struct blkio_cgroup blkio_root_cgroup = { .weight = 2*BLKIO_WEIGHT_DEFAULT };
EXPORT_SYMBOL_GPL(blkio_root_cgroup);
- static struct cgroup_subsys_state *blkiocg_create(struct cgroup_subsys *,
- struct cgroup *);
- static int blkiocg_can_attach(struct cgroup_subsys *, struct cgroup *,
- struct cgroup_taskset *);
- static int blkiocg_pre_destroy(struct cgroup_subsys *, struct cgroup *);
- static void blkiocg_destroy(struct cgroup_subsys *, struct cgroup *);
- static int blkiocg_populate(struct cgroup_subsys *, struct cgroup *);
-
+static struct blkio_policy_type *blkio_policy[BLKIO_NR_POLICIES];
+
/* for encoding cft->private value on file */
#define BLKIOFILE_PRIVATE(x, val) (((x) << 16) | (val))
/* What policy owns the file, proportional or throttle */
#define BLKIOFILE_POLICY(val) (((val) >> 16) & 0xffff)
#define BLKIOFILE_ATTR(val) ((val) & 0xffff)
- struct cgroup_subsys blkio_subsys = {
- .name = "blkio",
- .create = blkiocg_create,
- .can_attach = blkiocg_can_attach,
- .pre_destroy = blkiocg_pre_destroy,
- .destroy = blkiocg_destroy,
- .populate = blkiocg_populate,
- .subsys_id = blkio_subsys_id,
- .module = THIS_MODULE,
- };
- EXPORT_SYMBOL_GPL(blkio_subsys);
-static inline void blkio_policy_insert_node(struct blkio_cgroup *blkcg,
- struct blkio_policy_node *pn)
-{
- list_add(&pn->node, &blkcg->policy_list);
-}
-
-static inline bool cftype_blkg_same_policy(struct cftype *cft,
- struct blkio_group *blkg)
-{
- enum blkio_policy_id plid = BLKIOFILE_POLICY(cft->private);
-
- if (blkg->plid == plid)
- return 1;
-
- return 0;
-}
-
-/* Determines if policy node matches cgroup file being accessed */
-static inline bool pn_matches_cftype(struct cftype *cft,
- struct blkio_policy_node *pn)
-{
- enum blkio_policy_id plid = BLKIOFILE_POLICY(cft->private);
- int fileid = BLKIOFILE_ATTR(cft->private);
-
- return (plid == pn->plid && fileid == pn->fileid);
-}
-
-/* Must be called with blkcg->lock held */
-static inline void blkio_policy_delete_node(struct blkio_policy_node *pn)
-{
- list_del(&pn->node);
-}
-
-/* Must be called with blkcg->lock held */
-static struct blkio_policy_node *
-blkio_policy_search_node(const struct blkio_cgroup *blkcg, dev_t dev,
- enum blkio_policy_id plid, int fileid)
-{
- struct blkio_policy_node *pn;
-
- list_for_each_entry(pn, &blkcg->policy_list, node) {
- if (pn->dev == dev && pn->plid == plid && pn->fileid == fileid)
- return pn;
- }
-
- return NULL;
-}
--
struct blkio_cgroup *cgroup_to_blkio_cgroup(struct cgroup *cgroup)
{
return container_of(cgroup_subsys_state(cgroup, blkio_subsys_id),
.read_map = blkiocg_file_read_map,
},
#endif
+ { } /* terminate */
};
- static int blkiocg_populate(struct cgroup_subsys *subsys, struct cgroup *cgroup)
- {
- return cgroup_add_files(cgroup, subsys, blkio_files,
- ARRAY_SIZE(blkio_files));
- }
-
-static void blkiocg_destroy(struct cgroup *cgroup)
+/**
+ * blkiocg_pre_destroy - cgroup pre_destroy callback
- * @subsys: cgroup subsys
+ * @cgroup: cgroup of interest
+ *
+ * This function is called when @cgroup is about to go away and responsible
+ * for shooting down all blkgs associated with @cgroup. blkgs should be
+ * removed while holding both q and blkcg locks. As blkcg lock is nested
+ * inside q lock, this function performs reverse double lock dancing.
+ *
+ * This is the blkcg counterpart of ioc_release_fn().
