| /* SPDX-License-Identifier: GPL-2.0 */ |
| #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/percpu_counter.h> |
| #include <linux/seq_file.h> |
| #include <linux/radix-tree.h> |
| #include <linux/blkdev.h> |
| #include <linux/atomic.h> |
| #include <linux/kthread.h> |
| #include <linux/fs.h> |
| |
| /* percpu_counter batch for blkg_[rw]stats, per-cpu drift doesn't matter */ |
| #define BLKG_STAT_CPU_BATCH (INT_MAX / 2) |
| |
| /* Max limits for throttle policy */ |
| #define THROTL_IOPS_MAX UINT_MAX |
| |
| #ifdef CONFIG_BLK_CGROUP |
| |
| enum blkg_rwstat_type { |
| BLKG_RWSTAT_READ, |
| BLKG_RWSTAT_WRITE, |
| BLKG_RWSTAT_SYNC, |
| BLKG_RWSTAT_ASYNC, |
| BLKG_RWSTAT_DISCARD, |
| |
| 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 __rcu *blkg_hint; |
| struct hlist_head blkg_list; |
| |
| struct blkcg_policy_data *cpd[BLKCG_MAX_POLS]; |
| |
| struct list_head all_blkcgs_node; |
| #ifdef CONFIG_CGROUP_WRITEBACK |
| struct list_head cgwb_list; |
| refcount_t cgwb_refcnt; |
| #endif |
| }; |
| |
| /* |
| * blkg_[rw]stat->aux_cnt is excluded for local stats but included for |
| * recursive. Used to carry stats of dead children. |
| */ |
| struct blkg_rwstat { |
| struct percpu_counter cpu_cnt[BLKG_RWSTAT_NR]; |
| atomic64_t aux_cnt[BLKG_RWSTAT_NR]; |
| }; |
| |
| struct blkg_rwstat_sample { |
| u64 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 blkg:policy pair is |
| * represented by a blkg_policy_data which is allocated and freed by each |
| * policy's pd_alloc/free_fn() methods. A policy can allocate private data |
| * area by allocating larger data structure which embeds blkg_policy_data |
| * at the beginning. |
| */ |
| struct blkg_policy_data { |
| /* the blkg and policy id this per-policy data belongs to */ |
| struct blkcg_gq *blkg; |
| int plid; |
| }; |
| |
| /* |
| * Policies that need to keep per-blkcg data which is independent from any |
| * request_queue associated to it should implement cpd_alloc/free_fn() |
| * methods. A policy can allocate private data area by allocating larger |
| * data structure which embeds blkcg_policy_data at the beginning. |
| * cpd_init() is invoked to let each policy handle per-blkcg data. |
| */ |
| struct blkcg_policy_data { |
| /* the blkcg and policy id this per-policy data belongs to */ |
| struct blkcg *blkcg; |
| int plid; |
| }; |
| |
| /* 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; |
| |
| /* |
| * Each blkg gets congested separately and the congestion state is |
| * propagated to the matching bdi_writeback_congested. |
| */ |
| struct bdi_writeback_congested *wb_congested; |
| |
| /* all non-root blkcg_gq's are guaranteed to have access to parent */ |
| struct blkcg_gq *parent; |
| |
| /* reference count */ |
| struct percpu_ref refcnt; |
| |
| /* is this blkg online? protected by both blkcg and q locks */ |
| bool online; |
| |
| struct blkg_rwstat stat_bytes; |
| struct blkg_rwstat stat_ios; |
| |
| struct blkg_policy_data *pd[BLKCG_MAX_POLS]; |
| |
| spinlock_t async_bio_lock; |
| struct bio_list async_bios; |
| struct work_struct async_bio_work; |
| |
| atomic_t use_delay; |
| atomic64_t delay_nsec; |
| atomic64_t delay_start; |
| u64 last_delay; |
| int last_use; |
| |
| struct rcu_head rcu_head; |
| }; |
| |
| typedef struct blkcg_policy_data *(blkcg_pol_alloc_cpd_fn)(gfp_t gfp); |
