Try to decommit new chunks.

Always leave decommit disabled on non-Windows systems.

3 files changed, 13 insertions, 4 deletions

diff --git a/src/chunk_dss.c b/src/chunk_dss.c
index 1035581..de0546d 100644
--- a/src/chunk_dss.c
+++ b/src/chunk_dss.c
@@ -145,7 +145,8 @@ chunk_alloc_dss(arena_t *arena, void *new_addr, size_t size, size_t alignment,
 					    ret, size);
 					memset(ret, 0, size);
 				}
-				*commit = true;
+				if (!*commit)
+					*commit = pages_decommit(ret, size);
 				return (ret);
 			}
 		} while (dss_prev != (void *)-1);
diff --git a/src/chunk_mmap.c b/src/chunk_mmap.c
index a91a14c..36eb075 100644
--- a/src/chunk_mmap.c
+++ b/src/chunk_mmap.c
@@ -24,7 +24,8 @@ chunk_alloc_mmap_slow(size_t size, size_t alignment, bool *zero, bool *commit)
 
 	assert(ret != NULL);
 	*zero = true;
-	*commit = true;
+	if (!*commit)
+		*commit = pages_decommit(ret, size);
 	return (ret);
 }
 
@@ -61,7 +62,8 @@ chunk_alloc_mmap(size_t size, size_t alignment, bool *zero, bool *commit)
 
 	assert(ret != NULL);
 	*zero = true;
-	*commit = true;
+	if (!*commit)
+		*commit = pages_decommit(ret, size);
 	return (ret);
 }
 
diff --git a/src/pages.c b/src/pages.c
index 6f775dc..83a167f 100644
--- a/src/pages.c
+++ b/src/pages.c
@@ -102,7 +102,13 @@ pages_commit_impl(void *addr, size_t size, bool commit)
 {
 
 #ifndef _WIN32
-	if (config_debug) {
+	/*
+	 * The following decommit/commit implementation is functional, but
+	 * always disabled because it doesn't add value beyong improved
+	 * debugging (at the cost of extra system calls) on systems that
+	 * overcommit.
+	 */
+	if (false) {
 		int prot = commit ? (PROT_READ | PROT_WRITE) : PROT_NONE;
 		void *result = mmap(addr, size, prot, MAP_PRIVATE | MAP_ANON |
 		    MAP_FIXED, -1, 0);