Messages in this thread | | | Subject | Re: Deadlocks due to per-process plugging | From | Mike Galbraith <> | Date | Sat, 21 Jul 2012 09:47:15 +0200 |
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On Wed, 2012-07-18 at 07:30 +0200, Mike Galbraith wrote: > On Wed, 2012-07-18 at 06:44 +0200, Mike Galbraith wrote: > > > The patch in question for missing Cc. Maybe should be only mutex, but I > > see no reason why IO dependency can only possibly exist for mutexes... > > Well that was easy, box quickly said "nope, mutex only does NOT cut it".
And I also learned (ouch) that both doesn't cut it either. Ksoftirqd (or sirq-blk) being nailed by q->lock in blk_done_softirq() is.. not particularly wonderful. As long as that doesn't happen, IO deadlock doesn't happen, troublesome filesystems just work. If it does happen though, you've instantly got a problem.
-Mike
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