From: Hugh Dickins <hughd@google.com>
To: Rik van Riel <riel@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Mel Gorman <mgorman@suse.de>, Linux-MM <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>,
Konstantin Khlebnikov <khlebnikov@openvz.org>
Subject: Re: [RFC PATCH 0/2] Removal of lumpy reclaim
Date: Mon, 9 Apr 2012 12:18:14 -0700 (PDT) [thread overview]
Message-ID: <alpine.LSU.2.00.1204091205130.1536@eggly.anvils> (raw)
In-Reply-To: <4F8325FB.80409@redhat.com>
On Mon, 9 Apr 2012, Rik van Riel wrote:
> On 04/06/2012 04:31 PM, Hugh Dickins wrote:
> > On Fri, 6 Apr 2012, Andrew Morton wrote:
> > > On Wed, 28 Mar 2012 17:06:21 +0100
> > > Mel Gorman<mgorman@suse.de> wrote:
> > >
> > > > (cc'ing active people in the thread "[patch 68/92] mm: forbid
> > > > lumpy-reclaim
> > > > in shrink_active_list()")
> > > >
> > > > In the interest of keeping my fingers from the flames at LSF/MM, I'm
> > > > releasing an RFC for lumpy reclaim removal.
> > >
> > > I grabbed them, thanks.
> >
> > I do have a concern with this: I was expecting lumpy reclaim to be
> > replaced by compaction, and indeed it is when CONFIG_COMPACTION=y.
> > But when CONFIG_COMPACTION is not set, we're back to 2.6.22 in
> > relying upon blind chance to provide order>0 pages.
>
> Is this an issue for any architecture?
Dunno about any architecture as a whole; but I'd expect users of SLOB
or TINY config options to want to still use lumpy rather than the more
efficient but weightier COMPACTION+MIGRATION.
Though "size migrate.o compaction.o" on my 32-bit config does not
reach 8kB, so maybe it's not a big deal after all.
>
> I could see NOMMU being unable to use compaction, but
Yes, COMPACTION depends on MMU.
> chances are lumpy reclaim would be sufficient for that
> configuration, anyway...
That's an argument for your patch in 3.4-rc, which uses lumpy only
when !COMPACTION_BUILD. But here we're worrying about Mel's patch,
which removes the lumpy code completely.
Hugh
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next prev parent reply other threads:[~2012-04-09 19:18 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-28 16:06 Mel Gorman
2012-03-28 16:06 ` [PATCH 1/2] mm: vmscan: Remove " Mel Gorman
2012-04-06 23:52 ` Ying Han
2012-04-10 8:24 ` Mel Gorman
2012-04-10 9:29 ` Mel Gorman
2012-04-10 17:25 ` Ying Han
2012-03-28 16:06 ` [PATCH 2/2] mm: vmscan: Remove reclaim_mode_t Mel Gorman
2012-04-06 19:34 ` [RFC PATCH 0/2] Removal of lumpy reclaim Andrew Morton
2012-04-06 20:31 ` Hugh Dickins
2012-04-07 3:00 ` KOSAKI Motohiro
2012-04-09 18:10 ` Rik van Riel
2012-04-09 19:18 ` Hugh Dickins [this message]
2012-04-09 23:40 ` Rik van Riel
2012-04-10 8:32 ` Mel Gorman
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