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Commit ca32aefc authored by Tejun Heo's avatar Tejun Heo Committed by Jens Axboe
Browse files

blkcg: use q and plid instead of opaque void * for blkio_group association 



blkgio_group is association between a block cgroup and a queue for a
given policy.  Using opaque void * for association makes things
confusing and hinders factoring of common code.  Use request_queue *
and, if necessary, policy id instead.

This will help block cgroup API cleanup.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 0a5a7d0e

block/blk-cgroup.c

+15 −17
Original line number Diff line number Diff line
@@ -129,7 +129,7 @@ blkio_update_group_weight(struct blkio_group *blkg, unsigned int weight) 
		if (blkiop->plid != blkg->plid)

			continue;

		if (blkiop->ops.blkio_update_group_weight_fn)

			blkiop->ops.blkio_update_group_weight_fn(blkg->key,

			blkiop->ops.blkio_update_group_weight_fn(blkg->q,

							blkg, weight);

	}

}
@@ -147,12 +147,12 @@ static inline void blkio_update_group_bps(struct blkio_group *blkg, u64 bps, 


		if (fileid == BLKIO_THROTL_read_bps_device

		    && blkiop->ops.blkio_update_group_read_bps_fn)

			blkiop->ops.blkio_update_group_read_bps_fn(blkg->key,

			blkiop->ops.blkio_update_group_read_bps_fn(blkg->q,

								blkg, bps);



		if (fileid == BLKIO_THROTL_write_bps_device

		    && blkiop->ops.blkio_update_group_write_bps_fn)

			blkiop->ops.blkio_update_group_write_bps_fn(blkg->key,

			blkiop->ops.blkio_update_group_write_bps_fn(blkg->q,

								blkg, bps);

	}

}
@@ -170,12 +170,12 @@ static inline void blkio_update_group_iops(struct blkio_group *blkg, 


		if (fileid == BLKIO_THROTL_read_iops_device

		    && blkiop->ops.blkio_update_group_read_iops_fn)

			blkiop->ops.blkio_update_group_read_iops_fn(blkg->key,

			blkiop->ops.blkio_update_group_read_iops_fn(blkg->q,

								blkg, iops);



		if (fileid == BLKIO_THROTL_write_iops_device

		    && blkiop->ops.blkio_update_group_write_iops_fn)

			blkiop->ops.blkio_update_group_write_iops_fn(blkg->key,

			blkiop->ops.blkio_update_group_write_iops_fn(blkg->q,

								blkg,iops);

	}

}
@@ -478,14 +478,14 @@ int blkio_alloc_blkg_stats(struct blkio_group *blkg) 
EXPORT_SYMBOL_GPL(blkio_alloc_blkg_stats);



void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg,

		struct blkio_group *blkg, void *key, dev_t dev,

		struct blkio_group *blkg, struct request_queue *q, dev_t dev,

		enum blkio_policy_id plid)

{

	unsigned long flags;



	spin_lock_irqsave(&blkcg->lock, flags);

	spin_lock_init(&blkg->stats_lock);

	rcu_assign_pointer(blkg->key, key);

	rcu_assign_pointer(blkg->q, q);

	blkg->blkcg_id = css_id(&blkcg->css);

	hlist_add_head_rcu(&blkg->blkcg_node, &blkcg->blkg_list);

	blkg->plid = plid;
@@ -531,18 +531,16 @@ int blkiocg_del_blkio_group(struct blkio_group *blkg) 
EXPORT_SYMBOL_GPL(blkiocg_del_blkio_group);



/* called under rcu_read_lock(). */

struct blkio_group *blkiocg_lookup_group(struct blkio_cgroup *blkcg, void *key)

struct blkio_group *blkiocg_lookup_group(struct blkio_cgroup *blkcg,

					 struct request_queue *q,

					 enum blkio_policy_id plid)

{

	struct blkio_group *blkg;

	struct hlist_node *n;

	void *__key;



	hlist_for_each_entry_rcu(blkg, n, &blkcg->blkg_list, blkcg_node) {

		__key = blkg->key;

		if (__key == key)

	hlist_for_each_entry_rcu(blkg, n, &blkcg->blkg_list, blkcg_node)

		if (blkg->q == q && blkg->plid == plid)

			return blkg;

