Currently, there's no way for a controller to find out whether a new
cgroup finished all ->create() allocatinos successfully and is
considered "live" by cgroup.
This becomes a problem later when we add generic descendants walking
to cgroup which can be used by controllers as controllers don't have a
synchronization point where it can synchronize against new cgroups
appearing in such walks.
This patch adds ->post_create(). It's called after all ->create()
succeeded and the cgroup is linked into the generic cgroup hierarchy.
This plays the counterpart of ->pre_destroy().
When used in combination with the to-be-added generic descendant
iterators, ->post_create() can be used to implement reliable state
inheritance. It will be explained with the descendant iterators.
v2: Added a paragraph about its future use w/ descendant iterators per
Michal.
v3: Forgot to add ->post_create() invocation to cgroup_load_subsys().
Fixed.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Glauber Costa <glommer@parallels.com>
Pull rmdir updates into for-3.8 so that further callback updates can
be put on top. This pull created a trivial conflict between the
following two commits.
8c7f6edbda ("cgroup: mark subsystems with broken hierarchy support and whine if cgroups are nested for them")
ed95779340 ("cgroup: kill cgroup_subsys->__DEPRECATED_clear_css_refs")
The former added a field to cgroup_subsys and the latter removed one
from it. They happen to be colocated causing the conflict. Keeping
what's added and removing what's removed resolves the conflict.
Signed-off-by: Tejun Heo <tj@kernel.org>
All ->pre_destory() implementations return 0 now, which is the only
allowed return value. Make it return void.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
CGRP_WAIT_ON_RMDIR is another kludge which was added to make cgroup
destruction rollback somewhat working. cgroup_rmdir() used to drain
CSS references and CGRP_WAIT_ON_RMDIR and the associated waitqueue and
helpers were used to allow the task performing rmdir to wait for the
next relevant event.
Unfortunately, the wait is visible to controllers too and the
mechanism got exposed to memcg by 887032670d ("cgroup avoid permanent
sleep at rmdir").
Now that the draining and retries are gone, CGRP_WAIT_ON_RMDIR is
unnecessary. Remove it and all the mechanisms supporting it. Note
that memcontrol.c changes are essentially revert of 887032670d
("cgroup avoid permanent sleep at rmdir").
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Balbir Singh <bsingharora@gmail.com>
CSS_REMOVED is one of the several contortions which were necessary to
support css reference draining on cgroup removal. All css->refcnts
which need draining should be deactivated and verified to equal zero
atomically w.r.t. css_tryget(). If any one isn't zero, all refcnts
needed to be re-activated and css_tryget() shouldn't fail in the
process.
This was achieved by letting css_tryget() busy-loop until either the
refcnt is reactivated (failed removal attempt) or CSS_REMOVED is set
(committing to removal).
Now that css refcnt draining is no longer used, there's no need for
atomic rollback mechanism. css_tryget() simply can look at the
reference count and fail if it's deactivated - it's never getting
re-activated.
This patch removes CSS_REMOVED and updates __css_tryget() to fail if
the refcnt is deactivated. As deactivation and removal are a single
step now, they no longer need to be protected against css_tryget()
happening from irq context. Remove local_irq_disable/enable() from
cgroup_rmdir().
Note that this removes css_is_removed() whose only user is VM_BUG_ON()
in memcontrol.c. We can replace it with a check on the refcnt but
given that the only use case is a debug assert, I think it's better to
simply unexport it.
v2: Comment updated and explanation on local_irq_disable/enable()
added per Michal Hocko.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Li Zefan <lizefan@huawei.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Balbir Singh <bsingharora@gmail.com>
2ef37d3fe4 ("memcg: Simplify mem_cgroup_force_empty_list error
handling") removed the last user of __DEPRECATED_clear_css_refs. This
patch removes __DEPRECATED_clear_css_refs and mechanisms to support
it.
* Conditionals dependent on __DEPRECATED_clear_css_refs removed.
* cgroup_clear_css_refs() can no longer fail. All that needs to be
done are deactivating refcnts, setting CSS_REMOVED and putting the
base reference on each css. Remove cgroup_clear_css_refs() and the
failure path, and open-code the loops into cgroup_rmdir().
This patch keeps the two for_each_subsys() loops separate while open
coding them. They can be merged now but there are scheduled changes
which need them to be separate, so keep them separate to reduce the
amount of churn.
local_irq_save/restore() from cgroup_clear_css_refs() are replaced
with local_irq_disable/enable() for simplicity. This is safe as
cgroup_rmdir() is always called with IRQ enabled. Note that this IRQ
switching is necessary to ensure that css_tryget() isn't called from
IRQ context on the same CPU while lower context is between CSS
deactivation and setting CSS_REMOVED as css_tryget() would hang
forever in such cases waiting for CSS to be re-activated or
CSS_REMOVED set. This will go away soon.
v2: cgroup_call_pre_destroy() removal dropped per Michal. Commit
message updated to explain local_irq_disable/enable() conversion.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Li Zefan <lizefan@huawei.com>
cgroup core has a bug which violates a basic rule about event
notifications - when a new entity needs to be added, you add that to
the notification list first and then make the new entity conform to
the current state. If done in the reverse order, an event happening
inbetween will be lost.
cgroup_subsys->fork() is invoked way before the new task is added to
the css_set. Currently, cgroup_freezer is the only user of ->fork()
and uses it to make new tasks conform to the current state of the
freezer. If FROZEN state is requested while fork is in progress
between cgroup_fork_callbacks() and cgroup_post_fork(), the child
could escape freezing - the cgroup isn't frozen when ->fork() is
called and the freezer couldn't see the new task on the css_set.
This patch moves cgroup_subsys->fork() invocation to
cgroup_post_fork() after the new task is added to the css_set.
cgroup_fork_callbacks() is removed.
