Hello! On Mon 25-04-22 21:34:16, yukuai (C) wrote: > 在 2022/04/25 17:48, Jan Kara 写道: > > On Sat 16-04-22 17:37:50, Yu Kuai wrote: > > > Weight-raised queue is not inserted to weights_tree, which makes it > > > impossible to track how many queues have pending requests through > > > weights_tree insertion and removel. This patch add fake weight_counter > > > for weight-raised queue to do that. > > > > > > Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx> > > > > This is a bit hacky. I was looking into a better place where to hook to > > count entities in a bfq_group with requests and I think bfq_add_bfqq_busy() > > and bfq_del_bfqq_busy() are ideal for this. It also makes better sense > > conceptually than hooking into weights tree handling. > > bfq_del_bfqq_busy() will be called when all the reqs in the bfqq are > dispatched, however there might still some reqs are't completed yet. > > Here what we want to track is how many bfqqs have pending reqs, > specifically if the bfqq have reqs are't complted. > > Thus I think bfq_del_bfqq_busy() is not the right place to do that. Yes, I'm aware there will be a difference. But note that bfqq can stay busy with only dispatched requests because the logic in __bfq_bfqq_expire() will not call bfq_del_bfqq_busy() if idling is needed for service guarantees. So I think using bfq_add/del_bfqq_busy() would work OK. Honza -- Jan Kara <jack@xxxxxxxx> SUSE Labs, CR
