Messages in this thread | | | Date | Thu, 2 Sep 2010 16:43:28 +0100 | Subject | Re: I/O scheduler deadlocks on Xen virtual block devices | From | Doug Neal <> |
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On Thu, Sep 2, 2010 at 4:25 PM, Jeff Moyer <jmoyer@redhat.com> wrote: > 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 >
No problem, thanks for your assistance.
Doug -- 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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