block/blk-cgroup.h - LeafOS-Devices/android_kernel_samsung_gta4xl - Gitiles

 #ifndef _BLK_CGROUP_H
 #define _BLK_CGROUP_H
 /*
  * Common Block IO controller cgroup interface
  *
  * Based on ideas and code from CFQ, CFS and BFQ:
  * Copyright (C) 2003 Jens Axboe <axboe@kernel.dk>
  *
  * Copyright (C) 2008 Fabio Checconi <fabio@gandalf.sssup.it>
  *		      Paolo Valente <paolo.valente@unimore.it>
  *
  * Copyright (C) 2009 Vivek Goyal <vgoyal@redhat.com>
  * 	              Nauman Rafique <nauman@google.com>
  */

 #include <linux/cgroup.h>
 #include <linux/u64_stats_sync.h>

 enum blkio_policy_id {
 	BLKIO_POLICY_PROP = 0,		/* Proportional Bandwidth division */
 	BLKIO_POLICY_THROTL,		/* Throttling */

 	BLKIO_NR_POLICIES,
 };

 /* Max limits for throttle policy */
 #define THROTL_IOPS_MAX		UINT_MAX

 #ifdef CONFIG_BLK_CGROUP

 enum stat_type {
 	/* Total time spent (in ns) between request dispatch to the driver and
 	 * request completion for IOs doen by this cgroup. This may not be
 	 * accurate when NCQ is turned on. */
 	BLKIO_STAT_SERVICE_TIME = 0,
 	/* Total time spent waiting in scheduler queue in ns */
 	BLKIO_STAT_WAIT_TIME,
 	/* Number of IOs queued up */
 	BLKIO_STAT_QUEUED,
 	/* All the single valued stats go below this */
 	BLKIO_STAT_TIME,
 #ifdef CONFIG_DEBUG_BLK_CGROUP
 	/* Time not charged to this cgroup */
 	BLKIO_STAT_UNACCOUNTED_TIME,
 	BLKIO_STAT_AVG_QUEUE_SIZE,
 	BLKIO_STAT_IDLE_TIME,
 	BLKIO_STAT_EMPTY_TIME,
 	BLKIO_STAT_GROUP_WAIT_TIME,
 	BLKIO_STAT_DEQUEUE
 #endif
 };

 /* Per cpu stats */
 enum stat_type_cpu {
 	BLKIO_STAT_CPU_SECTORS,
 	/* Total bytes transferred */
 	BLKIO_STAT_CPU_SERVICE_BYTES,
 	/* Total IOs serviced, post merge */
 	BLKIO_STAT_CPU_SERVICED,
 	/* Number of IOs merged */
 	BLKIO_STAT_CPU_MERGED,
 	BLKIO_STAT_CPU_NR
 };

 enum stat_sub_type {
 	BLKIO_STAT_READ = 0,
 	BLKIO_STAT_WRITE,
 	BLKIO_STAT_SYNC,
 	BLKIO_STAT_ASYNC,
 	BLKIO_STAT_TOTAL
 };

 /* blkg state flags */
 enum blkg_state_flags {
 	BLKG_waiting = 0,
 	BLKG_idling,
 	BLKG_empty,
 };

 /* cgroup files owned by proportional weight policy */
 enum blkcg_file_name_prop {
 	BLKIO_PROP_weight = 1,
 	BLKIO_PROP_weight_device,
 	BLKIO_PROP_io_service_bytes,
 	BLKIO_PROP_io_serviced,
 	BLKIO_PROP_time,
 	BLKIO_PROP_sectors,
 	BLKIO_PROP_unaccounted_time,
 	BLKIO_PROP_io_service_time,
 	BLKIO_PROP_io_wait_time,
 	BLKIO_PROP_io_merged,
 	BLKIO_PROP_io_queued,
 	BLKIO_PROP_avg_queue_size,
 	BLKIO_PROP_group_wait_time,
 	BLKIO_PROP_idle_time,
 	BLKIO_PROP_empty_time,
 	BLKIO_PROP_dequeue,
 };

