This is a note to let you know that I've just added the patch titled
swap: cond_resched in swap_cgroup_prepare()
to the 3.18-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:
swap-cond_resched-in-swap_cgroup_prepare.patch
and it can be found in the queue-3.18 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From ef70762948dde012146926720b70e79736336764 Mon Sep 17 00:00:00 2001
From: Yu Zhao <yuzhao@xxxxxxxxxx>
Date: Fri, 16 Jun 2017 14:02:31 -0700
Subject: swap: cond_resched in swap_cgroup_prepare()
From: Yu Zhao <yuzhao@xxxxxxxxxx>
commit ef70762948dde012146926720b70e79736336764 upstream.
I saw need_resched() warnings when swapping on large swapfile (TBs)
because continuously allocating many pages in swap_cgroup_prepare() took
too long.
We already cond_resched when freeing page in swap_cgroup_swapoff(). Do
the same for the page allocation.
Link: http://lkml.kernel.org/r/20170604200109.17606-1-yuzhao@xxxxxxxxxx
Signed-off-by: Yu Zhao <yuzhao@xxxxxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
Acked-by: Vladimir Davydov <vdavydov.dev@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
mm/page_cgroup.c | 3 +++
1 file changed, 3 insertions(+)
--- a/mm/page_cgroup.c
+++ b/mm/page_cgroup.c
@@ -368,6 +368,9 @@ static int swap_cgroup_prepare(int type)
if (!page)
goto not_enough_page;
ctrl->map[idx] = page;
+
+ if (!(idx % SWAP_CLUSTER_MAX))
+ cond_resched();
}
return 0;
not_enough_page:
Patches currently in stable-queue which might be from yuzhao@xxxxxxxxxx are
queue-3.18/swap-cond_resched-in-swap_cgroup_prepare.patch