Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755331Ab0BSVnM (ORCPT ); Fri, 19 Feb 2010 16:43:12 -0500 Received: from mx1.redhat.com ([209.132.183.28]:29202 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754807Ab0BSVnJ (ORCPT ); Fri, 19 Feb 2010 16:43:09 -0500 Message-ID: <4B7F05BA.4080903@redhat.com> Date: Fri, 19 Feb 2010 16:42:18 -0500 From: Rik van Riel Organization: Red Hat, Inc User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.5) Gecko/20091209 Fedora/3.0-4.fc12 Lightning/1.0pre Thunderbird/3.0 MIME-Version: 1.0 To: Mel Gorman CC: Andrea Arcangeli , Christoph Lameter , Adam Litke , Avi Kivity , David Rientjes , KOSAKI Motohiro , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH 03/12] mm: Share the anon_vma ref counts between KSM and page migration References: <1266516162-14154-1-git-send-email-mel@csn.ul.ie> <1266516162-14154-4-git-send-email-mel@csn.ul.ie> In-Reply-To: <1266516162-14154-4-git-send-email-mel@csn.ul.ie> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1203 Lines: 36 On 02/18/2010 01:02 PM, Mel Gorman wrote: > struct anon_vma { > spinlock_t lock; /* Serialize access to vma list */ > -#ifdef CONFIG_KSM > - atomic_t ksm_refcount; > -#endif > -#ifdef CONFIG_MIGRATION > - atomic_t migrate_refcount; > +#if defined(CONFIG_KSM) || defined(CONFIG_MIGRATION) > + > + /* > + * The refcount is taken by either KSM or page migration > + * to take a reference to an anon_vma when there is no > + * guarantee that the vma of page tables will exist for > + * the duration of the operation. A caller that takes > + * the reference is responsible for clearing up the > + * anon_vma if they are the last user on release > + */ > + atomic_t refcount; Calling it just refcount is probably confusing, since the anon_vma is also referenced by being on the chain with others. Maybe "other_refcount" because it is refcounts taken by things other than VMAs? I am sure there is a better name possible... -- All rights reversed. -- 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/