 /* cgroup files owned by throttle policy */
 enum blkcg_file_name_throtl {
 	BLKIO_THROTL_read_bps_device,
 	BLKIO_THROTL_write_bps_device,
 	BLKIO_THROTL_read_iops_device,
 	BLKIO_THROTL_write_iops_device,
 	BLKIO_THROTL_io_service_bytes,
 	BLKIO_THROTL_io_serviced,
 };

 struct blkio_cgroup {
 	struct cgroup_subsys_state css;
 	unsigned int weight;
 	spinlock_t lock;
 	struct hlist_head blkg_list;
 };

 struct blkio_group_stats {
 	/* total disk time and nr sectors dispatched by this group */
 	uint64_t time;
 	uint64_t stat_arr[BLKIO_STAT_QUEUED + 1][BLKIO_STAT_TOTAL];
 #ifdef CONFIG_DEBUG_BLK_CGROUP
 	/* Time not charged to this cgroup */
 	uint64_t unaccounted_time;

 	/* Sum of number of IOs queued across all samples */
 	uint64_t avg_queue_size_sum;
 	/* Count of samples taken for average */
 	uint64_t avg_queue_size_samples;
 	/* How many times this group has been removed from service tree */
 	unsigned long dequeue;

 	/* Total time spent waiting for it to be assigned a timeslice. */
 	uint64_t group_wait_time;
 	uint64_t start_group_wait_time;

 	/* Time spent idling for this blkio_group */
 	uint64_t idle_time;
 	uint64_t start_idle_time;
 	/*
 	 * Total time when we have requests queued and do not contain the
 	 * current active queue.
 	 */
 	uint64_t empty_time;
 	uint64_t start_empty_time;
 	uint16_t flags;
 #endif
 };

 /* Per cpu blkio group stats */
 struct blkio_group_stats_cpu {
 	uint64_t sectors;
 	uint64_t stat_arr_cpu[BLKIO_STAT_CPU_NR][BLKIO_STAT_TOTAL];
 	struct u64_stats_sync syncp;
 };

 struct blkio_group_conf {
 	unsigned int weight;
 	unsigned int iops[2];
 	u64 bps[2];
 };

 /* per-blkg per-policy data */
 struct blkg_policy_data {
 	/* the blkg this per-policy data belongs to */
 	struct blkio_group *blkg;

 	/* Configuration */
 	struct blkio_group_conf conf;

 	struct blkio_group_stats stats;
 	/* Per cpu stats pointer */
 	struct blkio_group_stats_cpu __percpu *stats_cpu;

 	/* pol->pdata_size bytes of private data used by policy impl */
 	char pdata[] __aligned(__alignof__(unsigned long long));
 };

 struct blkio_group {
 	/* Pointer to the associated request_queue */
 	struct request_queue *q;
 	struct list_head q_node;
 	struct hlist_node blkcg_node;
 	struct blkio_cgroup *blkcg;
 	/* Store cgroup path */
 	char path[128];
 	/* reference count */
 	int refcnt;

 	/* Need to serialize the stats in the case of reset/update */
 	spinlock_t stats_lock;
 	struct blkg_policy_data *pd[BLKIO_NR_POLICIES];

 	/* List of blkg waiting for per cpu stats memory to be allocated */
 	struct list_head alloc_node;
 	struct rcu_head rcu_head;
 };

 typedef void (blkio_init_group_fn)(struct blkio_group *blkg);
 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)(struct request_queue *q,
 			struct blkio_group *blkg, u64 read_bps);
 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)(struct request_queue *q,
 			struct blkio_group *blkg, unsigned int read_iops);
 typedef void (blkio_update_group_write_iops_fn)(struct request_queue *q,
 			struct blkio_group *blkg, unsigned int write_iops);

 struct blkio_policy_ops {
 	blkio_init_group_fn *blkio_init_group_fn;
 	blkio_update_group_weight_fn *blkio_update_group_weight_fn;
 	blkio_update_group_read_bps_fn *blkio_update_group_read_bps_fn;
 	blkio_update_group_write_bps_fn *blkio_update_group_write_bps_fn;
 	blkio_update_group_read_iops_fn *blkio_update_group_read_iops_fn;
 	blkio_update_group_write_iops_fn *blkio_update_group_write_iops_fn;
 };

 struct blkio_policy_type {
 	struct list_head list;
 	struct blkio_policy_ops ops;
 	enum blkio_policy_id plid;
 	size_t pdata_size;		/* policy specific private data size */
 };

 extern int blkcg_init_queue(struct request_queue *q);
 extern void blkcg_drain_queue(struct request_queue *q);
 extern void blkcg_exit_queue(struct request_queue *q);

