chunk->ndirty != 0)
+		arena_chunk_dirty_remove(&arena->chunks_dirty, chunk);
+
+	if (maybe_adjac_pred && arena_avail_adjac_pred(chunk, pageind))
+		chunk->nruns_adjac++;
+	if (maybe_adjac_succ && arena_avail_adjac_succ(chunk, pageind, npages))
+		chunk->nruns_adjac++;
+	chunk->nruns_avail++;
+	assert(chunk->nruns_avail > chunk->nruns_adjac);
+
+	if (arena_mapbits_dirty_get(chunk, pageind) != 0) {
+		arena->ndirty += npages;
+		chunk->ndirty += npages;
+	}
+	if (chunk->ndirty != 0)
+		arena_chunk_dirty_insert(&arena->chunks_dirty, chunk);
+
+	arena_avail_tree_insert(&arena->runs_avail, arena_mapp_get(chunk,
+	    pageind));
+}
+
+static void
+arena_avail_remove(arena_t *arena, arena_chunk_t *chunk, size_t pageind,
+    size_t npages, bool maybe_adjac_pred, bool maybe_adjac_succ)
+{
+
+	assert(npages == (arena_mapbits_unallocated_size_get(chunk, pageind) >>
+	    LG_PAGE));
+
+	/*
+	 * chunks_dirty is keyed by nruns_{avail,adjac}, so the chunk must be
+	 * removed and reinserted even if the run to be removed is clean.
+	 */
+	if (chunk->ndirty != 0)
+		arena_chunk_dirty_remove(&arena->chunks_dirty, chunk);
+
+	if (maybe_adjac_pred && arena_avail_adjac_pred(chunk, pageind))
+		chunk->nruns_adjac--;
+	if (maybe_adjac_succ && arena_avail_adjac_succ(chunk, pageind, npages))
+		chunk->nruns_adjac--;
+	chunk->nruns_avail--;
+	assert(chunk->nruns_avail > chunk->nruns_adjac || (chunk->nruns_avail
+	    == 0 && chunk->nruns_adjac == 0));
+
+	if (arena_mapbits_dirty_get(chunk, pageind) != 0) {
+		arena->ndirty -= npages;
+		chunk->ndirty -= npages;
+	}
+	if (chunk->ndirty != 0)
+		arena_chunk_dirty_insert(&arena->chunks_dirty, chunk);
+
+	arena_avail_tree_remove(&arena->runs_avail, arena_mapp_get(chunk,
+	    pageind));
+}
+
 static inline void *
 arena_run_reg_alloc(arena_run_t *run, arena_bin_info_t *bin_info)
 {
@@ -193,7 +375,6 @@ arena_run_split(arena_t *arena, arena_run_t *run, size_t size, bool large,
 	arena_chunk_t *chunk;
 	size_t run_ind, total_pages, need_pages, rem_pages, i;
 	size_t flag_dirty;
-	arena_avail_tree_t *runs_avail;
 
 	assert((large && binind == BININD_INVALID) || (large == false && binind
 	    != BININD_INVALID));
@@ -201,8 +382,6 @@ arena_run_split(arena_t *arena, arena_run_t *run, size_t size, bool large,
 	chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(run);
 	run_ind = (unsigned)(((uintptr_t)run - (uintptr_t)chunk) >> LG_PAGE);
 	flag_dirty = arena_mapbits_dirty_get(chunk, run_ind);
-	runs_avail = (flag_dirty != 0) ? &arena->runs_avail_dirty :
-	    &arena->runs_avail_clean;
 	total_pages = arena_mapbits_unallocated_size_get(chunk, run_ind) >>
 	    LG_PAGE;
 	assert(arena_mapbits_dirty_get(chunk, run_ind+total_pages-1) ==
@@ -212,7 +391,7 @@ arena_run_split(arena_t *arena, arena_run_t *run, size_t size, bool large,
 	assert(need_pages <= total_pages);
 	rem_pages = total_pages - need_pages;
 
-	arena_avail_tree_remove(runs_avail, arena_mapp_get(chunk, run_ind));
+	arena_avail_remove(arena, chunk, run_ind, total_pages, true, true);
 	if (config_stats) {
 		/*
 		 * Update stats_cactive if nactive is crossing a chunk
@@ -244,14 +423,8 @@ arena_run_split(arena_t *arena, arena_run_t *run, size_t size, bool large,
 			    arena_mapbits_unzeroed_get(chunk,
 			    run_ind+total_pages-1));
 		}
-		arena_avail_tree_insert(runs_avail, arena_mapp_get(chunk,
-		    run_ind+need_pages));
-	}
-
-	/* Update dirty page accounting. */
-	if (flag_dirty != 0) {
-		chunk->ndirty -= need_pages;
-		arena->ndirty -= need_pages;
+		arena_avail_insert(arena, chunk, run_ind+need_pages, rem_pages,
+		    false, true);
 	}
 
