linux-stable.git/include/linux/cgroup.h, branch v3.11.2

Merge branch 'for-3.11-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup

2013-07-23T22:48:35+00:00

Pull cgroup changes from Tejun Heo:
 "This contains two patches, both of which aren't fixes per-se but I
  think it'd be better to fast-track them.

  One removes bcache_subsys_id which was added without proper review
  through the block tree.  Fortunately, bcache cgroup code is
  unconditionally disabled, so this was never exposed to userland.  The
  cgroup subsys_id is removed.  Kent will remove the affected (disabled)
  code through bcache branch.

  The other simplifies task_group_path_from_hierarchy().  The function
  doesn't currently have in-kernel users but there are external code and
  development going on dependent on the function and making the function
  available for 3.11 would make things go smoother"

* 'for-3.11-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  cgroup: replace task_cgroup_path_from_hierarchy() with task_cgroup_path()
  cgroup: remove bcache_subsys_id which got added stealthily

cgroup: replace task_cgroup_path_from_hierarchy() with task_cgroup_path()

2013-07-12T19:49:05+00:00

task_cgroup_path_from_hierarchy() was added for the planned new users
and none of the currently planned users wants to know about multiple
hierarchies.  This patch drops the multiple hierarchy part and makes
it always return the path in the first non-dummy hierarchy.

As unified hierarchy will always have id 1, this is guaranteed to
return the path for the unified hierarchy if mounted; otherwise, it
will return the path from the hierarchy which happens to occupy the
lowest hierarchy id, which will usually be the first hierarchy mounted
after boot.

Signed-off-by: Tejun Heo 
Acked-by: Li Zefan 
Cc: Lennart Poettering 
Cc: Kay Sievers 
Cc: Jan Kaluža

Merge branch 'for-3.11/core' of git://git.kernel.dk/linux-block

2013-07-11T20:03:24+00:00

Pull core block IO updates from Jens Axboe:
"Here are the core IO block bits for 3.11. It contains:

- A tweak to the reserved tag logic from Jan, for weirdo devices with
just 3 free tags. But for those it improves things substantially
for random writes.

- Periodic writeback fix from Jan. Marked for stable as well.

- Fix for a race condition in IO scheduler switching from Jianpeng.

- The hierarchical blk-cgroup support from Tejun. This is the grunt
of the series.

- blk-throttle fix from Vivek.

Just a note that I'm in the middle of a relocation, whole family is
flying out tomorrow. Hence I will be awal the remainder of this week,
but back at work again on Monday the 15th. CC'ing Tejun, since any
potential "surprises" will most likely be from the blk-cgroup work.
But it's been brewing for a while and sitting in my tree and
linux-next for a long time, so should be solid."

* 'for-3.11/core' of git://git.kernel.dk/linux-block: (36 commits)
elevator: Fix a race in elevator switching
block: Reserve only one queue tag for sync IO if only 3 tags are available
writeback: Fix periodic writeback after fs mount
blk-throttle: implement proper hierarchy support
blk-throttle: implement throtl_grp->has_rules[]
blk-throttle: Account for child group's start time in parent while bio climbs up
blk-throttle: add throtl_qnode for dispatch fairness
blk-throttle: make throtl_pending_timer_fn() ready for hierarchy
blk-throttle: make tg_dispatch_one_bio() ready for hierarchy
blk-throttle: make blk_throtl_bio() ready for hierarchy
blk-throttle: make blk_throtl_drain() ready for hierarchy
blk-throttle: dispatch from throtl_pending_timer_fn()
blk-throttle: implement dispatch looping
blk-throttle: separate out throtl_service_queue->pending_timer from throtl_data->dispatch_work
blk-throttle: set REQ_THROTTLED from throtl_charge_bio() and gate stats update with it
blk-throttle: implement sq_to_tg(), sq_to_td() and throtl_log()
blk-throttle: add throtl_service_queue->parent_sq
blk-throttle: generalize update_disptime optimization in blk_throtl_bio()
blk-throttle: dispatch to throtl_data->service_queue.bio_lists[]
blk-throttle: move bio_lists[] and friends to throtl_service_queue
...

Merge branch 'for-3.11-cpuset' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup

2013-07-03T03:04:25+00:00

Pull cpuset changes from Tejun Heo:
 "cpuset has always been rather odd about its configurations - a cgroup
  right after creation didn't allow any task executions before
  configuration, changing configuration in the parent modifies the
  descendants irreversibly and so on.  These behaviors are inherently
  nasty and almost hostile against sharing the hierarchy with other
  controllers making it very difficult to use in unified hierarchy.

  Li is currently in the process of updating the behaviors for
  __DEVEL__sane_behavior which is the bulk of changes in this pull
  request.  It isn't complete yet and the behaviors will change further
  but all changes are gated behind sane_behavior.  In the process, the
  rather hairy work-item punting which was used to work around the
  limitations of cgroup descendant iterator was simplified."

