From owner-freebsd-hackers Wed Jan 21 15:06:05 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id PAA06771 for hackers-outgoing; Wed, 21 Jan 1998 15:06:05 -0800 (PST) (envelope-from owner-freebsd-hackers@FreeBSD.ORG) Received: from dyson.iquest.net (dyson.iquest.net [198.70.144.127]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id PAA06650 for ; Wed, 21 Jan 1998 15:05:39 -0800 (PST) (envelope-from toor@dyson.iquest.net) Received: (from root@localhost) by dyson.iquest.net (8.8.8/8.8.8) id SAA29056; Wed, 21 Jan 1998 18:04:58 -0500 (EST) (envelope-from toor) From: "John S. Dyson" Message-Id: <199801212304.SAA29056@dyson.iquest.net> Subject: Re: Locking on disk slice I/O--yes, no or how? In-Reply-To: <199801212236.PAA09564@usr09.primenet.com> from Terry Lambert at "Jan 21, 98 10:36:44 pm" To: tlambert@primenet.com (Terry Lambert) Date: Wed, 21 Jan 1998 18:04:58 -0500 (EST) Cc: grog@lemis.com, hackers@FreeBSD.ORG X-Mailer: ELM [version 2.4ME+ PL32 (25)] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk Terry Lambert said: > > I'm currently trying to perform low-level I/O to disk slices in a > > driver. I've read section 9 of the manual, which tells me that all > > reads and writes should be protected with a VOP_LOCK/VOP_UNLOCK pair. > > I've tried this, and get a panic: "lockmgr: locking against myself" > > Yick. Someone's trying to use the lockmgr for finer grained SMP > locking. That'll never work... it must have snuck in when I wasn't > looking. > Terry, I think that your answer is orthogonal to the question asked. Also, lockmgr is perfect (except for being slightly high overhead) for the purpose that it is being used. I am moving towards a TSM scheme for both better UP and SMP performance. When my work settles down, I will try to help with some of the questions that have come across my mailbox in the last week or so. -- John | Never try to teach a pig to sing, dyson@freebsd.org | it just makes you look stupid, jdyson@nc.com | and it irritates the pig.