• Linus Torvalds's avatar
    Merge branch 'for-4.4' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup · 69234ace
    Linus Torvalds authored
    Pull cgroup updates from Tejun Heo:
     "The cgroup core saw several significant updates this cycle:
    
       - percpu_rwsem for threadgroup locking is reinstated.  This was
         temporarily dropped due to down_write latency issues.  Oleg's
         rework of percpu_rwsem which is scheduled to be merged in this
         merge window resolves the issue.
    
       - On the v2 hierarchy, when controllers are enabled and disabled, all
         operations are atomic and can fail and revert cleanly.  This allows
         ->can_attach() failure which is necessary for cpu RT slices.
    
       - Tasks now stay associated with the original cgroups after exit
         until released.  This allows tracking resources held by zombies
         (e.g.  pids) and makes it easy to find out where zombies came from
         on the v2 hierarchy.  The pids controller was broken before these
         changes as zombies escaped the limits; unfortunately, updating this
         behavior required too many invasive changes and I don't think it's
         a good idea to backport them, so the pids controller on 4.3, the
         first version which included the pids controller, will stay broken
         at least until I'm sure about the cgroup core changes.
    
       - Optimization of a couple common tests using static_key"
    
    * 'for-4.4' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: (38 commits)
      cgroup: fix race condition around termination check in css_task_iter_next()
      blkcg: don't create "io.stat" on the root cgroup
      cgroup: drop cgroup__DEVEL__legacy_files_on_dfl
      cgroup: replace error handling in cgroup_init() with WARN_ON()s
      cgroup: add cgroup_subsys->free() method and use it to fix pids controller
      cgroup: keep zombies associated with their original cgroups
      cgroup: make css_set_rwsem a spinlock and rename it to css_set_lock
      cgroup: don't hold css_set_rwsem across css task iteration
      cgroup: reorganize css_task_iter functions
      cgroup: factor out css_set_move_task()
      cgroup: keep css_set and task lists in chronological order
      cgroup: make cgroup_destroy_locked() test cgroup_is_populated()
      cgroup: make css_sets pin the associated cgroups
      cgroup: relocate cgroup_[try]get/put()
      cgroup: move check_for_release() invocation
      cgroup: replace cgroup_has_tasks() with cgroup_is_populated()
      cgroup: make cgroup->nr_populated count the number of populated css_sets
      cgroup: remove an unused parameter from cgroup_task_migrate()
      cgroup: fix too early usage of static_branch_disable()
      cgroup: make cgroup_update_dfl_csses() migrate all target processes atomically
      ...
    69234ace
backing-dev.h 13.8 KB