Re: [PATCH] queue stall with blk-mq-sched

[Hannes Reinecke <hare@suse.de>]

On 01/24/2017 05:03 PM, Jens Axboe wrote:
> On 01/24/2017 08:54 AM, Hannes Reinecke wrote:
>> Hi Jens,
>>
>> I'm trying to debug a queue stall with your blk-mq-sched branch; with my
>> latest mpt3sas patches fio stops basically directly after starting a
>> sequential read :-(
>>
>> I've debugged things and came up with the attached patch; we need to
>> restart waiters with blk_mq_tag_idle() after completing a tag.
>> We're already calling blk_mq_tag_busy() when fetching a tag, so I think
>> calling blk_mq_tag_idle() is required when retiring a tag.
>
> I'll take a look at this. It sounds like all your grief is related to
> shared tag maps, which I don't have anything that uses here. I'll see
> if we are leaking it, you should be able to check that by reading the
> 'active' file in the sysfs directory.
>
Ah. That'll explain it.

Basically _all_ my HBAs I'm testing with have shared tag maps :-(

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		      zSeries & Storage
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