Re: [PATCH 2/2] nvme: pass BLK_MQ_F_NOT_USE_MANAGED_IRQ for fc/rdma/tcp/loop

Hannes Reinecke
2021-06-30T08:15:49Z

On 6/29/21 9:49 AM, Ming Lei wrote:
> All the 4 host drivers don't use managed irq for completing request, so
> it is correct to pass the flag to blk-mq.
>
> Secondly with this flag, blk-mq will help us dispatch connect request
> allocated via blk_mq_alloc_request_hctx() to driver even though all
> CPU in the specified hctx's cpumask are offline.
>
How is this supposed to work?
To my understanding, only cpus in the hctx cpumask are eligible to send
I/O. So if all of these CPUs are offline, who exactly is submitting I/O?
More to the point, which CPU will be submitting the connect request?

Cheers,

Hannes
--
Dr. Hannes Reinecke Kernel Storage Architect
hare@suse.de +49 911 74053 688
SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), Geschäftsführer: Felix Imendörffer