Hello, On Wed, Apr 17, 2024 at 09:13:34AM +0800, Yu Kuai wrote: > > Probably a better interface is for unloading to force blk-throtl to be > > deactivated rather than asking the user to nuke all configs. > > I was thinking that rmmod in this case should return busy, for example, > if bfq is currently used for some disk, rmmod bfq will return busy. > > Is there any example that unloading will deactivate resources that users > are still using? Hmm... yeah, I'm not sure. Pinning the module while in use is definitely more conventional, so let's stick with that. It's usually achieved by inc'ing the module's ref on each usage, so here, the module refs would be counting the number of active rules, I guess. I'm not sure about modularization tho mostly because we've historically had a lot of lifetime issues around block and blkcg data structures and the supposed gain here is rather minimal. We only have a handful of these policies and they aren't that big. If hot path overhead when not being used is concern, lazy init solves most of it, no? Thanks. -- tejun
