From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758009Ab0J2OzR (ORCPT ); Fri, 29 Oct 2010 10:55:17 -0400 Received: from smtp110.prem.mail.ac4.yahoo.com ([76.13.13.93]:27180 "HELO smtp110.prem.mail.ac4.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1757398Ab0J2OzM (ORCPT ); Fri, 29 Oct 2010 10:55:12 -0400 X-Yahoo-SMTP: _Dag8S.swBC1p4FJKLCXbs8NQzyse1SYSgnAbY0- X-YMail-OSG: dwXfj8sVM1mZd.baM0V0XHG9dvaV15cY2AwcPTV.h9Kk9PU MSorjB2b8GhLjfsyTQsGUAmfKQzVx2X6MMEbcbCO2tK94ZvSXVVCc_QYQo.T CtrKC9hQvB6a7HUH0wP..aujUJVAYEe1V5KtwsVCVvHwafq58wAYWP944Kef ZcggHb5LsbH5vkeK9Y5aGdgLH9asmXAI3LH8aFrVpvqKgZ9c0.AA9x7.psPU Q0PH1H0uYSdmul_GAr1qrGwHASgO4h6YljgSKvtXyEg-- X-Yahoo-Newman-Property: ymail-3 Date: Fri, 29 Oct 2010 09:55:08 -0500 (CDT) From: Christoph Lameter X-X-Sender: cl@router.home To: Andrew Morton cc: Linus Torvalds , Eric Dumazet , Mel Gorman , Lee Schermerhorn , Tejun Heo , Peter Zijlstra , Brian Gerst , x86@kernel.org, linux-kernel@vger.kernel.org, mingo@elte.hu Subject: Re: [PATCH] numa: fix slab_node(MPOL_BIND) In-Reply-To: <20101028140725.755aea50.akpm@linux-foundation.org> Message-ID: References: <1288158182-1753-1-git-send-email-brgerst@gmail.com> <1288159670.2652.181.camel@edumazet-laptop> <1288173442.15336.1490.camel@twins> <1288186405.2709.117.camel@edumazet-laptop> <4CC82C2F.1020707@kernel.org> <1288187870.2709.128.camel@edumazet-laptop> <4CC83067.5000009@kernel.org> <1288189461.2709.144.camel@edumazet-laptop> <1288190387.2709.147.camel@edumazet-laptop> <4CC83A85.3070608@kernel.org> <1288192868.2709.152.camel@edumazet-laptop> <4CC846D5.50106@kernel.org> <1288195668.2709.167.camel@edumazet-laptop> <1288200823.5619.46.camel@edumazet-laptop> <20101028140725.755aea50.akpm@linux-foundation.org> User-Agent: Alpine 2.00 (DEB 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 28 Oct 2010, Andrew Morton wrote: > On Thu, 28 Oct 2010 11:55:18 -0500 (CDT) > Christoph Lameter wrote: > > > On Thu, 28 Oct 2010, Linus Torvalds wrote: > > > > > And so does - although less obviously - mm/vmscan.c for the > > > wait_iff_confgested() thing. > > > > > > So are those buggy too, since first_zones_zonelist() can apparently return NULL? > > > > The code is fine. > > > > first_zones_zonelist() can only return NULL for the case that a nodemask > > was specified and the code in vmscan.c does not specify a nodemask. > > Geeze, how did you work that out and how the heck was anyone else > supposed to know this :( Look at the code and how it was modified by Lee. The initial assumption before his patch was that the zonelist contains all zones of the system. Therefore you will allways find all possible zone types in the system. The function did not contain a check for the end of the zonelist and does not now for the nodemask == NULL. However, the modification to filter the zonelist then makes it possible to have subsets of zones not containing the requested zone types now. Therefore Lee added a check for the end of the zonelist for that case. Could be better documented. Took me some staring at the code to figure it out.