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

[Chen Ridong <chenridong@huawei.com>]

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.

This patchset is based on -next commit c79c85875f1a ("Add linux-next
specific files for 20240823") and assumes that "Some optimizations about
cpuset" series are merged, which are applied to cgroup/for-6.12.


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                        |   8 +-
 init/Kconfig                                  |  13 +
 kernel/cgroup/Makefile                        |   1 +
 kernel/cgroup/cpuset-internal.h               | 307 +++++++
 kernel/cgroup/cpuset-v1.c                     | 565 ++++++++++++
 kernel/cgroup/cpuset.c                        | 850 +-----------------
 .../selftests/cgroup/test_cpuset_v1_base.sh   |  77 ++
 8 files changed, 987 insertions(+), 837 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

-- 
2.34.1