| typedef void (blkcg_pol_init_cpd_fn)(struct blkcg_policy_data *cpd); |
| typedef void (blkcg_pol_free_cpd_fn)(struct blkcg_policy_data *cpd); |
| typedef void (blkcg_pol_bind_cpd_fn)(struct blkcg_policy_data *cpd); |
| typedef struct blkg_policy_data *(blkcg_pol_alloc_pd_fn)(gfp_t gfp, |
| struct request_queue *q, struct blkcg *blkcg); |
| typedef void (blkcg_pol_init_pd_fn)(struct blkg_policy_data *pd); |
| typedef void (blkcg_pol_online_pd_fn)(struct blkg_policy_data *pd); |
| typedef void (blkcg_pol_offline_pd_fn)(struct blkg_policy_data *pd); |
| typedef void (blkcg_pol_free_pd_fn)(struct blkg_policy_data *pd); |
| typedef void (blkcg_pol_reset_pd_stats_fn)(struct blkg_policy_data *pd); |
| typedef size_t (blkcg_pol_stat_pd_fn)(struct blkg_policy_data *pd, char *buf, |
| size_t size); |
| |
| struct blkcg_policy { |
| int plid; |
| /* cgroup files for the policy */ |
| struct cftype *dfl_cftypes; |
| struct cftype *legacy_cftypes; |
| |
| /* operations */ |
| blkcg_pol_alloc_cpd_fn *cpd_alloc_fn; |
| blkcg_pol_init_cpd_fn *cpd_init_fn; |
| blkcg_pol_free_cpd_fn *cpd_free_fn; |
| blkcg_pol_bind_cpd_fn *cpd_bind_fn; |
| |
| blkcg_pol_alloc_pd_fn *pd_alloc_fn; |
| 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_free_pd_fn *pd_free_fn; |
| blkcg_pol_reset_pd_stats_fn *pd_reset_stats_fn; |
| blkcg_pol_stat_pd_fn *pd_stat_fn; |
| }; |
| |
| extern struct blkcg blkcg_root; |
| extern struct cgroup_subsys_state * const blkcg_root_css; |
| extern bool blkcg_debug_stats; |
| |
| struct blkcg_gq *blkg_lookup_slowpath(struct blkcg *blkcg, |
| struct request_queue *q, bool update_hint); |
| struct blkcg_gq *__blkg_lookup_create(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); |
| |
| static inline u64 blkg_rwstat_read_counter(struct blkg_rwstat *rwstat, |
| unsigned int idx) |
| { |
| return atomic64_read(&rwstat->aux_cnt[idx]) + |
| percpu_counter_sum_positive(&rwstat->cpu_cnt[idx]); |
| } |
| |
| const char *blkg_dev_name(struct blkcg_gq *blkg); |
| 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_sample *rwstat); |
| u64 blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd, |
| int off); |
| void blkg_rwstat_recursive_sum(struct blkcg_gq *blkg, struct blkcg_policy *pol, |
| int off, struct blkg_rwstat_sample *sum); |
| |
| struct blkg_conf_ctx { |
| struct gendisk *disk; |
| struct blkcg_gq *blkg; |
| char *body; |
| }; |
| |
| struct gendisk *blkcg_conf_get_disk(char **inputp); |
| int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol, |
| char *input, struct blkg_conf_ctx *ctx); |
| void blkg_conf_finish(struct blkg_conf_ctx *ctx); |
| |
| /** |
| * blkcg_css - find the current css |
| * |
| * Find the css associated with either the kthread or the current task. |
| * This may return a dying css, so it is up to the caller to use tryget logic |
| * to confirm it is alive and well. |
| */ |
| static inline struct cgroup_subsys_state *blkcg_css(void) |
| { |
| struct cgroup_subsys_state *css; |
| |
| css = kthread_blkcg(); |
| if (css) |
| return css; |
| return task_css(current, io_cgrp_id); |
| } |
| |
| static inline struct blkcg *css_to_blkcg(struct cgroup_subsys_state *css) |
| { |
| return css ? container_of(css, struct blkcg, css) : NULL; |
| } |
| |
| /** |
| * __bio_blkcg - internal, inconsistent version to get blkcg |
| * |
