Re: [PATCH] doc: Add CPU Isolation documentation

[Waiman Long]

On 3/24/26 11:38 AM, Sebastian Andrzej Siewior wrote:
> On 2025-08-09 11:42:47 [+0200], Frederic Weisbecker wrote:
> …
> > --- /dev/null
> > +++ b/Documentation/admin-guide/cpu-isolation.rst
> > @@ -0,0 +1,338 @@
> …
> > +CPUSET configuration (cgroup v2)
> > +--------------------------------
> > +
> > +Assuming cgroup v2 is mounted to /sys/fs/cgroup, the following script
> > +isolates CPU 7 from scheduler domains.
> > +
> > +  cd /sys/fs/cgroup
> > +  # Activate the cpuset subsystem
> > +  echo +cpuset > cgroup.subtree_control
> > +  # Create partition to be isolated
> > +  mkdir test
> > +  cd test
> > +  echo +cpuset > cgroup.subtree_control
> > +  # Isolate CPU 7
> > +  echo 7 > cpuset.cpus
> > +  echo "isolated" > cpuset.cpus.partition
> while looking at this again, shouldn't you also do
> 	echo 7 > cpuset.cpus.exclusive
>
> to ensure the CPU isn't used somewhere else?

For backport compatibility, the use of cpuset.cpus.exclusive is optional 
for creating a local partition underneath the cgroup root. The example 
should still work without setting cpuset.cpus.exclusive.

Cheers,
Longman