Messages in this thread | | | From | Jeff Moyer <> | Subject | Re: I/O scheduler deadlocks on Xen virtual block devices | Date | Thu, 02 Sep 2010 11:25:18 -0400 |
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Doug Neal <dneallkml@gmail.com> writes:
>>>> >>>> Did you try these different I/O schedulers in the domU or on the dom0? >>>> Does switching I/O schedulers in either place make the problem go away >>>> when it happens? >>>> >>> >>> In the domU, and the bug was present in all cases. The dom0 was using >>> cfq. I'll run the tests again using each scheduler in the dom0 with >>> domU set to noop and report back. >> >> While I think this is an interesting test, you need only test one I/O >> scheduler in the dom0. Also, I think you misunderstood the second >> question. I'd like to know if switching I/O schedulers while the system >> is in this bad state helps get I/O going again. >> > Jeff, > > Issue confirmed in the following cases: > > dom0:domU > noop:noop > noop:deadline > noop:anticipatory > cfq:noop > cfq:deadline > cfq:anticipatory > cfq:cfq > > I try switching schedulers in the domU during the lockup, the echo x > > /sys/block/xvda/queue/scheduler command also hangs. In the dom0, no > effect.
OK. So, this means that the I/O is not hung up in the I/O scheduler. I don't have a whole lot of experience with the Xen I/O stack, but I think that's where I'd start digging (especially if there's nothing in the logs about command timed out).
I hope this was a somewhat helpful exercise. Sorry I can't be of more help.
Cheers! Jeff -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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