On 4/8/21 2:36 AM, Ming Lei wrote:
> Hello Jens,
>
> On Tue, Apr 06, 2021 at 11:19:33AM +0800, Ming Lei wrote:
>> Yanhui found that write performance is degraded a lot after applying
>> hctx shared tagset on one test machine with megaraid_sas. And turns out
>> it is caused by none scheduler which becomes default elevator caused by
>> hctx shared tagset patchset.
>>
>> Given more scsi HBAs will apply hctx shared tagset, and the similar
>> performance exists for them too.
>>
>> So keep previous behavior by still using default mq-deadline for queues
>> which apply hctx shared tagset, just like before.
>>
>> Fixes: 32bc15afed04 ("blk-mq: Facilitate a shared sbitmap per tagset")
>> Reported-by: Yanhui Ma <yama@xxxxxxxxxx>
>> Cc: John Garry <john.garry@xxxxxxxxxx>
>> Cc: Hannes Reinecke <hare@xxxxxxx>
>> Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx>
>
> Any chance to make it in 5.12 if you are fine?
Let's just queue it through stable when it's in Linus's tree. This isn't
a new regression, so there should be no need to expedite into the current
release.
--
Jens Axboe
