Date: Wed, 21 Jan 1998 18:04:58 -0500 (EST) From: "John S. Dyson" <toor@dyson.iquest.net> To: tlambert@primenet.com (Terry Lambert) Cc: grog@lemis.com, hackers@FreeBSD.ORG Subject: Re: Locking on disk slice I/O--yes, no or how? Message-ID: <199801212304.SAA29056@dyson.iquest.net> In-Reply-To: <199801212236.PAA09564@usr09.primenet.com> from Terry Lambert at "Jan 21, 98 10:36:44 pm"
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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.
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