Граф коммитов

162 Коммитов

Автор SHA1 Сообщение Дата
Li Zefan 0670e08bdf cgroups: don't change release_agent when remount failed
Remount can fail in either case:
  - wrong mount options is specified, or option 'noprefix' is changed.
  - a to-be-added subsys is already mounted/active.

When using remount to change 'release_agent', for the above former failure
case, remount will return errno with release_agent unchanged, but for the
latter case, remount will return EBUSY with relase_agent changed, which is
unexpected I think:

 # mount -t cgroup -o cpu xxx /cgrp1
 # mount -t cgroup -o cpuset,release_agent=agent1 yyy /cgrp2
 # cat /cgrp2/release_agent
 agent1
 # mount -t cgroup -o remount,cpuset,noprefix,release_agent=agent2 yyy /cgrp2
 mount: /cgrp2 not mounted already, or bad option
 # cat /cgrp2/release_agent
 agent1     <-- ok
 # mount -t cgroup -o remount,cpu,cpuset,release_agent=agent2 yyy /cgrp2
 mount: /cgrp2 is busy
 # cat /cgrp2/release_agent
 agent2     <-- unexpected!

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-02 19:04:54 -07:00
Li Zefan 099fca3225 cgroups: show correct file mode
We have some read-only files and write-only files, but currently they are
all set to 0644, which is counter-intuitive and cause trouble for some
cgroup tools like libcgroup.

This patch adds 'mode' to struct cftype to allow cgroup subsys to set it's
own files' file mode, and for the most cases cft->mode can be default to 0
and cgroup will figure out proper mode.

Acked-by: Paul Menage <menage@google.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-02 19:04:54 -07:00
Jesper Juhl 66bdc9cfc7 kernel/cgroup.c: kfree(NULL) is legal
Reduces object file size a bit:

Before:
$ size kernel/cgroup.o
   text    data     bss     dec     hex filename
  21593    7804    4924   34321    8611 kernel/cgroup.o
After:
$ size kernel/cgroup.o
   text    data     bss     dec     hex filename
  21537    7744    4924   34205    859d kernel/cgroup.o

Signed-off-by: Jesper Juhl <jj@chaosbits.net>
Cc: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-02 19:04:54 -07:00
KAMEZAWA Hiroyuki ec64f51545 cgroup: fix frequent -EBUSY at rmdir
In following situation, with memory subsystem,

	/groupA use_hierarchy==1
		/01 some tasks
		/02 some tasks
		/03 some tasks
		/04 empty

When tasks under 01/02/03 hit limit on /groupA, hierarchical reclaim
is triggered and the kernel walks tree under groupA. In this case,
rmdir /groupA/04 fails with -EBUSY frequently because of temporal
refcnt from the kernel.

In general. cgroup can be rmdir'd if there are no children groups and
no tasks. Frequent fails of rmdir() is not useful to users.
(And the reason for -EBUSY is unknown to users.....in most cases)

This patch tries to modify above behavior, by
	- retries if css_refcnt is got by someone.
	- add "return value" to pre_destroy() and allows subsystem to
	  say "we're really busy!"

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-02 19:04:54 -07:00
KAMEZAWA Hiroyuki 38460b48d0 cgroup: CSS ID support
Patch for Per-CSS(Cgroup Subsys State) ID and private hierarchy code.

This patch attaches unique ID to each css and provides following.

 - css_lookup(subsys, id)
   returns pointer to struct cgroup_subysys_state of id.
 - css_get_next(subsys, id, rootid, depth, foundid)
   returns the next css under "root" by scanning

When cgroup_subsys->use_id is set, an id for css is maintained.

The cgroup framework only parepares
	- css_id of root css for subsys
	- id is automatically attached at creation of css.
	- id is *not* freed automatically. Because the cgroup framework
	  don't know lifetime of cgroup_subsys_state.
	  free_css_id() function is provided. This must be called by subsys.

There are several reasons to develop this.
	- Saving space .... For example, memcg's swap_cgroup is array of
	  pointers to cgroup. But it is not necessary to be very fast.
	  By replacing pointers(8bytes per ent) to ID (2byes per ent), we can
	  reduce much amount of memory usage.

	- Scanning without lock.
	  CSS_ID provides "scan id under this ROOT" function. By this, scanning
	  css under root can be written without locks.
	  ex)
	  do {
		rcu_read_lock();
		next = cgroup_get_next(subsys, id, root, &found);
		/* check sanity of next here */
		css_tryget();
		rcu_read_unlock();
		id = found + 1
	 } while(...)

Characteristics:
	- Each css has unique ID under subsys.
	- Lifetime of ID is controlled by subsys.
	- css ID contains "ID" and "Depth in hierarchy" and stack of hierarchy
	- Allowed ID is 1-65535, ID 0 is UNUSED ID.

Design Choices:
	- scan-by-ID v.s. scan-by-tree-walk.
	  As /proc's pid scan does, scan-by-ID is robust when scanning is done
	  by following kind of routine.
	  scan -> rest a while(release a lock) -> conitunue from interrupted
	  memcg's hierarchical reclaim does this.

	- When subsys->use_id is set, # of css in the system is limited to
	  65535.

[bharata@linux.vnet.ibm.com: remove rcu_read_lock() from css_get_next()]
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Paul Menage <menage@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-02 19:04:53 -07:00
Grzegorz Nosek 313e924c08 cgroups: relax ns_can_attach checks to allow attaching to grandchild cgroups
The ns_proxy cgroup allows moving processes to child cgroups only one
level deep at a time.  This commit relaxes this restriction and makes it
possible to attach tasks directly to grandchild cgroups, e.g.:

($pid is in the root cgroup)
echo $pid > /cgroup/CG1/CG2/tasks

Previously this operation would fail with -EPERM and would have to be
performed as two steps:
echo $pid > /cgroup/CG1/tasks
echo $pid > /cgroup/CG1/CG2/tasks

Also, the target cgroup no longer needs to be empty to move a task there.

Signed-off-by: Grzegorz Nosek <root@localdomain.pl>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Reviewed-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-02 19:04:53 -07:00
Sukadev Bhattiprolu a3ec947c85 vfs: simple_set_mnt() should return void
simple_set_mnt() is defined as returning 'int' but always returns 0.
Callers assume simple_set_mnt() never fails and don't properly cleanup if
it were to _ever_ fail.  For instance, get_sb_single() and get_sb_nodev()
should:

        up_write(sb->s_unmount);
        deactivate_super(sb);

if simple_set_mnt() fails.

Since simple_set_mnt() never fails, would be cleaner if it did not
return anything.

[akpm@linux-foundation.org: fix build]
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-03-27 14:44:03 -04:00
Al Viro 3ba13d179e constify dentry_operations: rest
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-03-27 14:44:03 -04:00
Li Zefan 67e055d144 cgroups: fix possible use after free
In cgroup_kill_sb(), root is freed before sb is detached from the list, so
another sget() may find this sb and call cgroup_test_super(), which will
access the root that has been freed.

Reported-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-02-18 15:37:54 -08:00
Li Zefan cfebe563bd cgroups: fix lockdep subclasses overflow
I enabled all cgroup subsystems when compiling kernel, and then:
 # mount -t cgroup -o net_cls xxx /mnt
 # mkdir /mnt/0

This showed up immediately:
 BUG: MAX_LOCKDEP_SUBCLASSES too low!
 turning off the locking correctness validator.

