On 11/28/23 11:46, Tejun Heo wrote:
Hello,
On Mon, Nov 27, 2023 at 02:51:05PM -0500, Waiman Long wrote:
The root-only cpuset.cpus.isolated control file shows the current set
of isolated CPUs in isolated partitions. This control file is currently
exposed only with the cgroup_debug boot command line option which also
adds the ".__DEBUG__." prefix. This is actually a useful control file if
users want to find out which CPUs are currently in an isolated state by
the cpuset controller. Remove CFTYPE_DEBUG flag for this control file and
make it available by default without any prefix.
The test_cpuset_prs.sh test script and the cgroup-v2.rst documentation
file are also updated accordingly. Minor code change is also made in
test_cpuset_prs.sh to avoid false test failure when running on debug
kernel.
Applied to cgroup/for-6.8 but I wonder whether this would be useful in
non-root cgroups too. e.g. In a delegated partition which is namespaced,
wouldn't this be useful too?
Thanks.
For simplicity,we only maintain one cpumask of isolated CPUs that
includes all the exclusive CPUs in isolated partitions. We haven't
maintain separate masks for delegation purposes. We can certainly extend
that if the needs arise. At this point, the set of isolated CPUs is
mainly used for determining what kernel background services can be
disabled to reduce interference from the whole kernel point of view.
Cheers,
Longman
