From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263045AbUKTB7A (ORCPT ); Fri, 19 Nov 2004 20:59:00 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262871AbUKTB67 (ORCPT ); Fri, 19 Nov 2004 20:58:59 -0500 Received: from fw.osdl.org ([65.172.181.6]:18823 "EHLO mail.osdl.org") by vger.kernel.org with ESMTP id S262743AbUKTB6j (ORCPT ); Fri, 19 Nov 2004 20:58:39 -0500 Date: Fri, 19 Nov 2004 17:58:25 -0800 (PST) From: Linus Torvalds To: Christoph Lameter cc: Nick Piggin , akpm@osdl.org, Benjamin Herrenschmidt , Hugh Dickins , linux-mm@kvack.org, linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: page fault scalability patch V11 [0/7]: overview In-Reply-To: Message-ID: References: <419D581F.2080302@yahoo.com.au> <419D5E09.20805@yahoo.com.au> <1100848068.25520.49.camel@gaston> <419E98E7.1080402@yahoo.com.au> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 19 Nov 2004, Christoph Lameter wrote: > > Note though that the mmap_sem is no protection. It is a read lock and may > be held by multiple processes while incrementing and decrementing rss. > This is likely reducing the number of collisions significantly but it wont > be a guarantee like locking or atomic ops. It is, though, if you hold it for a write. The point being that you _can_ get an exact rss value if you want to. Not that I really see any overwhelming evidence of anybody ever really caring, but it's nice to know that you have the option. Linus