On 11/16/18 1:38 AM, Christoph Hellwig wrote: > On Thu, Nov 15, 2018 at 12:51:27PM -0700, Jens Axboe wrote: >> Put the short code in the fast path, where we don't have any >> functions attached to the queue. This minimizes the impact on >> the hot path in the core code. > > This looks mechanically fine: > > Reviewed-by: Christoph Hellwig <[email protected]> > > But since I seem to have missed the introduction of it - why do we need > multiple struct rq_qos per request to start with? This sort of stacking > seems rather odd and counter-productive, and the commit introducing > this code doesn't explain the rationale at all.
Per request-queue, not per request. One would be iolatency, one would be wbt, etc. -- Jens Axboe