* 'for-3.11-cpuset' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  cpuset: rename @cont to @cgrp
  cpuset: fix to migrate mm correctly in a corner case
  cpuset: allow to move tasks to empty cpusets
  cpuset: allow to keep tasks in empty cpusets
  cpuset: introduce effective_{cpumask|nodemask}_cpuset()
  cpuset: record old_mems_allowed in struct cpuset
  cpuset: remove async hotplug propagation work
  cpuset: let hotplug propagation work wait for task attaching
  cpuset: re-structure update_cpumask() a bit
  cpuset: remove cpuset_test_cpumask()
  cpuset: remove unnecessary variable in cpuset_attach()
  cpuset: cleanup guarantee_online_{cpus|mems}()
  cpuset: remove redundant check in cpuset_cpus_allowed_fallback()

cgroup: CGRP_ROOT_SUBSYS_BOUND should be ignored when comparing mount options

2013-06-28T02:37:26+00:00

1672d04070 ("cgroup: fix cgroupfs_root early destruction path")
introduced CGRP_ROOT_SUBSYS_BOUND which is used to mark completion of
subsys binding on a new root; however, this broke remounts.
cgroup_remount() doesn't allow changing root options via remount and
CGRP_ROOT_SUBSYS_BOUND, which is set on all fully initialized roots,
makes the function reject all remounts.

Fix it by putting the options part in the lower 16 bits of root->flags
and masking the comparions.  While at it, make cgroup_remount() emit
an error message explaining why it's rejecting a remount request, so
that it's less of a mystery.

Signed-off-by: Tejun Heo

cgroup: fix RCU accesses to task->cgroups

2013-06-26T17:42:46+00:00

task->cgroups is a RCU pointer pointing to struct css_set.  A task
switches to a different css_set on cgroup migration but a css_set
doesn't change once created and its pointers to cgroup_subsys_states
aren't RCU protected.

task_subsys_state[_check]() is the macro to acquire css given a task
and subsys_id pair.  It RCU-dereferences task->cgroups->subsys[] not
task->cgroups, so the RCU pointer task->cgroups ends up being
dereferenced without read_barrier_depends() after it.  It's broken.

Fix it by introducing task_css_set[_check]() which does
RCU-dereference on task->cgroups.  task_subsys_state[_check]() is
reimplemented to directly dereference ->subsys[] of the css_set
returned from task_css_set[_check]().

This removes some of sparse RCU warnings in cgroup.

v2: Fixed unbalanced parenthsis and there's no need to use
    rcu_dereference_raw() when !CONFIG_PROVE_RCU.  Both spotted by Li.

Signed-off-by: Tejun Heo 
Reported-by: Fengguang Wu 
Acked-by: Li Zefan 
Cc: stable@vger.kernel.org

cgroup: fix cgroupfs_root early destruction path

2013-06-26T17:39:46+00:00

cgroupfs_root used to have ->actual_subsys_mask in addition to
->subsys_mask.  a8a648c4ac ("cgroup: remove
cgroup->actual_subsys_mask") removed it noting that the subsys_mask is
essentially temporary and doesn't belong in cgroupfs_root; however,
the patch made it impossible to tell whether a cgroupfs_root actually
has the subsystems bound or just have the bits set leading to the
following BUG when trying to mount with subsystems which are already
mounted elsewhere.

 kernel BUG at kernel/cgroup.c:1038!
 invalid opcode: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
 ...
 CPU: 1 PID: 7973 Comm: mount Tainted: G        W    3.10.0-rc7-next-20130625-sasha-00011-g1c1dc0e #1105
 task: ffff880fc0ae8000 ti: ffff880fc0b9a000 task.ti: ffff880fc0b9a000
 RIP: 0010:[]  [] rebind_subsystems+0x409/0x5f0
 ...
 Call Trace:
  [] cgroup_kill_sb+0xff/0x210
  [] deactivate_locked_super+0x4f/0x90
  [] cgroup_mount+0x673/0x6e0
  [] cpuset_mount+0xd9/0x110
  [] mount_fs+0xb0/0x2d0
  [] vfs_kern_mount+0xbd/0x180
  [] do_new_mount+0x145/0x2c0
  [] do_mount+0x356/0x3c0
  [] SyS_mount+0xfd/0x140
  [] tracesys+0xdd/0xe2

We still want rebind_subsystems() to take added/removed masks, so
let's fix it by marking whether a cgroupfs_root has finished binding
or not.  Also, document what's going on around ->subsys_mask
initialization so that similar mistakes aren't repeated.

Signed-off-by: Tejun Heo 
Reported-by: Sasha Levin 
Acked-by: Li Zefan

cgroup: remove cgroup->actual_subsys_mask

2013-06-24T22:21:47+00:00

cgroup curiously has two subsystem masks, ->subsys_mask and
->actual_subsys_mask.  The latter only exists because the new target
subsys_mask is passed into rebind_subsystems() via @root>subsys_mask.
rebind_subsystems() needs to know what the current mask is to decide
how to reach the target mask so ->actual_subsys_mask is used as the
temp location to remember the current state.

Adding a temporary field to a permanent data structure is rather silly
and can be misleading.  Update rebind_subsystems() to take @added_mask
and @removed_mask instead and remove @root->actual_subsys_mask.

This patch shouldn't introduce any behavior changes.

v2: Comment and description updated as suggested by Li.

Signed-off-by: Tejun Heo 
Acked-by: Li Zefan

cgroup: convert CFTYPE_* flags to enums

2013-06-24T22:21:47+00:00

Purely cosmetic.

Signed-off-by: Tejun Heo 
Acked-by: Li Zefan

cgroup: rename cont to cgrp

2013-06-19T08:22:50+00:00

Cont is short for container. control group was named process container
at first, but then people found container already has a meaning in
linux kernel.

Clean up the leftover variable name @cont.

Signed-off-by: Li Zefan 
Signed-off-by: Tejun Heo