| * DO NOT USE. |
| * This function is inconsistent and consequently is dangerous to use. The |
| * first part of the function returns a blkcg where a reference is owned by the |
| * bio. This means it does not need to be rcu protected as it cannot go away |
| * with the bio owning a reference to it. However, the latter potentially gets |
| * it from task_css(). This can race against task migration and the cgroup |
| * dying. It is also semantically different as it must be called rcu protected |
| * and is susceptible to failure when trying to get a reference to it. |
| * Therefore, it is not ok to assume that *_get() will always succeed on the |
| * blkcg returned here. |
| */ |
| static inline struct blkcg *__bio_blkcg(struct bio *bio) |
| { |
| if (bio && bio->bi_blkg) |
| return bio->bi_blkg->blkcg; |
| return css_to_blkcg(blkcg_css()); |
| } |
| |
| /** |
| * bio_blkcg - grab the blkcg associated with a bio |
| * @bio: target bio |
| * |
| * This returns the blkcg associated with a bio, %NULL if not associated. |
| * Callers are expected to either handle %NULL or know association has been |
| * done prior to calling this. |
| */ |
| static inline struct blkcg *bio_blkcg(struct bio *bio) |
| { |
| if (bio && bio->bi_blkg) |
| return bio->bi_blkg->blkcg; |
| return NULL; |
| } |
| |
| static inline bool blk_cgroup_congested(void) |
| { |
| struct cgroup_subsys_state *css; |
| bool ret = false; |
| |
| rcu_read_lock(); |
| css = kthread_blkcg(); |
| if (!css) |
| css = task_css(current, io_cgrp_id); |
| while (css) { |
| if (atomic_read(&css->cgroup->congestion_count)) { |
| ret = true; |
| break; |
| } |
| css = css->parent; |
| } |
| rcu_read_unlock(); |
| return ret; |
| } |
| |
| /** |
| * bio_issue_as_root_blkg - see if this bio needs to be issued as root blkg |
| * @return: true if this bio needs to be submitted with the root blkg context. |
| * |
| * In order to avoid priority inversions we sometimes need to issue a bio as if |
| * it were attached to the root blkg, and then backcharge to the actual owning |
| * blkg. The idea is we do bio_blkcg() to look up the actual context for the |
| * bio and attach the appropriate blkg to the bio. Then we call this helper and |
| * if it is true run with the root blkg for that queue and then do any |
| * backcharging to the originating cgroup once the io is complete. |
| */ |
| static inline bool bio_issue_as_root_blkg(struct bio *bio) |
| { |
| return (bio->bi_opf & (REQ_META | REQ_SWAP)) != 0; |
| } |
| |
| /** |
| * blkcg_parent - get the parent of a blkcg |
| * @blkcg: blkcg of interest |
| * |
| * Return the parent blkcg of @blkcg. Can be called anytime. |
| */ |
| static inline struct blkcg *blkcg_parent(struct blkcg *blkcg) |
| { |
| return css_to_blkcg(blkcg->css.parent); |
| } |
| |
| /** |
| * __blkg_lookup - internal version of blkg_lookup() |
| * @blkcg: blkcg of interest |
| * @q: request_queue of interest |
| * @update_hint: whether to update lookup hint with the result or not |
| * |
| * This is internal version and shouldn't be used by policy |
| * implementations. Looks up blkgs for the @blkcg - @q pair regardless of |
| * @q's bypass state. If @update_hint is %true, the caller should be |
| * holding @q->queue_lock and lookup hint is updated on success. |
| */ |
