From f427d909648aa592c9588d0f66b5b457752a0cd1 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Wed, 9 Jan 2013 08:05:12 -0800 Subject: [PATCH] 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 Acked-by: Vivek Goyal --- block/blk-cgroup.c | 21 ++++++++++++++++++++- block/blk-cgroup.h | 7 +++++++ 2 files changed, 27 insertions(+), 1 deletion(-) diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c index 3a8de32..4d625d2 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 40f5b97..678e89e 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; }; -- 2.7.4