[PATCH v3 0/9] cgroup/cpuset: Add new cpuset partition type & empty effecitve cpus

From: Waiman Long
Date: Tue Jul 20 2021 - 10:25:53 EST


v3:
- Add two new patches (patches 2 & 3) to fix bugs found during the
testing process.
- Add a new patch to enable inotify event notification when partition
become invalid.
- Add a test to test event notification when partition become invalid.

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 fixes two bugs and makes four enhancements to the cpuset
v2 code.

Bug fixes:

Patch 2: Fix a hotplug handling bug when just all cpus in subparts_cpus
are offlined.

Patch 3: Fix violation of cpuset locking rule.

Enhancements:

Patch 4: Enable event notification on "cpuset.cpus.partition" when
a partition become invalid.

Patch 5: 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 6: 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 7: 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 8 updates the cgroup-v2.rst file accordingly. Patch 9 adds a new
cpuset test to test the new cpuset partition code.

Waiman Long (9):
cgroup/cpuset: Miscellaneous code cleanup
cgroup/cpuset: Fix a partition bug with hotplug
cgroup/cpuset: Fix violation of cpuset locking rule
cgroup/cpuset: Enable event notification when partition become invalid
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 | 94 ++-
kernel/cgroup/cpuset.c | 360 +++++++---
tools/testing/selftests/cgroup/Makefile | 5 +-
.../selftests/cgroup/test_cpuset_prs.sh | 626 ++++++++++++++++++
tools/testing/selftests/cgroup/wait_inotify.c | 67 ++
5 files changed, 1007 insertions(+), 145 deletions(-)
create mode 100755 tools/testing/selftests/cgroup/test_cpuset_prs.sh
create mode 100644 tools/testing/selftests/cgroup/wait_inotify.c

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2.18.1