> Il giorno 23 gen 2017, alle ore 18:42, Jens Axboe <ax...@fb.com> ha scritto: > > On 01/23/2017 10:04 AM, Paolo Valente wrote: >> >>> Il giorno 18 gen 2017, alle ore 17:21, Jens Axboe <ax...@fb.com> ha scritto: >>> >>> On 01/18/2017 08:14 AM, Paolo Valente wrote: >>>> according to the function blk_mq_sched_put_request, the >>>> mq.completed_request hook seems to always be invoked (if set) for a >>>> request for which the mq.put_rq_priv is invoked (if set). >>> >>> Correct, any request that came out of blk_mq_sched_get_request() >>> will always have completed called on it, regardless of whether it >>> had IO started on it or not. >>> >> >> It seems that some request, after being dispatched, happens to have no >> mq.put_rq_priv invoked on it now or then. Is it expected? If it is, >> could you point me to the path through which the end of the life of >> such a request is handled? > > I'm guessing that's a flush request. I added RQF_QUEUED to check for > that, if RQF_QUEUED is set, you know it has come from your get_request > handler. >
Exactly, the completion-without-put_rq_priv pattern seems to occur only for requests coming from the flusher, precisely because they have the flag RQF_ELVPRIV unset. Just to understand: why is this flag unset for these requests, if they do have private elevator (bfq) data attached? What am I misunderstanding? Just to be certain: this should be the only case where the completed_request hook is invoked while the put_rq_priv is not, right? Thanks, Paolo > I'm assuming that is it, let me know. > > -- > Jens Axboe >
