Re: [PATCH] mm,vmscan: Use accurate values for zone_reclaimable() checks

From: Tejun Heo
Date: Mon Nov 02 2015 - 14:21:02 EST


On Mon, Nov 02, 2015 at 04:01:37PM +0100, Michal Hocko wrote:
...
> which is perfectly suited for the stable backport, OOM sysrq resp. any
> sysrq which runs from the WQ context should be as robust as possible and
> shouldn't rely on all the code running from WQ context to issue a sleep
> to get unstuck. So I definitely support something like this patch.

Well, sysrq wouldn't run successfully either on a cpu which is busy
looping with preemption off. I don't think this calls for a new flag
to modify workqueue behavior especially given that missing such flag
would lead to the same kind of lockup. It's a shitty solution. If
the possibility of sysrq getting stuck behind concurrency management
is an issue, queueing them on an unbound or highpri workqueue should
be good enough.

Thanks.

--
tejun
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