linux-toradex.git/include/linux/cgroup.h, branch v2.6.34

cgroup: Check task_lock in task_subsys_state()

2010-05-04T16:25:02+00:00

Expand task_subsys_state()'s rcu_dereference_check() to include the full
locking rule as documented in Documentation/cgroups/cgroups.txt by adding
a check for task->alloc_lock being held.

This fixes an RCU false positive when resuming from suspend. The warning
comes from freezer cgroup in cgroup_freezing_or_frozen().

Signed-off-by: Li Zefan 
Acked-by: Matt Helsley 
Signed-off-by: Paul E. McKenney

cgroups: remove events before destroying subsystem state objects

2010-03-12T23:52:37+00:00

Events should be removed after rmdir of cgroup directory, but before
destroying subsystem state objects.  Let's take reference to cgroup
directory dentry to do that.

Signed-off-by: Kirill A. Shutemov 
Acked-by: KAMEZAWA Hiroyuki 
Cc: Paul Menage 
Acked-by: Li Zefan 
Cc: Balbir Singh 
Cc: Pavel Emelyanov 
Cc: Dan Malek 
Cc: Daisuke Nishimura 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

cgroup: implement eventfd-based generic API for notifications

2010-03-12T23:52:37+00:00

This patchset introduces eventfd-based API for notifications in cgroups
and implements memory notifications on top of it.

It uses statistics in memory controler to track memory usage.

Output of time(1) on building kernel on tmpfs:

Root cgroup before changes:
	make -j2  506.37 user 60.93s system 193% cpu 4:52.77 total
Non-root cgroup before changes:
	make -j2  507.14 user 62.66s system 193% cpu 4:54.74 total
Root cgroup after changes (0 thresholds):
	make -j2  507.13 user 62.20s system 193% cpu 4:53.55 total
Non-root cgroup after changes (0 thresholds):
	make -j2  507.70 user 64.20s system 193% cpu 4:55.70 total
Root cgroup after changes (1 thresholds, never crossed):
	make -j2  506.97 user 62.20s system 193% cpu 4:53.90 total
Non-root cgroup after changes (1 thresholds, never crossed):
	make -j2  507.55 user 64.08s system 193% cpu 4:55.63 total

This patch:

Introduce the write-only file "cgroup.event_control" in every cgroup.

To register new notification handler you need:
- create an eventfd;
- open a control file to be monitored. Callbacks register_event() and
  unregister_event() must be defined for the control file;
- write "  " to cgroup.event_control.
  Interpretation of args is defined by control file implementation;

eventfd will be woken up by control file implementation or when the
cgroup is removed.

To unregister notification handler just close eventfd.

If you need notification functionality for a control file you have to
implement callbacks register_event() and unregister_event() in the
struct cftype.

[kamezawa.hiroyu@jp.fujitsu.com: Kconfig fix]
Signed-off-by: Kirill A. Shutemov 
Reviewed-by: KAMEZAWA Hiroyuki 
Paul Menage 
Cc: Li Zefan 
Cc: Balbir Singh 
Cc: Pavel Emelyanov 
Cc: Dan Malek 
Cc: Vladislav Buzov 
Cc: Daisuke Nishimura 
Cc: Alexander Shishkin 
Cc: Davide Libenzi 
Signed-off-by: KAMEZAWA Hiroyuki 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

cgroups: subsystem module unloading

2010-03-12T23:52:36+00:00

Provides support for unloading modular subsystems.

This patch adds a new function cgroup_unload_subsys which is to be used
for removing a loaded subsystem during module deletion.  Reference
counting of the subsystems' modules is moved from once (at load time) to
once per attached hierarchy (in parse_cgroupfs_options and
rebind_subsystems) (i.e., 0 or 1).

Signed-off-by: Ben Blum 
Acked-by: Li Zefan 
Cc: Paul Menage 
Cc: "David S. Miller" 
Cc: KAMEZAWA Hiroyuki 
Cc: Lai Jiangshan 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

cgroups: subsystem module loading interface

2010-03-12T23:52:36+00:00

Add interface between cgroups subsystem management and module loading

This patch implements rudimentary module-loading support for cgroups -
namely, a cgroup_load_subsys (similar to cgroup_init_subsys) for use as a
module initcall, and a struct module pointer in struct cgroup_subsys.

Several functions that might be wanted by modules have had EXPORT_SYMBOL
added to them, but it's unclear exactly which functions want it and which
won't.

Signed-off-by: Ben Blum 
Acked-by: Li Zefan 
Cc: Paul Menage 
Cc: "David S. Miller" 
Cc: KAMEZAWA Hiroyuki 
Cc: Lai Jiangshan 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

cgroups: revamp subsys array

2010-03-12T23:52:36+00:00

This patch series provides the ability for cgroup subsystems to be
compiled as modules both within and outside the kernel tree.  This is
mainly useful for classifiers and subsystems that hook into components
that are already modules.  cls_cgroup and blkio-cgroup serve as the
example use cases for this feature.

