Re: [PATCH v3 0/9] cgroup/cpuset: Add new cpuset partition type & empty effecitve cpus

Hello, Waiman. Sorry about the delay. Was off for a while.

On Tue, Jul 27, 2021 at 05:14:27PM -0400, Waiman Long wrote:

However, if we have a complicated partition setup with multiple child
partitions. Invalid cpuset.cpus change in a parent partition will cause all
the child partitions to become invalid too. That is the scenario that I
don't want to happen inadvertently. Alternatively, we can restrict those

I don't think there's anything fundamentally wrong with it given the
requirement that userland has to monitor invalid state transitions.
The same mass transition can happen through cpu hotplug operations,
right?

invalid changes if a child partition exist and let it pass through and make
it invalid if it is a standalone partition.

Please let me know which approach do you want me to take.

I think it'd be best if we can stick to some principles rather than
trying to adjust it for specific scenarios. e.g.:

* If a given state can be reached through cpu hot [un]plug, any
  configuration attempt which reaches the same state should be allowed
  with the same end result as cpu hot [un]plug.

* If a given state can't ever be reached in whichever way, the
  configuration attempting to reach such state should be rejected.

Thanks.

-- 
tejun