It's caused by the cgroup hierarchy lock:
	for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) {
		struct cgroup_subsys *ss = subsys[i];
		if (ss->root == root)
			mutex_lock_nested(&ss->hierarchy_mutex, i);
	}

Now we have 9 cgroup subsystems, and the above 'i' for net_cls is 8, but
MAX_LOCKDEP_SUBCLASSES is 8.

This patch uses different lockdep keys for different subsystems.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-02-11 14:25:36 -08:00
Paul Menage 839ec5452e cgroup: fix root_count when mount fails due to busy subsystem
root_count was being incremented in cgroup_get_sb() after all error
checking was complete, but decremented in cgroup_kill_sb(), which can be
called on a superblock that we gave up on due to an error.  This patch
changes cgroup_kill_sb() to only decrement root_count if the root was
previously linked into the list of roots.

Signed-off-by: Paul Menage <menage@google.com>
Tested-by: Serge Hallyn <serue@us.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-29 18:04:45 -08:00
Paul Menage 804b3c28a4 cgroups: add cpu_relax() calls in css_tryget() and cgroup_clear_css_refs()
css_tryget() and cgroup_clear_css_refs() contain polling loops; these
loops should have cpu_relax calls in them to reduce cross-cache traffic.

Signed-off-by: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-29 18:04:45 -08:00
Li Zefan 1404f06565 cgroups: fix lock inconsistency in cgroup_clone()
I fixed a bug in cgroup_clone() in Linus' tree in commit 7b574b7
("cgroups: fix a race between cgroup_clone and umount") without noticing
there was a cleanup patch in -mm tree that should be rebased (now commit
104cbd5, "cgroups: use task_lock() for access tsk->cgroups safe in
cgroup_clone()"), thus resulted in lock inconsistency.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-29 18:04:45 -08:00
KAMEZAWA Hiroyuki baef99a08a cgroups: use hierarchy mutex in creation failure path
Now, cgrp->sibling is handled under hierarchy mutex.
error route should do so, too.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Acked-by Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-29 18:04:43 -08:00
Paul Menage e7c5ec9193 cgroups: add css_tryget()
Add css_tryget(), that obtains a counted reference on a CSS.  It is used
in situations where the caller has a "weak" reference to the CSS, i.e.
one that does not protect the cgroup from removal via a reference count,
but would instead be cleaned up by a destroy() callback.

css_tryget() will return true on success, or false if the cgroup is being
removed.

This is similar to Kamezawa Hiroyuki's patch from a week or two ago, but
with the difference that in the event of css_tryget() racing with a
cgroup_rmdir(), css_tryget() will only return false if the cgroup really
does get removed.

This implementation is done by biasing css->refcnt, so that a refcnt of 1
means "releasable" and 0 means "released or releasing".  In the event of a
race, css_tryget() distinguishes between "released" and "releasing" by
checking for the CSS_REMOVED flag in css->flags.

Signed-off-by: Paul Menage <menage@google.com>
Tested-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-08 08:31:10 -08:00
Paul Menage 999cd8a450 cgroups: add a per-subsystem hierarchy_mutex
These patches introduce new locking/refcount support for cgroups to
reduce the need for subsystems to call cgroup_lock(). This will
ultimately allow the atomicity of cgroup_rmdir() (which was removed
recently) to be restored.

These three patches give:

1/3 - introduce a per-subsystem hierarchy_mutex which a subsystem can
     use to prevent changes to its own cgroup tree

2/3 - use hierarchy_mutex in place of calling cgroup_lock() in the
     memory controller

3/3 - introduce a css_tryget() function similar to the one recently
      proposed by Kamezawa, but avoiding spurious refcount failures in
      the event of a race between a css_tryget() and an unsuccessful
      cgroup_rmdir()

Future patches will likely involve:

- using hierarchy mutex in place of cgroup_lock() in more subsystems
 where appropriate

- restoring the atomicity of cgroup_rmdir() with respect to cgroup_create()

This patch:

Add a hierarchy_mutex to the cgroup_subsys object that protects changes to
the hierarchy observed by that subsystem.  It is taken by the cgroup
subsystem (in addition to cgroup_mutex) for the following operations:

- linking a cgroup into that subsystem's cgroup tree
- unlinking a cgroup from that subsystem's cgroup tree
- moving the subsystem to/from a hierarchy (including across the
  bind() callback)

Thus if the subsystem holds its own hierarchy_mutex, it can safely
traverse its own hierarchy.

Signed-off-by: Paul Menage <menage@google.com>
Tested-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-08 08:31:10 -08:00
Paul Menage a47295e6bc cgroups: make cgroup_path() RCU-safe
Fix races between /proc/sched_debug by freeing cgroup objects via an RCU
callback.  Thus any cgroup reference obtained from an RCU-safe source will
remain valid during the RCU section.  Since dentries are also RCU-safe,
this allows us to traverse up the tree safely.

Additionally, make cgroup_path() check for a NULL cgrp->dentry to avoid
trying to report a path for a partially-created cgroup.

[lizf@cn.fujitsu.com: call deactive_super() in cgroup_diput()]
Signed-off-by: Paul Menage <menage@google.com>
Reviewed-by: Li Zefan <lizf@cn.fujitsu.com>
Tested-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-08 08:31:03 -08:00
Gowrishankar M e7b80bb695 cgroups: skip processes from other namespaces when listing a cgroup
Once tasks are populated from system namespace inside cgroup, container
replaces other namespace task with 0 while listing tasks, inside
container.

Though this is expected behaviour from container end, there is no use of
showing unwanted 0s.

In this patch, we check if a process is in same namespace before loading
into pid array.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Gowrishankar M <gowrishankar.m@in.ibm.com>
Acked-by: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-08 08:31:03 -08:00
Li Zefan c12f65d439 cgroups: introduce link_css_set() to remove duplicate code
Add a common function link_css_set() to link a css_set to a cgroup.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-08 08:31:03 -08:00
Li Zefan 33a68ac1c1 cgroups: add inactive subsystems to rootnode.subsys_list
Though for an inactive hierarchy, we have subsys->root == &rootnode, but
rootnode's subsys_list is always empty.

This conflicts with the code in find_css_set():

	for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) {
		...
		if (ss->root->subsys_list.next == &ss->sibling) {
			...
		}
	}
	if (list_empty(&rootnode.subsys_list)) {
		...
	}

The above code assumes rootnode.subsys_list links all inactive
hierarchies.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-08 08:31:03 -08:00
Li Zefan e5f6a8609b cgroups: make root_list contains active hierarchies only
Don't link rootnode to the root list, so root_list contains active
hierarchies only as the comment indicates.  And rename for_each_root() to
for_each_active_root().

Also remove redundant check in cgroup_kill_sb().

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-08 08:31:03 -08:00
Lai Jiangshan 7534432dcc cgroups: remove rcu_read_lock() in cgroupstats_build()
cgroup_iter_* do not need rcu_read_lock().

In cgroup_enable_task_cg_lists(), do_each_thread() and while_each_thread()
are protected by RCU, it's OK, for write_lock(&css_set_lock) implies
rcu_read_lock() in non-RT kernel.