It provides an interface cgroup_load_subsys() and cgroup_unload_subsys()
which modular subsystems can use to register and depart during runtime.
The net_cls classifier subsystem serves as the example for a subsystem
which can be converted into a module using these changes.

Patch #1 sets up the subsys[] array so its contents can be dynamic as
modules appear and (eventually) disappear.  Iterations over the array are
modified to handle when subsystems are absent, and the dynamic section of
the array is protected by cgroup_mutex.

Patch #2 implements an interface for modules to load subsystems, called
cgroup_load_subsys, similar to cgroup_init_subsys, and adds a module
pointer in struct cgroup_subsys.

Patch #3 adds a mechanism for unloading modular subsystems, which includes
a more advanced rework of the rudimentary reference counting introduced in
patch 2.

Patch #4 modifies the net_cls subsystem, which already had some module
declarations, to be configurable as a module, which also serves as a
simple proof-of-concept.

Part of implementing patches 2 and 4 involved updating css pointers in
each css_set when the module appears or leaves.  In doing this, it was
discovered that css_sets always remain linked to the dummy cgroup,
regardless of whether or not any subsystems are actually bound to it
(i.e., not mounted on an actual hierarchy).  The subsystem loading and
unloading code therefore should keep in mind the special cases where the
added subsystem is the only one in the dummy cgroup (and therefore all
css_sets need to be linked back into it) and where the removed subsys was
the only one in the dummy cgroup (and therefore all css_sets should be
unlinked from it) - however, as all css_sets always stay attached to the
dummy cgroup anyway, these cases are ignored.  Any fix that addresses this
issue should also make sure these cases are addressed in the subsystem
loading and unloading code.

This patch:

Make subsys[] able to be dynamically populated to support modular
subsystems

This patch reworks the way the subsys[] array is used so that subsystems
can register themselves after boot time, and enables the internals of
cgroups to be able to handle when subsystems are not present or may
appear/disappear.

Signed-off-by: Ben Blum 
Acked-by: Li Zefan 
Cc: Paul Menage 
Cc: "David S. Miller" 
Cc: KAMEZAWA Hiroyuki 
Cc: Lai Jiangshan 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

cgroup: introduce coalesce css_get() and css_put()

2010-03-12T23:52:36+00:00

Current css_get() and css_put() increment/decrement css->refcnt one by
one.

This patch add a new function __css_get(), which takes "count" as a arg
and increment the css->refcnt by "count".  And this patch also add a new
arg("count") to __css_put() and change the function to decrement the
css->refcnt by "count".

These coalesce version of __css_get()/__css_put() will be used to improve
performance of memcg's moving charge feature later, where instead of
calling css_get()/css_put() repeatedly, these new functions will be used.

No change is needed for current users of css_get()/css_put().

Signed-off-by: Daisuke Nishimura 
Acked-by: Paul Menage 
Cc: Balbir Singh 
Acked-by: KAMEZAWA Hiroyuki 
Cc: Li Zefan 
Cc: Daisuke Nishimura 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

cgroup: introduce cancel_attach()

2010-03-12T23:52:35+00:00

Add cancel_attach() operation to struct cgroup_subsys.  cancel_attach()
can be used when can_attach() operation prepares something for the subsys,
but we should rollback what can_attach() operation has prepared if attach
task fails after we've succeeded in can_attach().

Signed-off-by: Daisuke Nishimura 
Acked-by: Li Zefan 
Reviewed-by: Paul Menage 
Cc: Balbir Singh 
Acked-by: KAMEZAWA Hiroyuki 
Cc: Daisuke Nishimura 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

sched: Use lockdep-based checking on rcu_dereference()

2010-02-25T09:34:26+00:00

Update the rcu_dereference() usages to take advantage of the new
lockdep-based checking.

Signed-off-by: Paul E. McKenney 
Cc: laijs@cn.fujitsu.com
Cc: dipankar@in.ibm.com
Cc: mathieu.desnoyers@polymtl.ca
Cc: josh@joshtriplett.org
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: peterz@infradead.org
Cc: rostedt@goodmis.org
Cc: Valdis.Kletnieks@vt.edu
Cc: dhowells@redhat.com
LKML-Reference: <1266887105-1528-6-git-send-email-paulmck@linux.vnet.ibm.com>
[ -v2: fix allmodconfig missing symbol export build failure on x86 ]
Signed-off-by: Ingo Molnar

const: constify remaining file_operations

2009-10-01T23:11:11+00:00

[akpm@linux-foundation.org: fix KVM]
Signed-off-by: Alexey Dobriyan 
Acked-by: Mike Frysinger 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds