[0/9] cgroup v1 deprecation warnings

Message

Michal Koutný March 4, 2025, 3:37 p.m. UTC

Memory controller had begun to print warning messages when using some
attributes that do no have a counterpart in its cgroup v2
implementation. This is informative to users who run (unwittingly) on v1
or to distros that run v1 (they can learn about such users or prepare
for disabling v1 configs).

I consider the deprecated files in three categories:
  - RE) replacement exists,
  - DN) dropped as non-ideal concept (e.g. non-hierarchical resources),
  - NE) not evaluated (yet).

For RE, I added the replacement into the warning message, DN have only a
plain deprecation message and I marked the commits with NE as RFC.
Also I'd be happy if you would point out some forgotten knobs that'd
deserve similar warnings.
At the end are some cleanup patches I encountered en route.

Michal Koutný (9):
  cgroup/cpuset-v1: Add deprecation warnings to sched_load_balance and
    memory_pressure_enabled
  cgroup/cpuset-v1: Add deprecation warnings to memory_spread_page and
    memory_spread_slab
  cgroup/blkio: Add deprecation warnings to reset_stats
  cgroup: Print warning when /proc/cgroups is read on v2-only system
  RFC cgroup/cpuset-v1: Add deprecation warnings to mem_exclusive and
    mem_hardwall
  RFC cgroup/cpuset-v1: Add deprecation warnings to memory_migrate
  RFC cgroup/cpuset-v1: Add deprecation warnings to
    sched_relax_domain_level
  cgroup: Update file naming comment
  blk-cgroup: Simplify policy files registration

 block/blk-cgroup.c              |  8 ++++++--
 block/blk-ioprio.c              | 23 +++++++----------------
 include/linux/cgroup-defs.h     |  5 ++---
 include/linux/cgroup.h          |  1 +
 kernel/cgroup/cgroup-internal.h |  1 +
 kernel/cgroup/cgroup-v1.c       |  7 +++++++
 kernel/cgroup/cgroup.c          |  4 ++--
 kernel/cgroup/cpuset-v1.c       |  8 ++++++++
 8 files changed, 34 insertions(+), 23 deletions(-)


base-commit: 76544811c850a1f4c055aa182b513b7a843868ea