Because now a task may be migrated during cgroup_subsys->fork(),
freezer_fork() is updated so that it adheres to the usual RCU locking
and the rather pointless comment on why locking can be different there
is removed (if it doesn't make anything simpler, why even bother?).
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Rafael J. Wysocki <rjw@sisk.pl>
Cc: stable@vger.kernel.org
Pull cgroup hierarchy update from Tejun Heo:
"Currently, different cgroup subsystems handle nested cgroups
completely differently. There's no consistency among subsystems and
the behaviors often are outright broken.
People at least seem to agree that the broken hierarhcy behaviors need
to be weeded out if any progress is gonna be made on this front and
that the fallouts from deprecating the broken behaviors should be
acceptable especially given that the current behaviors don't make much
sense when nested.
This patch makes cgroup emit warning messages if cgroups for
subsystems with broken hierarchy behavior are nested to prepare for
fixing them in the future. This was put in a separate branch because
more related changes were expected (didn't make it this round) and the
memory cgroup wanted to pull in this and make changes on top."
* 'for-3.7-hierarchy' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
cgroup: mark subsystems with broken hierarchy support and whine if cgroups are nested for them
Currently, cgroup hierarchy support is a mess. cpu related subsystems
behave correctly - configuration, accounting and control on a parent
properly cover its children. blkio and freezer completely ignore
hierarchy and treat all cgroups as if they're directly under the root
cgroup. Others show yet different behaviors.
These differing interpretations of cgroup hierarchy make using cgroup
confusing and it impossible to co-mount controllers into the same
hierarchy and obtain sane behavior.
Eventually, we want full hierarchy support from all subsystems and
probably a unified hierarchy. Users using separate hierarchies
expecting completely different behaviors depending on the mounted
subsystem is deterimental to making any progress on this front.
This patch adds cgroup_subsys.broken_hierarchy and sets it to %true
for controllers which are lacking in hierarchy support. The goal of
this patch is two-fold.
* Move users away from using hierarchy on currently non-hierarchical
subsystems, so that implementing proper hierarchy support on those
doesn't surprise them.
* Keep track of which controllers are broken how and nudge the
subsystems to implement proper hierarchy support.
For now, start with a single warning message. We can whine louder
later on.
v2: Fixed a typo spotted by Michal. Warning message updated.
v3: Updated memcg part so that it doesn't generate warning in the
cases where .use_hierarchy=false doesn't make the behavior
different from root.use_hierarchy=true. Fixed a typo spotted by
Glauber.
v4: Check ->broken_hierarchy after cgroup creation is complete so that
->create() can affect the result per Michal. Dropped unnecessary
memcg root handling per Michal.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Li Zefan <lizefan@huawei.com>
Acked-by: Serge E. Hallyn <serue@us.ibm.com>
Cc: Glauber Costa <glommer@parallels.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul Turner <pjt@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Thomas Graf <tgraf@suug.ch>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Neil Horman <nhorman@tuxdriver.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Since we know exactly how many subsystems exists at compile time we are
able to define CGROUP_SUBSYS_COUNT correctly. CGROUP_SUBSYS_COUNT will
be at max 12 (all controllers enabled). Depending on the architecture
we safe either 32 - 12 pointers (80 bytes) or 64 - 12 pointers (416
bytes) per cgroup.
With this change we can also remove the temporary placeholder to avoid
compilation errors.
Signed-off-by: Daniel Wagner <daniel.wagner@bmw-carit.de>
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Cc: Gao feng <gaofeng@cn.fujitsu.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: John Fastabend <john.r.fastabend@intel.com>
Cc: netdev@vger.kernel.org
Cc: cgroups@vger.kernel.org
WARNING: With this change it is impossible to load external built
controllers anymore.
In case where CONFIG_NETPRIO_CGROUP=m and CONFIG_NET_CLS_CGROUP=m is
set, corresponding subsys_id should also be a constant. Up to now,
net_prio_subsys_id and net_cls_subsys_id would be of the type int and
the value would be assigned during runtime.
By switching the macro definition IS_SUBSYS_ENABLED from IS_BUILTIN
to IS_ENABLED, all *_subsys_id will have constant value. That means we
need to remove all the code which assumes a value can be assigned to
net_prio_subsys_id and net_cls_subsys_id.
A close look is necessary on the RCU part which was introduces by
following patch:
commit f845172531
Author: Herbert Xu <herbert@gondor.apana.org.au> Mon May 24 09:12:34 2010
Committer: David S. Miller <davem@davemloft.net> Mon May 24 09:12:34 2010
cls_cgroup: Store classid in struct sock
Tis code was added to init_cgroup_cls()
/* We can't use rcu_assign_pointer because this is an int. */
smp_wmb();
net_cls_subsys_id = net_cls_subsys.subsys_id;
respectively to exit_cgroup_cls()
net_cls_subsys_id = -1;
synchronize_rcu();
and in module version of task_cls_classid()
rcu_read_lock();
id = rcu_dereference(net_cls_subsys_id);
if (id >= 0)
classid = container_of(task_subsys_state(p, id),
struct cgroup_cls_state, css)->classid;
rcu_read_unlock();
Without an explicit explaination why the RCU part is needed. (The
rcu_deference was fixed by exchanging it to rcu_derefence_index_check()
in a later commit, but that is a minor detail.)
So here is my pondering why it was introduced and why it safe to
remove it now. Note that this code was copied over to net_prio the
reasoning holds for that subsystem too.
The idea behind the RCU use for net_cls_subsys_id is to make sure we
get a valid pointer back from task_subsys_state(). task_subsys_state()
is just blindly accessing the subsys array and returning the
pointer. Obviously, passing in -1 as id into task_subsys_state()
returns an invalid value (out of lower bound).
