From owner-cvs-all Wed Nov 15 9:22: 7 2000 Delivered-To: cvs-all@freebsd.org Received: from pike.osd.bsdi.com (pike.osd.bsdi.com [204.216.28.222]) by hub.freebsd.org (Postfix) with ESMTP id A2A2537B479; Wed, 15 Nov 2000 09:22:03 -0800 (PST) Received: from laptop.baldwin.cx (john@jhb-laptop.osd.bsdi.com [204.216.28.241]) by pike.osd.bsdi.com (8.11.0/8.9.3) with ESMTP id eAFHLqB24368; Wed, 15 Nov 2000 09:21:52 -0800 (PST) (envelope-from jhb@FreeBSD.org) Message-ID: X-Mailer: XFMail 1.4.0 on FreeBSD X-Priority: 3 (Normal) Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 8bit MIME-Version: 1.0 In-Reply-To: <200011150658.eAF6wPF01843@mass.osd.bsdi.com> Date: Wed, 15 Nov 2000 09:22:30 -0800 (PST) From: John Baldwin To: Mike Smith Subject: Re: cvs commit: src/sys/sys eventhandler.h Cc: jake@io.yi.org, cvs-committers@FreeBSD.org, cvs-all@FreeBSD.org, Jake Burkholder Sender: owner-cvs-all@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On 15-Nov-00 Mike Smith wrote: >> Holding the mutex over the whole traversal also means you rely on mutex >> recursion in order to be able to deregister from an event handler. > > True. I've been thinking about Garrett's point about flagging deleted > list elements too. > > I'm actually trying to work out what the issue is with witness; I can > only assume that it doesn't like the fact that an eventhandler mutex may > be acquired either before or after giant, and this exposes a weakness in > witness - that it can't deal with the situation where lock ordering > *doesn't* matter. No, it is unrelated to lock order. It has to do with tsleeping() with a mutex held. Specifically, during shutdown when we suspend the bugdaemon and syncer kernel threads. -- John Baldwin -- http://www.FreeBSD.org/~jhb/ PGP Key: http://www.baldwin.cx/~john/pgpkey.asc "Power Users Use the Power to Serve!" - http://www.FreeBSD.org/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe cvs-all" in the body of the message