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SubjectRe: [PATCH] scsi: storvsc: Cap scsi_driver.can_queue to fix a hang issue during boot
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On 06/10/2021 17:08, Michael Kelley wrote:
>>> The calculated value of can_queue is not realistic. The blk-mq layer
>>> caps the number of tags at 10240,
>> nit: 1024, I think
> I was thinking about BLK_MQ_MAX_DEPTH (#define'd as 10240), which
> is used to limit the tag set size in blk_mq_alloc_tag_set(). When running
> on large VMs on Hyper-V, we can see the "blk-mq: reduced tag depth
> to 10240" message.:-(

Ah, right. The other related capping is the sdev queue depth, which is
now capped at max(1024, can_queue), see scsi_device_max_queue_depth().

Thanks,
John

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