Re: [PATCH] cgroup/cpuset: Disable cpuset_cpumask_can_shrink() test if not load balancing

[Waiman Long]

On 11/18/24 8:58 AM, Waiman Long wrote:
> > > The failing test isn't an isolated partition. The actual test 
> > > failure is
> > >
> > > Test TEST_MATRIX[62] failed result check!
> > > C0-4:X2-4:S+ C1-4:X2-4:S+:P2 C2-4:X4:P1 . . X5 . . 0 
> > > A1:0-4,A2:1-4,A3:2-4
> > > A1:P0,A2:P-2,A3:P-1
> > >
> > > In this particular case, cgroup A3 has the following setting before 
> > > the X5
> > > operation.
> > >
> > > A1/A2/A3/cpuset.cpus: 2-4
> > > A1/A2/A3/cpuset.cpus.exclusive: 4
> > > A1/A2/A3/cpuset.cpus.effective: 4
> > > A1/A2/A3/cpuset.cpus.exclusive.effective: 4
> > > A1/A2/A3/cpuset.cpus.partition: root
> > Right, and is this problematic already?
> We allow nested partition setup. So there can be a child partition 
> underneath a parent partition. So this is OK.
> > Then the test, I believe, does
> >
> > # echo 5 >cgroup/A1/A2/cpuset.cpus.exclusive
> >
> > and that goes through and makes the setup invalid - root domain reconf
> > and the following
> >
> > # cat cgroup/A1/cpuset.cpus.partition
> > member
> > # cat cgroup/A1/A2/cpuset.cpus.partition
> > isolated invalid (Parent is not a partition root)
> > # cat cgroup/A1/A2/A3/cpuset.cpus.partition
> > root invalid (Parent is an invalid partition root)
> >
> > Is this what shouldn't happen?
> A3 should become invalid because none of the CPUs in 
> cpuset.cpus.exclusive can be granted. However A2 should remain a valid 
> partition. I will look further into that. Thank for spotting this 
> inconsistency. 

Sorry, I misread the test. The X5 entry above refers to "echo 5 > 
A1/A2/cpuset.cpus.exclusive" not to A3. This invalidates the A2 
partition which further invalidates the child A3 partition. So the 
result is correct.

Cheers,
Longman