So this code makes sure that only after module is loaded and the
subsystem registered, the id is assigned.
Before unregistering the module all old readers must have left the
critical section. This is done by assigning -1 to the id and issuing a
synchronized_rcu(). Any new readers wont call task_subsys_state()
anymore and therefore it is safe to unregister the subsystem.
The new code relies on the same trick, but it looks at the subsys
pointer return by task_subsys_state() (remember the id is constant
and therefore we allways have a valid index into the subsys
array).
No precautions need to be taken during module loading
module. Eventually, all CPUs will get a valid pointer back from
task_subsys_state() because rebind_subsystem() which is called after
the module init() function will assigned subsys[net_cls_subsys_id] the
newly loaded module subsystem pointer.
When the subsystem is about to be removed, rebind_subsystem() will
called before the module exit() function. In this case,
rebind_subsys() will assign subsys[net_cls_subsys_id] a NULL pointer
and then it calls synchronize_rcu(). All old readers have left by then
the critical section. Any new reader wont access the subsystem
anymore. At this point we are safe to unregister the subsystem. No
synchronize_rcu() call is needed.
Signed-off-by: Daniel Wagner <daniel.wagner@bmw-carit.de>
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Gao feng <gaofeng@cn.fujitsu.com>
Cc: Glauber Costa <glommer@parallels.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: John Fastabend <john.r.fastabend@intel.com>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: netdev@vger.kernel.org
Cc: cgroups@vger.kernel.org
Before we are able to define all subsystem ids at compile time we need
a more fine grained control what gets defined when we include
cgroup_subsys.h. For example we define the enums for the subsystems or
to declare for struct cgroup_subsys (builtin subsystem) by including
cgroup_subsys.h and defining SUBSYS accordingly.
Currently, the decision if a subsys is used is defined inside the
header by testing if CONFIG_*=y is true. By moving this test outside
of cgroup_subsys.h we are able to control it on the include level.
This is done by introducing IS_SUBSYS_ENABLED which then is defined
according the task, e.g. is CONFIG_*=y or CONFIG_*=m.
Signed-off-by: Daniel Wagner <daniel.wagner@bmw-carit.de>
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Cc: Gao feng <gaofeng@cn.fujitsu.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: John Fastabend <john.r.fastabend@intel.com>
Cc: netdev@vger.kernel.org
Cc: cgroups@vger.kernel.org
CGROUP_BUILTIN_SUBSYS_COUNT is used as start index or stop index when
looping over the subsys array looking either at the builtin or the
module subsystems. Since all the builtin subsystems have an id which
is lower then CGROUP_BUILTIN_SUBSYS_COUNT we know that any module will
have an id larger than CGROUP_BUILTIN_SUBSYS_COUNT. In short the ids
are sorted.
We are about to change id assignment to happen only at compile time
later in this series. That means we can't rely on the above trick
since all ids will always be defined at compile time. Furthermore,
ordering the builtin subsystems and the module subsystems is not
really necessary.
So we need a different way to know which subsystem is a builtin or a
module one. We can use the subsys[]->module pointer for this. Any
place where we need to know if a subsys is module we just check for
the pointer. If it is NULL then the subsystem is a builtin one.
With this we are able to drop the CGROUP_BUILTIN_SUBSYS_COUNT
enum. Though we need to introduce a temporary placeholder so that we
don't get a compilation error when only CONFIG_CGROUP is selected and
no single controller. An empty enum definition is not valid. Later in
this series we are able to remove the placeholder again.
And with this change we get a fix for this:
kernel/cgroup.c: In function ‘cgroup_load_subsys’:
kernel/cgroup.c:4326:38: warning: array subscript is below array bounds [-Warray-bounds]
when CONFIG_CGROUP=y and no built in controller was enabled.
Signed-off-by: Daniel Wagner <daniel.wagner@bmw-carit.de>
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Cc: Gao feng <gaofeng@cn.fujitsu.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: John Fastabend <john.r.fastabend@intel.com>
Cc: netdev@vger.kernel.org
Cc: cgroups@vger.kernel.org
This is one of the items in the plumber's wish list.
For use cases:
>> What would the use case be for this?
>
> Attaching meta information to services, in an easily discoverable
> way. For example, in systemd we create one cgroup for each service, and
> could then store data like the main pid of the specific service as an
> xattr on the cgroup itself. That way we'd have almost all service state
> in the cgroupfs, which would make it possible to terminate systemd and
> later restart it without losing any state information. But there's more:
> for example, some very peculiar services cannot be terminated on
> shutdown (i.e. fakeraid DM stuff) and it would be really nice if the
> services in question could just mark that on their cgroup, by setting an
> xattr. On the more desktopy side of things there are other
> possibilities: for example there are plans defining what an application
> is along the lines of a cgroup (i.e. an app being a collection of
> processes). With xattrs one could then attach an icon or human readable
> program name on the cgroup.
>
> The key idea is that this would allow attaching runtime meta information
> to cgroups and everything they model (services, apps, vms), that doesn't
> need any complex userspace infrastructure, has good access control
> (i.e. because the file system enforces that anyway, and there's the
> "trusted." xattr namespace), notifications (inotify), and can easily be
> shared among applications.
>
> Lennart
v7:
- no changes
v6:
- remove user xattr namespace, only allow trusted and security
v5:
- check for capabilities before setting/removing xattrs
v4:
- no changes
v3:
- instead of config option, use mount option to enable xattr support
Original-patch-by: Li Zefan <lizefan@huawei.com>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Hillf Danton <dhillf@gmail.com>
Cc: Lennart Poettering <lpoetter@redhat.com>
Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Aristeu Rozanski <aris@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
It was introduced for memcg to iterate cgroup hierarchy without
holding cgroup_mutex, but soon after that it was replaced with
a lockless way in memcg.
