From mboxrd@z Thu Jan 1 00:00:00 1970 From: William Lee Irwin III Date: Sat, 20 Nov 2004 05:38:02 +0000 Subject: Re: page fault scalability patch V11 [0/7]: overview Message-Id: <20041120053802.GL2714@holomorphy.com> List-Id: References: <1100848068.25520.49.camel@gaston> <20041120020306.GA2714@holomorphy.com> <419EBBE0.4010303@yahoo.com.au> <20041120035510.GH2714@holomorphy.com> <419EC205.5030604@yahoo.com.au> <20041120042340.GJ2714@holomorphy.com> <419EC829.4040704@yahoo.com.au> In-Reply-To: <419EC829.4040704@yahoo.com.au> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Nick Piggin Cc: Linus Torvalds , Christoph Lameter , akpm@osdl.org, Benjamin Herrenschmidt , Hugh Dickins , linux-mm@kvack.org, linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org William Lee Irwin III wrote: >> Very, very wrong. The tasklist scans hold the read side of the lock >> and aren't even what's running with interrupts off. The contenders >> on the write side are what the NMI oopser oopses. On Sat, Nov 20, 2004 at 03:29:29PM +1100, Nick Piggin wrote: > *blinks* > So explain how this is "very very wrong", then? There isn't anything left to explain. So if there's a question, be specific about it. William Lee Irwin III wrote: >> And supposing the arch reenables interrupts in the write side's >> spinloop, you just get a box that silently goes out of service for >> extended periods of time, breaking cluster membership and more. The >> NMI oopser is just the report of the problem, not the problem itself. >> It's not a false report. The box is dead for > 5s at a time. On Sat, Nov 20, 2004 at 03:29:29PM +1100, Nick Piggin wrote: > The point is, adding a for-each-thread loop or two in /proc isn't > going to cause a problem that isn't already there. > If you had zero for-each-thread loops then you might have a valid > complaint. Seeing as you have more than zero, with slim chances of > reducing that number, then there is no valid complaint. This entire line of argument is bogus. A preexisting bug of a similar nature is not grounds for deliberately introducing any bug. -- wli From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263052AbUKTFmU (ORCPT ); Sat, 20 Nov 2004 00:42:20 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263013AbUKTFkS (ORCPT ); Sat, 20 Nov 2004 00:40:18 -0500 Received: from holomorphy.com ([207.189.100.168]:44162 "EHLO holomorphy.com") by vger.kernel.org with ESMTP id S261774AbUKTFiS (ORCPT ); Sat, 20 Nov 2004 00:38:18 -0500 Date: Fri, 19 Nov 2004 21:38:02 -0800 From: William Lee Irwin III To: Nick Piggin Cc: Linus Torvalds , Christoph Lameter , 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 Message-ID: <20041120053802.GL2714@holomorphy.com> References: <1100848068.25520.49.camel@gaston> <20041120020306.GA2714@holomorphy.com> <419EBBE0.4010303@yahoo.com.au> <20041120035510.GH2714@holomorphy.com> <419EC205.5030604@yahoo.com.au> <20041120042340.GJ2714@holomorphy.com> <419EC829.4040704@yahoo.com.au> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <419EC829.4040704@yahoo.com.au> 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 William Lee Irwin III wrote: >> Very, very wrong. The tasklist scans hold the read side of the lock >> and aren't even what's running with interrupts off. The contenders >> on the write side are what the NMI oopser oopses. On Sat, Nov 20, 2004 at 03:29:29PM +1100, Nick Piggin wrote: > *blinks* > So explain how this is "very very wrong", then? There isn't anything left to explain. So if there's a question, be specific about it. William Lee Irwin III wrote: >> And supposing the arch reenables interrupts in the write side's >> spinloop, you just get a box that silently goes out of service for >> extended periods of time, breaking cluster membership and more. The >> NMI oopser is just the report of the problem, not the problem itself. >> It's not a false report. The box is dead for > 5s at a time. On Sat, Nov 20, 2004 at 03:29:29PM +1100, Nick Piggin wrote: > The point is, adding a for-each-thread loop or two in /proc isn't > going to cause a problem that isn't already there. > If you had zero for-each-thread loops then you might have a valid > complaint. Seeing as you have more than zero, with slim chances of > reducing that number, then there is no valid complaint. This entire line of argument is bogus. A preexisting bug of a similar nature is not grounds for deliberately introducing any bug. -- wli From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Fri, 19 Nov 2004 21:38:02 -0800 From: William Lee Irwin III Subject: Re: page fault scalability patch V11 [0/7]: overview Message-ID: <20041120053802.GL2714@holomorphy.com> References: <1100848068.25520.49.camel@gaston> <20041120020306.GA2714@holomorphy.com> <419EBBE0.4010303@yahoo.com.au> <20041120035510.GH2714@holomorphy.com> <419EC205.5030604@yahoo.com.au> <20041120042340.GJ2714@holomorphy.com> <419EC829.4040704@yahoo.com.au> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <419EC829.4040704@yahoo.com.au> Sender: owner-linux-mm@kvack.org Return-Path: To: Nick Piggin Cc: Linus Torvalds , Christoph Lameter , akpm@osdl.org, Benjamin Herrenschmidt , Hugh Dickins , linux-mm@kvack.org, linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org List-ID: William Lee Irwin III wrote: >> Very, very wrong. The tasklist scans hold the read side of the lock >> and aren't even what's running with interrupts off. The contenders >> on the write side are what the NMI oopser oopses. On Sat, Nov 20, 2004 at 03:29:29PM +1100, Nick Piggin wrote: > *blinks* > So explain how this is "very very wrong", then? There isn't anything left to explain. So if there's a question, be specific about it. William Lee Irwin III wrote: >> And supposing the arch reenables interrupts in the write side's >> spinloop, you just get a box that silently goes out of service for >> extended periods of time, breaking cluster membership and more. The >> NMI oopser is just the report of the problem, not the problem itself. >> It's not a false report. The box is dead for > 5s at a time. On Sat, Nov 20, 2004 at 03:29:29PM +1100, Nick Piggin wrote: > The point is, adding a for-each-thread loop or two in /proc isn't > going to cause a problem that isn't already there. > If you had zero for-each-thread loops then you might have a valid > complaint. Seeing as you have more than zero, with slim chances of > reducing that number, then there is no valid complaint. This entire line of argument is bogus. A preexisting bug of a similar nature is not grounds for deliberately introducing any bug. -- wli -- 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: aart@kvack.org