[PATCHv2 4/7] nvme: export I/O requeue count when no path is available via sysfs

[Nilay Shroff]

On 2/7/26 7:03 PM, Sagi Grimberg wrote:
> 
>> When the NVMe namespace head determines that there is no currently
>> available path to handle I/O (for example, while a controller is
>> resetting/connecting or due to a transient link failure), incoming
>> I/Os are added to the requeue list.
>>
>> Currently, there is no visibility into how many I/Os have been requeued
>> in this situation. Add a new sysfs counter, requeue_no_available_path,
>> to expose the number of I/Os that were requeued due to the absence of
>> an available path.
>>
>> This statistic can help users understand I/O slowdowns or stalls caused
>> by temporary path unavailability, and can be consumed by monitoring
>> tools such as nvme-top for real-time observability.
> 
> Other than the debugfs comment, would it make sense to have a reset
> functionality to these files (via write to the file)?
> 
Hmm yes that can be added, however do you have any usecase in mind 
so you think that allowing resets of this counter could be useful?

Thanks,
--Nilay