From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752217AbZEGF3c (ORCPT ); Thu, 7 May 2009 01:29:32 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750826AbZEGF3W (ORCPT ); Thu, 7 May 2009 01:29:22 -0400 Received: from fgwmail7.fujitsu.co.jp ([192.51.44.37]:46343 "EHLO fgwmail7.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750754AbZEGF3W (ORCPT ); Thu, 7 May 2009 01:29:22 -0400 Date: Thu, 07 May 2009 14:29:15 +0900 From: Yasunori Goto To: Johannes Weiner Subject: Re: [PATCH] Double check memmap is actually valid with a memmap has unexpected holes Cc: Mel Gorman , akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, hartleys@visionengravers.com, mcrapet@gmail.com, linux@arm.linux.org.uk, fred99@carolina.rr.com, linux-arm-kernel@lists.arm.linux.org.uk, Badari Pulavarty In-Reply-To: <20090506155043.GA3084@cmpxchg.org> References: <20090506143059.GB20709@csn.ul.ie> <20090506155043.GA3084@cmpxchg.org> X-Mailer-Plugin: BkASPil for Becky!2 Ver.2.068 Message-Id: <20090507142143.0619.E1E9C6FF@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Mailer: Becky! ver. 2.50.05 [ja] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi. > > > + unsigned long pfn; > > > > > > - pgdat_resize_lock(pgdat, &flags); > > > > How sure are you about removing the acquisition of this lock? If anything, > > it appears that pagetypeinfo_showblockcount_print() should be taking this lock. > > I'm completely unsure about it. > > zone->zone_start_pfn and zone->spanned_pages may be changed by memory hotplug. The lock must be acquired before getting their values as Mel-san said. Thanks. -- Yasunori Goto