No one used hierarchy_mutex since that, so remove it.
Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
With memcg converted, cgroup_subsys->populate() doesn't have any user
left. Remove it.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizefan@huawei.com>
Currently, cgroup removal tries to drain all css references. If there
are active css references, the removal logic waits and retries
->pre_detroy() until either all refs drop to zero or removal is
cancelled.
This semantics is unusual and adds non-trivial complexity to cgroup
core and IMHO is fundamentally misguided in that it couples internal
implementation details (references to internal data structure) with
externally visible operation (rmdir). To userland, this is a behavior
peculiarity which is unnecessary and difficult to expect (css refs is
otherwise invisible from userland), and, to policy implementations,
this is an unnecessary restriction (e.g. blkcg wants to hold css refs
for caching purposes but can't as that becomes visible as rmdir hang).
Unfortunately, memcg currently depends on ->pre_destroy() retrials and
cgroup removal vetoing and can't be immmediately switched to the new
behavior. This patch introduces the new behavior of not waiting for
css refs to drain and maintains the old behavior for subsystems which
have __DEPRECATED_clear_css_refs set.
Once, memcg is updated, we can drop the code paths for the old
behavior as proposed in the following patch. Note that the following
patch is incorrect in that dput work item is in cgroup and may lose
some of dputs when multiples css's are released back-to-back, and
__css_put() triggers check_for_release() when refcnt reaches 0 instead
of 1; however, it shows what part can be removed.
http://thread.gmane.org/gmane.linux.kernel.containers/22559/focus=75251
Note that, in not-too-distant future, cgroup core will start emitting
warning messages for subsys which require the old behavior, so please
get moving.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
When a cgroup is about to be removed, cgroup_clear_css_refs() is
called to check and ensure that there are no active css references.
This is currently achieved by dropping the refcnt to zero iff it has
only the base ref. If all css refs could be dropped to zero, ref
clearing is successful and CSS_REMOVED is set on all css. If not, the
base ref is restored. While css ref is zero w/o CSS_REMOVED set, any
css_tryget() attempt on it busy loops so that they are atomic
w.r.t. the whole css ref clearing.
This does work but dropping and re-instating the base ref is somewhat
hairy and makes it difficult to add more logic to the put path as
there are two of them - the regular css_put() and the reversible base
ref clearing.
This patch updates css ref clearing such that blocking new
css_tryget() and putting the base ref are separate operations.
CSS_DEACT_BIAS, defined as INT_MIN, is added to css->refcnt and
css_tryget() busy loops while refcnt is negative. After all css refs
are deactivated, if they were all one, ref clearing succeeded and
CSS_REMOVED is set and the base ref is put using the regular
css_put(); otherwise, CSS_DEACT_BIAS is subtracted from the refcnts
and the original postive values are restored.
css_refcnt() accessor which always returns the unbiased positive
reference counts is added and used to simplify refcnt usages. While
at it, relocate and reformat comments in cgroup_has_css_refs().
This separates css->refcnt deactivation and putting the base ref,
which enables the next patch to make ref clearing optional.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizf@cn.fujitsu.com>
Implement cgroup_rm_cftypes() which removes an array of cftypes from a
subsystem. It can be called whether the target subsys is attached or
not. cgroup core will remove the specified file from all existing
cgroups.
This will be used to improve sub-subsys modularity and will be helpful
for unified hierarchy.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizf@cn.fujitsu.com>
This patch adds cfent (cgroup file entry) which is the association
between a cgroup and a file. This is in-cgroup representation of
files under a cgroup directory. This simplifies walking walking
cgroup files and thus cgroup_clear_directory(), which is now
implemented in two parts - cgroup_rm_file() and a loop around it.
cgroup_rm_file() will be used to implement cftype removal and cfent is
scheduled to serve cgroup specific per-file data (e.g. for sysfs-like
"sever" semantics).
v2: - cfe was freed from cgroup_rm_file() which led to use-after-free
if the file had openers at the time of removal. Moved to
cgroup_diput().
- cgroup_clear_directory() triggered WARN_ON_ONCE() if d_subdirs
wasn't empty after removing all files. This triggered
spuriously if some files were open during directory clearing.
Removed.
v3: - In cgroup_diput(), WARN_ONCE(!list_empty(&cfe->node)) could be
spuriously triggered for root cgroups because they don't go
through cgroup_clear_directory() on unmount. Don't trigger WARN
for root cgroups.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Glauber Costa <glommer@parallels.com>
No controller is using cgroup_add_files[s](). Unexport them, and
convert cgroup_add_files() to handle NULL entry terminated array
instead of taking count explicitly and continue creation on failure
for internal use.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizf@cn.fujitsu.com>
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: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizf@cn.fujitsu.com>
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: Tejun Heo <tj@kernel.org>
Acked-by: Li Zefan <lizf@cn.fujitsu.com>
Commit c1e2ee2dc4 ("memcg: replace ss->id_lock with a rwlock") has now
been seen to cause the unfair behavior we should have expected from
converting a spinlock to an rwlock: softlockup in cgroup_mkdir(), whose
get_new_cssid() is waiting for the wlock, while there are 19 tasks using
the rlock in css_get_next() to get on with their memcg workload (in an
artificial test, admittedly). Yet lib/idr.c was made suitable for RCU
way back: revert that commit, restoring ss->id_lock to a spinlock.