	}



	return NULL;

}

EXPORT_SYMBOL_GPL(blkiocg_lookup_group);
@@ -1582,7 +1580,7 @@ static void blkiocg_destroy(struct cgroup_subsys *subsys, struct cgroup *cgroup) 
	struct blkio_cgroup *blkcg = cgroup_to_blkio_cgroup(cgroup);

	unsigned long flags;

	struct blkio_group *blkg;

	void *key;

	struct request_queue *q;

	struct blkio_policy_type *blkiop;

	struct blkio_policy_node *pn, *pntmp;
@@ -1597,7 +1595,7 @@ static void blkiocg_destroy(struct cgroup_subsys *subsys, struct cgroup *cgroup) 


		blkg = hlist_entry(blkcg->blkg_list.first, struct blkio_group,

					blkcg_node);

		key = rcu_dereference(blkg->key);

		q = rcu_dereference(blkg->q);

		__blkiocg_del_blkio_group(blkg);



		spin_unlock_irqrestore(&blkcg->lock, flags);
@@ -1611,7 +1609,7 @@ static void blkiocg_destroy(struct cgroup_subsys *subsys, struct cgroup *cgroup) 
		list_for_each_entry(blkiop, &blkio_list, list) {

			if (blkiop->plid != blkg->plid)

				continue;

			blkiop->ops.blkio_unlink_group_fn(key, blkg);

			blkiop->ops.blkio_unlink_group_fn(q, blkg);

		}

		spin_unlock(&blkio_list_lock);

	} while (1);

block/blk-cgroup.h

+12 −10
Original line number Diff line number Diff line
@@ -153,8 +153,8 @@ struct blkio_group_stats_cpu { 
};



struct blkio_group {

	/* An rcu protected unique identifier for the group */

	void *key;

	/* Pointer to the associated request_queue, RCU protected */

	struct request_queue __rcu *q;

	struct hlist_node blkcg_node;

	unsigned short blkcg_id;

	/* Store cgroup path */
@@ -202,17 +202,18 @@ extern unsigned int blkcg_get_read_iops(struct blkio_cgroup *blkcg, 
extern unsigned int blkcg_get_write_iops(struct blkio_cgroup *blkcg,

				     dev_t dev);



typedef void (blkio_unlink_group_fn) (void *key, struct blkio_group *blkg);

typedef void (blkio_unlink_group_fn)(struct request_queue *q,

			struct blkio_group *blkg);

typedef bool (blkio_clear_queue_fn)(struct request_queue *q);

typedef void (blkio_update_group_weight_fn) (void *key,

typedef void (blkio_update_group_weight_fn)(struct request_queue *q,

			struct blkio_group *blkg, unsigned int weight);

typedef void (blkio_update_group_read_bps_fn) (void * key,

typedef void (blkio_update_group_read_bps_fn)(struct request_queue *q,

			struct blkio_group *blkg, u64 read_bps);

typedef void (blkio_update_group_write_bps_fn) (void *key,

typedef void (blkio_update_group_write_bps_fn)(struct request_queue *q,

			struct blkio_group *blkg, u64 write_bps);

typedef void (blkio_update_group_read_iops_fn) (void *key,

typedef void (blkio_update_group_read_iops_fn)(struct request_queue *q,

			struct blkio_group *blkg, unsigned int read_iops);

typedef void (blkio_update_group_write_iops_fn) (void *key,

typedef void (blkio_update_group_write_iops_fn)(struct request_queue *q,

			struct blkio_group *blkg, unsigned int write_iops);



struct blkio_policy_ops {
@@ -305,12 +306,13 @@ extern struct blkio_cgroup blkio_root_cgroup; 
extern struct blkio_cgroup *cgroup_to_blkio_cgroup(struct cgroup *cgroup);

extern struct blkio_cgroup *task_blkio_cgroup(struct task_struct *tsk);

