Re: [PATCH] docs: block: Create blk-mq documentation

[Andrà Almeida]

Hello Randy,

On 5/27/20 6:58 PM, Randy Dunlap wrote:
> On 5/27/20 1:09 PM, Andrà Almeida wrote:
>> Create a documentation providing a background and explanation around the
>> operation of the Multi-Queue Block IO Queueing Mechanism (blk-mq).

<snip>

>> +Hardware dispatch queues
>> +~~~~~~~~~~~~~~~~~~~~~~~~
>> +
>> +The hardware queue is a memory space shared with the block device (e.g. DMA)
>> +where the hardware can access and dispatch requests (represented by struct
>> +:c:type:`blk_mq_hw_ctx`). To run this queue, the block layer removes
>> +requests from the associated software queues and tries to dispatch to the
>> +hardware.
> 
> This paragraph (above) says to me that these HW devices understand struct blk_mq_hw_ctx.
> Is that correct?  Is is some kind of standard?  If so, where?
> 

This wasn't what I intended to say here. The struct blk_mq_hw_ctx is an
abstraction from the blk-mq API used by device drivers to map the
submission queue of the hardware. So no, HW devices can't understand
struct blk_mq_hw_ctx. This paragraph was reworked for v2.

> 
> thanks for the documentation.
> 

Thanks for the feedback.