Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754090Ab0BSPCp (ORCPT ); Fri, 19 Feb 2010 10:02:45 -0500 Received: from nlpi157.sbcis.sbc.com ([207.115.36.171]:53858 "EHLO nlpi157.prodigy.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753618Ab0BSPCo (ORCPT ); Fri, 19 Feb 2010 10:02:44 -0500 Date: Fri, 19 Feb 2010 09:01:44 -0600 (CST) From: Christoph Lameter X-X-Sender: cl@router.home To: Mel Gorman cc: KAMEZAWA Hiroyuki , Andrea Arcangeli , Adam Litke , Avi Kivity , David Rientjes , KOSAKI Motohiro , Rik van Riel , linux-kernel@vger.kernel.org, linux-mm@kvack.org, "hugh.dickins@tiscali.co.uk" Subject: Re: [PATCH 03/12] mm: Share the anon_vma ref counts between KSM and page migration In-Reply-To: <20100219140500.GG30258@csn.ul.ie> Message-ID: References: <1266516162-14154-1-git-send-email-mel@csn.ul.ie> <1266516162-14154-4-git-send-email-mel@csn.ul.ie> <20100219091859.195d922c.kamezawa.hiroyu@jp.fujitsu.com> <20100219140500.GG30258@csn.ul.ie> 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 Content-Length: 1077 Lines: 25 On Fri, 19 Feb 2010, Mel Gorman wrote: > > Nitpick: > > I think this refcnt has something different characteristics than other > > usual refcnts. Even when refcnt goes down to 0, anon_vma will not be freed. > > So, I think some kind of name as temporal_reference_count is better than > > simple "refcnt". Then, it will be clearer what this refcnt is for. > > > > When I read this in a few years, I'll have no idea what "temporal" is > referring to. The holder of this account is by a process that does not > necessarily own the page or its mappings but "remote" has special > meaning as well. "external_count" ? We could think about getting rid of RCU for anon_vmas and use the refcount for everything. Would make the handling consistent with other users but will have performance implications. Hugh what do you say about this? -- 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/