Re: shrink_active_list/try_to_release_page bug? (was Re: xfs trace in 4.4.2 / also in 4.3.3 WARNING fs/xfs/xfs_aops.c:1232 xfs_vm_releasepage)

From: Holger HoffstÃtte
Date: Thu Jun 02 2016 - 08:44:37 EST

On 06/02/16 14:13, Stefan Priebe - Profihost AG wrote:
> Am 31.05.2016 um 09:31 schrieb Dave Chinner:
>> On Tue, May 31, 2016 at 08:11:42AM +0200, Stefan Priebe - Profihost AG wrote:
>>>> I'm half tempted at this point to mostly ignore this mm/ behavour
>>>> because we are moving down the path of removing buffer heads from
>>>> XFS. That will require us to do different things in ->releasepage
>>>> and so just skipping dirty pages in the XFS code is the best thing
>>>> to do....
>>> does this change anything i should test? Or is 4.6 still the way to go?
>> Doesn't matter now - the warning will still be there on 4.6. I think
>> you can simply ignore it as the XFS code appears to be handling the
>> dirty page that is being passed to it correctly. We'll work out what
>> needs to be done to get rid of the warning for this case, wether it
>> be a mm/ change or an XFS change.
> Any idea what i could do with 4.4.X? Can i safely remove the WARN_ONCE
> statement?

By definition it won't break anything since it's just a heads-up message,
so yes, it should be "safe". However if my understanding of the situation
is correct, mainline commit f0281a00fe "mm: workingset: only do workingset
activations on reads" (+ friends) in 4.7 should effectively prevent this
from happenning. Can someone confirm or deny this?


PS: Stefan: I backported that commit (and friends) to my 4.4.x patch queue,
so if you want to try that for today's 4.4.12 the warning should be gone.
No guarantees though :)