#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 * * Copyright (C) 2008 Fabio Checconi * Paolo Valente * * Copyright (C) 2009 Vivek Goyal * Nauman Rafique */ #include #include #include #include /* Max limits for throttle policy */ #define THROTL_IOPS_MAX UINT_MAX /* CFQ specific, out here for blkcg->cfq_weight */ #define CFQ_WEIGHT_MIN 10 #define CFQ_WEIGHT_MAX 1000 #define CFQ_WEIGHT_DEFAULT 500 #ifdef CONFIG_BLK_CGROUP enum blkg_rwstat_type { BLKG_RWSTAT_READ, BLKG_RWSTAT_WRITE, BLKG_RWSTAT_SYNC, BLKG_RWSTAT_ASYNC, BLKG_RWSTAT_NR, BLKG_RWSTAT_TOTAL = BLKG_RWSTAT_NR, }; struct blkcg_gq; struct blkcg { struct cgroup_subsys_state css; spinlock_t lock; struct radix_tree_root blkg_tree; struct blkcg_gq *blkg_hint; struct hlist_head blkg_list; /* for policies to test whether associated blkcg has changed */ uint64_t id; /* TODO: per-policy storage in blkcg */ unsigned int cfq_weight; /* belongs to cfq */ }; struct blkg_stat { struct u64_stats_sync syncp; uint64_t cnt; }; struct blkg_rwstat { struct u64_stats_sync syncp; uint64_t cnt[BLKG_RWSTAT_NR]; }; /* * A blkcg_gq (blkg) is association between a block cgroup (blkcg) and a * request_queue (q). This is used by blkcg policies which need to track * information per blkcg - q pair. * * There can be multiple active blkcg policies and each has its private * data on each blkg, the size of which is determined by * blkcg_policy->pd_size. blkcg core allocates and frees such areas * together with blkg and invokes pd_init/exit_fn() methods. * * Such private data must embed struct blkg_policy_data (pd) at the * beginning and pd_size can't be smaller than pd. */ struct blkg_policy_data { /* the blkg this per-policy data belongs to */ struct blkcg_gq *blkg; /* used during policy activation */ struct list_head alloc_node; }; /* association between a blk cgroup and a request queue */ struct blkcg_gq { /* Pointer to the associated request_queue */ struct request_queue *q; struct list_head q_node; struct hlist_node blkcg_node; struct blkcg *blkcg; /* reference count */ int refcnt; 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_exit_pd_fn)(struct blkcg_gq *blkg); typedef void (blkcg_pol_reset_pd_stats_fn)(struct blkcg_gq *blkg); struct blkcg_policy { int plid; /* policy specific private data size */ size_t pd_size; /* cgroup files for the policy */ struct cftype *cftypes; /* operations */ blkcg_pol_init_pd_fn *pd_init_fn; blkcg_pol_exit_pd_fn *pd_exit_fn; blkcg_pol_reset_pd_stats_fn *pd_reset_stats_fn; }; extern struct blkcg blkcg_root; struct blkcg *cgroup_to_blkcg(struct cgroup *cgroup); struct blkcg *bio_blkcg(struct bio *bio); struct blkcg_gq *blkg_lookup(struct blkcg *blkcg, struct request_queue *q); struct blkcg_gq *blkg_lookup_create(struct blkcg *blkcg, struct request_queue *q); int blkcg_init_queue(struct request_queue *q); void blkcg_drain_queue(struct request_queue *q); void blkcg_exit_queue(struct request_queue *q); /* Blkio controller policy registration */ int blkcg_policy_register(struct blkcg_policy *pol); void blkcg_policy_unregister(struct blkcg_policy *pol); int blkcg_activate_policy(struct request_queue *q, const struct blkcg_policy *pol); void blkcg_deactivate_policy(struct request_queue *q, const struct blkcg_policy *pol); void blkcg_print_blkgs(struct seq_file *sf, struct blkcg *blkcg, u64 (*prfill)(struct seq_file *, struct blkg_policy_data *, int), const struct blkcg_policy *pol, int data, bool show_total); u64 __blkg_prfill_u64(struct seq_file *sf, struct blkg_policy_data *pd, u64 v); u64 __blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd, const struct blkg_rwstat *rwstat); u64 blkg_prfill_stat(struct seq_file *sf, struct blkg_policy_data *pd, int off); u64 blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd, int off); struct blkg_conf_ctx { struct gendisk *disk; struct blkcg_gq *blkg; u64 v; }; int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol, const char *input, struct blkg_conf_ctx *ctx); void blkg_conf_finish(struct blkg_conf_ctx *ctx); /** * 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 struct blkg_policy_data *blkg_to_pd(struct blkcg_gq *blkg, struct blkcg_policy *pol) { return blkg ? blkg->pd[pol->plid] : NULL; } /** * pdata_to_blkg - get blkg associated with policy private data * @pd: policy private data of interest * * @pd is policy private data. Determine the blkg it's associated with. */ static inline struct blkcg_gq *pd_to_blkg(struct blkg_policy_data *pd) { return pd ? pd->blkg : NULL; } /** * blkg_path - format cgroup path of blkg * @blkg: blkg of interest * @buf: target buffer * @buflen: target buffer length * * Format the path of the cgroup of @blkg into @buf. */ static inline int blkg_path(struct blkcg_gq *blkg, char *buf, int buflen) { int ret; rcu_read_lock(); ret = cgroup_path(blkg->blkcg->css.cgroup, buf, buflen); rcu_read_unlock(); if (ret) strncpy(buf, "", buflen); return ret; } /** * 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 blkcg_gq *blkg) { lockdep_assert_held(blkg->q->queue_lock); WARN_ON_ONCE(!blkg->refcnt); blkg->refcnt++; } void __blkg_release(struct blkcg_gq *blkg); /** * blkg_put - put a blkg reference * @blkg: blkg to put * * The caller should be holding queue_lock. */ static inline void blkg_put(struct blkcg_gq *blkg) { lockdep_assert_held(blkg->q->queue_lock); WARN_ON_ONCE(blkg->refcnt <= 0); if (!