If we need explicit rcu_read_lock(), we should add rcu_read_lock() in
cgroup_enable_task_cg_lists(), not cgroup_iter_*.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Acked-by: Paul Menage <menage@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-08 08:31:03 -08:00
Lai Jiangshan 77efecd9e0 cgroups: call find_css_set() safely in cgroup_attach_task()
In cgroup_attach_task(), tsk maybe exit when we call find_css_set().  and
find_css_set() will access to invalid css_set.

This patch increases the count before get_css_set(), and decreases it
after find_css_set().

NOTE:

css_set's refcount is also taskcount, after this patch applied, taskcount
may be off-by-one WHEN cgroup_lock() is not held.  but I reviewed other
code which use taskcount, they are still correct.  No regression found by
reviewing and simply testing.

So I do not use two counters in css_set.  (one counter for taskcount, the
other for refcount.  like struct mm_struct) If this fix cause regression,
we will use two counters in css_set.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-08 08:31:02 -08:00
Lai Jiangshan 104cbd5537 cgroups: use task_lock() for access tsk->cgroups safe in cgroup_clone()
Use task_lock() protect tsk->cgroups and get_css_set(tsk->cgroups).

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Acked-by: Paul Menage <menage@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-08 08:31:02 -08:00
Lai Jiangshan b2aa30f7bb cgroups: don't put struct cgroupfs_root protected by RCU
We don't access struct cgroupfs_root in fast path, so we should not put
struct cgroupfs_root protected by RCU

But the comment in struct cgroup_subsys.root confuse us.

struct cgroup_subsys.root is used in these places:

1 find_css_set(): if (ss->root->subsys_list.next == &ss->sibling)
2 rebind_subsystems(): if (ss->root != &rootnode)
                       rcu_assign_pointer(ss->root, root);
                       rcu_assign_pointer(subsys[i]->root, &rootnode);
3 cgroup_has_css_refs(): if (ss->root != cgrp->root)
4 cgroup_init_subsys(): ss->root = &rootnode;
5 proc_cgroupstats_show(): ss->name, ss->root->subsys_bits,
                           ss->root->number_of_cgroups, !ss->disabled);
6 cgroup_clone(): root = subsys->root;
                  if ((root != subsys->root) ||

All these place we have held cgroup_lock() or we don't dereference to
struct cgroupfs_root.  It's means wo don't need RCU when use struct
cgroup_subsys.root, and we should not put struct cgroupfs_root protected
by RCU.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Reviewed-by: Paul Menage <menage@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-08 08:31:02 -08:00
Lai Jiangshan 2019f634ce cgroups: fix cgroup_iter_next() bug
We access res->cgroups without the task_lock(), so res->cgroups may be
changed.  it's unreliable, and "if (l == &res->cgroups->tasks)" may be
false forever.

We don't need add any lock for fixing this bug.  we just access to struct
css_set by struct cg_cgroup_link, not by struct task_struct.

Since we hold css_set_lock, struct cg_cgroup_link is reliable.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Reviewed-by: Paul Menage <menage@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-08 08:31:02 -08:00
Lai Jiangshan b12b533fa5 cgroups: add lock for child->cgroups in cgroup_post_fork()
When cgroup_post_fork() is called, child is seen by find_task_by_vpid(),
so child->cgroups maybe be changed, It'll incorrect.

child->cgroups<old>'s refcnt is decreased
child->cgroups<new>'s refcnt is increased
but child->cg_list is added to child->cgroups<old>'s list.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Reviewed-by: Paul Menage <menage@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-08 08:31:02 -08:00
Li Zefan 75139b8274 cgroups: remove some redundant NULL checks
- In cgroup_clone(), if vfs_mkdir() returns successfully,
  dentry->d_fsdata will be the pointer to the newly created
  cgroup and won't be NULL.

- a cgroup file's dentry->d_fsdata won't be NULL, guaranteed
  by cgroup_add_file().

- When walking through the subsystems of a cgroup_fs (using
  for_each_subsys), cgrp->subsys[ss->subsys_id] won't be NULL,
  guaranteed by cgroup_create().

(Also remove 2 unused variables in cgroup_rmdir().

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-08 08:31:01 -08:00
Hugh Dickins e5991371ee mm: remove cgroup_mm_owner_callbacks
cgroup_mm_owner_callbacks() was brought in to support the memrlimit
controller, but sneaked into mainline ahead of it.  That controller has
now been shelved, and the mm_owner_changed() args were inadequate for it
anyway (they needed an mm pointer instead of a task pointer).

Remove the dead code, and restore mm_update_next_owner() locking to how it
was before: taking mmap_sem there does nothing for memcontrol.c, now the
only user of mm->owner.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Cc: Paul Menage <menage@google.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-06 15:59:01 -08:00
Linus Torvalds 520c853466 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6:
  inotify: fix type errors in interfaces
  fix breakage in reiserfs_new_inode()
  fix the treatment of jfs special inodes
  vfs: remove duplicate code in get_fs_type()
  add a vfs_fsync helper
  sys_execve and sys_uselib do not call into fsnotify
  zero i_uid/i_gid on inode allocation
  inode->i_op is never NULL
  ntfs: don't NULL i_op
  isofs check for NULL ->i_op in root directory is dead code
  affs: do not zero ->i_op
  kill suid bit only for regular files
  vfs: lseek(fd, 0, SEEK_CUR) race condition
2009-01-05 18:32:06 -08:00
Al Viro 56ff5efad9 zero i_uid/i_gid on inode allocation
... and don't bother in callers.  Don't bother with zeroing i_blocks,
while we are at it - it's already been zeroed.

i_mode is not worth the effort; it has no common default value.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-01-05 11:54:28 -05:00
Li Zefan 7b574b7b01 cgroups: fix a race between cgroup_clone and umount
The race is calling cgroup_clone() while umounting the ns cgroup subsys,
and thus cgroup_clone() might access invalid cgroup_fs, or kill_sb() is
called after cgroup_clone() created a new dir in it.

The BUG I triggered is BUG_ON(root->number_of_cgroups != 1);

  ------------[ cut here ]------------
  kernel BUG at kernel/cgroup.c:1093!
  invalid opcode: 0000 [#1] SMP
  ...
  Process umount (pid: 5177, ti=e411e000 task=e40c4670 task.ti=e411e000)
  ...
  Call Trace:
   [<c0493df7>] ? deactivate_super+0x3f/0x51
   [<c04a3600>] ? mntput_no_expire+0xb3/0xdd
   [<c04a3ab2>] ? sys_umount+0x265/0x2ac
   [<c04a3b06>] ? sys_oldumount+0xd/0xf
   [<c0403911>] ? sysenter_do_call+0x12/0x31
  ...
  EIP: [<c0456e76>] cgroup_kill_sb+0x23/0xe0 SS:ESP 0068:e411ef2c
  ---[ end trace c766c1be3bf944ac ]---

Cc: Serge E. Hallyn <serue@us.ibm.com>
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Cc: "Serge E. Hallyn" <serue@us.ibm.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-04 13:33:19 -08:00
James Morris cbacc2c7f0 Merge branch 'next' into for-linus 2008-12-25 11:40:09 +11:00
Li Zefan 20ca9b3f4c cgroups: avoid accessing uninitialized data in failure path
If cgroup_get_rootdir() failed, free_cg_links() will be called in the
failure path, but tmp_cg_links hasn't been initialized at that time.