+ */
- static int blkiocg_pre_destroy(struct cgroup_subsys *subsys,
- struct cgroup *cgroup)
++static int blkiocg_pre_destroy(struct cgroup *cgroup)
{
struct blkio_cgroup *blkcg = cgroup_to_blkio_cgroup(cgroup);
- unsigned long flags;
- struct blkio_group *blkg;
- void *key;
- struct blkio_policy_type *blkiop;
- struct blkio_policy_node *pn, *pntmp;
- rcu_read_lock();
- do {
- spin_lock_irqsave(&blkcg->lock, flags);
+ spin_lock_irq(&blkcg->lock);
- if (hlist_empty(&blkcg->blkg_list)) {
- spin_unlock_irqrestore(&blkcg->lock, flags);
- break;
+ while (!hlist_empty(&blkcg->blkg_list)) {
+ struct blkio_group *blkg = hlist_entry(blkcg->blkg_list.first,
+ struct blkio_group, blkcg_node);
+ struct request_queue *q = blkg->q;
+
+ if (spin_trylock(q->queue_lock)) {
+ blkg_destroy(blkg);
+ spin_unlock(q->queue_lock);
+ } else {
+ spin_unlock_irq(&blkcg->lock);
+ cpu_relax();
+ spin_lock_irq(&blkcg->lock);
}
+ }
- blkg = hlist_entry(blkcg->blkg_list.first, struct blkio_group,
- blkcg_node);
- key = rcu_dereference(blkg->key);
- __blkiocg_del_blkio_group(blkg);
-
- spin_unlock_irqrestore(&blkcg->lock, flags);
-
- /*
- * This blkio_group is being unlinked as associated cgroup is
- * going away. Let all the IO controlling policies know about
- * this event.
- */
- spin_lock(&blkio_list_lock);
- list_for_each_entry(blkiop, &blkio_list, list) {
- if (blkiop->plid != blkg->plid)
- continue;
- blkiop->ops.blkio_unlink_group_fn(key, blkg);
- }
- spin_unlock(&blkio_list_lock);
- } while (1);
+ spin_unlock_irq(&blkcg->lock);
+ return 0;
+}
- static void blkiocg_destroy(struct cgroup_subsys *subsys, struct cgroup *cgroup)
- list_for_each_entry_safe(pn, pntmp, &blkcg->policy_list, node) {
- blkio_policy_delete_node(pn);
- kfree(pn);
- }
++static void blkiocg_destroy(struct cgroup *cgroup)
+{
+ struct blkio_cgroup *blkcg = cgroup_to_blkio_cgroup(cgroup);
- free_css_id(&blkio_subsys, &blkcg->css);
- rcu_read_unlock();
if (blkcg != &blkio_root_cgroup)
kfree(blkcg);
}
- static struct cgroup_subsys_state *
- blkiocg_create(struct cgroup_subsys *subsys, struct cgroup *cgroup)
+ static struct cgroup_subsys_state *blkiocg_create(struct cgroup *cgroup)
{
+ static atomic64_t id_seq = ATOMIC64_INIT(0);
struct blkio_cgroup *blkcg;
struct cgroup *parent = cgroup->parent;
}
}
- .attach = blkiocg_attach,
+static void blkcg_bypass_end(void)
+ __releases(&all_q_mutex)
+{
+ struct request_queue *q;
+
+ list_for_each_entry(q, &all_q_list, all_q_node)
+ blk_queue_bypass_end(q);
+
+ mutex_unlock(&all_q_mutex);
+}
+
+ struct cgroup_subsys blkio_subsys = {
+ .name = "blkio",
+ .create = blkiocg_create,
+ .can_attach = blkiocg_can_attach,
-#ifdef CONFIG_BLK_CGROUP
- /* note: blkio_subsys_id is otherwise defined in blk-cgroup.h */
++ .pre_destroy = blkiocg_pre_destroy,
+ .destroy = blkiocg_destroy,
-#endif
+ .subsys_id = blkio_subsys_id,
- .use_id = 1,
+ .base_cftypes = blkio_files,
+ .module = THIS_MODULE,
+ };
+ EXPORT_SYMBOL_GPL(blkio_subsys);
+
void blkio_policy_register(struct blkio_policy_type *blkiop)
{
+ struct request_queue *q;
+
+ blkcg_bypass_start();
spin_lock(&blkio_list_lock);
+
+ BUG_ON(blkio_policy[blkiop->plid]);
+ blkio_policy[blkiop->plid] = blkiop;
list_add_tail(&blkiop->list, &blkio_list);
+
spin_unlock(&blkio_list_lock);
+ list_for_each_entry(q, &all_q_list, all_q_node)
+ update_root_blkg_pd(q, blkiop->plid);
+ blkcg_bypass_end();
}
EXPORT_SYMBOL_GPL(blkio_policy_register);
projects / karo-tx-linux.git / commitdiff