extern void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg,

	struct blkio_group *blkg, void *key, dev_t dev,

	struct blkio_group *blkg, struct request_queue *q, dev_t dev,

	enum blkio_policy_id plid);

extern int blkio_alloc_blkg_stats(struct blkio_group *blkg);

extern int blkiocg_del_blkio_group(struct blkio_group *blkg);

extern struct blkio_group *blkiocg_lookup_group(struct blkio_cgroup *blkcg,

						void *key);

						struct request_queue *q,

						enum blkio_policy_id plid);

void blkiocg_update_timeslice_used(struct blkio_group *blkg,

					unsigned long time,

					unsigned long unaccounted_time);

block/blk-throttle.c

+23 −27
Original line number Diff line number Diff line
@@ -252,7 +252,7 @@ static void throtl_init_add_tg_lists(struct throtl_data *td, 
	__throtl_tg_fill_dev_details(td, tg);



	/* Add group onto cgroup list */

	blkiocg_add_blkio_group(blkcg, &tg->blkg, (void *)td,

	blkiocg_add_blkio_group(blkcg, &tg->blkg, td->queue,

				tg->blkg.dev, BLKIO_POLICY_THROTL);



	tg->bps[READ] = blkcg_get_read_bps(blkcg, tg->blkg.dev);
@@ -288,7 +288,6 @@ static struct 
throtl_grp *throtl_find_tg(struct throtl_data *td, struct blkio_cgroup *blkcg)

{

	struct throtl_grp *tg = NULL;

	void *key = td;



	/*

	 * This is the common case when there are no blkio cgroups.
@@ -297,7 +296,8 @@ throtl_grp *throtl_find_tg(struct throtl_data *td, struct blkio_cgroup *blkcg) 
	if (blkcg == &blkio_root_cgroup)

		tg = td->root_tg;

	else

		tg = tg_of_blkg(blkiocg_lookup_group(blkcg, key));

		tg = tg_of_blkg(blkiocg_lookup_group(blkcg, td->queue,

						     BLKIO_POLICY_THROTL));



	__throtl_tg_fill_dev_details(td, tg);

	return tg;
@@ -1012,22 +1012,22 @@ static bool throtl_release_tgs(struct throtl_data *td, bool release_root) 
 * no new IO will come in this group. So get rid of this group as soon as

 * any pending IO in the group is finished.

 *

 * This function is called under rcu_read_lock(). key is the rcu protected

 * pointer. That means "key" is a valid throtl_data pointer as long as we are

 * rcu read lock.

 * This function is called under rcu_read_lock(). @q is the rcu protected

 * pointer. That means @q is a valid request_queue pointer as long as we

 * are rcu read lock.

 *

 * "key" was fetched from blkio_group under blkio_cgroup->lock. That means

 * @q was fetched from blkio_group under blkio_cgroup->lock. That means

 * it should not be NULL as even if queue was going away, cgroup deltion

 * path got to it first.

 */

void throtl_unlink_blkio_group(void *key, struct blkio_group *blkg)

void throtl_unlink_blkio_group(struct request_queue *q,

			       struct blkio_group *blkg)

{

	unsigned long flags;

	struct throtl_data *td = key;



	spin_lock_irqsave(td->queue->queue_lock, flags);

	throtl_destroy_tg(td, tg_of_blkg(blkg));

	spin_unlock_irqrestore(td->queue->queue_lock, flags);

	spin_lock_irqsave(q->queue_lock, flags);

	throtl_destroy_tg(q->td, tg_of_blkg(blkg));

	spin_unlock_irqrestore(q->queue_lock, flags);

}



static bool throtl_clear_queue(struct request_queue *q)
@@ -1054,52 +1054,48 @@ static void throtl_update_blkio_group_common(struct throtl_data *td, 
}



/*

 * For all update functions, key should be a valid pointer because these

 * For all update functions, @q should be a valid pointer because these

 * update functions are called under blkcg_lock, that means, blkg is

 * valid and in turn key is valid. queue exit path can not race because

 * valid and in turn @q is valid. queue exit path can not race because

 * of blkcg_lock

 *

 * Can not take queue lock in update functions as queue lock under blkcg_lock

 * is not allowed. Under other paths we take blkcg_lock under queue_lock.

