Re: [patch v4] Soft limit rework

From: Michal Hocko
Date: Tue Jun 04 2013 - 14:09:09 EST


On Tue 04-06-13 23:27:05, Balbir Singh wrote:
> > OK, let me summarize. The primary intention is to get rid of the current
> > soft reclaim infrastructure which basically bypasses the standard
> > reclaim and tight it directly into shrink_zone code. This also means
> > that the soft reclaim doesn't reclaim at priority 0 and that it is
> > active also for the targeted (aka limit) reclaim.
> >
> > Does this help?
> >
>
> Yes. What are the limitations of no-priority 0 reclaim?

I am not sure I understand the question. What do you mean by
limitations?

The priority-0 scan was always a crude hack. With a lot of pages in on
the LRU it might cause huge big stalls during direct reclaim. There are
workloads which benefited from such an aggressive reclaim - e.g.
streaming IO but that doesn't justify this kind of reclaim.
--
Michal Hocko
SUSE Labs
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