Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S270688AbTHEVIL (ORCPT ); Tue, 5 Aug 2003 17:08:11 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S270691AbTHEVIL (ORCPT ); Tue, 5 Aug 2003 17:08:11 -0400 Received: from fw.osdl.org ([65.172.181.6]:39329 "EHLO mail.osdl.org") by vger.kernel.org with ESMTP id S270688AbTHEVIG (ORCPT ); Tue, 5 Aug 2003 17:08:06 -0400 Date: Tue, 5 Aug 2003 14:07:53 -0700 (PDT) From: Linus Torvalds To: Arjan van de Ven cc: Andi Kleen , Andrew Morton , Andi Kleen , Subject: Re: [PATCH] Export touch_nmi_watchdog In-Reply-To: <20030805203137.E30256@devserv.devel.redhat.com> Message-ID: 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 Content-Length: 1782 Lines: 47 On Tue, 5 Aug 2003, Arjan van de Ven wrote: > On Tue, Aug 05, 2003 at 01:25:09PM -0700, Linus Torvalds wrote: > > > > - either fix the driver > > or > > - disable the watchdog entirely. > > In principle you are soooo right. Just that it sometimes is HARD to fix > such long delays... That's why I said "disable the watchdog". The thing is, if you start doing things like this in drivers, then you just hide the problem to the point where users end up not even being _aware_ of the problem. Do you _really_ think most users will think of "Oh, let's grep for 'touch_nmi_watchdog' in that driver" when they have latency issues? No. Obviously they won't. Instead, they'll scratch their head about occasional bad packet routing latency, report it as a networking bug, and just generally look in the wrong place. And enabling lockup debugging will do zero for them. So this is a case of trying to paper over the symptoms. Which is perfectly ok in the sense that "we don't have the resources to fix it right now, so let's just give it two aspirins and ask it to call in the morning". That's fine. But since the whole _point_ of watchdogging is to find places like this, when you paper over _these_ symptoms, you end up killing the whole idea. Which is why I'd suggest making it a more conscious decision: just turn off watchdog support. And if somebody needs watchdog support with a broken driver, maybe, just _maybe_, he'll find the energy to fix the frigging thing. Otherwise this will just keep on expanding. Linus - 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/