Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263168AbUKTTdx (ORCPT ); Sat, 20 Nov 2004 14:33:53 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263167AbUKTTdx (ORCPT ); Sat, 20 Nov 2004 14:33:53 -0500 Received: from holomorphy.com ([207.189.100.168]:39304 "EHLO holomorphy.com") by vger.kernel.org with ESMTP id S263165AbUKTTdk (ORCPT ); Sat, 20 Nov 2004 14:33:40 -0500 Date: Sat, 20 Nov 2004 11:33:25 -0800 From: William Lee Irwin III To: Linus Torvalds Cc: Nick Piggin , Andrew Morton , clameter@sgi.com, benh@kernel.crashing.org, hugh@veritas.com, linux-mm@kvack.org, linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: page fault scalability patch V11 [0/7]: overview Message-ID: <20041120193325.GZ2714@holomorphy.com> References: <20041120053802.GL2714@holomorphy.com> <419EDB21.3070707@yahoo.com.au> <20041120062341.GM2714@holomorphy.com> <419EE911.20205@yahoo.com.au> <20041119225701.0279f846.akpm@osdl.org> <419EEE7F.3070509@yahoo.com.au> <1834180000.1100969975@[10.10.2.4]> <20041120190818.GX2714@holomorphy.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Organization: The Domain of Holomorphy User-Agent: Mutt/1.5.6+20040722i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1258 Lines: 28 On Sat, 20 Nov 2004, William Lee Irwin III wrote: >> "The perfect is the enemy of the good." On Sat, Nov 20, 2004 at 11:16:12AM -0800, Linus Torvalds wrote: > Yes. But in this case, my suggestion _is_ the good. You seem to be pushing > for a really horrid thing which allocates a per-cpu array for each > mm_struct. > What is it that you have against the per-thread rss? We already have > several places that do the thread-looping, so it's not like "you can't do > that" is a valid argument. Okay, first thread groups can share mm's, so it's worse than iterating over a thread group. Second, the long loops under tasklist_lock didn't stop causing rwlock starvation because what patches there were to do something about them didn't get merged. I'm not particularly "stuck on" the per-cpu business, it was merely the most obvious method of splitting the RSS counter without catastrophes elsewhere. Robin Holt's 2.4 performance studies actually show that splitting the counter is not even essential. -- wli - 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/