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
It's just a wrapper of cgroup_attach_task_all(), and it's no longer
used after commit 87d6a412bd
(vhost: fix attach to cgroups regression)
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
* 'for-3.3' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: (21 commits)
cgroup: fix to allow mounting a hierarchy by name
cgroup: move assignement out of condition in cgroup_attach_proc()
cgroup: Remove task_lock() from cgroup_post_fork()
cgroup: add sparse annotation to cgroup_iter_start() and cgroup_iter_end()
cgroup: mark cgroup_rmdir_waitq and cgroup_attach_proc() as static
cgroup: only need to check oldcgrp==newgrp once
cgroup: remove redundant get/put of task struct
cgroup: remove redundant get/put of old css_set from migrate
cgroup: Remove unnecessary task_lock before fetching css_set on migration
cgroup: Drop task_lock(parent) on cgroup_fork()
cgroups: remove redundant get/put of css_set from css_set_check_fetched()
resource cgroups: remove bogus cast
cgroup: kill subsys->can_attach_task(), pre_attach() and attach_task()
cgroup, cpuset: don't use ss->pre_attach()
cgroup: don't use subsys->can_attach_task() or ->attach_task()
cgroup: introduce cgroup_taskset and use it in subsys->can_attach(), cancel_attach() and attach()
cgroup: improve old cgroup handling in cgroup_attach_proc()
cgroup: always lock threadgroup during migration
threadgroup: extend threadgroup_lock() to cover exit and exec
threadgroup: rename signal->threadgroup_fork_lock to ->group_rwsem
...
Fix up conflict in kernel/cgroup.c due to commit e0197aae59e5: "cgroups:
fix a css_set not found bug in cgroup_attach_proc" that already
mentioned that the bug is fixed (differently) in Tejun's cgroup
patchset. This one, in other words.
These three methods are no longer used. Kill them.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Paul Menage <paul@paulmenage.org>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Currently, there's no way to pass multiple tasks to cgroup_subsys
methods necessitating the need for separate per-process and per-task
methods. This patch introduces cgroup_taskset which can be used to
pass multiple tasks and their associated cgroups to cgroup_subsys
methods.
Three methods - can_attach(), cancel_attach() and attach() - are
converted to use cgroup_taskset. This unifies passed parameters so
that all methods have access to all information. Conversions in this
patchset are identical and don't introduce any behavior change.
-v2: documentation updated as per Paul Menage's suggestion.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Paul Menage <paul@paulmenage.org>
Acked-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: James Morris <jmorris@namei.org>
While back-porting Johannes Weiner's patch "mm: memcg-aware global
reclaim" for an internal effort, we noticed a significant performance
regression during page-reclaim heavy workloads due to high contention of
the ss->id_lock. This lock protects idr map, and serializes calls to
idr_get_next() in css_get_next() (which is used during the memcg hierarchy
walk).
Since idr_get_next() is just doing a look up, we need only serialize it
with respect to idr_remove()/idr_get_new(). By making the ss->id_lock a
rwlock, contention is greatly reduced and performance improves.
Tested: cat a 256m file from a ramdisk in a 128m container 50 times on
each core (one file + container per core) in parallel on a NUMA machine.
Result is the time for the test to complete in 1 of the containers.
Both kernels included Johannes' memcg-aware global reclaim patches.
Before rwlock patch: 1710.778s
After rwlock patch: 152.227s
Signed-off-by: Andrew Bresticker <abrestic@google.com>
Cc: Paul Menage <menage@gmail.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Ying Han <yinghan@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Since ca5ecddf (rcu: define __rcu address space modifier for sparse)
rcu_dereference_check use rcu_read_lock_held as a part of condition
automatically so callers do not have to do that as well.
Signed-off-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
The ns_cgroup is an annoying cgroup at the namespace / cgroup frontier and
leads to some problems:
* cgroup creation is out-of-control
* cgroup name can conflict when pids are looping
* it is not possible to have a single process handling a lot of
namespaces without falling in a exponential creation time
* we may want to create a namespace without creating a cgroup
The ns_cgroup was replaced by a compatibility flag 'clone_children',
where a newly created cgroup will copy the parent cgroup values.
The userspace has to manually create a cgroup and add a task to
the 'tasks' file.
This patch removes the ns_cgroup as suggested in the following thread:
https://lists.linux-foundation.org/pipermail/containers/2009-June/018616.html
The 'cgroup_clone' function is removed because it is no longer used.
This is a userspace-visible change. Commit 45531757b4 ("cgroup: notify
ns_cgroup deprecated") (merged into 2.6.27) caused the kernel to emit a
printk warning users that the feature is planned for removal. Since that
time we have heard from XXX users who were affected by this.
Signed-off-by: Daniel Lezcano <daniel.lezcano@free.fr>
Signed-off-by: Serge E. Hallyn <serge.hallyn@canonical.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Jamal Hadi Salim <hadi@cyberus.ca>
Reviewed-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Paul Menage <menage@google.com>
Acked-by: Matt Helsley <matthltc@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add cgroup subsystem callbacks for per-thread attachment in atomic contexts
Add can_attach_task(), pre_attach(), and attach_task() as new callbacks
for cgroups's subsystem interface. Unlike can_attach and attach, these
are for per-thread operations, to be called potentially many times when
attaching an entire threadgroup.
Also, the old "bool threadgroup" interface is removed, as replaced by
this. All subsystems are modified for the new interface - of note is
cpuset, which requires from/to nodemasks for attach to be globally scoped
(though per-cpuset would work too) to persist from its pre_attach to
attach_task and attach.
This is a pre-patch for cgroup-procs-writable.patch.
Signed-off-by: Ben Blum <bblum@andrew.cmu.edu>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Matt Helsley <matthltc@us.ibm.com>
Reviewed-by: Paul Menage <menage@google.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This kernel patch adds the ability to filter monitoring based on
container groups (cgroups). This is for use in per-cpu mode only.
The cgroup to monitor is passed as a file descriptor in the pid
argument to the syscall. The file descriptor must be opened to
the cgroup name in the cgroup filesystem. For instance, if the
cgroup name is foo and cgroupfs is mounted in /cgroup, then the
file descriptor is opened to /cgroup/foo. Cgroup mode is
activated by passing PERF_FLAG_PID_CGROUP in the flags argument
to the syscall.
