Re: [PATCH v9 0/7] Enable cpuset controller in default hierarchy

[Juri Lelli <juri.lelli@redhat.com>]

On 30/05/18 08:56, Waiman Long wrote:
> On 05/30/2018 06:13 AM, Juri Lelli wrote:
> > Hi,
> >
> > On 29/05/18 09:41, Waiman Long wrote:
> >> v9:
> >>  - Rename cpuset.sched.domain to cpuset.sched.domain_root to better
> >>    identify its purpose as the root of a new scheduling domain or
> >>    partition.
> >>  - Clarify in the document about the purpose of domain_root and
> >>    load_balance. Using domain_root is th only way to create new
> >>    partition.
> >>  - Fix a lockdep warning in update_isolated_cpumask() function.
> >>  - Add a new patch to eliminate call to generate_sched_domains() for
> >>    v2 when a change in cpu list does not touch a domain_root.
> > I was playing with this and ended up with the situation below:
> >
> >  g1/cgroup.controllers:cpuset
> >  g1/cgroup.events:populated 0
> >  g1/cgroup.max.depth:max
> >  g1/cgroup.max.descendants:max
> >  g1/cgroup.stat:nr_descendants 1
> >  g1/cgroup.stat:nr_dying_descendants 0
> >  g1/cgroup.subtree_control:cpuset
> >  g1/cgroup.type:domain
> >  g1/cpuset.cpus:0-5                   <---
> >  g1/cpuset.cpus.effective:0-5
> >  g1/cpuset.mems.effective:0-1
> >  g1/cpuset.sched.domain_root:1        <---
> >  g1/cpuset.sched.load_balance:1
> >  g1/cpu.stat:usage_usec 0
> >  g1/cpu.stat:user_usec 0
> >  g1/cpu.stat:system_usec 0
> >  g1/g11/cgroup.events:populated 0
> >  g1/g11/cgroup.max.descendants:max
> >  g1/g11/cpu.stat:usage_usec 0
> >  g1/g11/cpu.stat:user_usec 0
> >  g1/g11/cpu.stat:system_usec 0
> >  g1/g11/cgroup.type:domain
> >  g1/g11/cgroup.stat:nr_descendants 0
> >  g1/g11/cgroup.stat:nr_dying_descendants 0
> >  g1/g11/cpuset.cpus.effective:0-5
> >  g1/g11/cgroup.controllers:cpuset
> >  g1/g11/cpuset.sched.load_balance:1
> >  g1/g11/cpuset.mems.effective:0-1
> >  g1/g11/cpuset.cpus:6-11              <---
> >  g1/g11/cgroup.max.depth:max
> >  g1/g11/cpuset.sched.domain_root:0
> >
> > Should this be allowed? I was expecting subgroup g11 should be
> > restricted to a subset of g1's cpus.
> >
> > Best,
> >
> > - Juri
> 
> That shouldn't be allowed.The code is probably missing some checks that
> should have been done. What was the sequence of commands leading to the
> above configuration?

This is a E5-2609 v3 (12 cores) Fedora Server box (with systemd, so
first command is needed to be able to use cpuset controller with v2,
IIUC):

# umount /sys/fs/cgroup/cpuset 
# cd /sys/fs/cgroup/unified/
# echo "+cpuset" >cgroup.subtree_control 
# mkdir g1
# echo 0-5 >g1/cpuset.cpus
# echo 6-11 >init.scope/cpuset.cpus
# echo 6-11 >machine.slice/cpuset.cpus
# echo 6-11 >system.slice/cpuset.cpus
# echo 6-11 >user.slice/cpuset.cpus
# echo 1 >g1/cpuset.sched.domain_root 
# mkdir g1/g11
# echo "+cpuset" > g1/cgroup.subtree_control 
# echo 6-11 >g1/g11/cpuset.cpus
# grep -R . g1/*

That should be it. Am I doing something wrong?

Thanks,

- Juri