v2: - Drop v1 patch 1. - Break out some cosmetic changes into a separate patch (patch #1). - Add a new patch to clarify the transition to invalid partition root is mainly caused by hotplug events. - Enhance the partition root state test including CPU online/offline behavior and fix issues found by the test.

This patchset makes the following three major changes to the cpuset v2 code:

Patch 2: Clarify the use of invalid partition root and add new checks to make sure that normal cpuset control file operations will not be allowed to create invalid partition root. It also fixes some of the issues in existing code.

Patch 3: Add a new partition state "isolated" to create a partition root without load balancing. This is for handling intermitten workloads that have a strict low latency requirement.

Patch 4: Allow partition roots that are not the top cpuset to distribute all its cpus to child partitions as long as there is no task associated with that partition root. This allows more flexibility for middleware to manage multiple partitions.

Patch 5 updates the cgroup-v2.rst file accordingly. Patch 5 adds a new cpuset test to test the new cpuset partition code.

Waiman Long (6): cgroup/cpuset: Miscellaneous code cleanup cgroup/cpuset: Clarify the use of invalid partition root cgroup/cpuset: Add a new isolated cpus.partition type cgroup/cpuset: Allow non-top parent partition root to distribute out all CPUs cgroup/cpuset: Update description of cpuset.cpus.partition in cgroup-v2.rst kselftest/cgroup: Add cpuset v2 partition root state test

Documentation/admin-guide/cgroup-v2.rst | 65 +- kernel/cgroup/cpuset.c | 285 ++++++--- tools/testing/selftests/cgroup/Makefile | 2 +- .../selftests/cgroup/test_cpuset_prs.sh | 558 ++++++++++++++++++ 4 files changed, 794 insertions(+), 116 deletions(-) create mode 100755 tools/testing/selftests/cgroup/test_cpuset_prs.sh