Re: [RFC][PATCH 5/5] memcg softlimit hooks to kswapd

From: KAMEZAWA Hiroyuki
Date: Thu Mar 12 2009 - 00:03:36 EST


On Thu, 12 Mar 2009 09:28:37 +0530
Balbir Singh <balbir@xxxxxxxxxxxxxxxxxx> wrote:

> * KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> [2009-03-12 10:00:08]:

> > + return;
> > +}
>
> I experimented a *lot* with zone reclaim and found it to be not so
> effective. Here is why
>
> 1. We have no control over priority or how much to scan, that is
> controlled by balance_pgdat(). If we find that we are unable to scan
> anything, we continue scanning with the scan > 0 check, but we scan
> the same pages and the same number, because shrink_zone does scan >>
> priority.

If sc->nr_reclaimd==0, "false" is passed and mem_cgroup_schedule_end()
and it will be moved to INACTIVE queue. (and not appear here again.)


> 2. If we fail to reclaim pages in shrink_zone_softlimit, shrink_zone()
> will reclaim pages independent of the soft limit for us
>
yes. It's intentional behavior.

Thanks,
-Kame

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