For instance to measure in cgroup foo on CPU1 assuming
cgroupfs is mounted under /cgroup:
struct perf_event_attr attr;
int cgroup_fd, fd;
cgroup_fd = open("/cgroup/foo", O_RDONLY);
fd = perf_event_open(&attr, cgroup_fd, 1, -1, PERF_FLAG_PID_CGROUP);
close(cgroup_fd);
Signed-off-by: Stephane Eranian <eranian@google.com>
[ added perf_cgroup_{exit,attach} ]
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <4d590250.114ddf0a.689e.4482@mx.google.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Make the ::exit method act like ::attach, it is after all very nearly
the same thing.
The bug had no effect on correctness - fixing it is an optimization for
the scheduler. Also, later perf-cgroups patches rely on it.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Paul Menage <menage@google.com>
LKML-Reference: <1297160655.13327.92.camel@laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The ns_cgroup is a control group interacting with the namespaces. When a
new namespace is created, a corresponding cgroup is automatically created
too. The cgroup name is the pid of the process who did 'unshare' or the
child of 'clone'.
This cgroup is tied with the namespace because it prevents a process to
escape the control group and use the post_clone callback, so the child
cgroup inherits the values of the parent cgroup.
Unfortunately, the more we use this cgroup and the more we are facing
problems with it:
(1) when a process unshares, the cgroup name may conflict with a
previous cgroup with the same pid, so unshare or clone return -EEXIST
(2) the cgroup creation is out of control because there may have an
application creating several namespaces where the system will
automatically create several cgroups in his back and let them on the
cgroupfs (eg. a vrf based on the network namespace).
(3) the mix of (1) and (2) force an administrator to regularly check
and clean these cgroups.
This patchset removes the ns_cgroup by adding a new flag to the cgroup and
the cgroupfs mount option. It enables the copy of the parent cgroup when
a child cgroup is created. We can then safely remove the ns_cgroup as
this flag brings a compatibility. We have now to manually create and add
the task to a cgroup, which is consistent with the cgroup framework.
This patch:
Sent as an answer to a previous thread around the ns_cgroup.
https://lists.linux-foundation.org/pipermail/containers/2009-June/018627.html
It adds a control file 'clone_children' for a cgroup. This control file
is a boolean specifying if the child cgroup should be a clone of the
parent cgroup or not. The default value is 'false'.
This flag makes the child cgroup to call the post_clone callback of all
the subsystem, if it is available.
At present, the cpuset is the only one which had implemented the
post_clone callback.
The option can be set at mount time by specifying the 'clone_children'
mount option.
Signed-off-by: Daniel Lezcano <daniel.lezcano@free.fr>
Signed-off-by: Serge E. Hallyn <serge.hallyn@canonical.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Acked-by: Paul Menage <menage@google.com>
Reviewed-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Jamal Hadi Salim <hadi@cyberus.ca>
Cc: Matt Helsley <matthltc@us.ibm.com>
Acked-by: 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>
Add cgroup_attach_task_all()
The existing cgroup_attach_task_current_cg() API is called by a thread to
attach another thread to all of its cgroups; this is unsuitable for cases
where a privileged task wants to attach itself to the cgroups of a less
privileged one, since the call must be made from the context of the target
task.
This patch adds a more generic cgroup_attach_task_all() API that allows
both the source task and to-be-moved task to be specified.
cgroup_attach_task_current_cg() becomes a specialization of the more
generic new function.
[menage@google.com: rewrote changelog]
[akpm@linux-foundation.org: address reviewer comments]
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Tested-by: Alex Williamson <alex.williamson@redhat.com>
Acked-by: Paul Menage <menage@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Ben Blum <bblum@google.com>
Cc: Sridhar Samudrala <sri@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next-2.6: (1443 commits)
phy/marvell: add 88ec048 support
igb: Program MDICNFG register prior to PHY init
e1000e: correct MAC-PHY interconnect register offset for 82579
hso: Add new product ID
can: Add driver for esd CAN-USB/2 device
l2tp: fix export of header file for userspace
can-raw: Fix skb_orphan_try handling
Revert "net: remove zap_completion_queue"
net: cleanup inclusion
phy/marvell: add 88e1121 interface mode support
u32: negative offset fix
net: Fix a typo from "dev" to "ndev"
igb: Use irq_synchronize per vector when using MSI-X
ixgbevf: fix null pointer dereference due to filter being set for VLAN 0
e1000e: Fix irq_synchronize in MSI-X case
e1000e: register pm_qos request on hardware activation
ip_fragment: fix subtracting PPPOE_SES_HLEN from mtu twice
net: Add getsockopt support for TCP thin-streams
cxgb4: update driver version
cxgb4: add new PCI IDs
...
Manually fix up conflicts in:
- drivers/net/e1000e/netdev.c: due to pm_qos registration
infrastructure changes
- drivers/net/phy/marvell.c: conflict between adding 88ec048 support
and cleaning up the IDs
- drivers/net/wireless/ipw2x00/ipw2100.c: trivial ipw2100_pm_qos_req
conflict (registration change vs marking it static)
Add a new kernel API to attach a task to current task's cgroup
in all the active hierarchies.
Signed-off-by: Sridhar Samudrala <sri@us.ibm.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Paul Menage <menage@google.com>
Acked-by: Li Zefan <lizf@cn.fujitsu.com>
PROVE_RCU has a few issues with the cpu_cgroup because the scheduler
typically holds rq->lock around the css rcu derefs but the generic
cgroup code doesn't (and can't) know about that lock.
Provide means to add extra checks to the css dereference and use that
in the scheduler to annotate its users.
