From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx112.postini.com [74.125.245.112]) by kanga.kvack.org (Postfix) with SMTP id D1F806B002B for ; Thu, 13 Dec 2012 05:34:24 -0500 (EST) Date: Thu, 13 Dec 2012 10:34:20 +0000 From: Mel Gorman Subject: Re: [patch 2/8] mm: vmscan: disregard swappiness shortly before going OOM Message-ID: <20121213103420.GW1009@suse.de> References: <1355348620-9382-1-git-send-email-hannes@cmpxchg.org> <1355348620-9382-3-git-send-email-hannes@cmpxchg.org> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <1355348620-9382-3-git-send-email-hannes@cmpxchg.org> Sender: owner-linux-mm@kvack.org List-ID: To: Johannes Weiner Cc: Andrew Morton , Rik van Riel , Michal Hocko , Hugh Dickins , linux-mm@kvack.org, linux-kernel@vger.kernel.org On Wed, Dec 12, 2012 at 04:43:34PM -0500, Johannes Weiner wrote: > When a reclaim scanner is doing its final scan before giving up and > there is swap space available, pay no attention to swappiness > preference anymore. Just swap. > > Note that this change won't make too big of a difference for general > reclaim: anonymous pages are already force-scanned when there is only > very little file cache left, and there very likely isn't when the > reclaimer enters this final cycle. > > Signed-off-by: Johannes Weiner Ok, I see the motivation for your patch but is the block inside still wrong for what you want? After your patch the block looks like this if (sc->priority || noswap) { scan >>= sc->priority; if (!scan && force_scan) scan = SWAP_CLUSTER_MAX; scan = div64_u64(scan * fraction[file], denominator); } if sc->priority == 0 and swappiness==0 then you enter this block but fraction[0] for anonymous pages will also be 0 and because of the ordering of statements there, scan will be scan = scan * 0 / denominator so you are still not reclaiming anonymous pages in the swappiness=0 case. What did I miss? -- Mel Gorman SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org