Re: Question on handling managed IRQs when hotplugging CPUs

Benjamin Block
2019-02-06T13:34:32Z

On Wed, Feb 06, 2019 at 09:21:40AM +0000, John Garry wrote:
> On 05/02/2019 18:23, Christoph Hellwig wrote:
> > On Tue, Feb 05, 2019 at 03:09:28PM +0000, John Garry wrote:
> > > For SCSI devices, unfortunately not all IO sent to the HW originates from
> > > blk-mq or any other single entity.
> >
> > Where else would SCSI I/O originate from?
>
> Please note that I was referring to other management IO, like SAS SMP, TMFs,
> and other proprietary commands which the driver may generate for the HBA -
> https://marc.info/?l=linux-scsi&m=154831889001973&w=2 discusses some of them
> also.
>

Especially the TMFs send via SCSI EH are a bit of a pain I guess,
because they are entirely managed by the device drivers, but depending
on the device driver they might not even qualify for the problem Hannes
is seeing.

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With Best Regards, Benjamin Block / Linux on IBM Z Kernel Development
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