From 4a2a3c9a6e5f8fda3536f48095d68ddaa13cd977 Mon Sep 17 00:00:00 2001
From: Mike Hommey <mh@glandium.org>
Date: Fri, 28 Aug 2015 13:45:51 +0900
Subject: [PATCH] Don't purge junk filled chunks when shrinking huge
 allocations

When junk filling is enabled, shrinking an allocation fills the bytes
that were previously allocated but now aren't. Purging the chunk before
doing that is just a waste of time.

This resolves #260.
---
 src/huge.c               | 14 ++++++++------
 test/integration/chunk.c |  4 ++++
 2 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/src/huge.c b/src/huge.c
index f49a9376..4d5887c4 100644
--- a/src/huge.c
+++ b/src/huge.c
@@ -148,11 +148,12 @@ huge_ralloc_no_move_similar(void *ptr, size_t oldsize, size_t usize,
 	/* Fill if necessary (shrinking). */
 	if (oldsize > usize) {
 		size_t sdiff = oldsize - usize;
-		zeroed = !chunk_purge_wrapper(arena, &chunk_hooks, ptr,
-		    CHUNK_CEILING(oldsize), usize, sdiff);
 		if (config_fill && unlikely(opt_junk_free)) {
 			memset((void *)((uintptr_t)ptr + usize), 0x5a, sdiff);
 			zeroed = false;
+		} else {
+			zeroed = !chunk_purge_wrapper(arena, &chunk_hooks, ptr,
+			    CHUNK_CEILING(oldsize), usize, sdiff);
 		}
 	} else
 		zeroed = true;
@@ -202,14 +203,15 @@ huge_ralloc_no_move_shrink(void *ptr, size_t oldsize, size_t usize)
 
 	if (oldsize > usize) {
 		size_t sdiff = oldsize - usize;
-		zeroed = !chunk_purge_wrapper(arena, &chunk_hooks,
-		    CHUNK_ADDR2BASE((uintptr_t)ptr + usize),
-		    CHUNK_CEILING(oldsize), CHUNK_ADDR2OFFSET((uintptr_t)ptr +
-		    usize), sdiff);
 		if (config_fill && unlikely(opt_junk_free)) {
 			huge_dalloc_junk((void *)((uintptr_t)ptr + usize),
 			    sdiff);
 			zeroed = false;
+		} else {
+			zeroed = !chunk_purge_wrapper(arena, &chunk_hooks,
+			    CHUNK_ADDR2BASE((uintptr_t)ptr + usize),
+			    CHUNK_CEILING(oldsize),
+			    CHUNK_ADDR2OFFSET((uintptr_t)ptr + usize), sdiff);
 		}
 	} else
 		zeroed = true;
diff --git a/test/integration/chunk.c b/test/integration/chunk.c
index 7eb1b6d2..af1c9a53 100644
--- a/test/integration/chunk.c
+++ b/test/integration/chunk.c
@@ -1,5 +1,9 @@
 #include "test/jemalloc_test.h"
 
+#ifdef JEMALLOC_FILL
+const char *malloc_conf = "junk:false";
+#endif
+
 static chunk_hooks_t orig_hooks;
 static chunk_hooks_t old_hooks;