Messages in this thread | | | Subject | Re: [PATCH 0/7] hisi_sas: Misc bugfixes and an optimisation patch | From | John Garry <> | Date | Thu, 11 Oct 2018 10:59:11 +0100 |
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On 11/10/2018 07:36, Christoph Hellwig wrote: > On Wed, Oct 10, 2018 at 09:58:25PM -0400, Martin K. Petersen wrote: >>> This is because the IPTT index must be a unique value per HBA. However, >>> if we switched to SCSI MQ, the block layer tag becomes unique per queue, >>> and not per HBA. >> >> That doesn't sound right. >
Hmmm, well this is what I was told ...
> blk-mq tags are always per-host (which has actually caused problems for > ATA, which is now using its own per-device tags). >
So, for example, if Scsi_host.can_queue = 2048 and Scsi_host.nr_hw_queues = 16, then rq tags are still in range [0, 2048) for that HBA, i.e. invariant on queue count?
> . >
Thanks, John
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