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Message-ID: <da74ba78-852a-84e5-89a1-d238302d8aef@oracle.com>
Date: Thu, 14 Dec 2017 10:14:31 +0800
From: "jianchao.wang" <jianchao.w.wang@...cle.com>
To: Tejun Heo <tj@...nel.org>
Cc: axboe@...nel.dk, linux-kernel@...r.kernel.org, oleg@...hat.com,
peterz@...radead.org, kernel-team@...com, osandov@...com
Subject: Re: [PATCH 6/6] blk-mq: remove REQ_ATOM_STARTED
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.
>
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