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authorTejun Heo <tj@kernel.org>2013-01-09 08:05:12 -0800
committerTejun Heo <tj@kernel.org>2013-01-09 08:05:12 -0800
commitf427d909648aa592c9588d0f66b5b457752a0cd1 (patch)
treed6f91a6d46a1302f0cca6137851f0806364b7965 /block
parentb276a876a014c5fa58a16f247c0933f6c42112e3 (diff)
downloadlinaro-lsk-f427d909648aa592c9588d0f66b5b457752a0cd1.tar.gz
blkcg: implement blkcg_policy->on/offline_pd_fn() and blkcg_gq->online
Add two blkcg_policy methods, ->online_pd_fn() and ->offline_pd_fn(), which are invoked as the policy_data gets activated and deactivated while holding both blkcg and q locks. Also, add blkcg_gq->online bool, which is set and cleared as the blkcg_gq gets activated and deactivated. This flag also is toggled while holding both blkcg and q locks. These will be used to implement hierarchical stats. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Vivek Goyal <vgoyal@redhat.com>
Diffstat (limited to 'block')
-rw-r--r--block/blk-cgroup.c21
-rw-r--r--block/blk-cgroup.h7
2 files changed, 27 insertions, 1 deletions
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 3a8de321d1f..4d625d28e07 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -182,7 +182,7 @@ static struct blkcg_gq *blkg_create(struct blkcg *blkcg,
struct blkcg_gq *new_blkg)
{
struct blkcg_gq *blkg;
- int ret;
+ int i, ret;
WARN_ON_ONCE(!rcu_read_lock_held());
lockdep_assert_held(q->queue_lock);
@@ -218,7 +218,15 @@ static struct blkcg_gq *blkg_create(struct blkcg *blkcg,
if (likely(!ret)) {
hlist_add_head_rcu(&blkg->blkcg_node, &blkcg->blkg_list);
list_add(&blkg->q_node, &q->blkg_list);
+
+ for (i = 0; i < BLKCG_MAX_POLS; i++) {
+ struct blkcg_policy *pol = blkcg_policy[i];
+
+ if (blkg->pd[i] && pol->pd_online_fn)
+ pol->pd_online_fn(blkg);
+ }
}
+ blkg->online = true;
spin_unlock(&blkcg->lock);
if (!ret)
@@ -291,6 +299,7 @@ EXPORT_SYMBOL_GPL(blkg_lookup_create);
static void blkg_destroy(struct blkcg_gq *blkg)
{
struct blkcg *blkcg = blkg->blkcg;
+ int i;
lockdep_assert_held(blkg->q->queue_lock);
lockdep_assert_held(&blkcg->lock);
@@ -299,6 +308,14 @@ static void blkg_destroy(struct blkcg_gq *blkg)
WARN_ON_ONCE(list_empty(&blkg->q_node));
WARN_ON_ONCE(hlist_unhashed(&blkg->blkcg_node));
+ for (i = 0; i < BLKCG_MAX_POLS; i++) {
+ struct blkcg_policy *pol = blkcg_policy[i];
+
+ if (blkg->pd[i] && pol->pd_offline_fn)
+ pol->pd_offline_fn(blkg);
+ }
+ blkg->online = false;
+
radix_tree_delete(&blkcg->blkg_tree, blkg->q->id);
list_del_init(&blkg->q_node);
hlist_del_init_rcu(&blkg->blkcg_node);
@@ -956,6 +973,8 @@ void blkcg_deactivate_policy(struct request_queue *q,
/* grab blkcg lock too while removing @pd from @blkg */
spin_lock(&blkg->blkcg->lock);
+ if (pol->pd_offline_fn)
+ pol->pd_offline_fn(blkg);
if (pol->pd_exit_fn)
pol->pd_exit_fn(blkg);
diff --git a/block/blk-cgroup.h b/block/blk-cgroup.h
index 40f5b9768aa..678e89ed8ec 100644
--- a/block/blk-cgroup.h
+++ b/block/blk-cgroup.h
@@ -106,12 +106,17 @@ struct blkcg_gq {
/* reference count */
int refcnt;
+ /* is this blkg online? protected by both blkcg and q locks */
+ bool online;
+
struct blkg_policy_data *pd[BLKCG_MAX_POLS];
struct rcu_head rcu_head;
};
typedef void (blkcg_pol_init_pd_fn)(struct blkcg_gq *blkg);
+typedef void (blkcg_pol_online_pd_fn)(struct blkcg_gq *blkg);
+typedef void (blkcg_pol_offline_pd_fn)(struct blkcg_gq *blkg);
typedef void (blkcg_pol_exit_pd_fn)(struct blkcg_gq *blkg);
typedef void (blkcg_pol_reset_pd_stats_fn)(struct blkcg_gq *blkg);
@@ -124,6 +129,8 @@ struct blkcg_policy {
/* operations */
blkcg_pol_init_pd_fn *pd_init_fn;
+ blkcg_pol_online_pd_fn *pd_online_fn;
+ blkcg_pol_offline_pd_fn *pd_offline_fn;
blkcg_pol_exit_pd_fn *pd_exit_fn;
blkcg_pol_reset_pd_stats_fn *pd_reset_stats_fn;
};