[PATCHSET sched_ext/for-6.12] sched_ext: Add cgroup support

[Tejun Heo <tj@kernel.org>]

This patchset is the cgroup integration part of the sched_ext v6 patchset:

  http://lkml.kernel.org/r/20240501151312.635565-1-tj@kernel.org

This patchset is on top of sched_ext/for-6.12 (2c390dda9e03 ("sched_ext:
Make task_can_run_on_remote_rq() use common task_allowed_on_cpu()")) and
contains the following patches:

 0001-cgroup-Implement-cgroup_show_cftypes.patch
 0002-sched-Expose-css_tg.patch
 0003-sched-Enumerate-CPU-cgroup-file-types.patch
 0004-sched-Make-cpu_shares_read_u64-use-tg_weight.patch
 0005-sched-Introduce-CONFIG_GROUP_SCHED_WEIGHT.patch
 0006-sched_ext-Add-cgroup-support.patch
 0007-sched_ext-Add-a-cgroup-scheduler-which-uses-flattene.patch

 0001 implements cgroup_show_cftype() so that SCX schedulers can only show
 cgroup knobs that it implements.

 0002-0005 are sched core preparations. Should be pretty straightforward. No
 functional changes.

 0006 adds cgroup support to sched_ext.

 0007 implements an example scheduler which uses the cgroup support.

The patchset is also available in the following git branch:

 git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext.git scx-cgroup

diffstat follows. Thanks.

 include/linux/cgroup-defs.h                     |    8
 include/linux/cgroup.h                          |    1
 include/linux/sched/ext.h                       |    3
 init/Kconfig                                    |   10
 kernel/cgroup/cgroup.c                          |   97 ++++
 kernel/sched/core.c                             |  115 +++--
 kernel/sched/ext.c                              |  522 ++++++++++++++++++++++++-
 kernel/sched/ext.h                              |   20
 kernel/sched/sched.h                            |   35 +
 tools/sched_ext/Makefile                        |    2
 tools/sched_ext/README.md                       |   12
 tools/sched_ext/include/scx/common.bpf.h        |    1
 tools/sched_ext/scx_flatcg.bpf.c                |  949 ++++++++++++++++++++++++++++++++++++++++++++++
 tools/sched_ext/scx_flatcg.c                    |  233 +++++++++++
 tools/sched_ext/scx_flatcg.h                    |   51 ++
 tools/testing/selftests/sched_ext/maximal.bpf.c |   32 +
 16 files changed, 2035 insertions(+), 56 deletions(-)

--
tejun