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Commit f427d909 authored by Tejun Heo's avatar Tejun Heo
Browse files

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: default avatarTejun Heo <tj@kernel.org>
Acked-by: default avatarVivek Goyal <vgoyal@redhat.com>
parent b276a876

block/blk-cgroup.c

+20 −1
Original line number Diff line number Diff line
@@ -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);

block/blk-cgroup.h

+7 −0
Original line number Diff line number Diff line
@@ -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;

};