Re: [PATCH] blk-cgroup: fix missing pd_online_fn() while activating policy

[Yu Kuai]

Hi,

在 2023/01/05 18:45, Michal Koutný 写道:
> On Thu, Jan 05, 2023 at 09:43:02AM +0800, Yu Kuai <yukuai1@xxxxxxxxxxxxxxx> wrote:
> > This is based only on code review, currently the only negative effects
> > is that root blkg from blk-throtl won't call pd_online_fn().
>
> Good, that's a NOP and there are no other uses of pd_online_fn.
>
> I wonder are the separate pd_init_fn and pd_online_fn callbacks
> necessary today?

I think online can combine to init, consider that only blk-throttle
implement pd_online_fn(), but I'm not sure...

It seems to me the policies(bfq, iocost...) seem don't honor how pd
apis works: alloc->init->online->offline->free, bfq combines online to
init, iocost combines offline to free, ...

Thanks,
Kuai