On Thu, Apr 29, 2021 at 02:01:10PM +0200, Christian Brauner wrote: > From: Christian Brauner <christian.brauner@xxxxxxxxxx> > > Give a brief overview of the cgroup.kill functionality. > > Cc: Roman Gushchin <guro@xxxxxx> > Cc: Tejun Heo <tj@xxxxxxxxxx> > Cc: cgroups@xxxxxxxxxxxxxxx > Signed-off-by: Christian Brauner <christian.brauner@xxxxxxxxxx> > --- > Documentation/admin-guide/cgroup-v2.rst | 17 +++++++++++++++++ > 1 file changed, 17 insertions(+) > > diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst > index 64c62b979f2f..c9f656a84590 100644 > --- a/Documentation/admin-guide/cgroup-v2.rst > +++ b/Documentation/admin-guide/cgroup-v2.rst > @@ -949,6 +949,23 @@ All cgroup core files are prefixed with "cgroup." > it's possible to delete a frozen (and empty) cgroup, as well as > create new sub-cgroups. > > + cgroup.kill > + A write-only single value file which exists in non-root cgroups. > + The only allowed value is "1". > + > + Writing "1" to the file causes the cgroup and all descendant cgroups to > + be killed. This means that all processes located in the affected cgroup > + tree will be killed via SIGKILL. > + > + Killing a cgroup tree will deal with concurrent forks appropriately and > + is protected against migrations. If callers require strict guarantees > + they can issue the cgroup.kill request after a freezing the cgroup via > + cgroup.freeze. Hm, is it necessarily? What additional guarantees adds using the freezer? > + > + In a threaded cgroup, writing this file fails with EOPNOTSUPP as > + killing cgroups is a process directed operation, i.e. it affects > + the whole thread-group. > + > Controllers > =========== > > -- > 2.27.0 >
