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RE: [GIT/PATCH 0/5] Re: [Xen-devel] unfair servicing of DomU vbd request

To: "MaoXiaoyun" <tinnycloud@xxxxxxxxxxx>
Subject: RE: [GIT/PATCH 0/5] Re: [Xen-devel] unfair servicing of DomU vbd requests
From: "James Harper" <james.harper@xxxxxxxxxxxxxxxx>
Date: Tue, 8 Mar 2011 13:22:13 +1100
Cc: ian.campbell@xxxxxxxxxxxxx, xen devel <xen-devel@xxxxxxxxxxxxxxxxxxx>
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Thread-topic: [GIT/PATCH 0/5] Re: [Xen-devel] unfair servicing of DomU vbd requests
> I go through the patch, since all its changes happens inside
> __xen_evtchn_do_upcall(),
> so I apply the patch into my 2.6.31.kernel by manual. (I was failed to
merge a
> usable,
> 2.6.38dom0, since quite a lot branch needed, such as blkback, netback)
> But still, the blue screen shows up. Log attached.
> Is the timeout better than before?
> Beside, I think I need find some to examine my harddisk.

Looking at the resets, every time you see "Completing in-flight srb ...
with status SRB_STATUS_BUS_RESET" you should subsequently see
"discarding reset shadow" indicating that Dom0 completed the request
also (even though we already told Windows that the reset was done). You
can see this after the first HwScsiResetBus, but not after any
subsequent resets, indicating that even after 72 seconds xenvbd hasn't
processed any further vbd requests. The last two requests confirm this
as no requests have been placed on the ring which must be full. That
says to me that either there is a bug in GPLPV, Dom0 still isn't
servicing IO requests fairly, or you do have a problem with your disk.

If it's a disk problem, you should be getting errors under Linux at some
level. If the drivers support SMART you can query their health that way


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