The addition of rq->lock to these checks is correct because the
cgroup_subsys::attach() method takes the rq->lock for each task it
moves, therefore by holding that lock, we ensure the task is pinned to
the current cgroup and the RCU derefence is valid.
That leaves one genuine race in __sched_setscheduler() where we used
task_group() without holding any of the required locks and thus raced
with the cgroup code. Solve this by moving the check under the
appropriate lock.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Since we are unable to handle an error returned by
cftype.unregister_event() properly, let's make the callback
void-returning.
mem_cgroup_unregister_event() has been rewritten to be a "never fail"
function. On mem_cgroup_usage_register_event() we save old buffer for
thresholds array and reuse it in mem_cgroup_usage_unregister_event() to
avoid allocation.
Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Phil Carmody <ext-phil.2.carmody@nokia.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
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>
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 <lizf@cn.fujitsu.com>
Acked-by: Matt Helsley <matthltc@us.ibm.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
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 <kirill@shutemov.name>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hioryu@jp.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Acked-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: Dan Malek <dan@embeddedalley.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>
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 "<event_fd> <control_fd> <args>" 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 <kirill@shutemov.name>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Paul Menage <menage@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: Dan Malek <dan@embeddedalley.com>
Cc: Vladislav Buzov <vbuzov@embeddedalley.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Alexander Shishkin <virtuoso@slind.org>
Cc: Davide Libenzi <davidel@xmailserver.org>
Signed-off-by: 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>
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 <bblum@andrew.cmu.edu>
Acked-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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 <bblum@andrew.cmu.edu>
Acked-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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 <bblum@andrew.cmu.edu>
Acked-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Paul Menage <menage@google.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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 <nishimura@mxp.nes.nec.co.jp>
Acked-by: Paul Menage <menage@google.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Li Zefan <lizf@cn.fujitsu.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>
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 <nishimura@mxp.nes.nec.co.jp>
Acked-by: Li Zefan <lizf@cn.fujitsu.com>
Reviewed-by: Paul Menage <menage@google.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.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>
Alter the ss->can_attach and ss->attach functions to be able to deal with
a whole threadgroup at a time, for use in cgroup_attach_proc. (This is a
pre-patch to cgroup-procs-writable.patch.)
Currently, new mode of the attach function can only tell the subsystem
about the old cgroup of the threadgroup leader. No subsystem currently
needs that information for each thread that's being moved, but if one were
to be added (for example, one that counts tasks within a group) this bit
would need to be reworked a bit to tell the subsystem the right
information.
[hidave.darkstar@gmail.com: fix build]
Signed-off-by: Ben Blum <bblum@google.com>
Signed-off-by: Paul Menage <menage@google.com>
Acked-by: Li Zefan <lizf@cn.fujitsu.com>
Reviewed-by: Matt Helsley <matthltc@us.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Dave Young <hidave.darkstar@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Changes css_set freeing mechanism to be under RCU
This is a prepatch for making the procs file writable. In order to free the
old css_sets for each task to be moved as they're being moved, the freeing
mechanism must be RCU-protected, or else we would have to have a call to
synchronize_rcu() for each task before freeing its old css_set.
Signed-off-by: Ben Blum <bblum@google.com>
Signed-off-by: Paul Menage <menage@google.com>
Cc: "Paul E. McKenney" <paulmck@us.ibm.com>
Acked-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Matt Helsley <matthltc@us.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Previously there was the problem in which two processes from different pid
namespaces reading the tasks or procs file could result in one process
seeing results from the other's namespace. Rather than one pidlist for
each file in a cgroup, we now keep a list of pidlists keyed by namespace
and file type (tasks versus procs) in which entries are placed on demand.
Each pidlist has its own lock, and that the pidlists themselves are passed
around in the seq_file's private pointer means we don't have to touch the
cgroup or its master list except when creating and destroying entries.
Signed-off-by: Ben Blum <bblum@google.com>
Signed-off-by: Paul Menage <menage@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Matt Helsley <matthltc@us.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
struct cgroup used to have a bunch of fields for keeping track of the
pidlist for the tasks file. Those are now separated into a new struct
cgroup_pidlist, of which two are had, one for procs and one for tasks.
The way the seq_file operations are set up is changed so that just the
pidlist struct gets passed around as the private data.
Interface example: Suppose a multithreaded process has pid 1000 and other
threads with ids 1001, 1002, 1003:
$ cat tasks
1000
1001
1002
1003
$ cat cgroup.procs
1000
$
Signed-off-by: Ben Blum <bblum@google.com>
Signed-off-by: Paul Menage <menage@google.com>
Acked-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Matt Helsley <matthltc@us.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The following series adds a "cgroup.procs" file to each cgroup that
reports unique tgids rather than pids, and allows all threads in a
threadgroup to be atomically moved to a new cgroup.
The subsystem "attach" interface is modified to support attaching whole
threadgroups at a time, which could introduce potential problems if any
subsystem were to need to access the old cgroup of every thread being
moved. The attach interface may need to be revised if this becomes the
case.
Also added is functionality for read/write locking all CLONE_THREAD
fork()ing within a threadgroup, by means of an rwsem that lives in the
sighand_struct, for per-threadgroup-ness and also for sharing a cacheline
with the sighand's atomic count. This scheme should introduce no extra
overhead in the fork path when there's no contention.
The final patch reveals potential for a race when forking before a
subsystem's attach function is called - one potential solution in case any
subsystem has this problem is to hang on to the group's fork mutex through
the attach() calls, though no subsystem yet demonstrates need for an
extended critical section.
This patch:
Revert
commit 096b7fe012
Author: Li Zefan <lizf@cn.fujitsu.com>
AuthorDate: Wed Jul 29 15:04:04 2009 -0700
Commit: Linus Torvalds <torvalds@linux-foundation.org>
CommitDate: Wed Jul 29 19:10:35 2009 -0700
cgroups: fix pid namespace bug
This is in preparation for some clashing cgroups changes that subsume the
original commit's functionaliy.
