The series consists of two parts: - pids.events rework (originally v2, patches 1-6, - migration charging, patches 7-9.
The changes are independent in principle, I stacked them for (my) convenience and because they both deserve RFC:
1) Changed semantics of v2 pids.events - similar change was proposed for memory.swap.events:max [1] 2) Migration charging is obsolete concept
How are the new events supposed to be useful?
- pids.events.local:max - tells that cgroup's limit is hit (too tight?) - pids.events.local:max.imposed - tells that cgroup's workload was restricted (generalization of 'cgroup: fork rejected by pids controller in %s' message) - pids.events:* - "only" directs top-down search to cgroups of interest
The migration charging is motivated by apparenty surprising pids.current > pids.max because supervised processes are forked in supervisor's cgroup (more details in commit cgroup/pids: Enforce pids.max on task migrations too)
Changes from v2 (https://lore.kernel.org/r/20200205134426.10570-1-mkoutny@suse.com) - implemented pids.events.local (Tejun) - added migration charging
[1] https://lore.kernel.org/r/20230202155626.1829121-1-hannes@cmpxchg.org/
Michal Koutný (9): cgroup/pids: Remove superfluous zeroing cgroup/pids: Separate semantics of pids.events related to pids.max cgroup/pids: Make event counters hierarchical cgroup/pids: Add pids.events.local selftests: cgroup: Lexicographic order in Makefile selftests: cgroup: Add basic tests for pids controller cgroup/pids: Replace uncharge/charge pair with a single function cgroup/pids: Enforce pids.max on task migrations selftests: cgroup: Add tests pids controller
Documentation/admin-guide/cgroup-v1/pids.rst | 3 +- Documentation/admin-guide/cgroup-v2.rst | 22 +- include/linux/cgroup-defs.h | 7 +- kernel/cgroup/cgroup.c | 16 +- kernel/cgroup/pids.c | 206 +++++++++---- tools/testing/selftests/cgroup/Makefile | 25 +- tools/testing/selftests/cgroup/test_pids.c | 302 +++++++++++++++++++ 7 files changed, 514 insertions(+), 67 deletions(-) create mode 100644 tools/testing/selftests/cgroup/test_pids.c
base-commit: 026e680b0a08a62b1d948e5a8ca78700bfac0e6e