This is a note to let you know that I've just added the patch titled
mm: page_alloc: do not update zlc unless the zlc is active
to the 3.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
mm-page_alloc-do-not-update-zlc-unless-the-zlc-is-active.patch
and it can be found in the queue-3.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 65bb371984d6a2c909244eb749e482bb40b72e36 Mon Sep 17 00:00:00 2001
From: Mel Gorman <mgorman@xxxxxxx>
Date: Wed, 4 Jun 2014 16:10:05 -0700
Subject: mm: page_alloc: do not update zlc unless the zlc is active
From: Mel Gorman <mgorman@xxxxxxx>
commit 65bb371984d6a2c909244eb749e482bb40b72e36 upstream.
The zlc is used on NUMA machines to quickly skip over zones that are full.
However it is always updated, even for the first zone scanned when the
zlc might not even be active. As it's a write to a bitmap that
potentially bounces cache line it's deceptively expensive and most
machines will not care. Only update the zlc if it was active.
Signed-off-by: Mel Gorman <mgorman@xxxxxxx>
Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Reviewed-by: Rik van Riel <riel@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Mel Gorman <mgorman@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
mm/page_alloc.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2059,7 +2059,7 @@ try_this_zone:
if (page)
break;
this_zone_full:
- if (IS_ENABLED(CONFIG_NUMA))
+ if (IS_ENABLED(CONFIG_NUMA) && zlc_active)
zlc_mark_zone_full(zonelist, z);
}
Patches currently in stable-queue which might be from mgorman@xxxxxxx are
queue-3.14/mm-page_alloc-use-jump-labels-to-avoid-checking-number_of_cpusets.patch
queue-3.14/mm-page_alloc-do-not-treat-a-zone-that-cannot-be-used-for-dirty-pages-as-full.patch
queue-3.14/mm-page_alloc-do-not-update-zlc-unless-the-zlc-is-active.patch
queue-3.14/mm-swap.c-clean-up-lru_cache_add-functions.patch
queue-3.14/include-linux-jump_label.h-expose-the-reference-count.patch
queue-3.14/mm-page_alloc-calculate-classzone_idx-once-from-the.patch
--
To unsubscribe from this list: send the line "unsubscribe stable" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html