I introduced this bug in the 2.6.27 merge window.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Cc: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-12-23 15:58:21 -08:00
Sharyathi Nagesh e368d3a836 cgroups: suppress bogus warning messages
Remove spurious warning messages that are thrown onto the console during
cgroup operations.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Sharyathi Nagesh <sharyathi@in.ibm.com>
Acked-by: Serge E. Hallyn <serge@hallyn.com>
Cc: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-12-23 15:58:21 -08:00
Paul Menage 307257cf47 cgroups: fix a race between rmdir and remount
When a cgroup is removed, it's unlinked from its parent's children list,
but not actually freed until the last dentry on it is released (at which
point cgrp->root->number_of_cgroups is decremented).

Currently rebind_subsystems checks for the top cgroup's child list being
empty in order to rebind subsystems into or out of a hierarchy - this can
result in the set of subsystems bound to a hierarchy being
removed-but-not-freed cgroup.

The simplest fix for this is to forbid remounts that change the set of
subsystems on a hierarchy that has removed-but-not-freed cgroups.  This
bug can be reproduced via:

mkdir /mnt/cg
mount -t cgroup -o ns,freezer cgroup /mnt/cg
mkdir /mnt/cg/foo
sleep 1h < /mnt/cg/foo &
rmdir /mnt/cg/foo
mount -t cgroup -o remount,ns,devices,freezer cgroup /mnt/cg
kill $!

Though the above will cause oops in -mm only but not mainline, but the bug
can cause memory leak in mainline (and even oops)

Signed-off-by: Paul Menage <menage@google.com>
Reviewed-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-12-15 16:27:07 -08:00
James Morris ec98ce480a Merge branch 'master' into next
Conflicts:
	fs/nfsd/nfs4recover.c

Manually fixed above to use new creds API functions, e.g.
nfs4_save_creds().

Signed-off-by: James Morris <jmorris@namei.org>
2008-12-04 17:16:36 +11:00
Li Zefan 33d283bef2 cgroups: fix a serious bug in cgroupstats
Try this, and you'll get oops immediately:
 # cd Documentation/accounting/
 # gcc -o getdelays getdelays.c
 # mount -t cgroup -o debug xxx /mnt
 # ./getdelays -C /mnt/tasks

Because a normal file's dentry->d_fsdata is a pointer to struct cftype,
not struct cgroup.

After the patch, it returns EINVAL if we try to get cgroupstats
from a normal file.

Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Paul Menage <menage@google.com>
Cc: <stable@kernel.org>		[2.6.25.x, 2.6.26.x, 2.6.27.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-11-19 18:50:00 -08:00
KAMEZAWA Hiroyuki 3fa59dfbc3 cgroup: fix potential deadlock in pre_destroy
As Balbir pointed out, memcg's pre_destroy handler has potential deadlock.

It has following lock sequence.

	cgroup_mutex (cgroup_rmdir)
	    -> pre_destroy -> mem_cgroup_pre_destroy-> force_empty
		-> cpu_hotplug.lock. (lru_add_drain_all->
				      schedule_work->
                                      get_online_cpus)

But, cpuset has following.
	cpu_hotplug.lock (call notifier)
		-> cgroup_mutex. (within notifier)

Then, this lock sequence should be fixed.

Considering how pre_destroy works, it's not necessary to holding
cgroup_mutex() while calling it.

As a side effect, we don't have to wait at this mutex while memcg's
force_empty works.(it can be long when there are tons of pages.)

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-11-19 18:49:58 -08:00
James Morris 2b82892565 Merge branch 'master' into next
Conflicts:
	security/keys/internal.h
	security/keys/process_keys.c
	security/keys/request_key.c

Fixed conflicts above by using the non 'tsk' versions.

Signed-off-by: James Morris <jmorris@namei.org>
2008-11-14 11:29:12 +11:00
David Howells c69e8d9c01 CRED: Use RCU to access another task's creds and to release a task's own creds
Use RCU to access another task's creds and to release a task's own creds.
This means that it will be possible for the credentials of a task to be
replaced without another task (a) requiring a full lock to read them, and (b)
seeing deallocated memory.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-14 10:39:19 +11:00
David Howells b6dff3ec5e CRED: Separate task security context from task_struct
Separate the task security context from task_struct.  At this point, the
security data is temporarily embedded in the task_struct with two pointers
pointing to it.

Note that the Alpha arch is altered as it refers to (E)UID and (E)GID in
entry.S via asm-offsets.

With comment fixes Signed-off-by: Marc Dionne <marc.c.dionne@gmail.com>

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-14 10:39:16 +11:00
David Howells 76aac0e9a1 CRED: Wrap task credential accesses in the core kernel
Wrap access to task credentials so that they can be separated more easily from
the task_struct during the introduction of COW creds.

Change most current->(|e|s|fs)[ug]id to current_(|e|s|fs)[ug]id().

Change some task->e?[ug]id to task_e?[ug]id().  In some places it makes more
sense to use RCU directly rather than a convenient wrapper; these will be
addressed by later patches.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: linux-audit@redhat.com
Cc: containers@lists.linux-foundation.org
Cc: linux-mm@kvack.org
Signed-off-by: James Morris <jmorris@namei.org>
2008-11-14 10:39:12 +11:00
Li Zefan 24eb089950 cgroups: fix invalid cgrp->dentry before cgroup has been completely removed
This fixes an oops when reading /proc/sched_debug.

A cgroup won't be removed completely until finishing cgroup_diput(), so we
shouldn't invalidate cgrp->dentry in cgroup_rmdir().  Otherwise, when a
group is being removed while cgroup_path() gets called, we may trigger
NULL dereference BUG.

The bug can be reproduced:

 # cat test.sh
 #!/bin/sh
 mount -t cgroup -o cpu xxx /mnt
 for (( ; ; ))
 {
	mkdir /mnt/sub
	rmdir /mnt/sub
 }
 # ./test.sh &
 # cat /proc/sched_debug

BUG: unable to handle kernel NULL pointer dereference at 00000038
IP: [<c045a47f>] cgroup_path+0x39/0x90
...
Call Trace:
 [<c0420344>] ? print_cfs_rq+0x6e/0x75d
 [<c0421160>] ? sched_debug_show+0x72d/0xc1e
...

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Paul Menage <menage@google.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: <stable@kernel.org>		[2.6.26.x, 2.6.27.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-11-06 15:41:19 -08:00
Stephen Rothwell 2077776641 cgroup: remove unused variable
/scratch/sfr/next/kernel/cgroup.c: In function 'cgroup_tasks_start':
/scratch/sfr/next/kernel/cgroup.c:2107: warning: unused variable 'i'

Introduced in commit cc31edceee "cgroups:
convert tasks file to use a seq_file with shared pid array".

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-26 09:38:17 -07:00
Paul Menage cc31edceee cgroups: convert tasks file to use a seq_file with shared pid array
Rather than pre-generating the entire text for the "tasks" file each
time the file is opened, we instead just generate/update the array of
process ids and use a seq_file to report these to userspace.  All open
file handles on the same "tasks" file can share a pid array, which may
be updated any time that no thread is actively reading the array.  By
sharing the array, the potential for userspace to DoS the system by
opening many handles on the same "tasks" file is removed.

