From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail172.messagelabs.com (mail172.messagelabs.com [216.82.254.3]) by kanga.kvack.org (Postfix) with SMTP id E660D6B01B4 for ; Thu, 20 May 2010 20:15:38 -0400 (EDT) Received: from m2.gw.fujitsu.co.jp ([10.0.50.72]) by fgwmail5.fujitsu.co.jp (Fujitsu Gateway) with ESMTP id o4L0FaFX001957 for (envelope-from kosaki.motohiro@jp.fujitsu.com); Fri, 21 May 2010 09:15:36 +0900 Received: from smail (m2 [127.0.0.1]) by outgoing.m2.gw.fujitsu.co.jp (Postfix) with ESMTP id 06D3745DE51 for ; Fri, 21 May 2010 09:15:36 +0900 (JST) Received: from s2.gw.fujitsu.co.jp (s2.gw.fujitsu.co.jp [10.0.50.92]) by m2.gw.fujitsu.co.jp (Postfix) with ESMTP id D998E45DE4F for ; Fri, 21 May 2010 09:15:35 +0900 (JST) Received: from s2.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s2.gw.fujitsu.co.jp (Postfix) with ESMTP id C10D91DB8038 for ; Fri, 21 May 2010 09:15:35 +0900 (JST) Received: from m105.s.css.fujitsu.com (m105.s.css.fujitsu.com [10.249.87.105]) by s2.gw.fujitsu.co.jp (Postfix) with ESMTP id 5CCC4E08006 for ; Fri, 21 May 2010 09:15:32 +0900 (JST) From: KOSAKI Motohiro Subject: Re: [patch 5/5] vmscan: remove may_swap scan control In-Reply-To: <20100519214459.GD2868@cmpxchg.org> References: <20100513122935.2161.A69D9226@jp.fujitsu.com> <20100519214459.GD2868@cmpxchg.org> Message-Id: <20100521081534.1E31.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Date: Fri, 21 May 2010 09:15:31 +0900 (JST) Sender: owner-linux-mm@kvack.org To: Johannes Weiner Cc: kosaki.motohiro@jp.fujitsu.com, Andrew Morton , Mel Gorman , linux-mm@kvack.org List-ID: > On Thu, May 13, 2010 at 12:36:12PM +0900, KOSAKI Motohiro wrote: > > > The may_swap scan control flag can be naturally merged into the > > > swappiness parameter: swap only if swappiness is non-zero. > > > > Sorry, NAK. > > > > AFAIK, swappiness==0 is very widely used in MySQL users community. > > They expect this parameter mean "very prefer to discard file cache > > rather than swap, but not completely disable swap". > > > > We shouldn't ignore the real world use case. even if it is a bit strange. > > Bummer. It's really ugly to have 'zero' mean 'almost nothing'. > > But since swappiness is passed around as an int, I think we can > instead use -1 for 'no swap'. Let me look into it and send a > follow-up patch for this as well. > > Thanks! Yup, -1 is perfectly acceptable. Moreover, I hope such strange habbit will disappear int the future. I think our recent activity help to change their mind. At that time, we can change the code more radically. Thanks. -- 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