Make dss non-optional, and fix an "arena.<i>.dss" mallctl bug.

Make dss non-optional on all platforms which support sbrk(2).

Fix the "arena.<i>.dss" mallctl to return an error if "primary" or
"secondary" precedence is specified, but sbrk(2) is not supported.

src/arena.c

@@ -2243,13 +2243,16 @@ arena_dss_prec_get(arena_t *arena)
 	return (ret);
 }
 
-void
+bool
 arena_dss_prec_set(arena_t *arena, dss_prec_t dss_prec)
 {
 
+	if (have_dss == false)
+		return (dss_prec != dss_prec_disabled);
 	malloc_mutex_lock(&arena->lock);
 	arena->dss_prec = dss_prec;
 	malloc_mutex_unlock(&arena->lock);
+	return (false);
 }
 
 void

src/chunk.c

@@ -153,7 +153,7 @@ chunk_alloc(size_t size, size_t alignment, bool base, bool *zero,
 	assert((alignment & chunksize_mask) == 0);
 
 	/* "primary" dss. */
-	if (config_dss && dss_prec == dss_prec_primary) {
+	if (have_dss && dss_prec == dss_prec_primary) {
 		if ((ret = chunk_recycle(&chunks_szad_dss, &chunks_ad_dss, size,
 		    alignment, base, zero)) != NULL)
 			goto label_return;
@@ -167,7 +167,7 @@ chunk_alloc(size_t size, size_t alignment, bool base, bool *zero,
 	if ((ret = chunk_alloc_mmap(size, alignment, zero)) != NULL)
 		goto label_return;
 	/* "secondary" dss. */
-	if (config_dss && dss_prec == dss_prec_secondary) {
+	if (have_dss && dss_prec == dss_prec_secondary) {
 		if ((ret = chunk_recycle(&chunks_szad_dss, &chunks_ad_dss, size,
 		    alignment, base, zero)) != NULL)
 			goto label_return;
@@ -305,7 +305,7 @@ chunk_unmap(void *chunk, size_t size)
 	assert(size != 0);
 	assert((size & chunksize_mask) == 0);
 
-	if (config_dss && chunk_in_dss(chunk))
+	if (have_dss && chunk_in_dss(chunk))
 		chunk_record(&chunks_szad_dss, &chunks_ad_dss, chunk, size);
 	else if (chunk_dealloc_mmap(chunk, size))
 		chunk_record(&chunks_szad_mmap, &chunks_ad_mmap, chunk, size);
@@ -348,7 +348,7 @@ chunk_boot(void)
 			return (true);
 		memset(&stats_chunks, 0, sizeof(chunk_stats_t));
 	}
-	if (config_dss && chunk_dss_boot())
+	if (have_dss && chunk_dss_boot())
 		return (true);
 	extent_tree_szad_new(&chunks_szad_mmap);
 	extent_tree_ad_new(&chunks_ad_mmap);

src/chunk_dss.c

@@ -32,7 +32,7 @@ static void *
 chunk_dss_sbrk(intptr_t increment)
 {
 
-#ifdef JEMALLOC_HAVE_SBRK
+#ifdef JEMALLOC_DSS
 	return (sbrk(increment));
 #else
 	not_implemented();
@@ -45,7 +45,7 @@ chunk_dss_prec_get(void)
 {
 	dss_prec_t ret;
 
-	if (config_dss == false)
+	if (have_dss == false)
 		return (dss_prec_disabled);
 	malloc_mutex_lock(&dss_mtx);
 	ret = dss_prec_default;
@@ -57,8 +57,8 @@ bool
 chunk_dss_prec_set(dss_prec_t dss_prec)
 {
 
-	if (config_dss == false)
-		return (true);
+	if (have_dss == false)
+		return (dss_prec != dss_prec_disabled);
 	malloc_mutex_lock(&dss_mtx);
 	dss_prec_default = dss_prec;
 	malloc_mutex_unlock(&dss_mtx);
@@ -70,7 +70,7 @@ chunk_alloc_dss(size_t size, size_t alignment, bool *zero)
 {
 	void *ret;
 
