From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail144.messagelabs.com (mail144.messagelabs.com [216.82.254.51]) by kanga.kvack.org (Postfix) with SMTP id 6F0A96B01EF for ; Mon, 5 Apr 2010 21:36:39 -0400 (EDT) Received: from m2.gw.fujitsu.co.jp ([10.0.50.72]) by fgwmail7.fujitsu.co.jp (Fujitsu Gateway) with ESMTP id o361aa2J016813 for (envelope-from kosaki.motohiro@jp.fujitsu.com); Tue, 6 Apr 2010 10:36:36 +0900 Received: from smail (m2 [127.0.0.1]) by outgoing.m2.gw.fujitsu.co.jp (Postfix) with ESMTP id 7D2AA45DE4E for ; Tue, 6 Apr 2010 10:36:36 +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 5F8171EF081 for ; Tue, 6 Apr 2010 10:36:36 +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 4633AE38001 for ; Tue, 6 Apr 2010 10:36:36 +0900 (JST) Received: from m106.s.css.fujitsu.com (m106.s.css.fujitsu.com [10.249.87.106]) by s2.gw.fujitsu.co.jp (Postfix) with ESMTP id E8DEAE38009 for ; Tue, 6 Apr 2010 10:36:32 +0900 (JST) From: KOSAKI Motohiro Subject: Re: [PATCH]vmscan: handle underflow for get_scan_ratio In-Reply-To: <20100406012536.GB18672@sli10-desk.sh.intel.com> References: <20100404231558.7E00.A69D9226@jp.fujitsu.com> <20100406012536.GB18672@sli10-desk.sh.intel.com> Message-Id: <20100406103500.7E2D.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Date: Tue, 6 Apr 2010 10:36:32 +0900 (JST) Sender: owner-linux-mm@kvack.org To: Shaohua Li Cc: kosaki.motohiro@jp.fujitsu.com, "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , "akpm@linux-foundation.org" , "Wu, Fengguang" List-ID: > On Sun, Apr 04, 2010 at 10:19:06PM +0800, KOSAKI Motohiro wrote: > > > On Fri, Apr 02, 2010 at 05:14:38PM +0800, KOSAKI Motohiro wrote: > > > > > > > This patch makes a lot of sense than previous. however I think <1% anon ratio > > > > > > > shouldn't happen anyway because file lru doesn't have reclaimable pages. > > > > > > > <1% seems no good reclaim rate. > > > > > > > > > > > > Oops, the above mention is wrong. sorry. only 1 page is still too big. > > > > > > because under streaming io workload, the number of scanning anon pages should > > > > > > be zero. this is very strong requirement. if not, backup operation will makes > > > > > > a lot of swapping out. > > > > > Sounds there is no big impact for the workload which you mentioned with the patch. > > > > > please see below descriptions. > > > > > I updated the description of the patch as fengguang suggested. > > > > > > > > Umm.. sorry, no. > > > > > > > > "one fix but introduce another one bug" is not good deal. instead, > > > > I'll revert the guilty commit at first as akpm mentioned. > > > Even we revert the commit, the patch still has its benefit, as it increases > > > calculation precision, right? > > > > no, you shouldn't ignore the regression case. > I don't think this is serious. In my calculation, there is only 1 page swapped out > for 6G anonmous memory. 1 page should haven't any performance impact. there is. I had received exactly opposite claim. because shrink_zone() is not called only once. it is called very much time. -- 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