block/blk-cgroup.h

   1 #ifndef _BLK_CGROUP_H
   2 #define _BLK_CGROUP_H
   3 /*
   4  * Common Block IO controller cgroup interface
   5  *
   6  * Based on ideas and code from CFQ, CFS and BFQ:
   7  * Copyright (C) 2003 Jens Axboe <axboe@kernel.dk>
   8  *
   9  * Copyright (C) 2008 Fabio Checconi <fabio@gandalf.sssup.it>
  10  *                    Paolo Valente <paolo.valente@unimore.it>
  11  *
  12  * Copyright (C) 2009 Vivek Goyal <vgoyal@redhat.com>
  13  *                    Nauman Rafique <nauman@google.com>
  14  */
  15
  16 #include <linux/cgroup.h>
  17 #include <linux/u64_stats_sync.h>
  18 #include <linux/seq_file.h>
  19
  20 enum blkio_policy_id {
  21         BLKIO_POLICY_PROP = 0,          /* Proportional Bandwidth division */
  22         BLKIO_POLICY_THROTL,            /* Throttling */
  23
  24         BLKIO_NR_POLICIES,
  25 };
  26
  27 /* Max limits for throttle policy */
  28 #define THROTL_IOPS_MAX         UINT_MAX
  29
  30 #ifdef CONFIG_BLK_CGROUP
  31
  32 /* cft->private [un]packing for stat printing */
  33 #define BLKCG_STAT_PRIV(pol, off)       (((unsigned)(pol) << 16) | (off))
  34 #define BLKCG_STAT_POL(prv)             ((unsigned)(prv) >> 16)
  35 #define BLKCG_STAT_OFF(prv)             ((unsigned)(prv) & 0xffff)
  36
  37 enum blkg_rwstat_type {
  38         BLKG_RWSTAT_READ,
  39         BLKG_RWSTAT_WRITE,
  40         BLKG_RWSTAT_SYNC,
  41         BLKG_RWSTAT_ASYNC,
  42
  43         BLKG_RWSTAT_NR,
  44         BLKG_RWSTAT_TOTAL = BLKG_RWSTAT_NR,
  45 };
  46
  47 /* blkg state flags */
  48 enum blkg_state_flags {
  49         BLKG_waiting = 0,
  50         BLKG_idling,
  51         BLKG_empty,
  52 };
  53
  54 struct blkio_cgroup {
  55         struct cgroup_subsys_state css;
  56         unsigned int weight;
  57         spinlock_t lock;
  58         struct hlist_head blkg_list;
  59
  60         /* for policies to test whether associated blkcg has changed */
  61         uint64_t id;
  62 };
  63
  64 struct blkg_stat {
  65         struct u64_stats_sync           syncp;
  66         uint64_t                        cnt;
  67 };
  68
  69 struct blkg_rwstat {
  70         struct u64_stats_sync           syncp;
  71         uint64_t                        cnt[BLKG_RWSTAT_NR];
  72 };
  73
  74 struct blkio_group_stats {
  75         /* number of ios merged */
  76         struct blkg_rwstat              merged;
  77         /* total time spent on device in ns, may not be accurate w/ queueing */
  78         struct blkg_rwstat              service_time;
  79         /* total time spent waiting in scheduler queue in ns */
  80         struct blkg_rwstat              wait_time;
  81         /* number of IOs queued up */
  82         struct blkg_rwstat              queued;
  83         /* total disk time and nr sectors dispatched by this group */
  84         struct blkg_stat                time;
  85 #ifdef CONFIG_DEBUG_BLK_CGROUP
  86         /* time not charged to this cgroup */
  87         struct blkg_stat                unaccounted_time;
  88         /* sum of number of ios queued across all samples */
  89         struct blkg_stat                avg_queue_size_sum;
  90         /* count of samples taken for average */
  91         struct blkg_stat                avg_queue_size_samples;
  92         /* how many times this group has been removed from service tree */
  93         struct blkg_stat                dequeue;
  94         /* total time spent waiting for it to be assigned a timeslice. */
  95         struct blkg_stat                group_wait_time;
  96         /* time spent idling for this blkio_group */
  97         struct blkg_stat                idle_time;
  98         /* total time with empty current active q with other requests queued */
  99         struct blkg_stat                empty_time;
 100         /* fields after this shouldn't be cleared on stat reset */
 101         uint64_t                        start_group_wait_time;
 102         uint64_t                        start_idle_time;
 103         uint64_t                        start_empty_time;
 104         uint16_t                        flags;
 105 #endif
 106 };
 107
 108 /* Per cpu blkio group stats */
 109 struct blkio_group_stats_cpu {
