Re: [patch 0/8] mm: memcg naturalization -rc2

Johannes Weiner
2011-06-09T08:43:21Z

On Wed, Jun 08, 2011 at 09:15:46PM -0400, Rik van Riel wrote:
> On 06/02/2011 08:59 AM, Hiroyuki Kamezawa wrote:
>
> >It seems your current series is a mixture of 2 works as
> >"re-desgin of softlimit" and "removal of global LRU".
> >I don't understand why you need 2 works at once.
>
> That seems pretty obvious.
>
> With the global LRU gone, the only way to reclaim
> pages in a global fashion (because the zone is low
> on memory), is to reclaim from all the memcgs in
> the zone.

That is correct.

> Doing that requires that the softlimit stuff is
> changed, and not only the biggest offender is
> attacked.

I think it's much more natural to do it that way, but it's not a
requirement as such. We could just keep the extra soft limit reclaim
invocation in kswapd that looks for the biggest offender and the
hierarchy below it, then does a direct call to do_shrink_zone() to
bypass the generic hierarchy walk.

It's not very nice to have that kind of code duplication, but it's
possible to leave it like that for now.