On Thu, Feb 24, 2022 at 10:50:22AM +0800, Wang Jianchao wrote: > Yes, right now, every policy has their own way to turn off, but we always need to > iterate the rqos list and enter into the policy's callback to check it. And every > blkio cgroup needs to allocate memory for it even we don't use it. > > I don't this patchset is adding a new layer, but blk-rq-qos layer has been already > there , we just add a unified interface to open/close the policies. We're talking in circles. We already know when a policy is inactive. If it sits in hot path in that state, take it off whatever gets iterated in hot path and put it back on when it actually gets enabled. The same goes for memory allocation. If there's substantial amount of memory allocted while not used, make that dynamic and trigger it when the policy starts getting used. It makes no sense to add another enable/disable interface on top. FWIW, please consider the series nacked on this side. Thanks. -- tejun