 */

static void throtl_update_blkio_group_read_bps(void *key,

static void throtl_update_blkio_group_read_bps(struct request_queue *q,

				struct blkio_group *blkg, u64 read_bps)

{

	struct throtl_data *td = key;

	struct throtl_grp *tg = tg_of_blkg(blkg);



	tg->bps[READ] = read_bps;

	throtl_update_blkio_group_common(td, tg);

	throtl_update_blkio_group_common(q->td, tg);

}



static void throtl_update_blkio_group_write_bps(void *key,

static void throtl_update_blkio_group_write_bps(struct request_queue *q,

				struct blkio_group *blkg, u64 write_bps)

{

	struct throtl_data *td = key;

	struct throtl_grp *tg = tg_of_blkg(blkg);



	tg->bps[WRITE] = write_bps;

	throtl_update_blkio_group_common(td, tg);

	throtl_update_blkio_group_common(q->td, tg);

}



static void throtl_update_blkio_group_read_iops(void *key,

static void throtl_update_blkio_group_read_iops(struct request_queue *q,

			struct blkio_group *blkg, unsigned int read_iops)

{

	struct throtl_data *td = key;

	struct throtl_grp *tg = tg_of_blkg(blkg);



	tg->iops[READ] = read_iops;

	throtl_update_blkio_group_common(td, tg);

	throtl_update_blkio_group_common(q->td, tg);

}



static void throtl_update_blkio_group_write_iops(void *key,

static void throtl_update_blkio_group_write_iops(struct request_queue *q,

			struct blkio_group *blkg, unsigned int write_iops)

{

	struct throtl_data *td = key;

	struct throtl_grp *tg = tg_of_blkg(blkg);



	tg->iops[WRITE] = write_iops;

	throtl_update_blkio_group_common(td, tg);

	throtl_update_blkio_group_common(q->td, tg);

}



static void throtl_shutdown_wq(struct request_queue *q)
@@ -1306,7 +1302,7 @@ void blk_throtl_exit(struct request_queue *q) 
	spin_unlock_irq(q->queue_lock);



	/*

	 * Wait for tg->blkg->key accessors to exit their grace periods.

	 * Wait for tg->blkg->q accessors to exit their grace periods.

	 * Do this wait only if there are other undestroyed groups out

	 * there (other than root group). This can happen if cgroup deletion

	 * path claimed the responsibility of cleaning up a group before

block/cfq-iosched.c

+16 −14
Original line number Diff line number Diff line
@@ -1020,7 +1020,8 @@ static inline struct cfq_group *cfqg_of_blkg(struct blkio_group *blkg) 
	return NULL;

}



static void cfq_update_blkio_group_weight(void *key, struct blkio_group *blkg,

static void cfq_update_blkio_group_weight(struct request_queue *q,

					  struct blkio_group *blkg,

					  unsigned int weight)

{

	struct cfq_group *cfqg = cfqg_of_blkg(blkg);
@@ -1043,10 +1044,10 @@ static void cfq_init_add_cfqg_lists(struct cfq_data *cfqd, 
	if (bdi->dev) {

		sscanf(dev_name(bdi->dev), "%u:%u", &major, &minor);

		cfq_blkiocg_add_blkio_group(blkcg, &cfqg->blkg,

					(void *)cfqd, MKDEV(major, minor));

					cfqd->queue, MKDEV(major, minor));

	} else

		cfq_blkiocg_add_blkio_group(blkcg, &cfqg->blkg,

					(void *)cfqd, 0);

					cfqd->queue, 0);



	cfqd->nr_blkcg_linked_grps++;

	cfqg->weight = blkcg_get_weight(blkcg, cfqg->blkg.dev);
@@ -1097,7 +1098,6 @@ static struct cfq_group * 
cfq_find_cfqg(struct cfq_data *cfqd, struct blkio_cgroup *blkcg)

