linux-kernel - [PATCH 3.14 28/37] mm, compaction: determine isolation mode only once

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

Date:	Tue,  7 Oct 2014 16:19:45 -0700
From:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:	linux-kernel@...r.kernel.org
Cc:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	stable@...r.kernel.org, David Rientjes <rientjes@...gle.com>,
	Mel Gorman <mgorman@...e.de>, Rik van Riel <riel@...hat.com>,
	Vlastimil Babka <vbabka@...e.cz>,
	Joonsoo Kim <iamjoonsoo.kim@....com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Linus Torvalds <torvalds@...ux-foundation.org>
Subject: [PATCH 3.14 28/37] mm, compaction: determine isolation mode only once

3.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: David Rientjes <rientjes@...gle.com>

commit da1c67a76f7cf2b3404823d24f9f10fa91aa5dc5 upstream.

The conditions that control the isolation mode in
isolate_migratepages_range() do not change during the iteration, so
extract them out and only define the value once.

This actually does have an effect, gcc doesn't optimize it itself because
of cc->sync.

Signed-off-by: David Rientjes <rientjes@...gle.com>
Cc: Mel Gorman <mgorman@...e.de>
Acked-by: Rik van Riel <riel@...hat.com>
Acked-by: Vlastimil Babka <vbabka@...e.cz>
Cc: Joonsoo Kim <iamjoonsoo.kim@....com>
Signed-off-by: Andrew Morton <akpm@...ux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@...ux-foundation.org>
Signed-off-by: Mel Gorman <mgorman@...e.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 mm/compaction.c |    9 ++-------
 1 file changed, 2 insertions(+), 7 deletions(-)

--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -460,12 +460,13 @@ isolate_migratepages_range(struct zone *
 	unsigned long last_pageblock_nr = 0, pageblock_nr;
 	unsigned long nr_scanned = 0, nr_isolated = 0;
 	struct list_head *migratelist = &cc->migratepages;
-	isolate_mode_t mode = 0;
 	struct lruvec *lruvec;
 	unsigned long flags;
 	bool locked = false;
 	struct page *page = NULL, *valid_page = NULL;
 	bool skipped_async_unsuitable = false;
+	const isolate_mode_t mode = (!cc->sync ? ISOLATE_ASYNC_MIGRATE : 0) |
+				    (unevictable ? ISOLATE_UNEVICTABLE : 0);
 
 	/*
 	 * Ensure that there are not too many pages isolated from the LRU
@@ -608,12 +609,6 @@ isolate_migratepages_range(struct zone *
 			continue;
 		}
 
-		if (!cc->sync)
-			mode |= ISOLATE_ASYNC_MIGRATE;
-
-		if (unevictable)
-			mode |= ISOLATE_UNEVICTABLE;
-
 		lruvec = mem_cgroup_page_lruvec(page, zone);
 
 		/* Try isolate the page */


--
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/