 /* Blkio controller policy registration */
 extern void blkio_policy_register(struct blkio_policy_type *);
 extern void blkio_policy_unregister(struct blkio_policy_type *);
 extern void blkg_destroy_all(struct request_queue *q, bool destroy_root);
 extern void update_root_blkg_pd(struct request_queue *q,
 				enum blkio_policy_id plid);

 /**
  * blkg_to_pdata - get policy private data
  * @blkg: blkg of interest
  * @pol: policy of interest
  *
  * Return pointer to private data associated with the @blkg-@pol pair.
  */
 static inline void *blkg_to_pdata(struct blkio_group *blkg,
 			      struct blkio_policy_type *pol)
 {
 	return blkg ? blkg->pd[pol->plid]->pdata : NULL;
 }

 /**
  * pdata_to_blkg - get blkg associated with policy private data
  * @pdata: policy private data of interest
  * @pol: policy @pdata is for
  *
  * @pdata is policy private data for @pol.  Determine the blkg it's
  * associated with.
  */
 static inline struct blkio_group *pdata_to_blkg(void *pdata,
 						struct blkio_policy_type *pol)
 {
 	if (pdata) {
 		struct blkg_policy_data *pd =
 			container_of(pdata, struct blkg_policy_data, pdata);
 		return pd->blkg;
 	}
 	return NULL;
 }

 static inline char *blkg_path(struct blkio_group *blkg)
 {
 	return blkg->path;
 }

 /**
  * blkg_get - get a blkg reference
  * @blkg: blkg to get
  *
  * The caller should be holding queue_lock and an existing reference.
  */
 static inline void blkg_get(struct blkio_group *blkg)
 {
 	lockdep_assert_held(blkg->q->queue_lock);
 	WARN_ON_ONCE(!blkg->refcnt);
 	blkg->refcnt++;
 }

 void __blkg_release(struct blkio_group *blkg);

 /**
  * blkg_put - put a blkg reference
  * @blkg: blkg to put
  *
  * The caller should be holding queue_lock.
  */
 static inline void blkg_put(struct blkio_group *blkg)
 {
 	lockdep_assert_held(blkg->q->queue_lock);
 	WARN_ON_ONCE(blkg->refcnt <= 0);
 	if (!--blkg->refcnt)
 		__blkg_release(blkg);
 }

 #else

 struct blkio_group {
 };

 struct blkio_policy_type {
 };

 static inline int blkcg_init_queue(struct request_queue *q) { return 0; }
 static inline void blkcg_drain_queue(struct request_queue *q) { }
 static inline void blkcg_exit_queue(struct request_queue *q) { }
 static inline void blkio_policy_register(struct blkio_policy_type *blkiop) { }
 static inline void blkio_policy_unregister(struct blkio_policy_type *blkiop) { }
 static inline void blkg_destroy_all(struct request_queue *q,
 				    bool destory_root) { }
 static inline void update_root_blkg_pd(struct request_queue *q,
 				       enum blkio_policy_id plid) { }

 static inline void *blkg_to_pdata(struct blkio_group *blkg,
 				struct blkio_policy_type *pol) { return NULL; }
 static inline struct blkio_group *pdata_to_blkg(void *pdata,
 				struct blkio_policy_type *pol) { return NULL; }
 static inline char *blkg_path(struct blkio_group *blkg) { return NULL; }
 static inline void blkg_get(struct blkio_group *blkg) { }
 static inline void blkg_put(struct blkio_group *blkg) { }

 #endif

 #define BLKIO_WEIGHT_MIN	10
 #define BLKIO_WEIGHT_MAX	1000
 #define BLKIO_WEIGHT_DEFAULT	500

 #ifdef CONFIG_DEBUG_BLK_CGROUP
 void blkiocg_update_avg_queue_size_stats(struct blkio_group *blkg,
 					 struct blkio_policy_type *pol);
 void blkiocg_update_dequeue_stats(struct blkio_group *blkg,
 				  struct blkio_policy_type *pol,
 				  unsigned long dequeue);
 void blkiocg_update_set_idle_time_stats(struct blkio_group *blkg,
 					struct blkio_policy_type *pol);
 void blkiocg_update_idle_time_stats(struct blkio_group *blkg,
 				    struct blkio_policy_type *pol);
 void blkiocg_set_start_empty_time(struct blkio_group *blkg,
 				  struct blkio_policy_type *pol);