| static inline struct blkcg_gq *__blkg_lookup(struct blkcg *blkcg, |
| struct request_queue *q, |
| bool update_hint) |
| { |
| struct blkcg_gq *blkg; |
| |
| if (blkcg == &blkcg_root) |
| return q->root_blkg; |
| |
| blkg = rcu_dereference(blkcg->blkg_hint); |
| if (blkg && blkg->q == q) |
| return blkg; |
| |
| return blkg_lookup_slowpath(blkcg, q, update_hint); |
| } |
| |
| /** |
| * blkg_lookup - lookup blkg for the specified blkcg - q pair |
| * @blkcg: blkcg of interest |
| * @q: request_queue of interest |
| * |
| * Lookup blkg for the @blkcg - @q pair. This function should be called |
| * under RCU read lock. |
| */ |
| static inline struct blkcg_gq *blkg_lookup(struct blkcg *blkcg, |
| struct request_queue *q) |
| { |
| WARN_ON_ONCE(!rcu_read_lock_held()); |
| return __blkg_lookup(blkcg, q, false); |
| } |
| |
| /** |
| * blk_queue_root_blkg - return blkg for the (blkcg_root, @q) pair |
| * @q: request_queue of interest |
| * |
| * Lookup blkg for @q at the root level. See also blkg_lookup(). |
| */ |
| static inline struct blkcg_gq *blk_queue_root_blkg(struct request_queue *q) |
| { |
| return q->root_blkg; |
| } |
| |
| /** |
| * 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; |
| } |
| |
| static inline struct blkcg_policy_data *blkcg_to_cpd(struct blkcg *blkcg, |
| struct blkcg_policy *pol) |
| { |
| return blkcg ? blkcg->cpd[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; |
| } |
| |
| static inline struct blkcg *cpd_to_blkcg(struct blkcg_policy_data *cpd) |
| { |
| return cpd ? cpd->blkcg : NULL; |
| } |
| |
| extern void blkcg_destroy_blkgs(struct blkcg *blkcg); |
| |
| #ifdef CONFIG_CGROUP_WRITEBACK |
| |
| /** |
| * blkcg_cgwb_get - get a reference for blkcg->cgwb_list |
| * @blkcg: blkcg of interest |
| * |
| * This is used to track the number of active wb's related to a blkcg. |
| */ |
| static inline void blkcg_cgwb_get(struct blkcg *blkcg) |
| { |
| refcount_inc(&blkcg->cgwb_refcnt); |
| } |
| |
| /** |
| * blkcg_cgwb_put - put a reference for @blkcg->cgwb_list |
| * @blkcg: blkcg of interest |
| * |
| * This is used to track the number of active wb's related to a blkcg. |
| * When this count goes to zero, all active wb has finished so the |
| * blkcg can continue destruction by calling blkcg_destroy_blkgs(). |
| * This work may occur in cgwb_release_workfn() on the cgwb_release |
| * workqueue. |
| */ |
| static inline void blkcg_cgwb_put(struct blkcg *blkcg) |
| { |
| if (refcount_dec_and_test(&blkcg->cgwb_refcnt)) |
| blkcg_destroy_blkgs(blkcg); |
| } |
| |
| #else |
| |
| static inline void blkcg_cgwb_get(struct blkcg *blkcg) { } |
| |
| static inline void blkcg_cgwb_put(struct blkcg *blkcg) |
| { |
| /* wb isn't being accounted, so trigger destruction right away */ |
| blkcg_destroy_blkgs(blkcg); |
| } |
| |
| #endif |
| |
| /** |
| * 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) |
| { |
| return cgroup_path(blkg->blkcg->css.cgroup, buf, buflen); |
| } |
| |
| /** |
| * blkg_get - get a blkg reference |
| * @blkg: blkg to get |
| * |
| * The caller should be holding an existing reference. |
| */ |
| static inline void blkg_get(struct blkcg_gq *blkg) |
| { |
| percpu_ref_get(&blkg->refcnt); |
| } |
| |
| /** |
| * blkg_tryget - try and get a blkg reference |
| * @blkg: blkg to get |
| * |
| * This is for use when doing an RCU lookup of the blkg. We may be in the midst |
