The patch titled
Subject: swap: cond_resched in swap_cgroup_prepare()
has been added to the -mm tree. Its filename is
swap-cond_resched-in-swap_cgroup_prepare.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/swap-cond_resched-in-swap_cgroup_prepare.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/swap-cond_resched-in-swap_cgroup_prepare.patch
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------------------------------------------------------
From: Yu Zhao <yuzhao@xxxxxxxxxx>
Subject: swap: cond_resched in swap_cgroup_prepare()
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>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/swap_cgroup.c | 3 +++
1 file changed, 3 insertions(+)
diff -puN mm/swap_cgroup.c~swap-cond_resched-in-swap_cgroup_prepare mm/swap_cgroup.c
--- a/mm/swap_cgroup.c~swap-cond_resched-in-swap_cgroup_prepare
+++ a/mm/swap_cgroup.c
@@ -48,6 +48,9 @@ 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 -mm which might be from yuzhao@xxxxxxxxxx are
swap-cond_resched-in-swap_cgroup_prepare.patch