[PATCH v2 -next 00/11] cgroup:cpuset:separate legacy cgroup v1 code and put under config option

Chen Ridong
2024-08-26T13:34:52Z

Cgroups v2 have been around for a while and many users have fully adopted
them, so they never use cgroups v1 features and functionality. Yet they
have to "pay" for the cgroup v1 support anyway:
1) the kernel binary contains an unused cgroup v1 code,
2) some code paths have additional checks which are not needed,
3) some common structures like task_struct and mem_cgroup contain unused
cgroup v1-specific members.

Cgroup memory controller has already separated legacy code to
memory-v1.c. So it is time to do the same thing for cpuset controller.

This patchset aims to do:
1) moving cgroup v1-specific cpuset code to the new cpuset-v1.c file,
2) putting definitions shared by cpuset.c and cpuset-v1.c into the
cpuset-internal.h header,
3) introducing the CONFIG_CPUSETS_V1 config option, turned off by default,
4) making cpuset-v1.c to compile only if CONFIG_CPUSETS_V1 is set.

---
V2:
- Update to base on the latest cgroup/for-6.12.
- Add CONFIG_CPUSETS_V1 for cpuset_memory_pressure_bump.

Chen Ridong (11):
cgroup/cpuset: introduce cpuset-v1.c
cgroup/cpuset: move common code to cpuset-internal.h
cgroup/cpuset: move memory_pressure to cpuset-v1.c
cgroup/cpuset: move relax_domain_level to cpuset-v1.c
cgroup/cpuset: move memory_spread to cpuset-v1.c
cgroup/cpuset: add callback_lock helper
cgroup/cpuset: move legacy hotplug update to cpuset-v1.c
cgroup/cpuset: move validate_change_legacy to cpuset-v1.c
cgroup/cpuset: move v1 interfaces to cpuset-v1.c
cgroup/cpuset: guard cpuset-v1 code under CONFIG_CPUSETS_V1
cgroup/cpuset: add sefltest for cpuset v1

MAINTAINERS | 3 +
include/linux/cpuset.h | 4 +
init/Kconfig | 13 +
kernel/cgroup/Makefile | 1 +
kernel/cgroup/cpuset-internal.h | 305 +++++++
kernel/cgroup/cpuset-v1.c | 563 ++++++++++++
kernel/cgroup/cpuset.c | 850 +-----------------
.../selftests/cgroup/test_cpuset_v1_base.sh | 77 ++
8 files changed, 986 insertions(+), 830 deletions(-)
create mode 100644 kernel/cgroup/cpuset-internal.h
create mode 100644 kernel/cgroup/cpuset-v1.c
create mode 100755 tools/testing/selftests/cgroup/test_cpuset_v1_base.sh

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2.34.1