cgroup: Set CGRP_RELEASABLE when adding to a cgroup
Changes the meaning of CGRP_RELEASABLE to be set on any cgroup
that has ever had a task or cgroup in it, or had css_get called
on it. The bit is set in cgroup_attach_task, cgroup_create,
and __css_get. It is not necessary to set the bit in
cgroup_fork, as the task is either in the root cgroup, in
which can never be released, or the task it was forked from
already set the bit in croup_attach_task.
Signed-off-by: Colin Cross <ccross@android.com>
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index ab4ac0c..1af8c35 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -84,12 +84,6 @@
CSS_REMOVED, /* This CSS is dead */
};
-/* Caller must verify that the css is not for root cgroup */
-static inline void __css_get(struct cgroup_subsys_state *css, int count)
-{
- atomic_add(count, &css->refcnt);
-}
-
/*
* Call css_get() to hold a reference on the css; it can be used
* for a reference obtained via:
@@ -97,6 +91,7 @@
* - task->cgroups for a locked task
*/
+extern void __css_get(struct cgroup_subsys_state *css, int count);
static inline void css_get(struct cgroup_subsys_state *css)
{
/* We don't need to reference count the root state */
@@ -143,10 +138,7 @@
enum {
/* Control Group is dead */
CGRP_REMOVED,
- /*
- * Control Group has previously had a child cgroup or a task,
- * but no longer (only if CGRP_NOTIFY_ON_RELEASE is set)
- */
+ /* Control Group has ever had a child cgroup or a task */
CGRP_RELEASABLE,
/* Control Group requires release notifications to userspace */
CGRP_NOTIFY_ON_RELEASE,