Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760786AbYBGBVS (ORCPT ); Wed, 6 Feb 2008 20:21:18 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758288AbYBGBVI (ORCPT ); Wed, 6 Feb 2008 20:21:08 -0500 Received: from fgwmail6.fujitsu.co.jp ([192.51.44.36]:57687 "EHLO fgwmail6.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758152AbYBGBVH (ORCPT ); Wed, 6 Feb 2008 20:21:07 -0500 Date: Thu, 07 Feb 2008 10:20:39 +0900 From: KOSAKI Motohiro To: Rik van Riel Subject: Re: [patch 05/19] split LRU lists into anon & file sets Cc: kosaki.motohiro@jp.fujitsu.com, Lee Schermerhorn , linux-kernel@vger.kernel.org, linux-mm@kvack.org In-Reply-To: <20080206193512.77b5f21f@bree.surriel.com> References: <20080130175439.1AFD.KOSAKI.MOTOHIRO@jp.fujitsu.com> <20080206193512.77b5f21f@bree.surriel.com> Message-Id: <20080207101634.4AC7.KOSAKI.MOTOHIRO@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Mailer: Becky! ver. 2.42 [ja] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2025 Lines: 70 Hi Rik Welcome back :) > > I found number of scan pages calculation bug. > > My latest version of get_scan_ratio() works differently, with the > percentages always adding up to 100. However, your patch gave me > the inspiration to (hopefully) find the bug in my version of the > code. OK. > > 2. wrong fraction omission > > > > nr[l] = zone->nr_scan[l] * percent[file] / 100; > > > > when percent is very small, > > nr[l] become 0. > > This is probably where the problem is. Kind of. > > I believe that the problem is that we scale nr[l] by the percentage, > instead of scaling the amount we add to zone->nr_scan[l] by the > percentage! Aahh, you are right. > Index: linux-2.6.24-rc6-mm1/mm/vmscan.c > =================================================================== > --- linux-2.6.24-rc6-mm1.orig/mm/vmscan.c 2008-02-06 19:23:16.000000000 -0500 > +++ linux-2.6.24-rc6-mm1/mm/vmscan.c 2008-02-06 19:22:55.000000000 -0500 > @@ -1275,13 +1275,17 @@ static unsigned long shrink_zone(int pri > for_each_lru(l) { > if (scan_global_lru(sc)) { > int file = is_file_lru(l); > + int scan; > /* > * Add one to nr_to_scan just to make sure that the > - * kernel will slowly sift through the active list. > + * kernel will slowly sift through each list. > */ > - zone->nr_scan[l] += (zone_page_state(zone, > - NR_INACTIVE_ANON + l) >> priority) + 1; > - nr[l] = zone->nr_scan[l] * percent[file] / 100; > + scan = zone_page_state(zone, NR_INACTIVE_ANON + l); > + scan >>= priority; > + scan = (scan * percent[file]) / 100; > + > + zone->nr_scan[l] += scan + 1; > + nr[l] = zone->nr_scan[l]; > if (nr[l] >= sc->swap_cluster_max) > zone->nr_scan[l] = 0; > else looks good. thank you clean up code. - kosaki -- 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/