 #define BLKG_FLAG_FNS(name)						\
 static inline void blkio_mark_blkg_##name(				\
 		struct blkio_group_stats *stats)			\
 {									\
 	stats->flags |= (1 << BLKG_##name);				\
 }									\
 static inline void blkio_clear_blkg_##name(				\
 		struct blkio_group_stats *stats)			\
 {									\
 	stats->flags &= ~(1 << BLKG_##name);				\
 }									\
 static inline int blkio_blkg_##name(struct blkio_group_stats *stats)	\
 {									\
 	return (stats->flags & (1 << BLKG_##name)) != 0;		\
 }									\

 BLKG_FLAG_FNS(waiting)
 BLKG_FLAG_FNS(idling)
 BLKG_FLAG_FNS(empty)
 #undef BLKG_FLAG_FNS
 #else
 static inline void blkiocg_update_avg_queue_size_stats(struct blkio_group *blkg,
 			struct blkio_policy_type *pol) { }
 static inline void blkiocg_update_dequeue_stats(struct blkio_group *blkg,
 			struct blkio_policy_type *pol, unsigned long dequeue) { }
 static inline void blkiocg_update_set_idle_time_stats(struct blkio_group *blkg,
 			struct blkio_policy_type *pol) { }
 static inline void blkiocg_update_idle_time_stats(struct blkio_group *blkg,
 			struct blkio_policy_type *pol) { }
 static inline void blkiocg_set_start_empty_time(struct blkio_group *blkg,
 			struct blkio_policy_type *pol) { }
 #endif

 #ifdef CONFIG_BLK_CGROUP
 extern struct blkio_cgroup blkio_root_cgroup;
 extern struct blkio_cgroup *cgroup_to_blkio_cgroup(struct cgroup *cgroup);
 extern struct blkio_cgroup *bio_blkio_cgroup(struct bio *bio);
 extern struct blkio_group *blkg_lookup(struct blkio_cgroup *blkcg,
 				       struct request_queue *q);
 struct blkio_group *blkg_lookup_create(struct blkio_cgroup *blkcg,
 				       struct request_queue *q,
 				       enum blkio_policy_id plid,
 				       bool for_root);
 void blkiocg_update_timeslice_used(struct blkio_group *blkg,
 				   struct blkio_policy_type *pol,
 				   unsigned long time,
 				   unsigned long unaccounted_time);
 void blkiocg_update_dispatch_stats(struct blkio_group *blkg,
 				   struct blkio_policy_type *pol,
 				   uint64_t bytes, bool direction, bool sync);
 void blkiocg_update_completion_stats(struct blkio_group *blkg,
 				     struct blkio_policy_type *pol,
 				     uint64_t start_time,
 				     uint64_t io_start_time, bool direction,
 				     bool sync);
 void blkiocg_update_io_merged_stats(struct blkio_group *blkg,
 				    struct blkio_policy_type *pol,
 				    bool direction, bool sync);
 void blkiocg_update_io_add_stats(struct blkio_group *blkg,
 				 struct blkio_policy_type *pol,
 				 struct blkio_group *curr_blkg, bool direction,
 				 bool sync);
 void blkiocg_update_io_remove_stats(struct blkio_group *blkg,
 				    struct blkio_policy_type *pol,
 				    bool direction, bool sync);
 #else
 struct cgroup;
 static inline struct blkio_cgroup *
 cgroup_to_blkio_cgroup(struct cgroup *cgroup) { return NULL; }
 static inline struct blkio_cgroup *
 bio_blkio_cgroup(struct bio *bio) { return NULL; }

