[PATCH][BZ #1128] Do not trim when arena is noncontiguous.

[Ondřej Bílka]

Hi,

When we call systrim we do not check if main arena is contiguous or not.

This can cause performance degradation like in bugzilla entry which can
be avoided by adding a check.
	
	[BZ #1128]
	* malloc/malloc.c (systrim): Do not trim when main arena is
	noncontiguous.

diff --git a/malloc/malloc.c b/malloc/malloc.c
index acfa9a2..ee98229 100644
--- a/malloc/malloc.c
+++ b/malloc/malloc.c
@@ -2716,6 +2716,9 @@ static int systrim(size_t pad, mstate av)
   size_t pagesz;
   long  top_area;
 
+  if (noncontiguous (av))
+    return 0;
+
   pagesz = GLRO(dl_pagesize);
   top_size = chunksize(av->top);