From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761246Ab1EAQyN (ORCPT ); Sun, 1 May 2011 12:54:13 -0400 Received: from mx3.mail.elte.hu ([157.181.1.138]:50363 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761221Ab1EAQyI (ORCPT ); Sun, 1 May 2011 12:54:08 -0400 Date: Sun, 1 May 2011 18:53:54 +0200 From: Ingo Molnar To: Tejun Heo Cc: Ingo Molnar , linux-kernel@vger.kernel.org, x86@kernel.org, Yinghai Lu Subject: Re: [PATCH tip:x86/urgent] x86, NUMA: Fix empty memblk detection in numa_cleanup_meminfo() Message-ID: <20110501165354.GC21833@elte.hu> References: <20110501104555.GN29280@htj.dyndns.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20110501104555.GN29280@htj.dyndns.org> User-Agent: Mutt/1.5.20 (2009-08-17) X-ELTE-SpamScore: -2.0 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-2.0 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.3.1 -2.0 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Tejun Heo wrote: > From: Yinghai Lu > > numa_cleanup_meminfo() trims each memblk between low (0) and high > (max_pfn) limits and discards empty ones. However, the emptiness > detection incorrectly used equality test. If the start of a memblk is > higher than max_pfn, it is empty but fails the equality test and > doesn't get discarded. > > Fix it by using >= instead of ==. > > tj: Extracted the actual fix from the original patch and rewrote patch > description. Well, the bit still missing from the description is why this fix matters for x86/urgent: under what scenarios does this cause problems, how frequent is it, how severe are the prolems, etc. etc. Would be nice to have something about that in the changelog as well. Thanks, Ingo