 static inline struct blkio_group *blkg_lookup(struct blkio_cgroup *blkcg,
 					      void *key) { return NULL; }
 static inline void blkiocg_update_timeslice_used(struct blkio_group *blkg,
 			struct blkio_policy_type *pol, unsigned long time,
 			unsigned long unaccounted_time) { }
 static inline void blkiocg_update_dispatch_stats(struct blkio_group *blkg,
 			struct blkio_policy_type *pol, uint64_t bytes,
 			bool direction, bool sync) { }
 static inline void blkiocg_update_completion_stats(struct blkio_group *blkg,
 			struct blkio_policy_type *pol, uint64_t start_time,
 			uint64_t io_start_time, bool direction, bool sync) { }
 static inline void blkiocg_update_io_merged_stats(struct blkio_group *blkg,
 			struct blkio_policy_type *pol, bool direction,
 			bool sync) { }
 static inline void blkiocg_update_io_add_stats(struct blkio_group *blkg,
 			struct blkio_policy_type *pol,
 			struct blkio_group *curr_blkg, bool direction,
 			bool sync) { }
 static inline void blkiocg_update_io_remove_stats(struct blkio_group *blkg,
 			struct blkio_policy_type *pol, bool direction,
 			bool sync) { }
 #endif
 #endif /* _BLK_CGROUP_H */
	#ifndef _BLK_CGROUP_H
	#define _BLK_CGROUP_H
	/*
	* Common Block IO controller cgroup interface
	*
	* Based on ideas and code from CFQ, CFS and BFQ:
	* Copyright (C) 2003 Jens Axboe <axboe@kernel.dk>
	*
	* Copyright (C) 2008 Fabio Checconi <fabio@gandalf.sssup.it>
	* Paolo Valente <paolo.valente@unimore.it>
	*
	* Copyright (C) 2009 Vivek Goyal <vgoyal@redhat.com>
	* Nauman Rafique <nauman@google.com>
	*/

	#include <linux/cgroup.h>
	#include <linux/u64_stats_sync.h>

	enum blkio_policy_id {
	BLKIO_POLICY_PROP = 0, /* Proportional Bandwidth division */
	BLKIO_POLICY_THROTL, /* Throttling */

	BLKIO_NR_POLICIES,
	};

	/* Max limits for throttle policy */
	#define THROTL_IOPS_MAX UINT_MAX

	#ifdef CONFIG_BLK_CGROUP

	enum stat_type {
	/* Total time spent (in ns) between request dispatch to the driver and
	* request completion for IOs doen by this cgroup. This may not be
	* accurate when NCQ is turned on. */
	BLKIO_STAT_SERVICE_TIME = 0,
	/* Total time spent waiting in scheduler queue in ns */
	BLKIO_STAT_WAIT_TIME,
	/* Number of IOs queued up */
	BLKIO_STAT_QUEUED,
	/* All the single valued stats go below this */
	BLKIO_STAT_TIME,
	#ifdef CONFIG_DEBUG_BLK_CGROUP
	/* Time not charged to this cgroup */
	BLKIO_STAT_UNACCOUNTED_TIME,
	BLKIO_STAT_AVG_QUEUE_SIZE,
	BLKIO_STAT_IDLE_TIME,
	BLKIO_STAT_EMPTY_TIME,
	BLKIO_STAT_GROUP_WAIT_TIME,
	BLKIO_STAT_DEQUEUE
	#endif
	};

	/* Per cpu stats */
	enum stat_type_cpu {
	BLKIO_STAT_CPU_SECTORS,
	/* Total bytes transferred */
	BLKIO_STAT_CPU_SERVICE_BYTES,
	/* Total IOs serviced, post merge */
	BLKIO_STAT_CPU_SERVICED,
	/* Number of IOs merged */
	BLKIO_STAT_CPU_MERGED,
	BLKIO_STAT_CPU_NR
	};

	enum stat_sub_type {
	BLKIO_STAT_READ = 0,
	BLKIO_STAT_WRITE,
	BLKIO_STAT_SYNC,
	BLKIO_STAT_ASYNC,
	BLKIO_STAT_TOTAL
	};

	/* blkg state flags */
	enum blkg_state_flags {
	BLKG_waiting = 0,
	BLKG_idling,
	BLKG_empty,
	};

	/* cgroup files owned by proportional weight policy */
	enum blkcg_file_name_prop {
	BLKIO_PROP_weight = 1,
	BLKIO_PROP_weight_device,
	BLKIO_PROP_io_service_bytes,
	BLKIO_PROP_io_serviced,
	BLKIO_PROP_time,
	BLKIO_PROP_sectors,
	BLKIO_PROP_unaccounted_time,
	BLKIO_PROP_io_service_time,
	BLKIO_PROP_io_wait_time,
	BLKIO_PROP_io_merged,
	BLKIO_PROP_io_queued,
	BLKIO_PROP_avg_queue_size,
	BLKIO_PROP_group_wait_time,
	BLKIO_PROP_idle_time,
	BLKIO_PROP_empty_time,
	BLKIO_PROP_dequeue,
	};