--blkg->refcnt) __blkg_release(blkg); } /** * blkg_stat_add - add a value to a blkg_stat * @stat: target blkg_stat * @val: value to add * * Add @val to @stat. The caller is responsible for synchronizing calls to * this function. */ static inline void blkg_stat_add(struct blkg_stat *stat, uint64_t val) { u64_stats_update_begin(&stat->syncp); stat->cnt += val; u64_stats_update_end(&stat->syncp); } /** * blkg_stat_read - read the current value of a blkg_stat * @stat: blkg_stat to read * * Read the current value of @stat. This function can be called without * synchroniztion and takes care of u64 atomicity. */ static inline uint64_t blkg_stat_read(struct blkg_stat *stat) { unsigned int start; uint64_t v; do { start = u64_stats_fetch_begin(&stat->syncp); v = stat->cnt; } while (u64_stats_fetch_retry(&stat->syncp, start)); return v; } /** * blkg_stat_reset - reset a blkg_stat * @stat: blkg_stat to reset */ static inline void blkg_stat_reset(struct blkg_stat *stat) { stat->cnt = 0; } /** * blkg_rwstat_add - add a value to a blkg_rwstat * @rwstat: target blkg_rwstat * @rw: mask of REQ_{WRITE|SYNC} * @val: value to add * * Add @val to @rwstat. The counters are chosen according to @rw. The * caller is responsible for synchronizing calls to this function. */ static inline void blkg_rwstat_add(struct blkg_rwstat *rwstat, int rw, uint64_t val) { u64_stats_update_begin(&rwstat->syncp); if (rw & REQ_WRITE) rwstat->cnt[BLKG_RWSTAT_WRITE] += val; else rwstat->cnt[BLKG_RWSTAT_READ] += val; if (rw & REQ_SYNC) rwstat->cnt[BLKG_RWSTAT_SYNC] += val; else rwstat->cnt[BLKG_RWSTAT_ASYNC] += val; u64_stats_update_end(&rwstat->syncp); } /** * blkg_rwstat_read - read the current values of a blkg_rwstat * @rwstat: blkg_rwstat to read * * Read the current snapshot of @rwstat and return it as the return value. * This function can be called without synchronization and takes care of * u64 atomicity. */ static inline struct blkg_rwstat blkg_rwstat_read(struct blkg_rwstat *rwstat) { unsigned int start; struct blkg_rwstat tmp; do { start = u64_stats_fetch_begin(&rwstat->syncp); tmp = *rwstat; } while (u64_stats_fetch_retry(&rwstat->syncp, start)); return tmp; } /** * blkg_rwstat_sum - read the total count of a blkg_rwstat * @rwstat: blkg_rwstat to read * * Return the total count of @rwstat regardless of the IO direction. This * function can be called without synchronization and takes care of u64 * atomicity. */ static inline uint64_t blkg_rwstat_sum(struct blkg_rwstat *rwstat) { struct blkg_rwstat tmp = blkg_rwstat_read(rwstat); return tmp.cnt[BLKG_RWSTAT_READ] + tmp.cnt[BLKG_RWSTAT_WRITE]; } /** * blkg_rwstat_reset - reset a blkg_rwstat * @rwstat: blkg_rwstat to reset */ static inline void blkg_rwstat_reset(struct blkg_rwstat *rwstat) { memset(rwstat->cnt, 0, sizeof(rwstat->cnt)); } #else /* CONFIG_BLK_CGROUP */ struct cgroup; struct blkg_policy_data { }; struct blkcg_gq { }; struct blkcg_policy { }; static inline struct blkcg *cgroup_to_blkcg(struct cgroup *cgroup) { return NULL; } static inline struct blkcg *bio_blkcg(struct bio *bio) { return NULL; } static inline struct blkcg_gq *blkg_lookup(struct blkcg *blkcg, void *key) { return NULL; } 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 int blkcg_policy_register(struct blkcg_policy *pol) { return 0; } static inline void blkcg_policy_unregister(struct blkcg_policy *pol) { } static inline int blkcg_activate_policy(struct request_queue *q, const struct blkcg_policy *pol) { return 0; } static inline void blkcg_deactivate_policy(struct request_queue *q, const struct blkcg_policy *pol) { } static inline struct blkg_policy_data *blkg_to_pd(struct blkcg_gq *blkg, struct blkcg_policy *pol) { return NULL; } static inline struct blkcg_gq *pd_to_blkg(struct blkg_policy_data *pd) { return NULL; } static inline char *blkg_path(struct blkcg_gq *blkg) { return NULL; } static inline void blkg_get(struct blkcg_gq *blkg) { } static inline void blkg_put(struct blkcg_gq *blkg) { } #endif /* CONFIG_BLK_CGROUP */ #endif /* _BLK_CGROUP_H */