diff options
| -rw-r--r-- | include/linux/cgroup.h | 11 | ||||
| -rw-r--r-- | kernel/cgroup.c | 11 |
2 files changed, 17 insertions, 5 deletions
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h index 76dadd77a120..1737db0c63fe 100644 --- a/include/linux/cgroup.h +++ b/include/linux/cgroup.h @@ -77,6 +77,7 @@ struct cgroup_subsys_state { /* bits in struct cgroup_subsys_state flags field */ enum { + CSS_NO_REF = (1 << 0), /* no reference counting for this css */ CSS_ONLINE = (1 << 1), /* between ->css_online() and ->css_offline() */ }; @@ -88,7 +89,8 @@ enum { */ static inline void css_get(struct cgroup_subsys_state *css) { - percpu_ref_get(&css->refcnt); + if (!(css->flags & CSS_NO_REF)) + percpu_ref_get(&css->refcnt); } /** @@ -103,7 +105,9 @@ static inline void css_get(struct cgroup_subsys_state *css) */ static inline bool css_tryget_online(struct cgroup_subsys_state *css) { - return percpu_ref_tryget_live(&css->refcnt); + if (!(css->flags & CSS_NO_REF)) + return percpu_ref_tryget_live(&css->refcnt); + return true; } /** @@ -114,7 +118,8 @@ static inline bool css_tryget_online(struct cgroup_subsys_state *css) */ static inline void css_put(struct cgroup_subsys_state *css) { - percpu_ref_put(&css->refcnt); + if (!(css->flags & CSS_NO_REF)) + percpu_ref_put(&css->refcnt); } /* bits in struct cgroup flags field */ diff --git a/kernel/cgroup.c b/kernel/cgroup.c index c01e8e8dfad0..0343d7ee6d62 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -4593,11 +4593,17 @@ static void __init cgroup_init_subsys(struct cgroup_subsys *ss, bool early) /* We don't handle early failures gracefully */ BUG_ON(IS_ERR(css)); init_and_link_css(css, ss, &cgrp_dfl_root.cgrp); + + /* + * Root csses are never destroyed and we can't initialize + * percpu_ref during early init. Disable refcnting. + */ + css->flags |= CSS_NO_REF; + if (early) { /* allocation can't be done safely during early init */ css->id = 1; } else { - BUG_ON(percpu_ref_init(&css->refcnt, css_release)); css->id = cgroup_idr_alloc(&ss->css_idr, css, 1, 2, GFP_KERNEL); BUG_ON(css->id < 0); } @@ -4636,6 +4642,8 @@ int __init cgroup_init_early(void) int i; init_cgroup_root(&cgrp_dfl_root, &opts); + cgrp_dfl_root.cgrp.self.flags |= CSS_NO_REF; + RCU_INIT_POINTER(init_task.cgroups, &init_css_set); for_each_subsys(ss, i) { @@ -4684,7 +4692,6 @@ int __init cgroup_init(void) struct cgroup_subsys_state *css = init_css_set.subsys[ss->id]; - BUG_ON(percpu_ref_init(&css->refcnt, css_release)); css->id = cgroup_idr_alloc(&ss->css_idr, css, 1, 2, GFP_KERNEL); BUG_ON(css->id < 0); |