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  1. 02 4月, 2012 5 次提交
    • T
      cgroup: merge cft_release_agent cftype array into the base files array · 6e6ff25b
      由 Tejun Heo 提交于 
      Now that cftype can express whether a file should only be on root,
cft_release_agent can be merged into the base files cftypes array.
Signed-off-by: NTejun Heo <tj@kernel.org>
Acked-by: NLi Zefan <lizf@cn.fujitsu.com>
      6e6ff25b
    • T
      cgroup: implement cgroup_add_cftypes() and friends · 8e3f6541
      由 Tejun Heo 提交于 
      Currently, cgroup directories are populated by subsys->populate()
callback explicitly creating files on each cgroup creation.  This
level of flexibility isn't needed or desirable.  It provides largely
unused flexibility which call for abuses while severely limiting what
the core layer can do through the lack of structure and conventions.

Per each cgroup file type, the only distinction that cgroup users is
making is whether a cgroup is root or not, which can easily be
expressed with flags.

This patch introduces cgroup_add_cftypes().  These deal with cftypes
instead of individual files - controllers indicate that certain types
of files exist for certain subsystem.  Newly added CFTYPE_*_ON_ROOT
flags indicate whether a cftype should be excluded or created only on
the root cgroup.

cgroup_add_cftypes() can be called any time whether the target
subsystem is currently attached or not.  cgroup core will create files
on the existing cgroups as necessary.

Also, cgroup_subsys->base_cftypes is added to ease registration of the
base files for the subsystem.  If non-NULL on subsys init, the cftypes
pointed to by ->base_cftypes are automatically registered on subsys
init / load.

Further patches will convert the existing users and remove the file
based interface.  Note that this interface allows dynamic addition of
files to an active controller.  This will be used for sub-controller
modularity and unified hierarchy in the longer term.

This patch implements the new mechanism but doesn't apply it to any
user.

v2: replaced DECLARE_CGROUP_CFTYPES[_COND]() with
    cgroup_subsys->base_cftypes, which works better for cgroup_subsys
    which is loaded as module.
Signed-off-by: NTejun Heo <tj@kernel.org>
Acked-by: NLi Zefan <lizf@cn.fujitsu.com>
      8e3f6541
    • T
      cgroup: build list of all cgroups under a given cgroupfs_root · b0ca5a84
      由 Tejun Heo 提交于 
      Build a list of all cgroups anchored at cgroupfs_root->allcg_list and
going through cgroup->allcg_node.  The list is protected by
cgroup_mutex and will be used to improve cgroup file handling.
Signed-off-by: NTejun Heo <tj@kernel.org>
Acked-by: NLi Zefan <lizf@cn.fujitsu.com>
      b0ca5a84
    • T
      cgroup: move cgroup_clear_directory() call out of cgroup_populate_dir() · ff4c8d50
      由 Tejun Heo 提交于 
      cgroup_populate_dir() currently clears all files and then repopulate
the directory; however, the clearing part is only useful when it's
called from cgroup_remount().  Relocate the invocation to
cgroup_remount().

This is to prepare for further cgroup file handling updates.
Signed-off-by: NTejun Heo <tj@kernel.org>
Acked-by: NLi Zefan <lizf@cn.fujitsu.com>
      ff4c8d50
    • T
      cgroup: deprecate remount option changes · 8b5a5a9d
      由 Tejun Heo 提交于 
      This patch marks the following features for deprecation.

* Rebinding subsys by remount: Never reached useful state - only works
  on empty hierarchies.

