Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756579Ab0HaBiQ (ORCPT ); Mon, 30 Aug 2010 21:38:16 -0400 Received: from fgwmail6.fujitsu.co.jp ([192.51.44.36]:34574 "EHLO fgwmail6.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756468Ab0HaBiP convert rfc822-to-8bit (ORCPT ); Mon, 30 Aug 2010 21:38:15 -0400 X-SecurityPolicyCheck-FJ: OK by FujitsuOutboundMailChecker v1.3.1 From: KOSAKI Motohiro To: Minchan Kim Subject: Re: [PATCH] vmscan: prevent background aging of anon page in no swap system Cc: kosaki.motohiro@jp.fujitsu.com, Ying Han , Rik van Riel , Andrew Morton , linux-mm , LKML , Venkatesh Pallipadi , Johannes Weiner In-Reply-To: References: <20100831095140.87C7.A69D9226@jp.fujitsu.com> Message-Id: <20100831102557.87D3.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 8BIT X-Mailer: Becky! ver. 2.50.07 [ja] Date: Tue, 31 Aug 2010 10:38:10 +0900 (JST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1697 Lines: 41 > > I think both Ying's and Minchan's opnion are right and makes sense. ?however I _personally_ > > like Ying version because 1) this version is simpler 2) swap full is very rarely event 3) > > no swap mounting is very common on HPC. so this version could have a chance to > > improvement hpc workload too. > > I agree. > > > > > In the other word, both avoiding unnecessary TLB flush and keeping proper page aging are > > performance matter. so when we are talking performance, we always need to think frequency > > of the event. > > Ying's one and mine both has a same effect. > Only difference happens swap is full. My version maintains old > behavior but Ying's one changes the behavior. I admit swap full is > rare event but I hoped not changed old behavior if we doesn't find any > problem. > If kswapd does aging when swap full happens, is it a problem? > We have been used to it from 2.6.28. > > If we regard a code consistency is more important than _unexpected_ > result, Okay. I don't mind it. :) To be honest, I don't mind the difference between you and Ying's version. because _practically_ swap full occur mean the application has a bug. so, proper page aging doesn't help so much. That's the reason why I said I prefer simper. I don't have strong opinion. I think it's not big matter. > But at least we should do more thing to make the patch to compile out > for non-swap configurable system. Yes, It makes embedded happy :) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/