The original commit fixed a pid namespace bug which Ben Blum fixed
independently (in the same way, but with different code) as part of a
series of patches. I played around with trying to reconcile Ben's patch
series with Li's patch, but concluded that it was simpler to just revert
Li's, given that Ben's patch series contained essentially the same fix.
Signed-off-by: Paul Menage <menage@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Matt Helsley <matthltc@us.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
After commit ec64f51545 ("cgroup: fix
frequent -EBUSY at rmdir"), cgroup's rmdir (especially against memcg)
doesn't return -EBUSY by temporary ref counts. That commit expects all
refs after pre_destroy() is temporary but...it wasn't. Then, rmdir can
wait permanently. This patch tries to fix that and change followings.
- set CGRP_WAIT_ON_RMDIR flag before pre_destroy().
- clear CGRP_WAIT_ON_RMDIR flag when the subsys finds racy case.
if there are sleeping ones, wakes them up.
- rmdir() sleeps only when CGRP_WAIT_ON_RMDIR flag is set.
Tested-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Reported-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Reviewed-by: Paul Menage <menage@google.com>
Acked-by: Balbir Sigh <balbir@linux.vnet.ibm.com>
Signed-off-by: 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>
The bug was introduced by commit cc31edceee
("cgroups: convert tasks file to use a seq_file with shared pid array").
We cache a pid array for all threads that are opening the same "tasks"
file, but the pids in the array are always from the namespace of the
last process that opened the file, so all other threads will read pids
from that namespace instead of their own namespaces.
To fix it, we maintain a list of pid arrays, which is keyed by pid_ns.
The list will be of length 1 at most time.
Reported-by: Paul Menage <menage@google.com>
Idea-by: Paul Menage <menage@google.com>
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Reviewed-by: Serge Hallyn <serue@us.ibm.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>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (28 commits)
trivial: Update my email address
trivial: NULL noise: drivers/mtd/tests/mtd_*test.c
trivial: NULL noise: drivers/media/dvb/frontends/drx397xD_fw.h
trivial: Fix misspelling of "Celsius".
trivial: remove unused variable 'path' in alloc_file()
trivial: fix a pdlfush -> pdflush typo in comment
trivial: jbd header comment typo fix for JBD_PARANOID_IOFAIL
trivial: wusb: Storage class should be before const qualifier
trivial: drivers/char/bsr.c: Storage class should be before const qualifier
trivial: h8300: Storage class should be before const qualifier
trivial: fix where cgroup documentation is not correctly referred to
trivial: Give the right path in Documentation example
trivial: MTD: remove EOL from MODULE_DESCRIPTION
trivial: Fix typo in bio_split()'s documentation
trivial: PWM: fix of #endif comment
trivial: fix typos/grammar errors in Kconfig texts
trivial: Fix misspelling of firmware
trivial: cgroups: documentation typo and spelling corrections
trivial: Update contact info for Jochen Hein
trivial: fix typo "resgister" -> "register"
...
We need to pass some data to test_task() or process_task() in some cases.
Will be used later.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.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>
This patch tries to fix OOM Killer problems caused by hierarchy.
Now, memcg itself has OOM KILL function (in oom_kill.c) and tries to
kill a task in memcg.
But, when hierarchy is used, it's broken and correct task cannot
be killed. For example, in following cgroup
/groupA/ hierarchy=1, limit=1G,
01 nolimit
02 nolimit
All tasks' memory usage under /groupA, /groupA/01, groupA/02 is limited to
groupA's 1Gbytes but OOM Killer just kills tasks in groupA.
This patch provides makes the bad process be selected from all tasks
under hierarchy. BTW, currently, oom_jiffies is updated against groupA
in above case. oom_jiffies of tree should be updated.
To see how oom_jiffies is used, please check mem_cgroup_oom_called()
callers.
[akpm@linux-foundation.org: build fix]
[akpm@linux-foundation.org: const fix]
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>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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>
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>
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>
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>
Fix the style of some multi-line comments in cgroup.h to match
Documentation/CodingStyle
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>
cgroup documentation was moved to Documentation/cgroups/. There are some
places that still refer to Documentation/controllers/,
Documentation/cgroups.txt and Documentation/cpusets.txt. Fix those.
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@holoscopio.com>
Reviewed-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Paul Menage <menage@google.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
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>
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>
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>
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>
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>
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>
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>
The choice of real/dummy declaration for cgroup_mm_owner_callbacks()
shouldn't be based on CONFIG_MM_OWNER, but on CONFIG_CGROUPS. Otherwise
kernel/exit.c fails to compile when something other than a cgroups
controller selects CONFIG_MM_OWNER
Signed-off-by: Paul Menage <menage@google.com>
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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>
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>
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>
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>
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>
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>
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>
This patch removes some extraneous spaces from method declarations in
struct cftype, to fit in with conventional kernel style.
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
Tejun Heo
Linus Torvalds
Daniel Wagner
Aristeu Rozanski
Li Zefan
Hugh Dickins
Li Zefan
Al Viro
Andrew Bresticker
Michal Hocko
Daniel Lezcano
Ben Blum
Lucas De Marchi
Stephane Eranian
Peter Zijlstra
Uwe Kleine-König
Ingo Molnar
Michael S. Tsirkin
Arnd Bergmann
Sridhar Samudrala
Kirill A. Shutemov
Daisuke Nishimura
Paul E. McKenney
Alexey Dobriyan
Ben Blum
Paul Menage
KAMEZAWA Hiroyuki
Grzegorz Nosek
Thadeu Lima de Souza Cascardo
Lai Jiangshan
Hugh Dickins
Balbir Singh
Serge E. Hallyn
Pavel Emelyanov