* release_agent update by remount: release_agent itself will be
  replaced with conventional fsnotify notification.

v2: Lennart pointed out that "name=" is necessary for mounts w/o any
    controller attached.  Drop "name=" deprecation.
Signed-off-by: NTejun Heo <tj@kernel.org>
Acked-by: NLi Zefan <lizf@cn.fujitsu.com>
Cc: Lennart Poettering <mzxreary@0pointer.de>
      8b5a5a9d
  3. 30 3月, 2012 1 次提交
    • T
      cgroup: cgroup_attach_task() could return -errno after success · 8f121918
      由 Tejun Heo 提交于 
      61d1d219 "cgroup: remove extra calls to find_existing_css_set" made
cgroup_task_migrate() return void.  An unfortunate side effect was
that cgroup_attach_task() was depending on that function's return
value to clear its @retval on the success path.  On cgroup mounts
without any subsystem with ->can_attach() callback,
cgroup_attach_task() ended up returning @retval without initializing
it on success.

For some reason, gcc failed to warn about it and it didn't cause
cgroup_attach_task() to return non-zero value in many cases, probably
due to difference in register allocation.  When the problem
materializes, systemd fails to populate /systemd cgroup mount and
fails to boot.

Fix it by initializing @retval to zero on declaration.
Signed-off-by: NTejun Heo <tj@kernel.org>
Reported-by: NJiri Kosina <jkosina@suse.cz>
LKML-Reference: <alpine.LNX.2.00.1203282354440.25526@pobox.suse.cz>
Reviewed-by: NMandeep Singh Baines <msb@chromium.org>
Acked-by: NLi Zefan <lizefan@huawei.com>
      8f121918
  5. 22 3月, 2012 2 次提交
  7. 21 3月, 2012 1 次提交
  9. 22 2月, 2012 2 次提交
    • F
      cgroup: Walk task list under tasklist_lock in cgroup_enable_task_cg_list · 3ce3230a
      由 Frederic Weisbecker 提交于 
      Walking through the tasklist in cgroup_enable_task_cg_list() inside
an RCU read side critical section is not enough because:

- RCU is not (yet) safe against while_each_thread()

- If we use only RCU, a forking task that has passed cgroup_post_fork()
  without seeing use_task_css_set_links == 1 is not guaranteed to have
  its child immediately visible in the tasklist if we walk through it
  remotely with RCU. In this case it will be missing in its css_set's
  task list.

Thus we need to traverse the list (unfortunately) under the
tasklist_lock. It makes us safe against while_each_thread() and also
make sure we see all forked task that have been added to the tasklist.

As a secondary effect, reading and writing use_task_css_set_links are
now well ordered against tasklist traversing and modification. The new
layout is:

CPU 0                                      CPU 1

use_task_css_set_links = 1                write_lock(tasklist_lock)
read_lock(tasklist_lock)                  add task to tasklist
do_each_thread() {                        write_unlock(tasklist_lock)
	add thread to css set links       if (use_task_css_set_links)
} while_each_thread()                         add thread to css set links
read_unlock(tasklist_lock)

If CPU 0 traverse the list after the task has been added to the tasklist
then it is correctly added to the css set links. OTOH if CPU 0 traverse
the tasklist before the new task had the opportunity to be added to the
tasklist because it was too early in the fork process, then CPU 1
catches up and add the task to the css set links after it added the task
to the tasklist. The right value of use_task_css_set_links is guaranteed
to be visible from CPU 1 due to the LOCK/UNLOCK implicit barrier properties:
the read_unlock on CPU 0 makes the write on use_task_css_set_links happening
and the write_lock on CPU 1 make the read of use_task_css_set_links that comes
afterward to return the correct value.
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Acked-by: NLi Zefan <lizf@cn.fujitsu.com>
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: Mandeep Singh Baines <msb@chromium.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
      3ce3230a
    • F
      cgroup: Remove wrong comment on cgroup_enable_task_cg_list() · 9a4b4304
      由 Frederic Weisbecker 提交于 
      Remove the stale comment about RCU protection. Many callers
(all of them?) of cgroup_enable_task_cg_list() don't seem
to be in an RCU read side critical section. Besides, RCU is
not helpful to protect against while_each_thread().
Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
Acked-by: NLi Zefan <lizf@cn.fujitsu.com>
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: Mandeep Singh Baines <msb@chromium.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
      9a4b4304
  11. 03 2月, 2012 1 次提交
    • L
      cgroup: remove cgroup_subsys argument from callbacks · 761b3ef5
      由 Li Zefan 提交于 
      The argument is not used at all, and it's not necessary, because
a specific callback handler of course knows which subsys it
belongs to.