 	/*
@@ -344,8 +517,6 @@ arena_chunk_alloc(arena_t *arena)
 	size_t i;
 
 	if (arena->spare != NULL) {
-		arena_avail_tree_t *runs_avail;
-
 		chunk = arena->spare;
 		arena->spare = NULL;
 
@@ -357,14 +528,6 @@ arena_chunk_alloc(arena_t *arena)
 		    chunk_npages-1) == arena_maxclass);
 		assert(arena_mapbits_dirty_get(chunk, map_bias) ==
 		    arena_mapbits_dirty_get(chunk, chunk_npages-1));
-
-		/* Insert the run into the appropriate runs_avail_* tree. */
-		if (arena_mapbits_dirty_get(chunk, map_bias) == 0)
-			runs_avail = &arena->runs_avail_clean;
-		else
-			runs_avail = &arena->runs_avail_dirty;
-		arena_avail_tree_insert(runs_avail, arena_mapp_get(chunk,
-		    map_bias));
 	} else {
 		bool zero;
 		size_t unzeroed;
@@ -380,8 +543,6 @@ arena_chunk_alloc(arena_t *arena)
 			arena->stats.mapped += chunksize;
 
 		chunk->arena = arena;
-		ql_elm_new(chunk, link_dirty);
-		chunk->dirtied = false;
 
 		/*
 		 * Claim that no pages are in use, since the header is merely
@@ -389,6 +550,9 @@ arena_chunk_alloc(arena_t *arena)
 		 */
 		chunk->ndirty = 0;
 
+		chunk->nruns_avail = 0;
+		chunk->nruns_adjac = 0;
+
 		/*
 		 * Initialize the map to contain one maximal free untouched run.
 		 * Mark the pages as zeroed iff chunk_alloc() returned a zeroed
@@ -412,20 +576,18 @@ arena_chunk_alloc(arena_t *arena)
 		}
 		arena_mapbits_unallocated_set(chunk, chunk_npages-1,
 		    arena_maxclass, unzeroed);
-
-		/* Insert the run into the runs_avail_clean tree. */
-		arena_avail_tree_insert(&arena->runs_avail_clean,
-		    arena_mapp_get(chunk, map_bias));
 	}
 
+	/* Insert the run into the runs_avail tree. */
+	arena_avail_insert(arena, chunk, map_bias, chunk_npages-map_bias,
+	    false, false);
+
 	return (chunk);
 }
 
 static void
 arena_chunk_dealloc(arena_t *arena, arena_chunk_t *chunk)
 {
-	arena_avail_tree_t *runs_avail;
-
 	assert(arena_mapbits_allocated_get(chunk, map_bias) == 0);
 	assert(arena_mapbits_allocated_get(chunk, chunk_npages-1) == 0);
 	assert(arena_mapbits_unallocated_size_get(chunk, map_bias) ==
@@ -436,24 +598,16 @@ arena_chunk_dealloc(arena_t *arena, arena_chunk_t *chunk)
 	    arena_mapbits_dirty_get(chunk, chunk_npages-1));
 
 	/*
-	 * Remove run from the appropriate runs_avail_* tree, so that the arena
-	 * does not use it.
+	 * Remove run from the runs_avail tree, so that the arena does not use
+	 * it.
 	 */
-	if (arena_mapbits_dirty_get(chunk, map_bias) == 0)
-		runs_avail = &arena->runs_avail_clean;
-	else
-		runs_avail = &arena->runs_avail_dirty;
-	arena_avail_tree_remove(runs_avail, arena_mapp_get(chunk, map_bias));
+	arena_avail_remove(arena, chunk, map_bias, chunk_npages-map_bias,
+	    false, false);
 
 	if (arena->spare != NULL) {
 		arena_chunk_t *spare = arena->spare;
 
 		arena->spare = chunk;
-		if (spare->dirtied) {
-			ql_remove(&chunk->arena->chunks_dirty, spare,
-			    link_dirty);
-			arena->ndirty -= spare->ndirty;
-		}
 		malloc_mutex_unlock(&arena->lock);
 		chunk_dealloc((void *)spare, chunksize, true);
 		malloc_mutex_lock(&arena->lock);
@@ -471,19 +625,7 @@ arena_run_alloc_helper(arena_t *arena, size_t size, bool large, size_t binind,
 	arena_chunk_map_t *mapelm, key;
 
