From owner-freebsd-current@FreeBSD.ORG Tue Oct 19 21:50:27 2004 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id DE8DB16A4CE for ; Tue, 19 Oct 2004 21:50:27 +0000 (GMT) Received: from mail4.speakeasy.net (mail4.speakeasy.net [216.254.0.204]) by mx1.FreeBSD.org (Postfix) with ESMTP id A79E643D48 for ; Tue, 19 Oct 2004 21:50:27 +0000 (GMT) (envelope-from john@baldwin.cx) Received: (qmail 26741 invoked from network); 19 Oct 2004 21:50:27 -0000 Received: from dsl027-160-063.atl1.dsl.speakeasy.net (HELO server.baldwin.cx) ([216.27.160.63]) (envelope-sender ) encrypted SMTP for ; 19 Oct 2004 21:50:27 -0000 Received: from zion.baldwin.cx (zion.baldwin.cx [192.168.0.7]) by server.baldwin.cx (8.12.11/8.12.11) with ESMTP id i9JLoO8S050729; Tue, 19 Oct 2004 17:50:24 -0400 (EDT) (envelope-from john@baldwin.cx) Received: from zion.baldwin.cx (localhost [127.0.0.1]) by zion.baldwin.cx (8.12.10/8.12.10) with ESMTP id i9JLoN8h005766; Tue, 19 Oct 2004 17:50:23 -0400 (EDT) (envelope-from john@zion.baldwin.cx) Received: from localhost (localhost [[UNIX: localhost]]) by zion.baldwin.cx (8.12.10/8.12.10/Submit) id i9JLoNOY005765; Tue, 19 Oct 2004 17:50:23 -0400 (EDT) (envelope-from john) From: John Baldwin To: Julian Elischer Date: Tue, 19 Oct 2004 17:29:42 -0400 User-Agent: KMail/1.6 References: <20041019023713.GA1072@green.homeunix.org> <200410191650.28544.jhb@FreeBSD.org> <4175862C.6030403@elischer.org> In-Reply-To: <4175862C.6030403@elischer.org> MIME-Version: 1.0 Content-Disposition: inline Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Message-Id: <200410191729.42330.jhb@FreeBSD.org> X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on server.baldwin.cx cc: freebsd-current@freebsd.org cc: Robert Huff cc: Kris Kennaway Subject: Re: WITNESS bug X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 19 Oct 2004 21:50:28 -0000 On Tuesday 19 October 2004 05:25 pm, Julian Elischer wrote: > John Baldwin wrote: > >On Tuesday 19 October 2004 12:01 pm, Kris Kennaway wrote: > >>On Tue, Oct 19, 2004 at 09:13:26AM -0400, Robert Huff wrote: > >>>Brian Fundakowski Feldman writes: > >>>> You should never not run with WITNESS_SKIPSPIN if you use > >>>> modules. Any spin mutexes not listed statically in the witness > >>>> code will cause your machine to immediately panic. > >>> > >>> If this is true (and I'm not disputing it), shouldn't it be > >>>noted in GENERIC and/or NOTES? For that matter, what's the penalty > >>>for not automatically including it as part of WITNESS? > >> > >>Sometimes you don't want to use it, e.g. if you actually want to trace > >>spinlock operations with witness. > > > >True spin mutexes should be rarely used anyways, so I don't think modules > >needing spin mutexes is all that big of an issue. Almost all mutexes > > should just be regular mutexes. > > netgraph uses a spin mutex for it's node locks This is likely a bug, esp. given that normal mutexes adaptively spin when it is advantageous to do so. :) -- John Baldwin <>< http://www.FreeBSD.org/~jhb/ "Power Users Use the Power to Serve!" - http://www.FreeBSD.org/