This is a note to let you know that I've just added the patch titled
mm: avoid swapping out with swappiness==0
to the 3.4-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-avoid-swapping-out-with-swappiness-0.patch
and it can be found in the queue-3.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From fe35004fbf9eaf67482b074a2e032abb9c89b1dd Mon Sep 17 00:00:00 2001
From: Satoru Moriya <[email protected]>
Date: Tue, 29 May 2012 15:06:47 -0700
Subject: mm: avoid swapping out with swappiness==0
From: Satoru Moriya <[email protected]>
commit fe35004fbf9eaf67482b074a2e032abb9c89b1dd upstream.
Sometimes we'd like to avoid swapping out anonymous memory. In
particular, avoid swapping out pages of important process or process
groups while there is a reasonable amount of pagecache on RAM so that we
can satisfy our customers' requirements.
OTOH, we can control how aggressive the kernel will swap memory pages with
/proc/sys/vm/swappiness for global and
/sys/fs/cgroup/memory/memory.swappiness for each memcg.
But with current reclaim implementation, the kernel may swap out even if
we set swappiness=0 and there is pagecache in RAM.
This patch changes the behavior with swappiness==0. If we set
swappiness==0, the kernel does not swap out completely (for global reclaim
until the amount of free pages and filebacked pages in a zone has been
reduced to something very very small (nr_free + nr_filebacked < high
watermark)).
Signed-off-by: Satoru Moriya <[email protected]>
Acked-by: Minchan Kim <[email protected]>
Reviewed-by: Rik van Riel <[email protected]>
Acked-by: Jerome Marchand <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
mm/vmscan.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1983,10 +1983,10 @@ static void get_scan_count(struct mem_cg
* proportional to the fraction of recently scanned pages on
* each list that were recently referenced and in active use.
*/
- ap = (anon_prio + 1) * (reclaim_stat->recent_scanned[0] + 1);
+ ap = anon_prio * (reclaim_stat->recent_scanned[0] + 1);
ap /= reclaim_stat->recent_rotated[0] + 1;
- fp = (file_prio + 1) * (reclaim_stat->recent_scanned[1] + 1);
+ fp = file_prio * (reclaim_stat->recent_scanned[1] + 1);
fp /= reclaim_stat->recent_rotated[1] + 1;
spin_unlock_irq(&mz->zone->lru_lock);
@@ -1999,7 +1999,7 @@ out:
unsigned long scan;
scan = zone_nr_lru_pages(mz, lru);
- if (priority || noswap) {
+ if (priority || noswap || !vmscan_swappiness(mz, sc)) {
scan >>= priority;
if (!scan && force_scan)
scan = SWAP_CLUSTER_MAX;
Patches currently in stable-queue which might be from [email protected] are
queue-3.4/mm-avoid-swapping-out-with-swappiness-0.patch
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