freezer for cgroup v2 This patchset implements freezer for cgroup v2. It provides similar functionality as v1 freezer, but the interface conforms to the cgroup v2 interface design principles, and it provides a better user experience: tasks can be killed, ptrace works, there is no separate controller, which has to be enabled, etc. Patches (1), (2) and (3) are some preparational work, patch (4) contains the implementation, patch (5) is a small cgroup kselftest fix, patch (6) covers freezer adds 6 new kselftests to cover the freezer functionality. Patch (7) adds corresponding docs. v4->v3: - fixed cgroup state transitions on task migration (by Tejun Heo) - reading nr_descendants doesn't require taking css_set_lock anymore - fixed docs based on Mike Rapoport's feedback - fixed double irq lock found by Dan Carpenter v3->v2: - dropped TASK_FROZEN for now, frozen tasks are put into TASK_INTERRUPTIBLE state; it's probably not the final version, but the API question can be discussed separately - don't clear TIF_SIGPENDING before going to sleep, instead add task->frozen check in signal_pending_state() and recalc_sigpending() - cgroup-level counter are now synchronized using css_set_lock, which simplified the whole code (e.g. per-cgroup works were removed) - the amount of comments increased significantly - many other improvements incorporating feedback from Tejun and Oleg v2->v1: - fixed locking aroung calling cgroup_freezer_leave() - added docs Roman Gushchin (7): cgroup: rename freezer.c into legacy_freezer.c cgroup: implement __cgroup_task_count() helper cgroup: protect cgroup->nr_(dying_)descendants by css_set_lock cgroup: cgroup v2 freezer kselftests: cgroup: don't fail on cg_kill_all() error in cg_destroy() kselftests: cgroup: add freezer controller self-tests cgroup: document cgroup v2 freezer interface Documentation/admin-guide/cgroup-v2.rst | 27 + include/linux/cgroup-defs.h | 31 + include/linux/cgroup.h | 42 ++ include/linux/sched.h | 2 + include/linux/sched/jobctl.h | 2 + include/linux/sched/signal.h | 3 + kernel/cgroup/Makefile | 4 +- kernel/cgroup/cgroup-internal.h | 1 + kernel/cgroup/cgroup-v1.c | 16 - kernel/cgroup/cgroup.c | 151 +++- kernel/cgroup/freezer.c | 653 +++++++---------- kernel/cgroup/legacy_freezer.c | 481 ++++++++++++ kernel/ptrace.c | 7 + kernel/signal.c | 58 +- tools/testing/selftests/cgroup/.gitignore | 1 + tools/testing/selftests/cgroup/Makefile | 2 + tools/testing/selftests/cgroup/cgroup_util.c | 85 ++- tools/testing/selftests/cgroup/cgroup_util.h | 7 + tools/testing/selftests/cgroup/test_freezer.c | 685 ++++++++++++++++++ 19 files changed, 1811 insertions(+), 447 deletions(-) create mode 100644 kernel/cgroup/legacy_freezer.c create mode 100644 tools/testing/selftests/cgroup/test_freezer.c -- 2.17.2
