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[PATCH] malloc/malloc.c: Avoid calling sbrk unnecessarily with zero
- From: Will Newton <will dot newton at linaro dot org>
- To: libc-alpha at sourceware dot org
- Date: Fri, 13 Jun 2014 16:41:44 +0100
- Subject: [PATCH] malloc/malloc.c: Avoid calling sbrk unnecessarily with zero
- Authentication-results: sourceware.org; auth=none
Due to my bad review suggestion for the fix for BZ #15089 a check
was removed from systrim to prevent sbrk being called with a zero
argument. Add the check back to avoid this useless work.
ChangeLog:
2014-06-13 Will Newton <will.newton@linaro.org>
* malloc/malloc.c (systrim): If extra is zero then return
early.
---
malloc/malloc.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/malloc/malloc.c b/malloc/malloc.c
index d8fd8b4..41fd76a 100644
--- a/malloc/malloc.c
+++ b/malloc/malloc.c
@@ -2749,6 +2749,9 @@ systrim (size_t pad, mstate av)
/* Release in pagesize units, keeping at least one page */
extra = (top_area - pad) & ~(pagesz - 1);
+ if (extra == 0)
+ return 0;
+
/*
Only proceed if end of memory is where we last set it.
This avoids problems if there were foreign sbrk calls.
--
1.9.3