Re: [PATCH 0/1] aoe: ensure we initialise the request_queuecorrectly

From: Bruno PrÃmont
Date: Tue Sep 01 2009 - 16:32:05 EST


On Tue, 01 September 2009 Ed Cashin <ecashin@xxxxxxxxxx> wrote:

> On Sat Aug 29 09:43:54 EDT 2009, bonbons@xxxxxxxxxxxxxxxxx wrote:
> ...
> > I finished bisecting the NULL object and ended up at this commit:
> > cd43e26f071524647e660706b784ebcbefbd2e44
> >
> > block: Expose stacked device queues in sysfs
> >
> > Currently stacking devices do not have a queue directory in sysfs.
> > However, many of the I/O characteristics like sector size, maximum
> > request size, etc. are queue properties.
> >
> > This patch enables the queue directory for MD/DM devices. The
> > elevator code has been modified to deal with queues that do not
> > have an I/O scheduler.
> >
> > Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
> > Signed-off-by: Jens Axboe <jens.axboe@xxxxxxxxxx>
> >
> >
> > This seems to generate /sys/block/$device/queue and its contents for
> > everyone who is using queues, not just for those queues that have a
> > non-NULL queue->request_fn.
>
> Thanks much for doing that. It makes sense that this change would
> have caused it to suddenly matter whether the unused queue is
> initialized.
>
> The patch looks fine to me.

Would it make sense to fine-tune the values reported by sys-fs in the
queue details so they match with the AoE device (as a separate
enhancement patch)?

Sure the queue itself won't use them, but some user-space tools might
be interested in this data.

I've not checked what information is provided by AoE protocol or can
be deducted from interface MTU.

Bruno
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