 	key.bits = size | CHUNK_MAP_KEY;
-	mapelm = arena_avail_tree_nsearch(&arena->runs_avail_dirty, &key);
-	if (mapelm != NULL) {
-		arena_chunk_t *run_chunk = CHUNK_ADDR2BASE(mapelm);
-		size_t pageind = (((uintptr_t)mapelm -
-		    (uintptr_t)run_chunk->map) / sizeof(arena_chunk_map_t))
-		    + map_bias;
-
-		run = (arena_run_t *)((uintptr_t)run_chunk + (pageind <<
-		    LG_PAGE));
-		arena_run_split(arena, run, size, large, binind, zero);
-		return (run);
-	}
-	mapelm = arena_avail_tree_nsearch(&arena->runs_avail_clean, &key);
+	mapelm = arena_avail_tree_nsearch(&arena->runs_avail, &key);
 	if (mapelm != NULL) {
 		arena_chunk_t *run_chunk = CHUNK_ADDR2BASE(mapelm);
 		size_t pageind = (((uintptr_t)mapelm -
@@ -537,29 +679,40 @@ arena_run_alloc(arena_t *arena, size_t size, bool large, size_t binind,
 static inline void
 arena_maybe_purge(arena_t *arena)
 {
+	size_t npurgeable, threshold;
 
-	/* Enforce opt_lg_dirty_mult. */
-	if (opt_lg_dirty_mult >= 0 && arena->ndirty > arena->npurgatory &&
-	    (arena->ndirty - arena->npurgatory) > chunk_npages &&
-	    (arena->nactive >> opt_lg_dirty_mult) < (arena->ndirty -
-	    arena->npurgatory))
-		arena_purge(arena, false);
+	/* Don't purge if the option is disabled. */
+	if (opt_lg_dirty_mult < 0)
+		return;
+	/* Don't purge if all dirty pages are already being purged. */
+	if (arena->ndirty <= arena->npurgatory)
+		return;
+	npurgeable = arena->ndirty - arena->npurgatory;
+	threshold = (arena->nactive >> opt_lg_dirty_mult);
+	/*
+	 * Don't purge unless the number of purgeable pages exceeds the
+	 * threshold.
+	 */
+	if (npurgeable <= threshold)
+		return;
+
+	arena_purge(arena, false);
 }
 
-static inline void
-arena_chunk_purge(arena_t *arena, arena_chunk_t *chunk)
+static inline size_t
+arena_chunk_purge(arena_t *arena, arena_chunk_t *chunk, bool all)
 {
+	size_t npurged;
 	ql_head(arena_chunk_map_t) mapelms;
 	arena_chunk_map_t *mapelm;
-	size_t pageind;
-	size_t ndirty;
+	size_t pageind, npages;
 	size_t nmadvise;
 
 	ql_new(&mapelms);
 
 	/*
 	 * If chunk is the spare, temporarily re-allocate it, 1) so that its
-	 * run is reinserted into runs_avail_dirty, and 2) so that it cannot be
+	 * run is reinserted into runs_avail, and 2) so that it cannot be
 	 * completely discarded by another thread while arena->lock is dropped
 	 * by this thread.  Note that the arena_run_dalloc() call will
 	 * implicitly deallocate the chunk, so no explicit action is required
@@ -579,54 +732,50 @@ arena_chunk_purge(arena_t *arena, arena_chunk_t *chunk)
 		arena_chunk_alloc(arena);
 	}
 
-	/* Temporarily allocate all free dirty runs within chunk. */
-	for (pageind = map_bias; pageind < chunk_npages;) {
+	if (config_stats)
+		arena->stats.purged += chunk->ndirty;
+
+	/*
+	 * Operate on all dirty runs if there is no clean/dirty run
+	 * fragmentation.
+	 */
+	if (chunk->nruns_adjac == 0)
+		all = true;
+
+	/*
+	 * Temporarily allocate free dirty runs within chunk.  If all is false,
+	 * only operate on dirty runs that are fragments; otherwise operate on
+	 * all dirty runs.
+	 */
+	for (pageind = map_bias; pageind < chunk_npages; pageind += npages) {
 		mapelm = arena_mapp_get(chunk, pageind);
 		if (arena_mapbits_allocated_get(chunk, pageind) == 0) {
-			size_t npages;
+			size_t run_size =
+			    arena_mapbits_unallocated_size_get(chunk, pageind);
 