| * of freeing this blkg, so we can only use it if the refcnt is not zero. |
| */ |
| static inline bool blkg_tryget(struct blkcg_gq *blkg) |
| { |
| return blkg && percpu_ref_tryget(&blkg->refcnt); |
| } |
| |
| /** |
| * blkg_tryget_closest - try and get a blkg ref on the closet blkg |
| * @blkg: blkg to get |
| * |
| * This needs to be called rcu protected. As the failure mode here is to walk |
| * up the blkg tree, this ensure that the blkg->parent pointers are always |
| * valid. This returns the blkg that it ended up taking a reference on or %NULL |
| * if no reference was taken. |
| */ |
| static inline struct blkcg_gq *blkg_tryget_closest(struct blkcg_gq *blkg) |
| { |
| struct blkcg_gq *ret_blkg = NULL; |
| |
| WARN_ON_ONCE(!rcu_read_lock_held()); |
| |
| while (blkg) { |
| if (blkg_tryget(blkg)) { |
| ret_blkg = blkg; |
| break; |
| } |
| blkg = blkg->parent; |
| } |
| |
| return ret_blkg; |
| } |
| |
| /** |
| * blkg_put - put a blkg reference |
| * @blkg: blkg to put |
| */ |
| static inline void blkg_put(struct blkcg_gq *blkg) |
| { |
| percpu_ref_put(&blkg->refcnt); |
| } |
| |
| /** |
| * blkg_for_each_descendant_pre - pre-order walk of a blkg's descendants |
| * @d_blkg: loop cursor pointing to the current descendant |
| * @pos_css: used for iteration |
| * @p_blkg: target blkg to walk descendants of |
| * |
| * Walk @c_blkg through the descendants of @p_blkg. Must be used with RCU |
| * read locked. If called under either blkcg or queue lock, the iteration |
| * is guaranteed to include all and only online blkgs. The caller may |
| * update @pos_css by calling css_rightmost_descendant() to skip subtree. |
| * @p_blkg is included in the iteration and the first node to be visited. |
| */ |
| #define blkg_for_each_descendant_pre(d_blkg, pos_css, p_blkg) \ |
| css_for_each_descendant_pre((pos_css), &(p_blkg)->blkcg->css) \ |
| if (((d_blkg) = __blkg_lookup(css_to_blkcg(pos_css), \ |
| (p_blkg)->q, false))) |
| |
| /** |
| * blkg_for_each_descendant_post - post-order walk of a blkg's descendants |
| * @d_blkg: loop cursor pointing to the current descendant |
| * @pos_css: used for iteration |
| * @p_blkg: target blkg to walk descendants of |
| * |
| * Similar to blkg_for_each_descendant_pre() but performs post-order |
| * traversal instead. Synchronization rules are the same. @p_blkg is |
| * included in the iteration and the last node to be visited. |
| */ |
| #define blkg_for_each_descendant_post(d_blkg, pos_css, p_blkg) \ |
| css_for_each_descendant_post((pos_css), &(p_blkg)->blkcg->css) \ |
| if (((d_blkg) = __blkg_lookup(css_to_blkcg(pos_css), \ |
| (p_blkg)->q, false))) |
| |
| static inline int blkg_rwstat_init(struct blkg_rwstat *rwstat, gfp_t gfp) |
| { |
| int i, ret; |
| |
| for (i = 0; i < BLKG_RWSTAT_NR; i++) { |
| ret = percpu_counter_init(&rwstat->cpu_cnt[i], 0, gfp); |
| if (ret) { |
| while (--i >= 0) |
| percpu_counter_destroy(&rwstat->cpu_cnt[i]); |
| return ret; |
| } |
| atomic64_set(&rwstat->aux_cnt[i], 0); |
| } |
| return 0; |
| } |
| |
| static inline void blkg_rwstat_exit(struct blkg_rwstat *rwstat) |
| { |
| int i; |
| |
| for (i = 0; i < BLKG_RWSTAT_NR; i++) |
| percpu_counter_destroy(&rwstat->cpu_cnt[i]); |
| } |
| |
| /** |
| * blkg_rwstat_add - add a value to a blkg_rwstat |
