Date: Thu, 01 Mar 2007 12:33:38 -0500 From: "Stephane E. Potvin" <sepotvin@FreeBSD.org> To: Robert Watson <rwatson@FreeBSD.org> Cc: brooks@FreeBSD.org, current@FreeBSD.org Subject: Re: HEADS UP: UNIX domain socket locking changes merged to CVS HEAD Message-ID: <45E70E72.60009@FreeBSD.org> In-Reply-To: <20070228234754.Q13593@fledge.watson.org> References: <20070226204916.C56223@fledge.watson.org> <45E5D589.3080202@FreeBSD.org> <20070228234754.Q13593@fledge.watson.org>
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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Robert Watson wrote: > > On Wed, 28 Feb 2007, Stephane E. Potvin wrote: > >>> Please let me know if you experience any problems with UNIX domain >>> sockets -- these changes will affect applications that consume UNIX >>> domain sockets directly, like MySQL and Postfix, as well as consumers >>> of POSIX fifos, which are implemented using UNIX domain sockets >>> in-kernel. >> >> Since this commit, I've been observing frequent deadlocks on my >> laptop, mostly when starting-up gnome. It usually takes less than 5 to >> 10 minutes for the deadlock to happens. >> >> I was able to drop into ddb once and got the following information: >> (there might be some typos as I had to copy this manually) > > Thanks, this information was very helpful, and indeed the problem is as > you surmise: cases existed where more than one unpcb lock was acquired > at a time when holding only a global read lock, not a global write > lock. I guess these slipped through from an earlier version of the > patch. In any case, could you try the patch at: > > http://www.watson.org/~robert/freebsd/netperf/20070228-unp_deadlock.diff > > This eliminates overlapped unpcb lock acquisition in both datagram and > stream cases, and with any luck will fix the deadlock problem. It may > also marginally improve performance by further reducing unpcb lock > contention. > The attached patch fixes the deadlock that I was experiencing. The laptop used to deadlock within a few minutes and I've been running with the patch for around 3 hours so far without problems. Thanks a lot for the quick fix. Regards Steph -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (FreeBSD) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFF5w5xmdOXtTCX/nsRAqpkAJ0RVBn/q5ZFk3AYO1mXJCOQie4HygCfVWjX Ut3ruvvdZjCczPqSNHjA6Mo= =qKEm -----END PGP SIGNATURE-----
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