Hello, Vivek.

On Wed, Apr 23, 2014 at 03:21:09PM -0400, Vivek Goyal wrote:

What about sync/async differentiation? Throttling layer seems to flag a request sync
only if bio->bi_rw flag has REQ_SYNC set. While CFQ seems to consider
request sync if bio is either read or bio->bi_rw has REQ_SYNC flag set.

Working on this again, AFAICS, both treat REQ_SYNC the same way as far
as stats are concerned.  If SYNC is set, it's sync; otherwise, it's
accounted as async whether read or write.

Thanks.

-- 
tejun