Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751027AbWAPPsK (ORCPT ); Mon, 16 Jan 2006 10:48:10 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751031AbWAPPsJ (ORCPT ); Mon, 16 Jan 2006 10:48:09 -0500 Received: from omx3-ext.sgi.com ([192.48.171.26]:55454 "EHLO omx3.sgi.com") by vger.kernel.org with ESMTP id S1751027AbWAPPsI (ORCPT ); Mon, 16 Jan 2006 10:48:08 -0500 Date: Mon, 16 Jan 2006 07:47:50 -0800 (PST) From: Christoph Lameter To: Hugh Dickins cc: Nick Piggin , Andrew Morton , Linux Kernel Mailing List , Linux Memory Management List Subject: Re: Race in new page migration code? In-Reply-To: Message-ID: References: <20060114155517.GA30543@wotan.suse.de> <20060114181949.GA27382@wotan.suse.de> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1275 Lines: 30 On Mon, 16 Jan 2006, Hugh Dickins wrote: > Indeed they are, at present and quite likely into posterity. But > they're not a common case here, and migrate_page_add now handles them > silently, so why bother to complicate it with an unnecessary check? check_range also is used for statistics and for checking if a range is policy compliant. Without that check zeropages may be counted or flagged as not on the right node with MPOL_MF_STRICT. For migrate_page_add this has now simply become an optimization since there is no WARN_ON occurring anymore. > Or have you found the zero page mapcount distorting get_stats stats? > If that's an issue, then better add a commented test for it there. It also applies to the policy compliance check. > Hmm, that battery of unusual tests at the start of migrate_page_add > is odd: the tests don't quite match the comment, and it isn't clear > what reasoning lies behind the comment anywa Hmm.... Maybe better clean up the thing a bit. Will do that when I get back to work next week. - 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/