Re: [PATCH 4.4 24/30] swap: cond_resched in swap_cgroup_prepare()

[Ben Hutchings]

On Mon, 2017-06-19 at 23:20 +0800, Greg Kroah-Hartman wrote:
> 4.4-stable review patch.  If anyone has any objections, please let me know.
> 
> ------------------
> 
> 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.
[...]

That seems to imply that this should also go into stable branches:

commit 460bcec84e11c75122ace5976214abbc596eb91b
Author: David Rientjes <rientjes@xxxxxxxxxx>
Date:   Fri Apr 7 16:05:00 2017 -0700

    mm, swap_cgroup: reschedule when neeed in swap_cgroup_swapoff()
    
Ben.

-- 
Ben Hutchings
Software Developer, Codethink Ltd.