-			npages = arena_mapbits_unallocated_size_get(chunk,
-			    pageind) >> LG_PAGE;
+			npages = run_size >> LG_PAGE;
 			assert(pageind + npages <= chunk_npages);
 			assert(arena_mapbits_dirty_get(chunk, pageind) ==
 			    arena_mapbits_dirty_get(chunk, pageind+npages-1));
-			if (arena_mapbits_dirty_get(chunk, pageind) != 0) {
-				arena_avail_tree_remove(
-				    &arena->runs_avail_dirty, mapelm);
 
-				arena_mapbits_large_set(chunk, pageind,
-				    (npages << LG_PAGE), 0);
-				if (npages > 1) {
-					arena_mapbits_large_set(chunk,
-					    pageind+npages-1, 0, 0);
-				}
+			if (arena_mapbits_dirty_get(chunk, pageind) != 0 &&
+			    (all || arena_avail_adjac(chunk, pageind,
+			    npages))) {
+				arena_run_t *run = (arena_run_t *)((uintptr_t)
+				    chunk + (uintptr_t)(pageind << LG_PAGE));
 
-				if (config_stats) {
-					/*
-					 * Update stats_cactive if nactive is
-					 * crossing a chunk multiple.
-					 */
-					size_t cactive_diff =
-					    CHUNK_CEILING((arena->nactive +
-					    npages) << LG_PAGE) -
-					    CHUNK_CEILING(arena->nactive <<
-					    LG_PAGE);
-					if (cactive_diff != 0)
-						stats_cactive_add(cactive_diff);
-				}
-				arena->nactive += npages;
+				arena_run_split(arena, run, run_size, true,
+				    BININD_INVALID, false);
 				/* Append to list for later processing. */
 				ql_elm_new(mapelm, u.ql_link);
 				ql_tail_insert(&mapelms, mapelm, u.ql_link);
 			}
-
-			pageind += npages;
 		} else {
-			/* Skip allocated run. */
-			if (arena_mapbits_large_get(chunk, pageind))
-				pageind += arena_mapbits_large_size_get(chunk,
+			/* Skip run. */
+			if (arena_mapbits_large_get(chunk, pageind) != 0) {
+				npages = arena_mapbits_large_size_get(chunk,
 				    pageind) >> LG_PAGE;
-			else {
+			} else {
 				size_t binind;
 				arena_bin_info_t *bin_info;
 				arena_run_t *run = (arena_run_t *)((uintptr_t)
@@ -636,36 +785,27 @@ arena_chunk_purge(arena_t *arena, arena_chunk_t *chunk)
 				    pageind) == 0);
 				binind = arena_bin_index(arena, run->bin);
 				bin_info = &arena_bin_info[binind];
-				pageind += bin_info->run_size >> LG_PAGE;
+				npages = bin_info->run_size >> LG_PAGE;
 			}
 		}
 	}
 	assert(pageind == chunk_npages);
-
-	if (config_debug)
-		ndirty = chunk->ndirty;
-	if (config_stats)
-		arena->stats.purged += chunk->ndirty;
-	arena->ndirty -= chunk->ndirty;
-	chunk->ndirty = 0;
-	ql_remove(&arena->chunks_dirty, chunk, link_dirty);
-	chunk->dirtied = false;
+	assert(chunk->ndirty == 0 || all == false);
+	assert(chunk->nruns_adjac == 0);
 
 	malloc_mutex_unlock(&arena->lock);
 	if (config_stats)
 		nmadvise = 0;
+	npurged = 0;
 	ql_foreach(mapelm, &mapelms, u.ql_link) {
-		size_t pageind = (((uintptr_t)mapelm - (uintptr_t)chunk->map) /
-		    sizeof(arena_chunk_map_t)) + map_bias;
-		size_t npages = arena_mapbits_large_size_get(chunk, pageind) >>
-		    LG_PAGE;
 		bool unzeroed;
 		size_t flag_unzeroed, i;
 