| * @rwstat: target blkg_rwstat |
| * @op: REQ_OP and flags |
| * @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, |
| unsigned int op, uint64_t val) |
| { |
| struct percpu_counter *cnt; |
| |
| if (op_is_discard(op)) |
| cnt = &rwstat->cpu_cnt[BLKG_RWSTAT_DISCARD]; |
| else if (op_is_write(op)) |
| cnt = &rwstat->cpu_cnt[BLKG_RWSTAT_WRITE]; |
| else |
| cnt = &rwstat->cpu_cnt[BLKG_RWSTAT_READ]; |
| |
| percpu_counter_add_batch(cnt, val, BLKG_STAT_CPU_BATCH); |
| |
| if (op_is_sync(op)) |
| cnt = &rwstat->cpu_cnt[BLKG_RWSTAT_SYNC]; |
| else |
| cnt = &rwstat->cpu_cnt[BLKG_RWSTAT_ASYNC]; |
| |
| percpu_counter_add_batch(cnt, val, BLKG_STAT_CPU_BATCH); |
| } |
| |
| /** |
| * 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 in the aux counts. |
| */ |
| static inline void blkg_rwstat_read(struct blkg_rwstat *rwstat, |
| struct blkg_rwstat_sample *result) |
| { |
| int i; |
| |
| for (i = 0; i < BLKG_RWSTAT_NR; i++) |
| result->cnt[i] = |
| percpu_counter_sum_positive(&rwstat->cpu_cnt[i]); |
| } |
| |
| /** |
| * blkg_rwstat_total - 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_total(struct blkg_rwstat *rwstat) |
| { |
| struct blkg_rwstat_sample tmp = { }; |
| |
| blkg_rwstat_read(rwstat, &tmp); |
| 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) |
| { |
| int i; |
| |
| for (i = 0; i < BLKG_RWSTAT_NR; i++) { |
| percpu_counter_set(&rwstat->cpu_cnt[i], 0); |
| atomic64_set(&rwstat->aux_cnt[i], 0); |
| } |
| } |
| |
| /** |
| * blkg_rwstat_add_aux - add a blkg_rwstat into another's aux count |
| * @to: the destination blkg_rwstat |
| * @from: the source |
| * |
| * Add @from's count including the aux one to @to's aux count. |
| */ |
| static inline void blkg_rwstat_add_aux(struct blkg_rwstat *to, |
| struct blkg_rwstat *from) |
| { |
| u64 sum[BLKG_RWSTAT_NR]; |
| int i; |
| |
| for (i = 0; i < BLKG_RWSTAT_NR; i++) |
| sum[i] = percpu_counter_sum_positive(&from->cpu_cnt[i]); |
| |
| for (i = 0; i < BLKG_RWSTAT_NR; i++) |
| atomic64_add(sum[i] + atomic64_read(&from->aux_cnt[i]), |
| &to->aux_cnt[i]); |
| } |
| |
| #ifdef CONFIG_BLK_DEV_THROTTLING |
| extern bool blk_throtl_bio(struct request_queue *q, struct blkcg_gq *blkg, |
| struct bio *bio); |
| #else |
| static inline bool blk_throtl_bio(struct request_queue *q, struct blkcg_gq *blkg, |
| struct bio *bio) { return false; } |
| #endif |
| |
| bool __blkcg_punt_bio_submit(struct bio *bio); |
| |
| static inline bool blkcg_punt_bio_submit(struct bio *bio) |
| { |
| if (bio->bi_opf & REQ_CGROUP_PUNT) |
| return __blkcg_punt_bio_submit(bio); |
| else |
| return false; |
| } |
| |
| static inline void blkcg_bio_issue_init(struct bio *bio) |
| { |
| bio_issue_init(&bio->bi_issue, bio_sectors(bio)); |
| } |
| |
| static inline bool blkcg_bio_issue_check(struct request_queue *q, |
| struct bio *bio) |
| { |
| struct blkcg_gq *blkg; |
| bool throtl = false; |
| |
| rcu_read_lock(); |
| |
| if (!bio->bi_blkg) { |
| char b[BDEVNAME_SIZE]; |
| |
| WARN_ONCE(1, |
| "no blkg associated for bio on block-device: %s\n", |
| bio_devname(bio, b)); |
| bio_associate_blkg(bio); |
| } |
| |
| blkg = bio->bi_blkg; |
| |
| throtl = blk_throtl_bio(q, blkg, bio); |
| |
| if (!throtl) { |
| /* |
| * If the bio is flagged with BIO_QUEUE_ENTERED it means this |
| * is a split bio and we would have already accounted for the |
