Re: [PATCH v3 1/2] block: skip elevator data initialization for flush requests

Tejun Heo
2011-02-03T13:38:28Z

Hey, Jens.

On Thu, Feb 03, 2011 at 02:24:42PM +0100, Jens Axboe wrote:
> On 2011-02-02 23:55, Mike Snitzer wrote:
> > REQ_SORTED is not set for flush requests because they are never put on
> > the IO scheduler.
>
> That looks very wrong. REQ_SORTED gets set _when_ the request is sorted
> into the IO scheduler. This is gross misuse, a bad hack.

The rationale behind suggesting was that it indicates to the allocator
that the request may be sorted as how the request will be used is
communicated using @rw_flags to the allocator. The patch is buggy
that the flag actually ends up on the request. Any better idea how to
communicate it?

Thanks.

--
tejun