 110         /* total bytes transferred */
 111         struct blkg_rwstat              service_bytes;
 112         /* total IOs serviced, post merge */
 113         struct blkg_rwstat              serviced;
 114         /* total sectors transferred */
 115         struct blkg_stat                sectors;
 116 };
 117
 118 struct blkio_group_conf {
 119         unsigned int weight;
 120         u64 iops[2];
 121         u64 bps[2];
 122 };
 123
 124 /* per-blkg per-policy data */
 125 struct blkg_policy_data {
 126         /* the blkg this per-policy data belongs to */
 127         struct blkio_group *blkg;
 128
 129         /* Configuration */
 130         struct blkio_group_conf conf;
 131
 132         struct blkio_group_stats stats;
 133         /* Per cpu stats pointer */
 134         struct blkio_group_stats_cpu __percpu *stats_cpu;
 135
 136         /* pol->pdata_size bytes of private data used by policy impl */
 137         char pdata[] __aligned(__alignof__(unsigned long long));
 138 };
 139
 140 struct blkio_group {
 141         /* Pointer to the associated request_queue */
 142         struct request_queue *q;
 143         struct list_head q_node;
 144         struct hlist_node blkcg_node;
 145         struct blkio_cgroup *blkcg;
 146         /* Store cgroup path */
 147         char path[128];
 148         /* reference count */
 149         int refcnt;
 150
 151         struct blkg_policy_data *pd[BLKIO_NR_POLICIES];
 152
 153         /* List of blkg waiting for per cpu stats memory to be allocated */
 154         struct list_head alloc_node;
 155         struct rcu_head rcu_head;
 156 };
 157
 158 typedef void (blkio_init_group_fn)(struct blkio_group *blkg);
 159
 160 struct blkio_policy_ops {
 161         blkio_init_group_fn *blkio_init_group_fn;
 162 };
 163
 164 struct blkio_policy_type {
 165         struct list_head list;
 166         struct blkio_policy_ops ops;
 167         enum blkio_policy_id plid;
 168         size_t pdata_size;              /* policy specific private data size */
 169         struct cftype *cftypes;         /* cgroup files for the policy */
 170 };
 171
 172 extern int blkcg_init_queue(struct request_queue *q);
 173 extern void blkcg_drain_queue(struct request_queue *q);
 174 extern void blkcg_exit_queue(struct request_queue *q);
 175
 176 /* Blkio controller policy registration */
 177 extern void blkio_policy_register(struct blkio_policy_type *);
 178 extern void blkio_policy_unregister(struct blkio_policy_type *);
 179 extern void blkg_destroy_all(struct request_queue *q, bool destroy_root);
 180 extern void update_root_blkg_pd(struct request_queue *q,
 181                                 enum blkio_policy_id plid);
 182
 183 void blkcg_print_blkgs(struct seq_file *sf, struct blkio_cgroup *blkcg,
 184                        u64 (*prfill)(struct seq_file *, struct blkg_policy_data *, int),
 185                        int pol, int data, bool show_total);
 186 u64 __blkg_prfill_u64(struct seq_file *sf, struct blkg_policy_data *pd, u64 v);
 187 u64 __blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd,
 188                          const struct blkg_rwstat *rwstat);
 189 int blkcg_print_stat(struct cgroup *cgrp, struct cftype *cft,
 190                      struct seq_file *sf);
 191 int blkcg_print_rwstat(struct cgroup *cgrp, struct cftype *cft,
 192                        struct seq_file *sf);
 193 int blkcg_print_cpu_stat(struct cgroup *cgrp, struct cftype *cft,
 194                          struct seq_file *sf);
 195 int blkcg_print_cpu_rwstat(struct cgroup *cgrp, struct cftype *cft,
 196                            struct seq_file *sf);
 197
 198 struct blkg_conf_ctx {
 199         struct gendisk          *disk;
 200         struct blkio_group      *blkg;
 201         u64                     v;
 202 };
 203
 204 int blkg_conf_prep(struct blkio_cgroup *blkcg, const char *input,
 205                    struct blkg_conf_ctx *ctx);
 206 void blkg_conf_finish(struct blkg_conf_ctx *ctx);
 207
 208
 209 /**
 210  * blkg_to_pdata - get policy private data
 211  * @blkg: blkg of interest
 212  * @pol: policy of interest
 213  *
 214  * Return pointer to private data associated with the @blkg-@pol pair.
