If cgroup is mounted in container,move container's
tasks to the top cgroup of container.
If cgroup is unmounted in container,move container's
tasks back to the host's cgroup.
Signed-off-by: Gao feng <gaofeng@xxxxxxxxxxxxxx>
---
kernel/cgroup.c | 48 ++++++++++++++++++++++++++++++++++++++++++------
1 files changed, 42 insertions(+), 6 deletions(-)
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index ac61027..e077660 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -1110,6 +1110,7 @@ static int __rebind_subsystems_ns(struct cgroupfs_root *root,
struct cgroup *parent = NULL;
struct cgroupfs_root *top_root = NULL;
unsigned long bit;
+ struct tgid_iter iter;
int i;
removed_mask = root->actual_subsys_mask & ~final_subsys_mask;
@@ -1126,6 +1127,25 @@ static int __rebind_subsystems_ns(struct cgroupfs_root *root,
BUG_ON(parent == NULL);
}
+ /*
+ * Attach container's tasks to host's cgroup,since this
+ * top cgroup may be destroyed or changed. If task attaching
+ * failed, return error immediately.
+ */
+ if (cgrp->parent) {
+ int error;
+ iter.task = NULL;
+ iter.tgid = 1;
+ for (iter = next_tgid(root->pid_ns, iter); iter.task;
+ iter.tgid += 1, iter = next_tgid(root->pid_ns, iter)) {
+ error = cgroup_attach_task(cgrp->parent, iter.task);
+ if (error && error != -ESRCH) {
+ put_task_struct(iter.task);
+ return error;
+ }
+ }
+ }
+
/* Process each subsystem */
for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) {
struct cgroup_subsys *ss = subsys[i];
@@ -1158,15 +1178,31 @@ static int __rebind_subsystems_ns(struct cgroupfs_root *root,
}
}
- root->top_root = top_root;
- cgrp->parent = parent;
-
/* Link to new top_root or unlink when umounting */
- if (top_root)
+ if (top_root) {
+ root->top_root = top_root;
+ cgrp->parent = parent;
+ /*
+ * Attach container's tasks to the new top cgroup.
+ * We don't care whether some tasks are not attached
+ * to this cgroup successfully, it totally does no harm.
+ */
+ iter.task = NULL;
+ iter.tgid = 1;
+ for (iter = next_tgid(root->pid_ns, iter); iter.task;
+ iter.tgid += 1, iter = next_tgid(root->pid_ns, iter)) {
+ cgroup_attach_task(cgrp, iter.task);
+ }
+ atomic_inc(&top_root->sb->s_active);
+ top_root->number_of_cgroups++;
list_move_tail(&cgrp->allcg_node, &top_root->allcg_list);
- else
+ } else {
+ root->top_root->number_of_cgroups--;
+ atomic_dec(&root->top_root->sb->s_active);
+ root->top_root = NULL;
+ cgrp->parent = NULL;
list_del_init(&cgrp->allcg_node);
-
+ }
return 0;
out:
for (i = 0; i < CGROUP_SUBSYS_COUNT; i++) {
--
1.7.7.6
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