On Wed, Dec 15, 2021 at 11:29:41AM -0500, Waiman Long longman@redhat.com wrote:
There are additional checks for the member to partition transition which requires that the target cpuset shouldn't have child cpuset.
Ah, I forgot the transition condition no. 4 will apply here. Clear.
So, currently full bottom up + top down walk is needed in (rare?) case the switch from root partition to member and back.
That prevents the recovering of a invalid partition root under a member cpuset. We could certainly remove that restriction by adding additional code as well as additional tests to verify it works. I haven't done that simply to avoid adding more complexity to the current code.
I agree this restriction can be lifted later independently when the rest settles. (It's not so different from controllers disabling on the unified hierarchy after all.)
Thanks, Michal