 215  */
 216 static inline void *blkg_to_pdata(struct blkio_group *blkg,
 217                               struct blkio_policy_type *pol)
 218 {
 219         return blkg ? blkg->pd[pol->plid]->pdata : NULL;
 220 }
 221
 222 /**
 223  * pdata_to_blkg - get blkg associated with policy private data
 224  * @pdata: policy private data of interest
 225  *
 226  * @pdata is policy private data.  Determine the blkg it's associated with.
 227  */
 228 static inline struct blkio_group *pdata_to_blkg(void *pdata)
 229 {
 230         if (pdata) {
 231                 struct blkg_policy_data *pd =
 232                         container_of(pdata, struct blkg_policy_data, pdata);
 233                 return pd->blkg;
 234         }
 235         return NULL;
 236 }
 237
 238 static inline char *blkg_path(struct blkio_group *blkg)
 239 {
 240         return blkg->path;
 241 }
 242
 243 /**
 244  * blkg_get - get a blkg reference
 245  * @blkg: blkg to get
 246  *
 247  * The caller should be holding queue_lock and an existing reference.
 248  */
 249 static inline void blkg_get(struct blkio_group *blkg)
 250 {
 251         lockdep_assert_held(blkg->q->queue_lock);
 252         WARN_ON_ONCE(!blkg->refcnt);
 253         blkg->refcnt++;
 254 }
 255
 256 void __blkg_release(struct blkio_group *blkg);
 257
 258 /**
 259  * blkg_put - put a blkg reference
 260  * @blkg: blkg to put
 261  *
 262  * The caller should be holding queue_lock.
 263  */
 264 static inline void blkg_put(struct blkio_group *blkg)
 265 {
 266         lockdep_assert_held(blkg->q->queue_lock);
 267         WARN_ON_ONCE(blkg->refcnt <= 0);
 268         if (!--blkg->refcnt)
 269                 __blkg_release(blkg);
 270 }
 271
 272 /**
 273  * blkg_stat_add - add a value to a blkg_stat
 274  * @stat: target blkg_stat
 275  * @val: value to add
 276  *
 277  * Add @val to @stat.  The caller is responsible for synchronizing calls to
 278  * this function.
 279  */
 280 static inline void blkg_stat_add(struct blkg_stat *stat, uint64_t val)
 281 {
 282         u64_stats_update_begin(&stat->syncp);
 283         stat->cnt += val;
 284         u64_stats_update_end(&stat->syncp);
 285 }
 286
 287 /**
 288  * blkg_stat_read - read the current value of a blkg_stat
 289  * @stat: blkg_stat to read
 290  *
 291  * Read the current value of @stat.  This function can be called without
 292  * synchroniztion and takes care of u64 atomicity.
 293  */
 294 static inline uint64_t blkg_stat_read(struct blkg_stat *stat)
 295 {
 296         unsigned int start;
 297         uint64_t v;
 298
 299         do {
 300                 start = u64_stats_fetch_begin(&stat->syncp);
 301                 v = stat->cnt;
 302         } while (u64_stats_fetch_retry(&stat->syncp, start));
 303
 304         return v;
 305 }
 306
 307 /**
 308  * blkg_stat_reset - reset a blkg_stat
 309  * @stat: blkg_stat to reset
 310  */
 311 static inline void blkg_stat_reset(struct blkg_stat *stat)
 312 {
 313         stat->cnt = 0;
 314 }
 315
 316 /**
 317  * blkg_rwstat_add - add a value to a blkg_rwstat
 318  * @rwstat: target blkg_rwstat
 319  * @rw: mask of REQ_{WRITE|SYNC}
 320  * @val: value to add
 321  *
 322  * Add @val to @rwstat.  The counters are chosen according to @rw.  The
 323  * caller is responsible for synchronizing calls to this function.
 324  */
 325 static inline void blkg_rwstat_add(struct blkg_rwstat *rwstat,
 326                                    int rw, uint64_t val)
 327 {
 328         u64_stats_update_begin(&rwstat->syncp);
 329
 330         if (rw & REQ_WRITE)
 331                 rwstat->cnt[BLKG_RWSTAT_WRITE] += val;
 332         else
 333                 rwstat->cnt[BLKG_RWSTAT_READ] += val;
 334         if (rw & REQ_SYNC)
 335                 rwstat->cnt[BLKG_RWSTAT_SYNC] += val;
 336         else
 337                 rwstat->cnt[BLKG_RWSTAT_ASYNC] += val;
 338
 339         u64_stats_update_end(&rwstat->syncp);
 340 }
 341
 342 /**
 343  * blkg_rwstat_read - read the current values of a blkg_rwstat
 344  * @rwstat: blkg_rwstat to read
 345  *
 346  * Read the current snapshot of @rwstat and return it as the return value.
 347  * This function can be called without synchronization and takes care of
 348  * u64 atomicity.
