From: Christian Brauner <christian.brauner@xxxxxxxxxx> Give a brief overview of the cgroup.kill functionality. Link: https://lore.kernel.org/r/20210503143922.3093755-2-brauner@xxxxxxxxxx Cc: Roman Gushchin <guro@xxxxxx> Cc: Tejun Heo <tj@xxxxxxxxxx> Cc: cgroups@xxxxxxxxxxxxxxx Reviewed-by: Shakeel Butt <shakeelb@xxxxxxxxxx> Signed-off-by: Christian Brauner <christian.brauner@xxxxxxxxxx> --- /* v2 */ - Roman Gushchin <guro@xxxxxx>: - Drop sentence that mentions combined useage of cgroup.kill and cgroup.freezer. /* v3 */ unchanged --- Documentation/admin-guide/cgroup-v2.rst | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst index 64c62b979f2f..6adc749d863e 100644 --- a/Documentation/admin-guide/cgroup-v2.rst +++ b/Documentation/admin-guide/cgroup-v2.rst @@ -949,6 +949,21 @@ 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. + + 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