	/* cgroup files owned by throttle policy */
	enum blkcg_file_name_throtl {
	BLKIO_THROTL_read_bps_device,
	BLKIO_THROTL_write_bps_device,
	BLKIO_THROTL_read_iops_device,
	BLKIO_THROTL_write_iops_device,
	BLKIO_THROTL_io_service_bytes,
	BLKIO_THROTL_io_serviced,
	};

	struct blkio_cgroup {
	struct cgroup_subsys_state css;
	unsigned int weight;
	spinlock_t lock;
	struct hlist_head blkg_list;
	};

	struct blkio_group_stats {
	/* total disk time and nr sectors dispatched by this group */
	uint64_t time;
	uint64_t stat_arr[BLKIO_STAT_QUEUED + 1][BLKIO_STAT_TOTAL];
	#ifdef CONFIG_DEBUG_BLK_CGROUP
	/* Time not charged to this cgroup */
	uint64_t unaccounted_time;

	/* Sum of number of IOs queued across all samples */
	uint64_t avg_queue_size_sum;
	/* Count of samples taken for average */
	uint64_t avg_queue_size_samples;
	/* How many times this group has been removed from service tree */
	unsigned long dequeue;

	/* Total time spent waiting for it to be assigned a timeslice. */
	uint64_t group_wait_time;
	uint64_t start_group_wait_time;

	/* Time spent idling for this blkio_group */
	uint64_t idle_time;
	uint64_t start_idle_time;
	/*
	* Total time when we have requests queued and do not contain the
	* current active queue.
	*/
	uint64_t empty_time;
	uint64_t start_empty_time;
	uint16_t flags;
	#endif
	};

	/* Per cpu blkio group stats */
	struct blkio_group_stats_cpu {
	uint64_t sectors;
	uint64_t stat_arr_cpu[BLKIO_STAT_CPU_NR][BLKIO_STAT_TOTAL];
	struct u64_stats_sync syncp;
	};

	struct blkio_group_conf {
	unsigned int weight;
	unsigned int iops[2];
	u64 bps[2];
	};

	/* per-blkg per-policy data */
	struct blkg_policy_data {
	/* the blkg this per-policy data belongs to */
	struct blkio_group *blkg;

	/* Configuration */
	struct blkio_group_conf conf;

	struct blkio_group_stats stats;
	/* Per cpu stats pointer */
	struct blkio_group_stats_cpu __percpu *stats_cpu;

	/* pol->pdata_size bytes of private data used by policy impl */
	char pdata[] __aligned(__alignof__(unsigned long long));
	};

	struct blkio_group {
	/* Pointer to the associated request_queue */
	struct request_queue *q;
	struct list_head q_node;
	struct hlist_node blkcg_node;
	struct blkio_cgroup *blkcg;
	/* Store cgroup path */
	char path[128];
	/* reference count */
	int refcnt;

	/* Need to serialize the stats in the case of reset/update */
	spinlock_t stats_lock;
	struct blkg_policy_data *pd[BLKIO_NR_POLICIES];

	/* List of blkg waiting for per cpu stats memory to be allocated */
	struct list_head alloc_node;
	struct rcu_head rcu_head;
	};

	typedef void (blkio_init_group_fn)(struct blkio_group *blkg);
	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)(struct request_queue *q,
	struct blkio_group *blkg, u64 read_bps);
	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)(struct request_queue *q,
	struct blkio_group *blkg, unsigned int read_iops);
	typedef void (blkio_update_group_write_iops_fn)(struct request_queue *q,
	struct blkio_group *blkg, unsigned int write_iops);

	struct blkio_policy_ops {
	blkio_init_group_fn *blkio_init_group_fn;
	blkio_update_group_weight_fn *blkio_update_group_weight_fn;
	blkio_update_group_read_bps_fn *blkio_update_group_read_bps_fn;
	blkio_update_group_write_bps_fn *blkio_update_group_write_bps_fn;
	blkio_update_group_read_iops_fn *blkio_update_group_read_iops_fn;
	blkio_update_group_write_iops_fn *blkio_update_group_write_iops_fn;
	};

	struct blkio_policy_type {
	struct list_head list;
	struct blkio_policy_ops ops;
	enum blkio_policy_id plid;
	size_t pdata_size; /* policy specific private data size */
	};

	extern int blkcg_init_queue(struct request_queue *q);
	extern void blkcg_drain_queue(struct request_queue *q);
	extern void blkcg_exit_queue(struct request_queue *q);