 349  */
 350 static struct blkg_rwstat blkg_rwstat_read(struct blkg_rwstat *rwstat)
 351 {
 352         unsigned int start;
 353         struct blkg_rwstat tmp;
 354
 355         do {
 356                 start = u64_stats_fetch_begin(&rwstat->syncp);
 357                 tmp = *rwstat;
 358         } while (u64_stats_fetch_retry(&rwstat->syncp, start));
 359
 360         return tmp;
 361 }
 362
 363 /**
 364  * blkg_rwstat_sum - read the total count of a blkg_rwstat
 365  * @rwstat: blkg_rwstat to read
 366  *
 367  * Return the total count of @rwstat regardless of the IO direction.  This
 368  * function can be called without synchronization and takes care of u64
 369  * atomicity.
 370  */
 371 static inline uint64_t blkg_rwstat_sum(struct blkg_rwstat *rwstat)
 372 {
 373         struct blkg_rwstat tmp = blkg_rwstat_read(rwstat);
 374
 375         return tmp.cnt[BLKG_RWSTAT_READ] + tmp.cnt[BLKG_RWSTAT_WRITE];
 376 }
 377
 378 /**
 379  * blkg_rwstat_reset - reset a blkg_rwstat
 380  * @rwstat: blkg_rwstat to reset
 381  */
 382 static inline void blkg_rwstat_reset(struct blkg_rwstat *rwstat)
 383 {
 384         memset(rwstat->cnt, 0, sizeof(rwstat->cnt));
 385 }
 386
 387 #else
 388
 389 struct blkio_group {
 390 };
 391
 392 struct blkio_policy_type {
 393 };
 394
 395 static inline int blkcg_init_queue(struct request_queue *q) { return 0; }
 396 static inline void blkcg_drain_queue(struct request_queue *q) { }
 397 static inline void blkcg_exit_queue(struct request_queue *q) { }
 398 static inline void blkio_policy_register(struct blkio_policy_type *blkiop) { }
 399 static inline void blkio_policy_unregister(struct blkio_policy_type *blkiop) { }
 400 static inline void blkg_destroy_all(struct request_queue *q,
 401                                     bool destory_root) { }
 402 static inline void update_root_blkg_pd(struct request_queue *q,
 403                                        enum blkio_policy_id plid) { }
 404
 405 static inline void *blkg_to_pdata(struct blkio_group *blkg,
 406                                 struct blkio_policy_type *pol) { return NULL; }
 407 static inline struct blkio_group *pdata_to_blkg(void *pdata,
 408                                 struct blkio_policy_type *pol) { return NULL; }
 409 static inline char *blkg_path(struct blkio_group *blkg) { return NULL; }
 410 static inline void blkg_get(struct blkio_group *blkg) { }
 411 static inline void blkg_put(struct blkio_group *blkg) { }
 412
 413 #endif
 414
 415 #define BLKIO_WEIGHT_MIN        10
 416 #define BLKIO_WEIGHT_MAX        1000
 417 #define BLKIO_WEIGHT_DEFAULT    500
 418
 419 #ifdef CONFIG_DEBUG_BLK_CGROUP
 420 void blkiocg_update_avg_queue_size_stats(struct blkio_group *blkg,
 421                                          struct blkio_policy_type *pol);
 422 void blkiocg_update_dequeue_stats(struct blkio_group *blkg,
 423                                   struct blkio_policy_type *pol,
 424                                   unsigned long dequeue);
 425 void blkiocg_update_set_idle_time_stats(struct blkio_group *blkg,
 426                                         struct blkio_policy_type *pol);
 427 void blkiocg_update_idle_time_stats(struct blkio_group *blkg,
 428                                     struct blkio_policy_type *pol);
 429 void blkiocg_set_start_empty_time(struct blkio_group *blkg,
 430                                   struct blkio_policy_type *pol);
 431
 432 #define BLKG_FLAG_FNS(name)                                             \
 433 static inline void blkio_mark_blkg_##name(                              \
 434                 struct blkio_group_stats *stats)                        \
 435 {                                                                       \
 436         stats->flags |= (1 << BLKG_##name);                             \
 437 }                                                                       \
 438 static inline void blkio_clear_blkg_##name(                             \
 439                 struct blkio_group_stats *stats)                        \
 440 {                                                                       \
 441         stats->flags &= ~(1 << BLKG_##name);                            \
 442 }                                                                       \
 443 static inline int blkio_blkg_##name(struct blkio_group_stats *stats)    \
 444 {                                                                       \
 445         return (stats->flags & (1 << BLKG_##name)) != 0;                \
 446 }                                                                       \
 447
 448 BLKG_FLAG_FNS(waiting)
 449 BLKG_FLAG_FNS(idling)
 450 BLKG_FLAG_FNS(empty)
