On Sat, Dec 17, 2022 at 11:05:26AM +0800, Yu Kuai wrote: > From: Yu Kuai <yukuai3@xxxxxxxxxx> > > Currently, if cgroup is removed while some bio is still throttled, such > bio will still wait for timer to dispatch. On the one hand, it > doesn't make sense to throttle bio while cgroup is removed, on the other > hand, this behaviour makes it hard to guarantee the exit order for > iocg(in ioc_pd_free() currently). Yeah, idk about this. So, now if you're in a cgroup with IO restriction, you can create a sub-cgroup shove all the IOs in there and then kill the cgroup and escape control and do so repeatedly. The refcnting is rather complicated in blkcg world because it gets pulled from several different directions but the problem you're trying to address likely should be addressed through refcnting. Thanks. -- tejun