	/* Blkio controller policy registration */
	extern void blkio_policy_register(struct blkio_policy_type *);
	extern void blkio_policy_unregister(struct blkio_policy_type *);
	extern void blkg_destroy_all(struct request_queue *q, bool destroy_root);
	extern void update_root_blkg_pd(struct request_queue *q,
	enum blkio_policy_id plid);

	/**
	* blkg_to_pdata - get policy private data
	* @blkg: blkg of interest
	* @pol: policy of interest
	*
	* Return pointer to private data associated with the @blkg-@pol pair.
	*/
	static inline void blkg_to_pdata(struct blkio_group blkg,
	struct blkio_policy_type *pol)
	{
	return blkg ? blkg->pd[pol->plid]->pdata : NULL;
	}

	/**
	* pdata_to_blkg - get blkg associated with policy private data
	* @pdata: policy private data of interest
	* @pol: policy @pdata is for
	*
	* @pdata is policy private data for @pol. Determine the blkg it's
	* associated with.
	*/
	static inline struct blkio_group pdata_to_blkg(void pdata,
	struct blkio_policy_type *pol)
	{
	if (pdata) {
	struct blkg_policy_data *pd =
	container_of(pdata, struct blkg_policy_data, pdata);
	return pd->blkg;
	}
	return NULL;
	}

	static inline char blkg_path(struct blkio_group blkg)
	{
	return blkg->path;
	}

	/**
	* blkg_get - get a blkg reference
	* @blkg: blkg to get
	*
	* The caller should be holding queue_lock and an existing reference.
	*/
	static inline void blkg_get(struct blkio_group *blkg)
	{
	lockdep_assert_held(blkg->q->queue_lock);
	WARN_ON_ONCE(!blkg->refcnt);
	blkg->refcnt++;
	}

	void __blkg_release(struct blkio_group *blkg);

	/**
	* blkg_put - put a blkg reference
	* @blkg: blkg to put
	*
	* The caller should be holding queue_lock.
	*/
	static inline void blkg_put(struct blkio_group *blkg)
	{
	lockdep_assert_held(blkg->q->queue_lock);
	WARN_ON_ONCE(blkg->refcnt <= 0);
	if (!--blkg->refcnt)
	__blkg_release(blkg);
	}

	#else

	struct blkio_group {
	};

	struct blkio_policy_type {
	};

	static inline int blkcg_init_queue(struct request_queue *q) { return 0; }
	static inline void blkcg_drain_queue(struct request_queue *q) { }
	static inline void blkcg_exit_queue(struct request_queue *q) { }
	static inline void blkio_policy_register(struct blkio_policy_type *blkiop) { }
	static inline void blkio_policy_unregister(struct blkio_policy_type *blkiop) { }
	static inline void blkg_destroy_all(struct request_queue *q,
	bool destory_root) { }
	static inline void update_root_blkg_pd(struct request_queue *q,
	enum blkio_policy_id plid) { }

	static inline void blkg_to_pdata(struct blkio_group blkg,
	struct blkio_policy_type *pol) { return NULL; }
	static inline struct blkio_group pdata_to_blkg(void pdata,
	struct blkio_policy_type *pol) { return NULL; }
	static inline char blkg_path(struct blkio_group blkg) { return NULL; }
	static inline void blkg_get(struct blkio_group *blkg) { }
	static inline void blkg_put(struct blkio_group *blkg) { }

	#endif

	#define BLKIO_WEIGHT_MIN 10
	#define BLKIO_WEIGHT_MAX 1000
	#define BLKIO_WEIGHT_DEFAULT 500

	#ifdef CONFIG_DEBUG_BLK_CGROUP
	void blkiocg_update_avg_queue_size_stats(struct blkio_group *blkg,
	struct blkio_policy_type *pol);
	void blkiocg_update_dequeue_stats(struct blkio_group *blkg,
	struct blkio_policy_type *pol,
	unsigned long dequeue);
	void blkiocg_update_set_idle_time_stats(struct blkio_group *blkg,
	struct blkio_policy_type *pol);
	void blkiocg_update_idle_time_stats(struct blkio_group *blkg,
	struct blkio_policy_type *pol);
	void blkiocg_set_start_empty_time(struct blkio_group *blkg,
	struct blkio_policy_type *pol);

