Re: [PATCH RFC v7 10/12] megaraid_sas: switch fusion adapters to MQ

John Garry
2020-07-06T09:27:58Z

On 06/07/2020 09:45, Hannes Reinecke wrote:
> Originally I thought it would help for CPU hotplug, too, but typically
> the internal commands are not bound to any specific CPU,

When we alloc the request in scsi_get_internal_cmd() - >
blk_mq_alloc_request() -> __blk_mq_alloc_request(), the request will
have an associated hctx.

As such, I would expect the LLDD to honor this, in that it should use
the hwq associated with the hctx to send/receive the command.

And from that, the hwq managed interrupt should not be shut down until
the queue is drained, including internal commands.

Is there something wrong with this idea?

Thanks,
John

> so they
> typically will not accounted for when looking at the CPU-related resources.
> But that depends on the driver etc, so it's hard to give a guideline.