diff options
| -rw-r--r-- | include/linux/cgroup.h | 9 | ||||
| -rw-r--r-- | kernel/cgroup.c | 59 | ||||
| -rw-r--r-- | mm/memcontrol.c | 4 |
3 files changed, 49 insertions, 23 deletions
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h index 793f70a48820..2dfabb3b749a 100644 --- a/include/linux/cgroup.h +++ b/include/linux/cgroup.h @@ -62,6 +62,12 @@ struct cgroup_subsys_state { /* the parent css */ struct cgroup_subsys_state *parent; + /* + * Subsys-unique ID. 0 is unused and root is always 1. The + * matching css can be looked up using css_from_id(). + */ + int id; + unsigned int flags; /* percpu_ref killing and RCU release */ @@ -655,6 +661,9 @@ struct cgroup_subsys { /* link to parent, protected by cgroup_lock() */ struct cgroup_root *root; + /* idr for css->id */ + struct idr css_idr; + /* * List of cftypes. Each entry is the first entry of an array * terminated by zero length name. diff --git a/kernel/cgroup.c b/kernel/cgroup.c index f1c98c527b2d..a1a20e8c973a 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -100,8 +100,8 @@ static DECLARE_RWSEM(css_set_rwsem); #endif /* - * Protects cgroup_idr so that IDs can be released without grabbing - * cgroup_mutex. + * Protects cgroup_idr and css_idr so that IDs can be released without + * grabbing cgroup_mutex. */ static DEFINE_SPINLOCK(cgroup_idr_lock); @@ -1089,12 +1089,6 @@ static void cgroup_put(struct cgroup *cgrp) if (WARN_ON_ONCE(cgrp->parent && !cgroup_is_dead(cgrp))) return; - /* - * XXX: cgrp->id is only used to look up css's. As cgroup and - * css's lifetimes will be decoupled, it should be made - * per-subsystem and moved to css->id so that lookups are - * successful until the target css is released. - */ cgroup_idr_remove(&cgrp->root->cgroup_idr, cgrp->id); cgrp->id = -1; @@ -4104,8 +4098,11 @@ static void css_release(struct percpu_ref *ref) { struct cgroup_subsys_state *css = container_of(ref, struct cgroup_subsys_state, refcnt); + struct cgroup_subsys *ss = css->ss; + + RCU_INIT_POINTER(css->cgroup->subsys[ss->id], NULL); + cgroup_idr_remove(&ss->css_idr, css->id); - RCU_INIT_POINTER(css->cgroup->subsys[css->ss->id], NULL); call_rcu(&css->rcu_head, css_free_rcu_fn); } @@ -4195,9 +4192,17 @@ static int create_css(struct cgroup *cgrp, struct cgroup_subsys *ss) if (err) goto err_free_css; + err = cgroup_idr_alloc(&ss->css_idr, NULL, 2, 0, GFP_NOWAIT); + if (err < 0) + goto err_free_percpu_ref; + css->id = err; + err = cgroup_populate_dir(cgrp, 1 << ss->id); if (err) - goto err_free_percpu_ref; + goto err_free_id; + + /* @css is ready to be brought online now, make it visible */ + cgroup_idr_replace(&ss->css_idr, css, css->id); err = online_css(css); if (err) @@ -4216,6 +4221,8 @@ static int create_css(struct cgroup *cgrp, struct cgroup_subsys *ss) err_clear_dir: cgroup_clear_dir(css->cgroup, 1 << css->ss->id); +err_free_id: + cgroup_idr_remove(&ss->css_idr, css->id); err_free_percpu_ref: percpu_ref_cancel_init(&css->refcnt); err_free_css: @@ -4642,7 +4649,7 @@ static struct kernfs_syscall_ops cgroup_kf_syscall_ops = { .rename = cgroup_rename, }; -static void __init cgroup_init_subsys(struct cgroup_subsys *ss) +static void __init cgroup_init_subsys(struct cgroup_subsys *ss, bool early) { struct cgroup_subsys_state *css; @@ -4651,6 +4658,7 @@ static void __init cgroup_init_subsys(struct cgroup_subsys *ss) mutex_lock(&cgroup_tree_mutex); mutex_lock(&cgroup_mutex); + idr_init(&ss->css_idr); INIT_LIST_HEAD(&ss->cfts); /* Create the root cgroup state for this subsystem */ @@ -4659,6 +4667,13 @@ static void __init cgroup_init_subsys(struct cgroup_subsys *ss) /* We don't handle early failures gracefully */ BUG_ON(IS_ERR(css)); init_and_link_css(css, ss, &cgrp_dfl_root.cgrp); + if (early) { + /* idr_alloc() can't be called safely during early init */ + css->id = 1; + } else { + css->id = cgroup_idr_alloc(&ss->css_idr, css, 1, 2, GFP_KERNEL); + BUG_ON(css->id < 0); + } /* Update the init_css_set to contain a subsys * pointer to this state - since the subsystem is @@ -4709,7 +4724,7 @@ int __init cgroup_init_early(void) ss->name = cgroup_subsys_name[i]; if (ss->early_init) - cgroup_init_subsys(ss); + cgroup_init_subsys(ss, true); } return 0; } @@ -4741,8 +4756,16 @@ int __init cgroup_init(void) mutex_unlock(&cgroup_tree_mutex); for_each_subsys(ss, ssid) { - if (!ss->early_init) - cgroup_init_subsys(ss); + if (ss->early_init) { + struct cgroup_subsys_state *css = + init_css_set.subsys[ss->id]; + + css->id = cgroup_idr_alloc(&ss->css_idr, css, 1, 2, + GFP_KERNEL); + BUG_ON(css->id < 0); + } else { + cgroup_init_subsys(ss, false); + } list_add_tail(&init_css_set.e_cset_node[ssid], &cgrp_dfl_root.cgrp.e_csets[ssid]); @@ -5196,14 +5219,8 @@ struct cgroup_subsys_state *css_tryget_from_dir(struct dentry *dentry, */ struct cgroup_subsys_state *css_from_id(int id, struct cgroup_subsys *ss) { - struct cgroup *cgrp; - WARN_ON_ONCE(!rcu_read_lock_held()); - - cgrp = idr_find(&ss->root->cgroup_idr, id); - if (cgrp) - return cgroup_css(cgrp, ss); - return NULL; + return idr_find(&ss->css_idr, id); } #ifdef CONFIG_CGROUP_DEBUG diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 1d0b29715b73..c3f82f69ef58 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -527,7 +527,7 @@ static inline bool mem_cgroup_is_root(struct mem_cgroup *memcg) static inline unsigned short mem_cgroup_id(struct mem_cgroup *memcg) { - return memcg->css.cgroup->id; + return memcg->css.id; } static inline struct mem_cgroup *mem_cgroup_from_id(unsigned short id) @@ -6401,7 +6401,7 @@ mem_cgroup_css_online(struct cgroup_subsys_state *css) struct mem_cgroup *memcg = mem_cgroup_from_css(css); struct mem_cgroup *parent = mem_cgroup_from_css(css_parent(css)); - if (css->cgroup->id > MEM_CGROUP_ID_MAX) + if (css->id > MEM_CGROUP_ID_MAX) return -ENOSPC; if (!parent) |