path: root/Documentation/cgroups
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authorTejun Heo <tj@kernel.org>2013-04-12 10:29:04 -0700
committerTejun Heo <tj@kernel.org>2013-04-12 10:29:04 -0700
commit26d5bbe5ba2073fc7ef9e69a55543b2376f5bad0 (patch)
treed4dcfdec4d3046bb3cee35864264669d44a3a3dc /Documentation/cgroups
parentef824fa129b7579f56b92d466ecda2e378879806 (diff)
Revert "cgroup: remove bind() method from cgroup_subsys."
This reverts commit 84cfb6ab484b442d5115eb3baf9db7d74a3ea626. There are scheduled changes which make use of the removed callback. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Rami Rosen <ramirose@gmail.com> Cc: Li Zefan <lizefan@huawei.com>
Diffstat (limited to 'Documentation/cgroups')
1 files changed, 15 insertions, 5 deletions
diff --git a/Documentation/cgroups/cgroups.txt b/Documentation/cgroups/cgroups.txt
index 2b51e12ce17..638bf17ff86 100644
--- a/Documentation/cgroups/cgroups.txt
+++ b/Documentation/cgroups/cgroups.txt
@@ -211,9 +211,10 @@ matches, and any of the requested subsystems are in use in an existing
hierarchy, the mount will fail with -EBUSY. Otherwise, a new hierarchy
is activated, associated with the requested subsystems.
-It's not possible to bind a new subsystem to an active cgroup
-hierarchy, or to unbind a subsystem from an active cgroup
+It's not currently possible to bind a new subsystem to an active
+cgroup hierarchy, or to unbind a subsystem from an active cgroup
+hierarchy. This may be possible in future, but is fraught with nasty
+error-recovery issues.
When a cgroup filesystem is unmounted, if there are any
child cgroups created below the top-level cgroup, that hierarchy
@@ -381,8 +382,10 @@ To Specify a hierarchy's release_agent:
Note that specifying 'release_agent' more than once will return failure.
-Note that changing the set of subsystems is only supported when the
-hierarchy consists of a single (root) cgroup.
+Note that changing the set of subsystems is currently only supported
+when the hierarchy consists of a single (root) cgroup. Supporting
+the ability to arbitrarily bind/unbind subsystems from an existing
+cgroup hierarchy is intended to be implemented in the future.
Then under /sys/fs/cgroup/rg1 you can find a tree that corresponds to the
tree of the cgroups in the system. For instance, /sys/fs/cgroup/rg1
@@ -640,6 +643,13 @@ void exit(struct task_struct *task)
Called during task exit.
+void bind(struct cgroup *root)
+(cgroup_mutex held by caller)
+Called when a cgroup subsystem is rebound to a different hierarchy
+and root cgroup. Currently this will only involve movement between
+the default hierarchy (which never has sub-cgroups) and a hierarchy
+that is being created/destroyed (and hence has no sub-cgroups).
4. Extended attribute usage