+		pageind = (((uintptr_t)mapelm - (uintptr_t)chunk->map) /
+		    sizeof(arena_chunk_map_t)) + map_bias;
+		npages = arena_mapbits_large_size_get(chunk, pageind) >>
+		    LG_PAGE;
 		assert(pageind + npages <= chunk_npages);
-		assert(ndirty >= npages);
-		if (config_debug)
-			ndirty -= npages;
 		unzeroed = pages_purge((void *)((uintptr_t)chunk + (pageind <<
 		    LG_PAGE)), (npages << LG_PAGE));
 		flag_unzeroed = unzeroed ? CHUNK_MAP_UNZEROED : 0;
@@ -683,10 +823,10 @@ arena_chunk_purge(arena_t *arena, arena_chunk_t *chunk)
 			arena_mapbits_unzeroed_set(chunk, pageind+i,
 			    flag_unzeroed);
 		}
+		npurged += npages;
 		if (config_stats)
 			nmadvise++;
 	}
-	assert(ndirty == 0);
 	malloc_mutex_lock(&arena->lock);
 	if (config_stats)
 		arena->stats.nmadvise += nmadvise;
@@ -694,14 +834,27 @@ arena_chunk_purge(arena_t *arena, arena_chunk_t *chunk)
 	/* Deallocate runs. */
 	for (mapelm = ql_first(&mapelms); mapelm != NULL;
 	    mapelm = ql_first(&mapelms)) {
-		size_t pageind = (((uintptr_t)mapelm - (uintptr_t)chunk->map) /
-		    sizeof(arena_chunk_map_t)) + map_bias;
-		arena_run_t *run = (arena_run_t *)((uintptr_t)chunk +
-		    (uintptr_t)(pageind << LG_PAGE));
+		arena_run_t *run;
 
+		pageind = (((uintptr_t)mapelm - (uintptr_t)chunk->map) /
+		    sizeof(arena_chunk_map_t)) + map_bias;
+		run = (arena_run_t *)((uintptr_t)chunk + (uintptr_t)(pageind <<
+		    LG_PAGE));
 		ql_remove(&mapelms, mapelm, u.ql_link);
-		arena_run_dalloc(arena, run, false);
+		arena_run_dalloc(arena, run, false, true);
 	}
+
+	return (npurged);
+}
+
+static arena_chunk_t *
+chunks_dirty_iter_cb(arena_chunk_tree_t *tree, arena_chunk_t *chunk, void *arg)
+{
+       size_t *ndirty = (size_t *)arg;
+
+       assert(chunk->ndirty != 0);
+       *ndirty += chunk->ndirty;
+       return (NULL);
 }
 
 static void
@@ -712,14 +865,11 @@ arena_purge(arena_t *arena, bool all)
 	if (config_debug) {
 		size_t ndirty = 0;
 
-		ql_foreach(chunk, &arena->chunks_dirty, link_dirty) {
-		    assert(chunk->dirtied);
-		    ndirty += chunk->ndirty;
-		}
+		arena_chunk_dirty_iter(&arena->chunks_dirty, NULL,
+		    chunks_dirty_iter_cb, (void *)&ndirty);
 		assert(ndirty == arena->ndirty);
 	}
 	assert(arena->ndirty > arena->npurgatory || all);
-	assert(arena->ndirty - arena->npurgatory > chunk_npages || all);
 	assert((arena->nactive >> opt_lg_dirty_mult) < (arena->ndirty -
 	    arena->npurgatory) || all);
 
@@ -731,16 +881,24 @@ arena_purge(arena_t *arena, bool all)
 	 * purge, and add the result to arena->npurgatory.  This will keep
 	 * multiple threads from racing to reduce ndirty below the threshold.
 	 */
-	npurgatory = arena->ndirty - arena->npurgatory;
-	if (all == false) {
-		assert(npurgatory >= arena->nactive >> opt_lg_dirty_mult);
-		npurgatory -= arena->nactive >> opt_lg_dirty_mult;
+	{
+		size_t npurgeable = arena->ndirty - arena->npurgatory;
+
+		if (all == false) {
+			size_t threshold = (arena->nactive >>
+			    opt_lg_dirty_mult);
+
+			npurgatory = npurgeable - threshold;
+		} else
+			npurgatory = npurgeable;
 	}
 	arena->npurgatory += npurgatory;
 
 	while (npurgatory > 0) {
+		size_t npurgeable, npurged, nunpurged;
+
 		/* Get next chunk with dirty pages. */
-		chunk = ql_first(&arena->chunks_dirty);
+		chunk = arena_chunk_dirty_first(&arena->chunks_dirty);
 		if (chunk == NULL) {
 			/*
 			 * This thread was unable to purge as many pages as
@@ -751,23 +909,15 @@ arena_purge(arena_t *arena, bool all)
 			arena->npurgatory -= npurgatory;
 			return;
 		}
-		while (chunk->ndirty == 0) {
-			ql_remove(&arena->chunks_dirty, chunk, link_dirty);
-			chunk->dirtied = false;
-			chunk = ql_first(&arena->chunks_dirty);
-			if (chunk == NULL) {
-				/* Same logic as for above. */
-				arena->npurgatory -= npurgatory;
-				return;
-			}
-		}
+		npurgeable = chunk->ndirty;
+		assert(npurgeable != 0);
 
