From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail203.messagelabs.com (mail203.messagelabs.com [216.82.254.243]) by kanga.kvack.org (Postfix) with SMTP id 5F2FE6B004D for ; Tue, 10 Nov 2009 15:22:50 -0500 (EST) Received: from localhost (smtp.ultrahosting.com [127.0.0.1]) by smtp.ultrahosting.com (Postfix) with ESMTP id 950E582C5A1 for ; Tue, 10 Nov 2009 15:22:48 -0500 (EST) Received: from smtp.ultrahosting.com ([74.213.174.254]) by localhost (smtp.ultrahosting.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id kkr82ZytG3l6 for ; Tue, 10 Nov 2009 15:22:48 -0500 (EST) Received: from V090114053VZO-1 (unknown [74.213.171.31]) by smtp.ultrahosting.com (Postfix) with ESMTP id DB20482C522 for ; Tue, 10 Nov 2009 15:22:43 -0500 (EST) Date: Tue, 10 Nov 2009 15:20:41 -0500 (EST) From: Christoph Lameter 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> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org 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" List-ID: 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, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org