Now only ->pupulate() takes this argument, because the handlers of
this callback always call cgroup_add_file()/cgroup_add_files().

So we reduce a few lines of code, though the shrinking of object size
is minimal.

 16 files changed, 113 insertions(+), 162 deletions(-)

   text    data     bss     dec     hex filename
5486240  656987 7039960 13183187         c928d3 vmlinux.o.orig
5486170  656987 7039960 13183117         c9288d vmlinux.o
Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com>
Signed-off-by: NTejun Heo <tj@kernel.org>
      761b3ef5
  13. 31 1月, 2012 1 次提交
    • M
      cgroup: remove extra calls to find_existing_css_set · 61d1d219
      由 Mandeep Singh Baines 提交于 
      In cgroup_attach_proc, we indirectly call find_existing_css_set 3
times. It is an expensive call so we want to call it a minimum
of times. This patch only calls it once and stores the result so
that it can be used later on when we call cgroup_task_migrate.

This required modifying cgroup_task_migrate to take the new css_set
(which we obtained from find_css_set) as a parameter. The nice side
effect of this is that cgroup_task_migrate is now identical for
cgroup_attach_task and cgroup_attach_proc. It also now returns a
void since it can never fail.

Changes in V5:
* https://lkml.org/lkml/2012/1/20/344 (Tejun Heo)
  * Remove css_set_refs
Changes in V4:
* https://lkml.org/lkml/2011/12/22/421 (Li Zefan)
  * Avoid GFP_KERNEL (sleep) in rcu_read_lock by getting css_set in
    a separate loop not under an rcu_read_lock
Changes in V3:
* https://lkml.org/lkml/2011/12/22/13 (Li Zefan)
  * Fixed earlier bug by creating a seperate patch to remove tasklist_lock
Changes in V2:
* https://lkml.org/lkml/2011/12/20/372 (Tejun Heo)
  * Move find_css_set call into loop which creates the flex array
* Author
  * Kill css_set_refs and use group_size instead
  * Fix an off-by-one error in counting css_set refs
  * Add a retval check in out_list_teardown
Signed-off-by: NMandeep Singh Baines <msb@chromium.org>
Acked-by: NLi Zefan <lizf@cn.fujitsu.com>
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: containers@lists.linux-foundation.org
Cc: cgroups@vger.kernel.org
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Paul Menage <paul@paulmenage.org>
      61d1d219
  15. 21 1月, 2012 3 次提交
  17. 07 1月, 2012 1 次提交
  19. 06 1月, 2012 1 次提交
    • L
      cgroup: fix to allow mounting a hierarchy by name · 0d19ea86
      由 Li Zefan 提交于 
      If we mount a hierarchy with a specified name, the name is unique,
and we can use it to mount the hierarchy without specifying its
set of subsystem names. This feature is documented is
Documentation/cgroups/cgroups.txt section 2.3

Here's an example:

	# mount -t cgroup -o cpuset,name=myhier xxx /cgroup1
	# mount -t cgroup -o name=myhier xxx /cgroup2

But it was broken by commit 32a8cf23
(cgroup: make the mount options parsing more accurate)

This fixes the regression.
Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com>
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: stable@vger.kernel.org
      0d19ea86
  21. 04 1月, 2012 3 次提交
  23. 28 12月, 2011 3 次提交
  25. 22 12月, 2011 5 次提交
  27. 20 12月, 2011 2 次提交
  29. 13 12月, 2011 6 次提交
  31. 03 11月, 2011 3 次提交