[Based on a patch by Lai Jiangshan, extended to use seq_file]

Signed-off-by: Paul Menage <menage@google.com>
Reviewed-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Serge Hallyn <serue@us.ibm.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-20 08:52:38 -07:00
Lai Jiangshan 146aa1bd05 cgroups: fix probable race with put_css_set[_taskexit] and find_css_set
put_css_set_taskexit may be called when find_css_set is called on other
cpu.  And the race will occur:

put_css_set_taskexit side                    find_css_set side

                                        |
atomic_dec_and_test(&kref->refcount)    |
    /* kref->refcount = 0 */            |
....................................................................
                                        |  read_lock(&css_set_lock)
                                        |  find_existing_css_set
                                        |  get_css_set
                                        |  read_unlock(&css_set_lock);
....................................................................
__release_css_set                       |
....................................................................
                                        | /* use a released css_set */
                                        |

[put_css_set is the same. But in the current code, all put_css_set are
put into cgroup mutex critical region as the same as find_css_set.]

[akpm@linux-foundation.org: repair comments]
[menage@google.com: eliminate race in css_set refcounting]
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-20 08:52:38 -07:00
Balbir Singh 9363b9f23c memrlimit: cgroup mm owner callback changes to add task info
This patch adds an additional field to the mm_owner callbacks. This field
is required to get to the mm that changed. Hold mmap_sem in write mode
before calling the mm_owner_changed callback

[hugh@veritas.com: fix mmap_sem deadlock]
Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Sudhir Kumar <skumar@linux.vnet.ibm.com>
Cc: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
Cc: Paul Menage <menage@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Pavel Emelianov <xemul@openvz.org>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-16 11:21:28 -07:00
Balbir Singh 31a78f23ba mm owner: fix race between swapoff and exit
There's a race between mm->owner assignment and swapoff, more easily
seen when task slab poisoning is turned on.  The condition occurs when
try_to_unuse() runs in parallel with an exiting task.  A similar race
can occur with callers of get_task_mm(), such as /proc/<pid>/<mmstats>
or ptrace or page migration.

CPU0                                    CPU1
                                        try_to_unuse
                                        looks at mm = task0->mm
                                        increments mm->mm_users
task 0 exits
mm->owner needs to be updated, but no
new owner is found (mm_users > 1, but
no other task has task->mm = task0->mm)
mm_update_next_owner() leaves
                                        mmput(mm) decrements mm->mm_users
task0 freed
                                        dereferencing mm->owner fails

The fix is to notify the subsystem via mm_owner_changed callback(),
if no new owner is found, by specifying the new task as NULL.

Jiri Slaby:
mm->owner was set to NULL prior to calling cgroup_mm_owner_callbacks(), but
must be set after that, so as not to pass NULL as old owner causing oops.

Daisuke Nishimura:
mm_update_next_owner() may set mm->owner to NULL, but mem_cgroup_from_task()
and its callers need to take account of this situation to avoid oops.

Hugh Dickins:
Lockdep warning and hang below exec_mmap() when testing these patches.
exit_mm() up_reads mmap_sem before calling mm_update_next_owner(),
so exec_mmap() now needs to do the same.  And with that repositioning,
there's now no point in mm_need_new_owner() allowing for NULL mm.

Reported-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-09-29 08:41:47 -07:00
Li Zefan 55b6fd0162 cgroup: uninline cgroup_has_css_refs()
It's not small enough, and has 2 call sites.

 text    data     bss     dec     hex filename
12813    1676    4832   19321    4b79 cgroup.o.orig
12775    1676    4832   19283    4b53 cgroup.o

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-30 09:41:44 -07:00
Li Zefan 36553434f4 cgroup: remove duplicate code in allocate_cg_link()
- just call free_cg_links() in allocate_cg_links()
- the list will get initialized in allocate_cg_links(), so don't init
  it twice

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-30 09:41:44 -07:00
Li Zefan 5a3eb9f6b7 cgroup: fix possible memory leak
There's a leak if copy_from_user() returns failure.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-30 09:41:44 -07:00
Al Viro 3f8206d496 [PATCH] get rid of indirect users of namei.h
fs.h needs path.h, not namei.h; nfs_fs.h doesn't need it at all.
Several places in the tree needed direct include.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-07-26 20:53:42 -04:00
Adrian Bunk 96930a6365 make cgroup_seqfile_release() static
cgroup_seqfile_release() can become static.

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Acked-by: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-26 12:00:11 -07:00
Serge E. Hallyn e885dcde75 cgroup_clone: use pid of newly created task for new cgroup
cgroup_clone creates a new cgroup with the pid of the task.  This works
correctly for unshare, but for clone cgroup_clone is called from
copy_namespaces inside copy_process, which happens before the new pid is
created.  As a result, the new cgroup was created with current's pid.
This patch:

	1. Moves the call inside copy_process to after the new pid
	   is created
	2. Passes the struct pid into ns_cgroup_clone (as it is not
	   yet attached to the task)
	3. Passes a name from ns_cgroup_clone() into cgroup_clone()
	   so as to keep cgroup_clone() itself simpler
	4. Uses pid_vnr() to get the process id value, so that the
	   pid used to name the new cgroup is always the pid as it
	   would be known to the task which did the cloning or
	   unsharing.  I think that is the most intuitive thing to
	   do.  This way, task t1 does clone(CLONE_NEWPID) to get
	   t2, which does clone(CLONE_NEWPID) to get t3, then the
	   cgroup for t3 will be named for the pid by which t2 knows
	   t3.

(Thanks to Dan Smith for finding the main bug)

Changelog:
	June 11: Incorporate Paul Menage's feedback:  don't pass
	         NULL to ns_cgroup_clone from unshare, and reduce
		 patch size by using 'nodename' in cgroup_clone.
	June 10: Original version

[akpm@linux-foundation.org: build fix]
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Serge Hallyn <serge@us.ibm.com>
Acked-by: Paul Menage <menage@google.com>
Tested-by: Dan Smith <danms@us.ibm.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25 10:53:37 -07:00
Paul Menage af351026aa cgroup files: turn attach_task_by_pid directly into a cgroup write handler
This patch changes attach_task_by_pid() to take a u64 rather than a
string; as a result it can be called directly as a control groups
write_u64 handler, and cgroup_common_file_write() can be removed.

Signed-off-by: Paul Menage <menage@google.com>
Cc: Paul Jackson <pj@sgi.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Serge Hallyn <serue@us.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25 10:53:36 -07:00
Paul Menage 6379c10615 cgroup files: move notify_on_release file to separate write handler
This patch moves the write handler for the cgroups notify_on_release
file into a separate handler. This handler requires no cgroups locking
since it relies on atomic bitops for synchronization.

Signed-off-by: Paul Menage <menage@google.com>
Cc: Paul Jackson <pj@sgi.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Serge Hallyn <serue@us.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25 10:53:36 -07:00
Paul Menage 84eea84288 cgroups: misc cleanups to write_string patchset
This patch contains cleanups suggested by reviewers for the recent
write_string() patchset:

- pair cgroup_lock_live_group() with cgroup_unlock() in cgroup.c for
  clarity, rather than directly unlocking cgroup_mutex.

- make the return type of cgroup_lock_live_group() a bool

- use a #define'd constant for the local buffer size in read/write functions

Signed-off-by: Paul Menage <menage@google.com>
Cc: Paul Jackson <pj@sgi.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: Balbir Singh <balbir@in.ibm.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25 10:53:35 -07:00
Paul Menage e788e066c6 cgroup files: move the release_agent file to use typed handlers
Adds cgroup_release_agent_write() and cgroup_release_agent_show()
methods to handle writing/reading the path to a cgroup hierarchy's
release agent. As a result, cgroup_common_file_read() is now unnecessary.

