Date: Thu, 16 Jul 2009 19:53:27 +0200 From: Attilio Rao <attilio@freebsd.org> To: Nick Esborn <nick@desert.net> Cc: freebsd-threads@freebsd.org Subject: Re: threads/136345: Recursive read rwlocks in thread A cause deadlock with write lock in thread B Message-ID: <3bbf2fe10907161053x3b6aa60dneb8dbd5217b4cb03@mail.gmail.com> In-Reply-To: <6E6A9516-6C69-4E41-803C-FE5F126F402C@desert.net> References: <200907152140.n6FLe42l045879@freefall.freebsd.org> <3bbf2fe10907160526l2f066698qce8a5e77aee6366b@mail.gmail.com> <3bbf2fe10907160548l74de896bka609de7a9a994899@mail.gmail.com> <6E6A9516-6C69-4E41-803C-FE5F126F402C@desert.net>
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2009/7/16 Nick Esborn <nick@desert.net>: > > > KDB, DDB, SCHED_ULE, and PREEMPTION are already turned on. I will try > FULL_PREEMPTION, INVARIANT_SUPPORT, INVARIANTS, and WITNESS, but when I > first upgraded to 8.0, this server was unable to handle its workload with > the INVARIANTS and WITNESS options turned on. What do you mean with 'unable'? What was happening precisely? > Also, it can take a while for it to become clear that the deadlock has > occurred -- usually our monitoring picks it up when replication falls > behind. So it may be 15-20 minutes after the deadlock that I am able to run > the above db commands. Of course the thread will still be deadlocked. > Hopefully that doesn't reduce the value of the data obtained. It should be still fine. Thanks, Attilio -- Peace can only be achieved by understanding - A. Einstein
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