linux-kernel - Re: [PATCH 5/8] mm: compaction: avoid overwork in migrate sync mode

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20111122095142.GI19415@suse.de>
Date:	Tue, 22 Nov 2011 09:51:42 +0000
From:	Mel Gorman <mgorman@...e.de>
To:	Rik van Riel <riel@...hat.com>
Cc:	Andrea Arcangeli <aarcange@...hat.com>, linux-mm@...ck.org,
	Minchan Kim <minchan.kim@...il.com>, Jan Kara <jack@...e.cz>,
	Andy Isaacson <adi@...apodia.org>,
	Johannes Weiner <jweiner@...hat.com>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 5/8] mm: compaction: avoid overwork in migrate sync mode

On Mon, Nov 21, 2011 at 04:59:36PM -0500, Rik van Riel wrote:
> On 11/19/2011 02:54 PM, Andrea Arcangeli wrote:
> >Add a lightweight sync migration (sync == 2) mode that avoids overwork
> >so more suitable to be used by compaction to provide lower latency but
> 
> >--- a/mm/compaction.c
> >+++ b/mm/compaction.c
> >@@ -552,7 +552,7 @@ static int compact_zone(struct zone *zone, struct compact_control *cc)
> >  		nr_migrate = cc->nr_migratepages;
> >  		err = migrate_pages(&cc->migratepages, compaction_alloc,
> >  				(unsigned long)cc, false,
> >-				cc->sync);
> >+				cc->sync ? 2 : 0);
> 
> Great idea, but it would be good if these numbers got
> a symbolic name so people trying to learn the code can
> figure it out a little easier.
> 

I took the bulk of this patch and gave them symbolic names when trying
to reconcile the two series. I didn't take all this patch such as
varying the number of passes because even if that turns out to be of
benefit, it should be a separate patch.

-- 
Mel Gorman
SUSE Labs
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/