From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail172.messagelabs.com (mail172.messagelabs.com [216.82.254.3]) by kanga.kvack.org (Postfix) with SMTP id 4DC1D6B0044 for ; Thu, 5 Nov 2009 15:58:56 -0500 (EST) Received: from localhost (smtp.ultrahosting.com [127.0.0.1]) by smtp.ultrahosting.com (Postfix) with ESMTP id 8E1ED82C365 for ; Thu, 5 Nov 2009 16:05:39 -0500 (EST) Received: from smtp.ultrahosting.com ([74.213.175.253]) by localhost (smtp.ultrahosting.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id XULfcnrNOrYk for ; Thu, 5 Nov 2009 16:05:39 -0500 (EST) Received: from V090114053VZO-1 (unknown [74.213.171.31]) by smtp.ultrahosting.com (Postfix) with ESMTP id 57EF182C36B for ; Thu, 5 Nov 2009 16:05:33 -0500 (EST) Date: Thu, 5 Nov 2009 15:57:23 -0500 (EST) From: Christoph Lameter Subject: Re: [RFC MM] Accessors for mm locking In-Reply-To: <87vdho7kzn.fsf@basil.nowhere.org> Message-ID: References: <87vdho7kzn.fsf@basil.nowhere.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org To: Andi Kleen 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 Thu, 5 Nov 2009, Andi Kleen wrote: > My assumption was that a suitable scalable lock (or rather multi locks) > would need to know about the virtual address, or at least the VMA. > As in doing range locking for different address space areas. Not sure why the address would matter. The main problem right now is that there are cachelines in mm_struct that are bouncing for concurrent page faults etc. Ranges wont help if you need to serialize access to mm_struct. > So this simple abstraction doesn't seem to be enough to really experiment? Look at the next patch which gives a rough implementation of using per cpu counters for read locking instead of the rw semaphore. -- 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