As part of the change, a previously-tolerated race in
cgroup_release_agent() is avoided by copying the current
release_agent_path prior to calling call_usermode_helper().

Signed-off-by: Paul Menage <menage@google.com>
Cc: Paul Jackson <pj@sgi.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: Balbir Singh <balbir@in.ibm.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25 10:53:35 -07:00
Paul Menage db3b14978a cgroup files: add write_string cgroup control file method
This patch adds a write_string() method for cgroups control files. The
semantics are that a buffer is copied from userspace to kernelspace
and the handler function invoked on that buffer.  The buffer is
guaranteed to be nul-terminated, and no longer than max_write_len
(defaulting to 64 bytes if unspecified). Later patches will convert
existing raw file write handlers in control group subsystems to use
this method.

Signed-off-by: Paul Menage <menage@google.com>
Cc: Paul Jackson <pj@sgi.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Acked-by: Balbir Singh <balbir@in.ibm.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25 10:53:35 -07:00
Li Zefan 8947f9d5b3 cgroups: annotate two variables with __read_mostly
- need_forkexit_callback will be read only after system boot.
- use_task_css_set_links will be read only after it's set.

And these 2 variables are checked when a new process is forked.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Paul Menage <menage@google.com>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25 10:53:35 -07:00
KOSAKI Motohiro 71cbb949d1 cgroup: list_for_each cleanup
--------------------------
while() {
	list_entry();
	...
}
--------------------------

is equivalent to following code.

--------------------------
list_for_each_entry(){
	...
}
--------------------------

later can review easily more.

this patch is just clean up.
it doesn't have any behavor change.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25 10:53:35 -07:00
Li Zefan 7e9abd89cb cgroup: use read lock to guard find_existing_css_set()
The function does not modify anything (except the temporary css template), so
it's sufficient to hold read lock.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Paul Menage <menage@google.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25 10:53:35 -07:00
Cedric Le Goater 5c02b57578 cgroups: remove node_ prefix_from ns subsystem
This is a slight change in the namespace cgroup subsystem api.

The change is that previously when cgroup_clone() was called (currently
only from the unshare path in ns_proxy cgroup, you'd get a new group named
"node_$pid" whereas now you'll get a group named after just your pid.)

The only users who would notice it are those who are using the ns_proxy
cgroup subsystem to auto-create cgroups when namespaces are unshared -
something of an experimental feature, which I think really needs more
complete container/namespace support in order to be useful.  I suspect the
only users are Cedric and Serge, or maybe a few others on
containers@lists.linux-foundation.org.  And in fact it would only be
noticed by the users who make the assumption about how the name is
generated, rather than getting it from the /proc/<pid>/cgroups file for
the process in question.

Whether the change is actually needed or not I'm fairly agnostic on, but I
guess it is more elegant to just use the pid as the new group name rather
than adding a fairly arbitrary "node_" prefix on the front.

[menage@google.com: provided changelog]
Signed-off-by: Cedric Le Goater <clg@fr.ibm.com>
Cc: "Paul Menage" <menage@google.com>
Cc: "Serge E. Hallyn" <serue@us.ibm.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-05-24 09:56:14 -07:00
Miklos Szeredi e4ad08fe64 mm: bdi: add separate writeback accounting capability
Add a new BDI capability flag: BDI_CAP_NO_ACCT_WB.  If this flag is
set, then don't update the per-bdi writeback stats from
test_set_page_writeback() and test_clear_page_writeback().

Misc cleanups:

 - convert bdi_cap_writeback_dirty() and friends to static inline functions
 - create a flag that includes all three dirty/writeback related flags,
   since almst all users will want to have them toghether

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30 08:29:50 -07:00
Balbir Singh cf475ad28a cgroups: add an owner to the mm_struct
Remove the mem_cgroup member from mm_struct and instead adds an owner.

This approach was suggested by Paul Menage.  The advantage of this approach
is that, once the mm->owner is known, using the subsystem id, the cgroup
can be determined.  It also allows several control groups that are
virtually grouped by mm_struct, to exist independent of the memory
controller i.e., without adding mem_cgroup's for each controller, to
mm_struct.

A new config option CONFIG_MM_OWNER is added and the memory resource
controller selects this config option.

This patch also adds cgroup callbacks to notify subsystems when mm->owner
changes.  The mm_cgroup_changed callback is called with the task_lock() of
the new task held and is called just prior to changing the mm->owner.

I am indebted to Paul Menage for the several reviews of this patchset and
helping me make it lighter and simpler.

This patch was tested on a powerpc box, it was compiled with both the
MM_OWNER config turned on and off.

After the thread group leader exits, it's moved to init_css_state by
cgroup_exit(), thus all future charges from runnings threads would be
redirected to the init_css_set's subsystem.

Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Pavel Emelianov <xemul@openvz.org>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Sudhir Kumar <skumar@linux.vnet.ibm.com>
Cc: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
Cc: Hirokazu Takahashi <taka@valinux.co.jp>
Cc: David Rientjes <rientjes@google.com>,
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Reviewed-by: Paul Menage <menage@google.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-29 08:06:10 -07:00
Serge E. Hallyn 29486df325 cgroups: introduce cft->read_seq()
Introduce a read_seq() helper in cftype, which uses seq_file to print out
lists.  Use it in the devices cgroup.  Also split devices.allow into two
files, so now devices.deny and devices.allow are the ones to use to manipulate
the whitelist, while devices.list outputs the cgroup's current whitelist.

Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Acked-by: Paul Menage <menage@google.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-29 08:06:10 -07:00
Li Zefan 28fd5dfc12 cgroups: remove the css_set linked-list
Now we can run through the hash table instead of running through the
linked-list.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Reviewed-by: Paul Menage <menage@google.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-29 08:06:10 -07:00
Li Zefan e8d55fdeb8 cgroups: simplify init_subsys()
We are at system boot and there is only 1 cgroup group (i,e, init_css_set), so
we don't need to run through the css_set linked list.  Neither do we need to
run through the task list, since no processes have been created yet.

Also referring to a comment in cgroup.h:

struct css_set
{
	...
	/*
	 * Set of subsystem states, one for each subsystem. This array
	 * is immutable after creation apart from the init_css_set
	 * during subsystem registration (at boot time).
	 */
	struct cgroup_subsys_state *subsys[CGROUP_SUBSYS_COUNT];
}

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Reviewed-by: Paul Menage <menage@google.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-29 08:06:10 -07:00
Li Zefan 472b1053f3 cgroups: use a hash table for css_set finding
When we attach a process to a different cgroup, the css_set linked-list will
be run through to find a suitable existing css_set to use.  This patch
implements a hash table for better performance.

The following benchmarks have been tested:

For N in 1, 5, 10, 50, 100, 500, 1000, create N cgroups with one sleeping
task in each, and then move an additional task through each cgroup in
turn.

