Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758096AbZKJUap (ORCPT ); Tue, 10 Nov 2009 15:30:45 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758091AbZKJUap (ORCPT ); Tue, 10 Nov 2009 15:30:45 -0500 Received: from smtp.ultrahosting.com ([74.213.174.254]:51905 "EHLO smtp.ultrahosting.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758092AbZKJUao (ORCPT ); Tue, 10 Nov 2009 15:30:44 -0500 X-Greylist: delayed 481 seconds by postgrey-1.27 at vger.kernel.org; Tue, 10 Nov 2009 15:30:44 EST Date: Tue, 10 Nov 2009 15:20:41 -0500 (EST) From: Christoph Lameter X-X-Sender: cl@V090114053VZO-1 To: Minchan Kim cc: npiggin@suse.de, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Tejun Heo , Ingo Molnar , KAMEZAWA Hiroyuki , "hugh.dickins@tiscali.co.uk" Subject: Re: Subject: [RFC MM] mmap_sem scaling: Use mutex and percpu counter instead In-Reply-To: <28c262360911062019q254f7541lbdc3d94491a69bd6@mail.gmail.com> Message-ID: References: <28c262360911060741x3f7ab0a2k15be645e287e05ac@mail.gmail.com> <28c262360911062019q254f7541lbdc3d94491a69bd6@mail.gmail.com> User-Agent: Alpine 1.10 (DEB 962 2008-03-14) 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: 1023 Lines: 31 On Sat, 7 Nov 2009, Minchan Kim wrote: > On Sat, Nov 7, 2009 at 2:10 AM, Christoph Lameter > wrote: > > On Sat, 7 Nov 2009, Minchan Kim wrote: > > > >> How about change from 'mm_readers' to 'is_readers' to improve your > >> goal 'scalibility'? > > > > Good idea. Thanks. Next rev will use your suggestion. > > > > Any creative thoughts on what to do about the 1 millisecond wait period? > > > > Hmm, > it would be importatn to prevent livelock for reader to hold lock > continuously before > hodling writer than 1 msec write ovhead. Livelock because there are too frequent readers? We could just keep the mutex locked to ensure that no new readers arrive. > First of all, After we solve it, second step is that optimize write > overhead, I think. -- 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/