The ns_cgroup will be removed very soon. Let's warn, for this
version, ns_cgroup is deprecated.
Make ns_cgroup and clone_children exclusive. If the clone_children
is set and the ns_cgroup is mounted, let's fail with EINVAL when
the ns_cgroup subsys is created (a printk will help the user to
understand why the creation fails).
Update the feature remove schedule file with the deprecated ns_cgroup.
Signed-off-by: Daniel Lezcano <daniel.lezcano@xxxxxxx>
---
Documentation/feature-removal-schedule.txt | 17 +++++++++++++++++
kernel/ns_cgroup.c | 8 ++++++++
2 files changed, 25 insertions(+), 0 deletions(-)
diff --git a/Documentation/feature-removal-schedule.txt b/Documentation/feature-removal-schedule.txt
index b32911b..a39e2f3 100644
--- a/Documentation/feature-removal-schedule.txt
+++ b/Documentation/feature-removal-schedule.txt
@@ -545,4 +545,21 @@ Why: This is a legacy interface which have been replaced by a more
Who: NeilBrown <neilb@xxxxxxx>
----------------------------
+
+What: namespace cgroup (ns_cgroup)
+When: 2.6.38
+Why: The ns_cgroup 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 is 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.
+Who: Daniel Lezcano <daniel.lezcano@xxxxxxx>
+
+----------------------------
diff --git a/kernel/ns_cgroup.c b/kernel/ns_cgroup.c
index 2a5dfec..2c98ad9 100644
--- a/kernel/ns_cgroup.c
+++ b/kernel/ns_cgroup.c
@@ -85,6 +85,14 @@ static struct cgroup_subsys_state *ns_create(struct cgroup_subsys *ss,
return ERR_PTR(-EPERM);
if (!cgroup_is_descendant(cgroup, current))
return ERR_PTR(-EPERM);
+ if (test_bit(CGRP_CLONE_CHILDREN, &cgroup->flags)) {
+ printk("ns_cgroup can't be created with parent "
+ "'clone_children' set.\n");
+ return ERR_PTR(-EINVAL);
+ }
+
+ printk_once("ns_cgroup deprecated: consider using the "
+ "'clone_children' flag without the ns_cgroup.\n");
ns_cgroup = kzalloc(sizeof(*ns_cgroup), GFP_KERNEL);
if (!ns_cgroup)
--
1.7.0.4
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