On 10/16/17 23:38, Hannes Reinecke wrote:

Again, these are just some pre-defined values to avoid I/O starvation
when having several LUNs. _if_ we can guarantee I/O fairness between
several (hundreds!) devices all sharing the same tagspace we wouldn't
need these variables.

I think we already have two mechanisms for guaranteeing I/O fairness:
* Scsi_Host.starved_list for both the legacy SCSI core and scsi-mq.
* For scsi-mq, the active_queues counter in the blk-mq core. See also
   hctx_may_queue().

Bart.