Re: [PATCH 6/6] blk-mq: remove REQ_ATOM_STARTED

[jianchao.wang]

On 12/14/2017 12:09 AM, Tejun Heo wrote:
> Hello,
> 
> On Wed, Dec 13, 2017 at 11:05:11AM +0800, jianchao.wang wrote:
>> Just don't quite understand the strict definition of "generation" you said.
>> A allocation->free cycle is a generation ? or a idle->in-flight cycle is a
>> generation? The idle->in-flight cycle could include the requeue case as above.
>> Can you clarify this?
> 
> So, a request is
> 
> * IN_FLIGHT, if it can be completed by the lower level driver
> 
> * COMPLETE, if the lower level driver indicated completion but block
>   layer is still processing.
> 
> * IDLE, if neither of the above two.
> 
> and generation is bumped up on IDLE -> IN_FLIGHT to distinguish
> different IN_FLIGHT instances.
> 

So a generation means a cycle from IDLE -> IN_FLIGHT.
Thanks for your response. That's really appreciated.

Jianchao
> Thanks.
>