-		if (chunk->ndirty > npurgatory) {
+		if (npurgeable > npurgatory && chunk->nruns_adjac == 0) {
 			/*
-			 * This thread will, at a minimum, purge all the dirty
-			 * pages in chunk, so set npurgatory to reflect this
-			 * thread's commitment to purge the pages.  This tends
-			 * to reduce the chances of the following scenario:
+			 * This thread will purge all the dirty pages in chunk,
+			 * so set npurgatory to reflect this thread's intent to
+			 * purge the pages.  This tends to reduce the chances
+			 * of the following scenario:
 			 *
 			 * 1) This thread sets arena->npurgatory such that
 			 *    (arena->ndirty - arena->npurgatory) is at the
@@ -781,13 +931,20 @@ arena_purge(arena_t *arena, bool all)
 			 * because all of the purging work being done really
 			 * needs to happen.
 			 */
-			arena->npurgatory += chunk->ndirty - npurgatory;
-			npurgatory = chunk->ndirty;
+			arena->npurgatory += npurgeable - npurgatory;
+			npurgatory = npurgeable;
 		}
 
-		arena->npurgatory -= chunk->ndirty;
-		npurgatory -= chunk->ndirty;
-		arena_chunk_purge(arena, chunk);
+		/*
+		 * Keep track of how many pages are purgeable, versus how many
+		 * actually get purged, and adjust counters accordingly.
+		 */
+		arena->npurgatory -= npurgeable;
+		npurgatory -= npurgeable;
+		npurged = arena_chunk_purge(arena, chunk, all);
+		nunpurged = npurgeable - npurged;
+		arena->npurgatory += nunpurged;
+		npurgatory += nunpurged;
 	}
 }
 
@@ -801,11 +958,10 @@ arena_purge_all(arena_t *arena)
 }
 
 static void
-arena_run_dalloc(arena_t *arena, arena_run_t *run, bool dirty)
+arena_run_dalloc(arena_t *arena, arena_run_t *run, bool dirty, bool cleaned)
 {
 	arena_chunk_t *chunk;
 	size_t size, run_ind, run_pages, flag_dirty;
-	arena_avail_tree_t *runs_avail;
 
 	chunk = (arena_chunk_t *)CHUNK_ADDR2BASE(run);
 	run_ind = (size_t)(((uintptr_t)run - (uintptr_t)chunk) >> LG_PAGE);
@@ -836,15 +992,14 @@ arena_run_dalloc(arena_t *arena, arena_run_t *run, bool dirty)
 
 	/*
 	 * The run is dirty if the caller claims to have dirtied it, as well as
-	 * if it was already dirty before being allocated.
+	 * if it was already dirty before being allocated and the caller
+	 * doesn't claim to have cleaned it.
 	 */
 	assert(arena_mapbits_dirty_get(chunk, run_ind) ==
 	    arena_mapbits_dirty_get(chunk, run_ind+run_pages-1));
-	if (arena_mapbits_dirty_get(chunk, run_ind) != 0)
+	if (cleaned == false && arena_mapbits_dirty_get(chunk, run_ind) != 0)
 		dirty = true;
 	flag_dirty = dirty ? CHUNK_MAP_DIRTY : 0;
-	runs_avail = dirty ? &arena->runs_avail_dirty :
-	    &arena->runs_avail_clean;
 
 	/* Mark pages as unallocated in the chunk map. */
 	if (dirty) {
@@ -852,9 +1007,6 @@ arena_run_dalloc(arena_t *arena, arena_run_t *run, bool dirty)
 		    CHUNK_MAP_DIRTY);
 		arena_mapbits_unallocated_set(chunk, run_ind+run_pages-1, size,
 		    CHUNK_MAP_DIRTY);
-
-		chunk->ndirty += run_pages;
-		arena->ndirty += run_pages;
 	} else {
 		arena_mapbits_unallocated_set(chunk, run_ind, size,
 		    arena_mapbits_unzeroed_get(chunk, run_ind));
@@ -878,8 +1030,8 @@ arena_run_dalloc(arena_t *arena, arena_run_t *run, bool dirty)
 		    run_ind+run_pages+nrun_pages-1) == nrun_size);
 		assert(arena_mapbits_dirty_get(chunk,
 		    run_ind+run_pages+nrun_pages-1) == flag_dirty);
-		arena_avail_tree_remove(runs_avail,
-		    arena_mapp_get(chunk, run_ind+run_pages));
+		arena_avail_remove(arena, chunk, run_ind+run_pages, nrun_pages,
+		    false, true);
 