{

	struct cfq_group *cfqg = NULL;

	void *key = cfqd;

	struct backing_dev_info *bdi = &cfqd->queue->backing_dev_info;

	unsigned int major, minor;
@@ -1108,7 +1108,8 @@ cfq_find_cfqg(struct cfq_data *cfqd, struct blkio_cgroup *blkcg) 
	if (blkcg == &blkio_root_cgroup)

		cfqg = &cfqd->root_group;

	else

		cfqg = cfqg_of_blkg(blkiocg_lookup_group(blkcg, key));

		cfqg = cfqg_of_blkg(blkiocg_lookup_group(blkcg, cfqd->queue,

							 BLKIO_POLICY_PROP));



	if (cfqg && !cfqg->blkg.dev && bdi->dev && dev_name(bdi->dev)) {

		sscanf(dev_name(bdi->dev), "%u:%u", &major, &minor);
@@ -1247,21 +1248,22 @@ static bool cfq_release_cfq_groups(struct cfq_data *cfqd) 
 * any pending IO in the group is finished.

 *

 * This function is called under rcu_read_lock(). key is the rcu protected

 * pointer. That means "key" is a valid cfq_data pointer as long as we are rcu

 * read lock.

 * pointer. That means @q is a valid request_queue pointer as long as we

 * are rcu read lock.

 *

 * "key" was fetched from blkio_group under blkio_cgroup->lock. That means

 * @q was fetched from blkio_group under blkio_cgroup->lock. That means

 * it should not be NULL as even if elevator was exiting, cgroup deltion

 * path got to it first.

 */

static void cfq_unlink_blkio_group(void *key, struct blkio_group *blkg)

static void cfq_unlink_blkio_group(struct request_queue *q,

				   struct blkio_group *blkg)

{

	struct cfq_data *cfqd = q->elevator->elevator_data;

	unsigned long flags;

	struct cfq_data *cfqd = key;



	spin_lock_irqsave(cfqd->queue->queue_lock, flags);

	spin_lock_irqsave(q->queue_lock, flags);

	cfq_destroy_cfqg(cfqd, cfqg_of_blkg(blkg));

	spin_unlock_irqrestore(cfqd->queue->queue_lock, flags);

	spin_unlock_irqrestore(q->queue_lock, flags);

}



static struct elevator_type iosched_cfq;
@@ -3718,7 +3720,7 @@ static int cfq_init_queue(struct request_queue *q) 
	rcu_read_lock();



	cfq_blkiocg_add_blkio_group(&blkio_root_cgroup, &cfqg->blkg,

					(void *)cfqd, 0);

				    cfqd->queue, 0);

	rcu_read_unlock();

	cfqd->nr_blkcg_linked_grps++;

block/cfq.h

+4 −3
Original line number Diff line number Diff line
@@ -68,8 +68,9 @@ static inline void cfq_blkiocg_update_completion_stats(struct blkio_group *blkg, 
}



static inline void cfq_blkiocg_add_blkio_group(struct blkio_cgroup *blkcg,

			struct blkio_group *blkg, void *key, dev_t dev) {

	blkiocg_add_blkio_group(blkcg, blkg, key, dev, BLKIO_POLICY_PROP);

		struct blkio_group *blkg, struct request_queue *q, dev_t dev)

{

	blkiocg_add_blkio_group(blkcg, blkg, q, dev, BLKIO_POLICY_PROP);

}



static inline int cfq_blkiocg_del_blkio_group(struct blkio_group *blkg)
@@ -105,7 +106,7 @@ static inline void cfq_blkiocg_update_dispatch_stats(struct blkio_group *blkg, 
static inline void cfq_blkiocg_update_completion_stats(struct blkio_group *blkg, uint64_t start_time, uint64_t io_start_time, bool direction, bool sync) {}



static inline void cfq_blkiocg_add_blkio_group(struct blkio_cgroup *blkcg,

			struct blkio_group *blkg, void *key, dev_t dev) {}

		struct blkio_group *blkg, struct request_queue *q, dev_t dev) {}

static inline int cfq_blkiocg_del_blkio_group(struct blkio_group *blkg)

{

	return 0;