On Thu, Feb 25, 2021 at 11:28:46AM -0800, Vipin Sharma [off-list ref] wrote:

My approach here is that it is the responsibility of the caller to:
1. Check the return value and proceed accordingly.
2. Ideally, let all of the usage be 0 before deactivating this resource
   by setting capacity to 0

If the calling side can ensure itself that no new units of the resource
are used from that moment on, then it can work this way -- but describe
that in misc_cg_set_capacity() comment.

Is the above change good?

I think both alternatives would work. But the latter (as I see it now)
would mandate dependency on CONFIG_CGROUP or it'd have to double the
similar logic itself. So maybe keeping the caller responsible explicitly
is simpler from this POV.

Will there be any objection to extra information?

IMO it's unnecessary (stating this just for consistency reasons), no
strong opinion.

Michal