	#define BLKG_FLAG_FNS(name) \
	static inline void blkio_mark_blkg_##name( \
	struct blkio_group_stats *stats) \
	{ \
	stats->flags \|= (1 << BLKG_##name); \
	} \
	static inline void blkio_clear_blkg_##name( \
	struct blkio_group_stats *stats) \
	{ \
	stats->flags &= ~(1 << BLKG_##name); \
	} \
	static inline int blkio_blkg_##name(struct blkio_group_stats *stats) \
	{ \
	return (stats->flags & (1 << BLKG_##name)) != 0; \
	} \

	BLKG_FLAG_FNS(waiting)
	BLKG_FLAG_FNS(idling)
	BLKG_FLAG_FNS(empty)
	#undef BLKG_FLAG_FNS
	#else
	static inline void blkiocg_update_avg_queue_size_stats(struct blkio_group *blkg,
	struct blkio_policy_type *pol) { }
	static inline void blkiocg_update_dequeue_stats(struct blkio_group *blkg,
	struct blkio_policy_type *pol, unsigned long dequeue) { }
	static inline void blkiocg_update_set_idle_time_stats(struct blkio_group *blkg,
	struct blkio_policy_type *pol) { }
	static inline void blkiocg_update_idle_time_stats(struct blkio_group *blkg,
	struct blkio_policy_type *pol) { }
	static inline void blkiocg_set_start_empty_time(struct blkio_group *blkg,
	struct blkio_policy_type *pol) { }
	#endif

	#ifdef CONFIG_BLK_CGROUP
	extern struct blkio_cgroup blkio_root_cgroup;
	extern struct blkio_cgroup cgroup_to_blkio_cgroup(struct cgroup cgroup);
	extern struct blkio_cgroup bio_blkio_cgroup(struct bio bio);
	extern struct blkio_group blkg_lookup(struct blkio_cgroup blkcg,
	struct request_queue *q);
	struct blkio_group blkg_lookup_create(struct blkio_cgroup blkcg,
	struct request_queue *q,
	enum blkio_policy_id plid,
	bool for_root);
	void blkiocg_update_timeslice_used(struct blkio_group *blkg,
	struct blkio_policy_type *pol,
	unsigned long time,
	unsigned long unaccounted_time);
	void blkiocg_update_dispatch_stats(struct blkio_group *blkg,
	struct blkio_policy_type *pol,
	uint64_t bytes, bool direction, bool sync);
	void blkiocg_update_completion_stats(struct blkio_group *blkg,
	struct blkio_policy_type *pol,
	uint64_t start_time,
	uint64_t io_start_time, bool direction,
	bool sync);
	void blkiocg_update_io_merged_stats(struct blkio_group *blkg,
	struct blkio_policy_type *pol,
	bool direction, bool sync);
	void blkiocg_update_io_add_stats(struct blkio_group *blkg,
	struct blkio_policy_type *pol,
	struct blkio_group *curr_blkg, bool direction,
	bool sync);
	void blkiocg_update_io_remove_stats(struct blkio_group *blkg,
	struct blkio_policy_type *pol,
	bool direction, bool sync);
	#else
	struct cgroup;
	static inline struct blkio_cgroup *
	cgroup_to_blkio_cgroup(struct cgroup *cgroup) { return NULL; }
	static inline struct blkio_cgroup *
	bio_blkio_cgroup(struct bio *bio) { return NULL; }

	static inline struct blkio_group blkg_lookup(struct blkio_cgroup blkcg,
	void *key) { return NULL; }
	static inline void blkiocg_update_timeslice_used(struct blkio_group *blkg,
	struct blkio_policy_type *pol, unsigned long time,
	unsigned long unaccounted_time) { }
	static inline void blkiocg_update_dispatch_stats(struct blkio_group *blkg,
	struct blkio_policy_type *pol, uint64_t bytes,
	bool direction, bool sync) { }
	static inline void blkiocg_update_completion_stats(struct blkio_group *blkg,
	struct blkio_policy_type *pol, uint64_t start_time,
	uint64_t io_start_time, bool direction, bool sync) { }
	static inline void blkiocg_update_io_merged_stats(struct blkio_group *blkg,
	struct blkio_policy_type *pol, bool direction,
	bool sync) { }
	static inline void blkiocg_update_io_add_stats(struct blkio_group *blkg,
	struct blkio_policy_type *pol,
	struct blkio_group *curr_blkg, bool direction,
	bool sync) { }
	static inline void blkiocg_update_io_remove_stats(struct blkio_group *blkg,
	struct blkio_policy_type *pol, bool direction,
	bool sync) { }
	#endif
	#endif /* _BLK_CGROUP_H */