On Thu, Feb 03, 2011 at 02:38:20PM +0100, Tejun Heo wrote:

Hey, Jens.

On Thu, Feb 03, 2011 at 02:24:42PM +0100, Jens Axboe wrote:

quoted

On 2011-02-02 23:55, Mike Snitzer wrote:

quoted

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?

Though you did not like the V1 of patch, personally I also liked just parsing
FLUSH or FUA flag in get_request().

Or how about intoducing a helper function blk_rq_should_init_elevator() 
or something like that and this function will parse FLUSH, FUA flags.

Thanks
Vivek