Here is a test result:

N	Loop	orig - Time(s)	hash - Time(s)
----------------------------------------------
1	10000	1.201231728	1.196311177
5	2000	1.065743872	1.040566424
10	1000	0.991054735	0.986876440
50	200	0.976554203	0.969608733
100	100	0.998504680	0.969218270
500	20	1.157347764	0.962602963
1000	10	1.619521852	1.085140172

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Reviewed-by: Paul Menage <menage@google.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-29 08:06:09 -07:00
Pavel Emelyanov d447ea2f30 cgroups: add the trigger callback to struct cftype
Trigger callback can be used to receive a kick-up from the user space.  The
string written is ignored.

The cftype->private is used for multiplexing events.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Acked-by: Paul Menage <menage@google.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-29 08:06:09 -07:00
Li Zefan 46ae220bea cgroup: switch to proc_create()
There is a race between create_proc_entry() and the assignment of file ops.
proc_create() is invented to fix it.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-29 08:06:09 -07:00
Li Zefan 06a119204d cgroup: annotate cgroup_init_subsys with __init
It is called by cgroup_init() and cgroup_init_early() only, which are
annotated with __init.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-29 08:06:09 -07:00
Paul Menage e73d2c61d1 CGroups _s64 files: add cgroups read_s64/write_s64 file methods
These patches add cgroups read_s64 and write_s64 control file methods (the
signed equivalent of read_u64/write_u64) and use them to implement the
cpu.rt_runtime_us control file in the CFS cgroup subsystem.

This patch:

These are the signed equivalents of the read_u64/write_u64 methods

Signed-off-by: Paul Menage <menage@google.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-29 08:06:09 -07:00
Paul Menage 3116f0e3df CGroup API files: move "releasable" to cgroup_debug subsystem
The "releasable" control file provided by the cgroup framework exports the
state of a per-cgroup flag that's related to the notify-on-release feature.
This isn't really generally useful, unless you're trying to debug this
particular feature of cgroups.

This patch moves the "releasable" file to the cgroup_debug subsystem.

Signed-off-by: Paul Menage <menage@google.com>
Cc: "Li Zefan" <lizf@cn.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Paul Jackson <pj@sgi.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: "YAMAMOTO Takashi" <yamamoto@valinux.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-29 08:06:09 -07:00
Paul Menage 9179656961 CGroup API files: add cgroup map data type
Adds a new type of supported control file representation, a map from strings
to u64 values.

Each map entry is printed as a line in a similar format to /proc/vmstat, i.e.
"$key $value\n"

Signed-off-by: Paul Menage <menage@google.com>
Cc: "Li Zefan" <lizf@cn.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Paul Jackson <pj@sgi.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: "YAMAMOTO Takashi" <yamamoto@valinux.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-29 08:06:08 -07:00
Paul Menage b7269dfc82 CGroup API files: strip all trailing whitespace in cgroup_write_u64
This removes the need for people to remember to pass the -n flag to echo when
writing values to cgroup control files.

Signed-off-by: Paul Menage <menage@google.com>
Cc: "Li Zefan" <lizf@cn.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Paul Jackson <pj@sgi.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: "YAMAMOTO Takashi" <yamamoto@valinux.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-29 08:06:08 -07:00
Paul Menage f4c753b7ea CGroup API files: rename read/write_uint methods to read_write_u64
Several people have justifiably complained that the "_uint" suffix is
inappropriate for functions that handle u64 values, so this patch just renames
all these functions and their users to have the suffic _u64.

[peterz@infradead.org: build fix]
Signed-off-by: Paul Menage <menage@google.com>
Cc: "Li Zefan" <lizf@cn.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Paul Jackson <pj@sgi.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: "YAMAMOTO Takashi" <yamamoto@valinux.co.jp>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-29 08:06:07 -07:00
Paul Jackson 4fe91d518e cgroup: fix sparse warning of shadow symbol in cgroup.c
Fix a code warning: symbol 'p' shadows an earlier one

This is a reincarnation of Harvey Harrison's patch:
	cpuset: sparse warnings in cpuset.c

Independently, Cliff Wickman moved the affected code,
from kernel/cpuset.c to kernel/cgroup.c, in his patch:
	cpusets: update_cpumask revision

Signed-off-by: Paul Jackson <pj@sgi.com>
Cc: Harvey Harrison <harvey.harrison@gmail.com>
Cc: Cliff Wickman <cpw@sgi.com>
Acked-by: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-29 08:06:07 -07:00
Adrian Bunk 3df91fe30a make cgroup_enable_task_cg_lists() static
Make the needlessly global cgroup_enable_task_cg_lists() static.

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Acked-by: David Rientjes <rientjes@google.com>
Cc: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-29 08:06:07 -07:00
Li Zefan 0e04388f01 cgroup: fix a race condition in manipulating tsk->cg_list
When I ran a test program to fork mass processes and at the same time
'cat /cgroup/tasks', I got the following oops:

  ------------[ cut here ]------------
  kernel BUG at lib/list_debug.c:72!
  invalid opcode: 0000 [#1] SMP
  Pid: 4178, comm: a.out Not tainted (2.6.25-rc9 #72)
  ...
  Call Trace:
   [<c044a5f9>] ? cgroup_exit+0x55/0x94
   [<c0427acf>] ? do_exit+0x217/0x5ba
   [<c0427ed7>] ? do_group_exit+0.65/0x7c
   [<c0427efd>] ? sys_exit_group+0xf/0x11
   [<c0404842>] ? syscall_call+0x7/0xb
   [<c05e0000>] ? init_cyrix+0x2fa/0x479
  ...
  EIP: [<c04df671>] list_del+0x35/0x53 SS:ESP 0068:ebc7df4
  ---[ end trace caffb7332252612b ]---
  Fixing recursive fault but reboot is needed!

After digging into the code and debugging, I finlly found out a race
situation:

				do_exit()
				  ->cgroup_exit()
				    ->if (!list_empty(&tsk->cg_list))
				        list_del(&tsk->cg_list);

  cgroup_iter_start()
    ->cgroup_enable_task_cg_list()
      ->list_add(&tsk->cg_list, ..);

In this case the list won't be deleted though the process has exited.

We got two bug reports in the past, which seem to be the same bug as
this one:
	http://lkml.org/lkml/2008/3/5/332
	http://lkml.org/lkml/2007/10/17/224

Actually sometimes I got oops on list_del, sometimes oops on list_add.
And I can change my test program a bit to trigger other oops.

The patch has been tested both on x86_32 and x86_64.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Paul Menage <menage@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-18 08:17:57 -07:00
Paul Menage b6c3006d20 cgroups: include hierarchy ids in /proc/<pid>/cgroup
Extend the /proc/<pid>/cgroup file to include the appropriate hierarchy ID on
each line.

Currently this ID isn't really needed since a hierarchy can be completely
identified by the set of subsystems bound to it, but this is likely to change
in the near future in order to support stateless subsystems and
merging/rebinding of subsystems.  Getting this change into 2.6.25 reduces the
need for an API change later.

Signed-off-by: Paul Menage <menage@google.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-11 08:06:43 -07:00
Paul Menage 8bab8dded6 cgroups: add cgroup support for enabling controllers at boot time
The effects of cgroup_disable=foo are:

- foo isn't auto-mounted if you mount all cgroups in a single hierarchy
- foo isn't visible as an individually mountable subsystem

As a result there will only ever be one call to foo->create(), at init time;
all processes will stay in this group, and the group will never be mounted on
a visible hierarchy.  Any additional effects (e.g.  not allocating metadata)
are up to the foo subsystem.

