Re: [PATCH v2] swap: cond_resched in swap_cgroup_prepare()

From	Michal Hocko <mhocko@kernel.org>
Newsgroups	linux.kernel
Subject	Re: [PATCH v2] swap: cond_resched in swap_cgroup_prepare()
Date	2017-06-05 07:20 +0200
Message-ID	<tOSAN-73f-3@gated-at.bofh.it> (permalink)
References	<tNEqe-73L-11@gated-at.bofh.it> <tOK0y-1qd-5@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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[CC Andrew]

On Sun 04-06-17 13:01:09, Yu Zhao wrote:
> 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.
> 
> Signed-off-by: Yu Zhao <yuzhao@google.com>
> Acked-by: Michal Hocko <mhocko@suse.com>
> Acked-by: Vladimir Davydov <vdavydov.dev@gmail.com>
> ---
> Changelog since v1:
> * clarify the problem in the commit message
> 
>  mm/swap_cgroup.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/mm/swap_cgroup.c b/mm/swap_cgroup.c
> index ac6318a064d3..3405b4ee1757 100644
> --- a/mm/swap_cgroup.c
> +++ b/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:
> -- 
> 2.13.0.506.g27d5fe0cd-goog

-- 
Michal Hocko
SUSE Labs

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[PATCH] swap: cond_resched in swap_cgroup_prepare() Yu Zhao <yuzhao@google.com> - 2017-06-01 22:00 +0200
  Re: [PATCH] swap: cond_resched in swap_cgroup_prepare() Michal Hocko <mhocko@kernel.org> - 2017-06-02 10:20 +0200
    Re: [PATCH] swap: cond_resched in swap_cgroup_prepare() Yu Zhao <yuzhao@google.com> - 2017-06-04 21:40 +0200
  Re: [PATCH] swap: cond_resched in swap_cgroup_prepare() Vladimir Davydov <vdavydov.dev@gmail.com> - 2017-06-03 17:00 +0200
  [PATCH v2] swap: cond_resched in swap_cgroup_prepare() Yu Zhao <yuzhao@google.com> - 2017-06-04 22:10 +0200
    Re: [PATCH v2] swap: cond_resched in swap_cgroup_prepare() Michal Hocko <mhocko@kernel.org> - 2017-06-05 07:20 +0200

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