 		size += nrun_size;
 		run_pages += nrun_pages;
@@ -905,8 +1057,8 @@ arena_run_dalloc(arena_t *arena, arena_run_t *run, bool dirty)
 		assert(arena_mapbits_unallocated_size_get(chunk, run_ind) ==
 		    prun_size);
 		assert(arena_mapbits_dirty_get(chunk, run_ind) == flag_dirty);
-		arena_avail_tree_remove(runs_avail, arena_mapp_get(chunk,
-		    run_ind));
+		arena_avail_remove(arena, chunk, run_ind, prun_pages, true,
+		    false);
 
 		size += prun_size;
 		run_pages += prun_pages;
@@ -921,19 +1073,7 @@ arena_run_dalloc(arena_t *arena, arena_run_t *run, bool dirty)
 	    arena_mapbits_unallocated_size_get(chunk, run_ind+run_pages-1));
 	assert(arena_mapbits_dirty_get(chunk, run_ind) ==
 	    arena_mapbits_dirty_get(chunk, run_ind+run_pages-1));
-	arena_avail_tree_insert(runs_avail, arena_mapp_get(chunk, run_ind));
-
-	if (dirty) {
-		/*
-		 * Insert into chunks_dirty before potentially calling
-		 * arena_chunk_dealloc(), so that chunks_dirty and
-		 * arena->ndirty are consistent.
-		 */
-		if (chunk->dirtied == false) {
-			ql_tail_insert(&arena->chunks_dirty, chunk, link_dirty);
-			chunk->dirtied = true;
-		}
-	}
+	arena_avail_insert(arena, chunk, run_ind, run_pages, true, true);
 
 	/* Deallocate chunk if it is now completely unused. */
 	if (size == arena_maxclass) {
@@ -982,7 +1122,7 @@ arena_run_trim_head(arena_t *arena, arena_chunk_t *chunk, arena_run_t *run,
 	arena_mapbits_large_set(chunk, pageind+head_npages, newsize,
 	    flag_dirty);
 
-	arena_run_dalloc(arena, run, false);
+	arena_run_dalloc(arena, run, false, false);
 }
 
 static void
@@ -1015,7 +1155,7 @@ arena_run_trim_tail(arena_t *arena, arena_chunk_t *chunk, arena_run_t *run,
 	    flag_dirty);
 
 	arena_run_dalloc(arena, (arena_run_t *)((uintptr_t)run + newsize),
-	    dirty);
+	    dirty, false);
 }
 
 static arena_run_t *
@@ -1526,7 +1666,7 @@ arena_dalloc_bin_run(arena_t *arena, arena_chunk_t *chunk, arena_run_t *run,
 		    ((past - run_ind) << LG_PAGE), false);
 		/* npages = past - run_ind; */
 	}
-	arena_run_dalloc(arena, run, true);
+	arena_run_dalloc(arena, run, true, false);
 	malloc_mutex_unlock(&arena->lock);
 	/****************************/
 	malloc_mutex_lock(&bin->lock);
@@ -1638,7 +1778,7 @@ arena_dalloc_large_locked(arena_t *arena, arena_chunk_t *chunk, void *ptr)
 		}
 	}
 
-	arena_run_dalloc(arena, (arena_run_t *)ptr, true);
+	arena_run_dalloc(arena, (arena_run_t *)ptr, true, false);
 }
 
 void
@@ -1985,15 +2125,14 @@ arena_new(arena_t *arena, unsigned ind)
 	arena->dss_prec = chunk_dss_prec_get();
 
 	/* Initialize chunks. */
-	ql_new(&arena->chunks_dirty);
+	arena_chunk_dirty_new(&arena->chunks_dirty);
 	arena->spare = NULL;
 
 	arena->nactive = 0;
 	arena->ndirty = 0;
 	arena->npurgatory = 0;
 
-	arena_avail_tree_new(&arena->runs_avail_clean);
-	arena_avail_tree_new(&arena->runs_avail_dirty);
+	arena_avail_tree_new(&arena->runs_avail);
 
 	/* Initialize bins. */
 	for (i = 0; i < NBINS; i++) {

src/chunk.c

@@ -146,40 +146,28 @@ chunk_alloc(size_t size, size_t alignment, bool base, bool *zero,
 	assert(alignment != 0);
 	assert((alignment & chunksize_mask) == 0);
 
