Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263126AbUKTEaZ (ORCPT ); Fri, 19 Nov 2004 23:30:25 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263106AbUKTEZW (ORCPT ); Fri, 19 Nov 2004 23:25:22 -0500 Received: from holomorphy.com ([207.189.100.168]:61313 "EHLO holomorphy.com") by vger.kernel.org with ESMTP id S263083AbUKTEXv (ORCPT ); Fri, 19 Nov 2004 23:23:51 -0500 Date: Fri, 19 Nov 2004 20:23:40 -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: <20041120042340.GJ2714@holomorphy.com> References: <419D5E09.20805@yahoo.com.au> <1100848068.25520.49.camel@gaston> <20041120020306.GA2714@holomorphy.com> <419EBBE0.4010303@yahoo.com.au> <20041120035510.GH2714@holomorphy.com> <419EC205.5030604@yahoo.com.au> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <419EC205.5030604@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 Content-Length: 1467 Lines: 36 William Lee Irwin III wrote: >> /proc/ triggering NMI oopses was a persistent problem even before that >> code was merged. I've not bothered testing it as it at best aggravates it. On Sat, Nov 20, 2004 at 03:03:17PM +1100, Nick Piggin wrote: > It isn't a problem. If it ever became a problem then we can just > touch the nmi oopser in the loop. 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. 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. William Lee Irwin III wrote: >> And thread groups can share mm's. do_for_each_thread() won't suffice. On Sat, Nov 20, 2004 at 03:03:17PM +1100, Nick Piggin wrote: > I think it will be just fine. And that makes it wrong on both counts. The above fails any time LD_ASSUME_KERNEL=2.4 is used, we well as when actual Linux features are used directly. -- 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/