linux-kernel - [PATCH 1/1] page_alloc.c: Slightly improve the logic in __alloc_pages_high

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:	Mon,  5 Mar 2012 09:18:25 -0500
From:	Kautuk Consul <consul.kautuk@...il.com>
To:	Andrew Morton <akpm@...ux-foundation.org>,
	Mel Gorman <mgorman@...e.de>,
	KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>,
	Tejun Heo <tj@...nel.org>, Minchan Kim <minchan.kim@...il.com>
Cc:	linux-mm@...ck.org, linux-kernel@...r.kernel.org,
	Kautuk Consul <consul.kautuk@...il.com>
Subject: [PATCH 1/1] page_alloc.c: Slightly improve the logic in __alloc_pages_high_priority

The loop in __alloc_pages_high_priority() seems to be checking for
(!page) and (gfp_mask & __GFP_NOFAIL) multiple times.

In fact, we don't really need to check (gfp_mask & __GFP_NOFAIL)
for every iteration of the loop as the gfp_mask remains constant.

Slightly improve the logic in __alloc_pages_high_priority() to
eliminate these multiple condition checks.

Signed-off-by: Kautuk Consul <consul.kautuk@...il.com>
---
 mm/page_alloc.c |   13 +++++++++----
 1 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index a13ded1..6bb8b6d 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2114,14 +2114,19 @@ __alloc_pages_high_priority(gfp_t gfp_mask, unsigned int order,
 {
 	struct page *page;
 
-	do {
-		page = get_page_from_freelist(gfp_mask, nodemask, order,
+	page = get_page_from_freelist(gfp_mask, nodemask, order,
 			zonelist, high_zoneidx, ALLOC_NO_WATERMARKS,
 			preferred_zone, migratetype);
 
-		if (!page && gfp_mask & __GFP_NOFAIL)
+	if (gfp_mask & __GFP_NOFAIL) {
+		while (!page) {
 			wait_iff_congested(preferred_zone, BLK_RW_ASYNC, HZ/50);
-	} while (!page && (gfp_mask & __GFP_NOFAIL));
+
+			page = get_page_from_freelist(gfp_mask, nodemask, order,
+				zonelist, high_zoneidx, ALLOC_NO_WATERMARKS,
+				preferred_zone, migratetype);
+		}
+	}
 
 	return page;
 }
-- 
1.7.5.4

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/