-	/*
-	 * Try to recycle an existing mapping.
-	 */
-
 	/* "primary" dss. */
-	if (config_dss && dss_prec == dss_prec_primary && (ret =
-	    chunk_recycle(&chunks_szad_dss, &chunks_ad_dss, size, alignment,
-	    base, zero)) != NULL)
-		goto label_return;
+	if (config_dss && dss_prec == dss_prec_primary) {
+		if ((ret = chunk_recycle(&chunks_szad_dss, &chunks_ad_dss, size,
+		    alignment, base, zero)) != NULL)
+			goto label_return;
+		if ((ret = chunk_alloc_dss(size, alignment, zero)) != NULL)
+			goto label_return;
+	}
 	/* mmap. */
 	if ((ret = chunk_recycle(&chunks_szad_mmap, &chunks_ad_mmap, size,
 	    alignment, base, zero)) != NULL)
 		goto label_return;
-	/* "secondary" dss. */
-	if (config_dss && dss_prec == dss_prec_secondary && (ret =
-	    chunk_recycle(&chunks_szad_dss, &chunks_ad_dss, size, alignment,
-	    base, zero)) != NULL)
-		goto label_return;
-
-	/*
-	 * Try to allocate a new mapping.
-	 */
-
-	/* "primary" dss. */
-	if (config_dss && dss_prec == dss_prec_primary && (ret =
-	    chunk_alloc_dss(size, alignment, zero)) != NULL)
-		goto label_return;
-	/* mmap. */
 	if ((ret = chunk_alloc_mmap(size, alignment, zero)) != NULL)
 		goto label_return;
 	/* "secondary" dss. */
-	if (config_dss && dss_prec == dss_prec_secondary && (ret =
-	    chunk_alloc_dss(size, alignment, zero)) != NULL)
-		goto label_return;
+	if (config_dss && dss_prec == dss_prec_secondary) {
+		if ((ret = chunk_recycle(&chunks_szad_dss, &chunks_ad_dss, size,
+		    alignment, base, zero)) != NULL)
+			goto label_return;
+		if ((ret = chunk_alloc_dss(size, alignment, zero)) != NULL)
+			goto label_return;
+	}
 
 	/* All strategies for allocation failed. */
 	ret = NULL;

src/ctl.c

@@ -113,7 +113,7 @@ 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);
+static void	arena_purge(unsigned arena_ind);
 CTL_PROTO(arena_i_dss)
 INDEX_PROTO(arena_i)
 CTL_PROTO(arenas_bin_i_size)
@@ -1274,35 +1274,27 @@ CTL_RO_NL_CGEN(config_prof, opt_prof_accum, opt_prof_accum, bool)
 
 /******************************************************************************/
 
-static int
+/* ctl_mutex must be held during execution of this function. */
+static void
 arena_purge(unsigned arena_ind)
 {
-	int ret;
+	VARIABLE_ARRAY(arena_t *, tarenas, ctl_stats.narenas);
 
-	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);
 
-		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]);
+	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
@@ -1313,8 +1305,11 @@ arena_i_purge_ctl(const size_t *mib, size_t miblen, void *oldp, size_t *oldlenp,
 
 	READONLY();
 	WRITEONLY();
-	ret = arena_purge(mib[1]);
+	malloc_mutex_lock(&ctl_mtx);
+	arena_purge(mib[1]);
+	malloc_mutex_unlock(&ctl_mtx);
 
+	ret = 0;
 label_return:
 	return (ret);
 }
@@ -1483,7 +1478,8 @@ arenas_purge_ctl(const size_t *mib, size_t miblen, void *oldp, size_t *oldlenp,
 	else {
 		if (arena_ind == UINT_MAX)
 			arena_ind = ctl_stats.narenas;
-		ret = arena_purge(arena_ind);
+		arena_purge(arena_ind);
+		ret = 0;
 	}
 
 label_return:

src/zone.c

@@ -171,6 +171,16 @@ void
 register_zone(void)
 {
 
+	/*
+	 * If something else replaced the system default zone allocator, don't
+	 * register jemalloc's.
+	 */
+	malloc_zone_t *default_zone = malloc_default_zone();
+	if (!default_zone->zone_name ||
+	    strcmp(default_zone->zone_name, "DefaultMallocZone") != 0) {
+		return;
+	}
+
 	zone.size = (void *)zone_size;
 	zone.malloc = (void *)zone_malloc;
 	zone.calloc = (void *)zone_calloc;
@@ -241,7 +251,7 @@ register_zone(void)
 	 * then becomes the default.
 	 */
 	do {
-		malloc_zone_t *default_zone = malloc_default_zone();
+		default_zone = malloc_default_zone();
 		malloc_zone_unregister(default_zone);
 		malloc_zone_register(default_zone);
 	} while (malloc_default_zone() != &zone);