This doesn't handle early_init subsystems (their "disabled" bit isn't set be,
but it could easily be extended to do so if any of the early_init systems
wanted it - I think it would just involve some nastier parameter processing
since it would occur before the command-line argument parser had been run.

Hugh said:

  Ballpark figures, I'm trying to get this question out rather than
  processing the exact numbers: CONFIG_CGROUP_MEM_RES_CTLR adds 15% overhead
  to the affected paths, booting with cgroup_disable=memory cuts that back to
  1% overhead (due to slightly bigger struct page).

  I'm no expert on distros, they may have no interest whatever in
  CONFIG_CGROUP_MEM_RES_CTLR=y; and the rest of us can easily build with or
  without it, or apply the cgroup_disable=memory patches.

Unix bench's execl test result on x86_64 was

== just after boot without mounting any cgroup fs.==
mem_cgorup=off : Execl Throughput       43.0     3150.1      732.6
mem_cgroup=on  : Execl Throughput       43.0     2932.6      682.0
==

[lizf@cn.fujitsu.com: fix boot option parsing]
Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Paul Menage <menage@google.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Sudhir Kumar <skumar@linux.vnet.ibm.com>
Cc: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-04 14:46:26 -07:00
Al Viro 9dce07f1a4 NULL noise: fs/*, mm/*, kernel/*
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-03-30 14:18:41 -07:00
Li Zefan b6abdb0e6c cgroup: fix default notify_on_release setting
The documentation says the default value of notify_on_release of a child
cgroup is inherited from its parent, which is reasonable, but the
implementation just sets the flag disabled.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-03-04 16:35:09 -08:00
Li Zefan bc231d2a04 cgroup: remove dead code in cgroup_get_rootdir()
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-23 17:13:25 -08:00
Li Zefan 68db38f153 cgroup: remove duplicate code in find_css_set()
The list head res->tasks gets initialized twice in find_css_set().

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-23 17:13:25 -08:00
Li Zefan 8d53d55d27 cgroup: fix subsys bitops
Cgroup uses unsigned long for subsys bitops, not unsigned long long.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-23 17:13:24 -08:00
Li Zefan f777073848 cgroup: fix memory leak in cgroup_get_sb()
opts.release_agent is not kfree()ed in all necessary places.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-23 17:13:24 -08:00
Li Zefan a043e3b2c6 cgroup: fix comments
fix:
- comments about need_forkexit_callback
- comments about release agent
- typo and comment style, etc.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-23 17:13:24 -08:00
Pavel Emelyanov 73507f335f Handle pid namespaces in cgroups code
There's one place that works with task pids - its the "tasks" file in cgroups.
 The read/write handlers assume, that the pid values go to/come from the user
space and thus it is a virtual pid, i.e.  the pid as it is seen from inside a
namespace.

Tune the code accordingly.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-07 08:42:22 -08:00
Cliff Wickman 956db3ca06 hotplug cpu: move tasks in empty cpusets to parent
This patch corrects a situation that occurs when one disables all the cpus in
a cpuset.

Currently, the disabled (cpu-less) cpuset inherits the cpus of its parent,
which is incorrect because it may then overlap its cpu-exclusive sibling.

Tasks of an empty cpuset should be moved to the cpuset which is the parent of
their current cpuset.  Or if the parent cpuset has no cpus, to its parent,
etc.

And the empty cpuset should be released (if it is flagged notify_on_release).

Depends on the cgroup_scan_tasks() function (proposed by David Rientjes) to
iterate through all tasks in the cpu-less cpuset.  We are deliberately
avoiding a walk of the tasklist.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Cliff Wickman <cpw@sgi.com>
Cc: Paul Menage <menage@google.com>
Cc: Paul Jackson <pj@sgi.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-07 08:42:22 -08:00
Cliff Wickman 31a7df01fd cgroups: mechanism to process each task in a cgroup
Provide cgroup_scan_tasks(), which iterates through every task in a cgroup,
calling a test function and a process function for each.  And call the process
function without holding the css_set_lock lock.

The idea is David Rientjes', predicting that such a function will make it much
easier in the future to extend things that require access to each task in a
cgroup without holding the lock,

[akpm@linux-foundation.org: cleanup]
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Cliff Wickman <cpw@sgi.com>
Cc: Paul Menage <menage@google.com>
Cc: Paul Jackson <pj@sgi.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-07 08:42:22 -08:00
KAMEZAWA Hiroyuki 4fca88c87b memory cgroup enhancements: add- pre_destroy() handler
Add a handler "pre_destroy" to cgroup_subsys.  It is called before
cgroup_rmdir() checks all subsys's refcnt.

I think this is useful for subsys which have some extra refs even if there
are no tasks in cgroup.  By adding pre_destroy(), the kernel keeps the rule
"destroy() against subsystem is called only when refcnt=0." and allows css
ref to be used by other objects than tasks.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Kirill Korotaev <dev@sw.ru>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Paul Menage <menage@google.com>
Cc: Pavel Emelianov <xemul@openvz.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-07 08:42:20 -08:00
Adrian Bunk e9685a03c8 kernel/cgroup.c: make 2 functions static
cgroup_is_releasable() and notify_on_release() should be static,
not global inline.

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Acked-by: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-07 08:42:18 -08:00
Paul Menage 8dc4f3e17d cgroups: move cgroups destroy() callbacks to cgroup_diput()
Move the calls to the cgroup subsystem destroy() methods from
cgroup_rmdir() to cgroup_diput().  This allows control file reads and
writes to access their subsystem state without having to be concerned with
locking against cgroup destruction - the control file dentry will keep the
cgroup and its subsystem state objects alive until the file is closed.

The documentation is updated to reflect the changed semantics of destroy();
additionally the locking comments for destroy() and some other methods were
clarified and decrustified.

Signed-off-by: Paul Menage <menage@google.com>
Cc: Paul Jackson <pj@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-07 08:42:18 -08:00
Paul Jackson 622d42cac9 cgroup simplify space stripping
Simplify the space stripping code in cgroup file write.

[akpm@linux-foundation.org: s/BUG_ON/BUILD_BUG_ON/]
Signed-off-by: Paul Jackson <pj@sgi.com>
Acked-by: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-07 08:42:18 -08:00
Paul Jackson e18f6318e5 cgroup brace coding style fix
Coding style fix - one line conditionals don't get braces.

Signed-off-by: Paul Jackson <pj@sgi.com>
Acked-by: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-07 08:42:17 -08:00
Adrian Bunk 3cdeed2986 kernel/cgroup.c: remove dead code
This patch removes dead code spotted by the Coverity checker
(look at the "(nbytes >= PATH_MAX)" check).

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Cc: Paul Jackson <pj@sgi.com>
Cc: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-07 08:42:17 -08:00
Diego Calleja cfe36bde59 Improve cgroup printks
When I boot with the 'quiet' parameter, I see on the screen:

[    0.000000] Initializing cgroup subsys cpuset
[    0.000000] Initializing cgroup subsys cpu
[   39.036026] Initializing cgroup subsys cpuacct
[   39.036080] Initializing cgroup subsys debug
[   39.036118] Initializing cgroup subsys ns

This patch lowers the priority of those messages, adds a "cgroup: " prefix
to another couple of printks and kills the useless reference to the source
file.

Signed-off-by: Diego Calleja <diegocg@gmail.com>
Cc: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-11-14 18:45:37 -08:00