 451 #undef BLKG_FLAG_FNS
 452 #else
 453 static inline void blkiocg_update_avg_queue_size_stats(struct blkio_group *blkg,
 454                         struct blkio_policy_type *pol) { }
 455 static inline void blkiocg_update_dequeue_stats(struct blkio_group *blkg,
 456                         struct blkio_policy_type *pol, unsigned long dequeue) { }
 457 static inline void blkiocg_update_set_idle_time_stats(struct blkio_group *blkg,
 458                         struct blkio_policy_type *pol) { }
 459 static inline void blkiocg_update_idle_time_stats(struct blkio_group *blkg,
 460                         struct blkio_policy_type *pol) { }
 461 static inline void blkiocg_set_start_empty_time(struct blkio_group *blkg,
 462                         struct blkio_policy_type *pol) { }
 463 #endif
 464
 465 #ifdef CONFIG_BLK_CGROUP
 466 extern struct blkio_cgroup blkio_root_cgroup;
 467 extern struct blkio_cgroup *cgroup_to_blkio_cgroup(struct cgroup *cgroup);
 468 extern struct blkio_cgroup *bio_blkio_cgroup(struct bio *bio);
 469 extern struct blkio_group *blkg_lookup(struct blkio_cgroup *blkcg,
 470                                        struct request_queue *q);
 471 struct blkio_group *blkg_lookup_create(struct blkio_cgroup *blkcg,
 472                                        struct request_queue *q,
 473                                        bool for_root);
 474 void blkiocg_update_timeslice_used(struct blkio_group *blkg,
 475                                    struct blkio_policy_type *pol,
 476                                    unsigned long time,
 477                                    unsigned long unaccounted_time);
 478 void blkiocg_update_dispatch_stats(struct blkio_group *blkg,
 479                                    struct blkio_policy_type *pol,
 480                                    uint64_t bytes, bool direction, bool sync);
 481 void blkiocg_update_completion_stats(struct blkio_group *blkg,
 482                                      struct blkio_policy_type *pol,
 483                                      uint64_t start_time,
 484                                      uint64_t io_start_time, bool direction,
 485                                      bool sync);
 486 void blkiocg_update_io_merged_stats(struct blkio_group *blkg,
 487                                     struct blkio_policy_type *pol,
 488                                     bool direction, bool sync);
 489 void blkiocg_update_io_add_stats(struct blkio_group *blkg,
 490                                  struct blkio_policy_type *pol,
 491                                  struct blkio_group *curr_blkg, bool direction,
 492                                  bool sync);
 493 void blkiocg_update_io_remove_stats(struct blkio_group *blkg,
 494                                     struct blkio_policy_type *pol,
 495                                     bool direction, bool sync);
 496 #else
 497 struct cgroup;
 498 static inline struct blkio_cgroup *
 499 cgroup_to_blkio_cgroup(struct cgroup *cgroup) { return NULL; }
 500 static inline struct blkio_cgroup *
 501 bio_blkio_cgroup(struct bio *bio) { return NULL; }
 502
 503 static inline struct blkio_group *blkg_lookup(struct blkio_cgroup *blkcg,
 504                                               void *key) { return NULL; }
 505 static inline void blkiocg_update_timeslice_used(struct blkio_group *blkg,
 506                         struct blkio_policy_type *pol, unsigned long time,
 507                         unsigned long unaccounted_time) { }
 508 static inline void blkiocg_update_dispatch_stats(struct blkio_group *blkg,
 509                         struct blkio_policy_type *pol, uint64_t bytes,
 510                         bool direction, bool sync) { }
 511 static inline void blkiocg_update_completion_stats(struct blkio_group *blkg,
 512                         struct blkio_policy_type *pol, uint64_t start_time,
 513                         uint64_t io_start_time, bool direction, bool sync) { }
 514 static inline void blkiocg_update_io_merged_stats(struct blkio_group *blkg,
 515                         struct blkio_policy_type *pol, bool direction,
 516                         bool sync) { }
 517 static inline void blkiocg_update_io_add_stats(struct blkio_group *blkg,
 518                         struct blkio_policy_type *pol,
 519                         struct blkio_group *curr_blkg, bool direction,
 520                         bool sync) { }
 521 static inline void blkiocg_update_io_remove_stats(struct blkio_group *blkg,
 522                         struct blkio_policy_type *pol, bool direction,
 523                         bool sync) { }
 524 #endif
 525 #endif /* _BLK_CGROUP_H */