| * size of the bio. |
| */ |
| if (!bio_flagged(bio, BIO_QUEUE_ENTERED)) |
| blkg_rwstat_add(&blkg->stat_bytes, bio->bi_opf, |
| bio->bi_iter.bi_size); |
| blkg_rwstat_add(&blkg->stat_ios, bio->bi_opf, 1); |
| } |
| |
| blkcg_bio_issue_init(bio); |
| |
| rcu_read_unlock(); |
| return !throtl; |
| } |
| |
| static inline void blkcg_use_delay(struct blkcg_gq *blkg) |
| { |
| if (atomic_add_return(1, &blkg->use_delay) == 1) |
| atomic_inc(&blkg->blkcg->css.cgroup->congestion_count); |
| } |
| |
| static inline int blkcg_unuse_delay(struct blkcg_gq *blkg) |
| { |
| int old = atomic_read(&blkg->use_delay); |
| |
| if (old == 0) |
| return 0; |
| |
| /* |
| * We do this song and dance because we can race with somebody else |
| * adding or removing delay. If we just did an atomic_dec we'd end up |
| * negative and we'd already be in trouble. We need to subtract 1 and |
| * then check to see if we were the last delay so we can drop the |
| * congestion count on the cgroup. |
| */ |
| while (old) { |
| int cur = atomic_cmpxchg(&blkg->use_delay, old, old - 1); |
| if (cur == old) |
| break; |
| old = cur; |
| } |
| |
| if (old == 0) |
| return 0; |
| if (old == 1) |
| atomic_dec(&blkg->blkcg->css.cgroup->congestion_count); |
| return 1; |
| } |
| |
| static inline void blkcg_clear_delay(struct blkcg_gq *blkg) |
| { |
| int old = atomic_read(&blkg->use_delay); |
| if (!old) |
| return; |
| /* We only want 1 person clearing the congestion count for this blkg. */ |
| while (old) { |
| int cur = atomic_cmpxchg(&blkg->use_delay, old, 0); |
| if (cur == old) { |
| atomic_dec(&blkg->blkcg->css.cgroup->congestion_count); |
| break; |
| } |
| old = cur; |
| } |
| } |
| |
| void blkcg_add_delay(struct blkcg_gq *blkg, u64 now, u64 delta); |
| void blkcg_schedule_throttle(struct request_queue *q, bool use_memdelay); |
| void blkcg_maybe_throttle_current(void); |
| #else /* CONFIG_BLK_CGROUP */ |
| |
| struct blkcg { |
| }; |
| |
| struct blkg_policy_data { |
| }; |
| |
| struct blkcg_policy_data { |
| }; |
| |
| struct blkcg_gq { |
| }; |
| |
| struct blkcg_policy { |
| }; |
| |
| #define blkcg_root_css ((struct cgroup_subsys_state *)ERR_PTR(-EINVAL)) |
| |
| static inline void blkcg_maybe_throttle_current(void) { } |
| static inline bool blk_cgroup_congested(void) { return false; } |
| |
| #ifdef CONFIG_BLOCK |
| |
| static inline void blkcg_schedule_throttle(struct request_queue *q, bool use_memdelay) { } |
| |
| static inline struct blkcg_gq *blkg_lookup(struct blkcg *blkcg, void *key) { return NULL; } |
| static inline struct blkcg_gq *blk_queue_root_blkg(struct request_queue *q) |
| { 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 blkcg *__bio_blkcg(struct bio *bio) { return NULL; } |
| static inline struct blkcg *bio_blkcg(struct bio *bio) { return NULL; } |
| |
| 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) { } |
| |
| static inline bool blkcg_punt_bio_submit(struct bio *bio) { return false; } |
| static inline void blkcg_bio_issue_init(struct bio *bio) { } |
| static inline bool blkcg_bio_issue_check(struct request_queue *q, |
| struct bio *bio) { return true; } |
| |
| #define blk_queue_for_each_rl(rl, q) \ |
| for ((rl) = &(q)->root_rl; (rl); (rl) = NULL) |
| |
| #endif /* CONFIG_BLOCK */ |
| #endif /* CONFIG_BLK_CGROUP */ |
| #endif /* _BLK_CGROUP_H */ |