On Tue 23-11-21 09:06:47, Jens Axboe wrote: > On 11/23/21 3:29 AM, Jan Kara wrote: > > Currently we lookup ICQ only after the request is allocated. However BFQ > > will want to decide how many scheduler tags it allows a given bfq queue > > (effectively a process) to consume based on cgroup weight. So lookup ICQ > > earlier and provide it in struct blk_mq_alloc_data so that BFQ can use > > it. > > I've been trying to clean this path up a bit, since I don't like having > something that just one scheduler needs in the fast path. See: > > https://git.kernel.dk/cgit/linux-block/commit/?h=perf-wip&id=f1f8191a8f9a0cdcd5ad99dfd7e551e8f444bec5 > > Would be better if we could avoid adding io_cq to blk_mq_alloc_data for > that reason, would it be possible to hide this away in the sched code > instead on top of the above? Understood. We could certainly handle ICQ allocation & assignment only inside BFQ. Just this would mean we would need to lookup ICQ once in bfq_limit_depth() and then second time in bfq_prepare_request(). I guess not a huge deal given the amount of work BFQ does for each request anyway. So can I pull the above commit into the series and rebase this patch on top of it? Honza -- Jan Kara <jack@xxxxxxxx> SUSE Labs, CR