-	cassert(config_dss);
+	cassert(have_dss);
 	assert(size > 0 && (size & chunksize_mask) == 0);
 	assert(alignment > 0 && (alignment & chunksize_mask) == 0);
 
@@ -143,7 +143,7 @@ chunk_in_dss(void *chunk)
 {
 	bool ret;
 
-	cassert(config_dss);
+	cassert(have_dss);
 
 	malloc_mutex_lock(&dss_mtx);
 	if ((uintptr_t)chunk >= (uintptr_t)dss_base
@@ -160,7 +160,7 @@ bool
 chunk_dss_boot(void)
 {
 
-	cassert(config_dss);
+	cassert(have_dss);
 
 	if (malloc_mutex_init(&dss_mtx))
 		return (true);
@@ -175,7 +175,7 @@ void
 chunk_dss_prefork(void)
 {
 
-	if (config_dss)
+	if (have_dss)
 		malloc_mutex_prefork(&dss_mtx);
 }
 
@@ -183,7 +183,7 @@ void
 chunk_dss_postfork_parent(void)
 {
 
-	if (config_dss)
+	if (have_dss)
 		malloc_mutex_postfork_parent(&dss_mtx);
 }
 
@@ -191,7 +191,7 @@ void
 chunk_dss_postfork_child(void)
 {
 
-	if (config_dss)
+	if (have_dss)
 		malloc_mutex_postfork_child(&dss_mtx);
 }
 

src/ctl.c

@@ -74,7 +74,6 @@ CTL_PROTO(thread_allocatedp)
 CTL_PROTO(thread_deallocated)
 CTL_PROTO(thread_deallocatedp)
 CTL_PROTO(config_debug)
-CTL_PROTO(config_dss)
 CTL_PROTO(config_fill)
 CTL_PROTO(config_lazy_lock)
 CTL_PROTO(config_mremap)
@@ -213,7 +212,6 @@ static const ctl_named_node_t	thread_node[] = {
 
 static const ctl_named_node_t	config_node[] = {
 	{NAME("debug"),			CTL(config_debug)},
-	{NAME("dss"),			CTL(config_dss)},
 	{NAME("fill"),			CTL(config_fill)},
 	{NAME("lazy_lock"),		CTL(config_lazy_lock)},
 	{NAME("mremap"),		CTL(config_mremap)},
@@ -1136,7 +1134,6 @@ label_return:
 /******************************************************************************/
 
 CTL_RO_BOOL_CONFIG_GEN(config_debug)
-CTL_RO_BOOL_CONFIG_GEN(config_dss)
 CTL_RO_BOOL_CONFIG_GEN(config_fill)
 CTL_RO_BOOL_CONFIG_GEN(config_lazy_lock)
 CTL_RO_BOOL_CONFIG_GEN(config_mremap)
@@ -1356,8 +1353,7 @@ arena_i_dss_ctl(const size_t *mib, size_t miblen, void *oldp, size_t *oldlenp,
 		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;
+			err = arena_dss_prec_set(arena, dss_prec);
 		} else
 			err = true;
 	} else {

src/huge.c

@@ -140,7 +140,7 @@ huge_ralloc(void *ptr, size_t oldsize, size_t size, size_t extra,
 	 * Use mremap(2) if this is a huge-->huge reallocation, and neither the
 	 * source nor the destination are in dss.
 	 */
-	if (oldsize >= chunksize && (config_dss == false || (chunk_in_dss(ptr)
+	if (oldsize >= chunksize && (have_dss == false || (chunk_in_dss(ptr)
 	    == false && chunk_in_dss(ret) == false))) {
 		size_t newsize = huge_salloc(ret);
 
@@ -198,12 +198,12 @@ static void
 huge_dalloc_junk(void *ptr, size_t usize)
 {
 
-	if (config_fill && config_dss && opt_junk) {
+	if (config_fill && have_dss && opt_junk) {
 		/*
 		 * Only bother junk filling if the chunk isn't about to be
 		 * unmapped.
 		 */
-		if (config_munmap == false || (config_dss && chunk_in_dss(ptr)))
+		if (config_munmap == false || (have_dss && chunk_in_dss(ptr)))
 			memset(ptr, 0x5a, usize);
 	}
 }