Re: [PATCH 5/5] writeback, memcg: Implement foreign dirty flushing

From: Tejun Heo
Date: Wed Aug 21 2019 - 12:04:36 EST


On Wed, Aug 21, 2019 at 09:00:37AM -0700, Tejun Heo wrote:
> > 2) When you invalidate frn entry here by writing 0 to 'at', it's likely to get
> > reused soon. Possibly while the writeback is still running. And then you
> > won't start any writeback for the new entry because of the
> > atomic_read(&frn->done.cnt) == 1 check. This seems like it could happen
> > pretty frequently?
>
> Hmm... yeah, the clearing might not make sense. I'll remove that.

Oh, the reuse logic checks whether done.cnt == 1 and only reuse if no
writeback is still in flight, so this one should be fine.

Thanks.

--
tejun