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 typedef void (blkio_update_group_weight_fn)(struct request_queue *q,
 160                         struct blkio_group *blkg, unsigned int weight);
 161 typedef void (blkio_update_group_read_bps_fn)(struct request_queue *q,
 162                         struct blkio_group *blkg, u64 read_bps);
 163 typedef void (blkio_update_group_write_bps_fn)(struct request_queue *q,
 164                         struct blkio_group *blkg, u64 write_bps);
 165 typedef void (blkio_update_group_read_iops_fn)(struct request_queue *q,
 166                         struct blkio_group *blkg, unsigned int read_iops);
 167 typedef void (blkio_update_group_write_iops_fn)(struct request_queue *q,
 168                         struct blkio_group *blkg, unsigned int write_iops);
 169
 170 struct blkio_policy_ops {
 171         blkio_init_group_fn *blkio_init_group_fn;
 172         blkio_update_group_weight_fn *blkio_update_group_weight_fn;
 173         blkio_update_group_read_bps_fn *blkio_update_group_read_bps_fn;
 174         blkio_update_group_write_bps_fn *blkio_update_group_write_bps_fn;
 175         blkio_update_group_read_iops_fn *blkio_update_group_read_iops_fn;
 176         blkio_update_group_write_iops_fn *blkio_update_group_write_iops_fn;
 177 };
 178
 179 struct blkio_policy_type {
 180         struct list_head list;
 181         struct blkio_policy_ops ops;
 182         enum blkio_policy_id plid;
 183         size_t pdata_size;              /* policy specific private data size */
 184         struct cftype *cftypes;         /* cgroup files for the policy */
 185 };
 186
 187 extern int blkcg_init_queue(struct request_queue *q);
 188 extern void blkcg_drain_queue(struct request_queue *q);
 189 extern void blkcg_exit_queue(struct request_queue *q);
 190
 191 /* Blkio controller policy registration */
 192 extern void blkio_policy_register(struct blkio_policy_type *);
 193 extern void blkio_policy_unregister(struct blkio_policy_type *);
 194 extern void blkg_destroy_all(struct request_queue *q, bool destroy_root);
 195 extern void update_root_blkg_pd(struct request_queue *q,
 196                                 enum blkio_policy_id plid);
 197
 198 void blkcg_print_blkgs(struct seq_file *sf, struct blkio_cgroup *blkcg,
 199                        u64 (*prfill)(struct seq_file *, struct blkg_policy_data *, int),
 200                        int pol, int data, bool show_total);
 201 u64 __blkg_prfill_u64(struct seq_file *sf, struct blkg_policy_data *pd, u64 v);
 202 u64 __blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd,
 203                          const struct blkg_rwstat *rwstat);
 204 int blkcg_print_stat(struct cgroup *cgrp, struct cftype *cft,
 205                      struct seq_file *sf);
 206 int blkcg_print_rwstat(struct cgroup *cgrp, struct cftype *cft,
 207                        struct seq_file *sf);
 208 int blkcg_print_cpu_stat(struct cgroup *cgrp, struct cftype *cft,
 209                          struct seq_file *sf);
 210 int blkcg_print_cpu_rwstat(struct cgroup *cgrp, struct cftype *cft,
 211                            struct seq_file *sf);
 212
 213 struct blkg_conf_ctx {
 214         struct gendisk          *disk;
 215         struct blkio_group      *blkg;
 216         u64                     v;
 217 };
 218
 219 int blkg_conf_prep(struct blkio_cgroup *blkcg, const char *input,
 220                    struct blkg_conf_ctx *ctx);
 221 void blkg_conf_finish(struct blkg_conf_ctx *ctx);
 222
 223
 224 /**
 225  * blkg_to_pdata - get policy private data
 226  * @blkg: blkg of interest
 227  * @pol: policy of interest
 228  *
 229  * Return pointer to private data associated with the @blkg-@pol pair.
 230  */
 231 static inline void *blkg_to_pdata(struct blkio_group *blkg,
 232                               struct blkio_policy_type *pol)
 233 {
 234         return blkg ? blkg->pd[pol->plid]->pdata : NULL;
 235 }
 236
 237 /**
 238  * pdata_to_blkg - get blkg associated with policy private data
 239  * @pdata: policy private data of interest
 240  *
 241  * @pdata is policy private data.  Determine the blkg it's associated with.
 242  */
 243 static inline struct blkio_group *pdata_to_blkg(void *pdata)
 244 {
 245         if (pdata) {
 246                 struct blkg_policy_data *pd =
 247                         container_of(pdata, struct blkg_policy_data, pdata);
 248                 return pd->blkg;
 249         }
 250         return NULL;
 251 }
 252
 253 static inline char *blkg_path(struct blkio_group *blkg)
 254 {
 255         return blkg->path;
 256 }
 257
 258 /**
 259  * blkg_get - get a blkg reference
 260  * @blkg: blkg to get
 261  *
 262  * The caller should be holding queue_lock and an existing reference.
 263  */
 264 static inline void blkg_get(struct blkio_group *blkg)
 265 {
 266         lockdep_assert_held(blkg->q->queue_lock);
 267         WARN_ON_ONCE(!blkg->refcnt);
 268         blkg->refcnt++;
 269 }
 270
 271 void __blkg_release(struct blkio_group *blkg);
 272
 273 /**
 274  * blkg_put - put a blkg reference
 275  * @blkg: blkg to put
 276  *
 277  * The caller should be holding queue_lock.
 278  */
 279 static inline void blkg_put(struct blkio_group *blkg)
 280 {
 281         lockdep_assert_held(blkg->q->queue_lock);
 282         WARN_ON_ONCE(blkg->refcnt <= 0);
 283         if (!--blkg->refcnt)
 284                 __blkg_release(blkg);
 285 }
 286
 287 /**
 288  * blkg_stat_add - add a value to a blkg_stat
 289  * @stat: target blkg_stat
 290  * @val: value to add
 291  *
 292  * Add @val to @stat.  The caller is responsible for synchronizing calls to
 293  * this function.
 294  */
 295 static inline void blkg_stat_add(struct blkg_stat *stat, uint64_t val)
 296 {
 297         u64_stats_update_begin(&stat->syncp);
 298         stat->cnt += val;
 299         u64_stats_update_end(&stat->syncp);
 300 }
 301
 302 /**
 303  * blkg_stat_read - read the current value of a blkg_stat
 304  * @stat: blkg_stat to read
 305  *
 306  * Read the current value of @stat.  This function can be called without
 307  * synchroniztion and takes care of u64 atomicity.
 308  */
 309 static inline uint64_t blkg_stat_read(struct blkg_stat *stat)
 310 {
 311         unsigned int start;
 312         uint64_t v;
 313
 314         do {
 315                 start = u64_stats_fetch_begin(&stat->syncp);
 316                 v = stat->cnt;
 317         } while (u64_stats_fetch_retry(&stat->syncp, start));
 318
 319         return v;
 320 }
 321
 322 /**
 323  * blkg_stat_reset - reset a blkg_stat
 324  * @stat: blkg_stat to reset
 325  */
 326 static inline void blkg_stat_reset(struct blkg_stat *stat)
 327 {
 328         stat->cnt = 0;
 329 }
 330
 331 /**
 332  * blkg_rwstat_add - add a value to a blkg_rwstat
 333  * @rwstat: target blkg_rwstat
 334  * @rw: mask of REQ_{WRITE|SYNC}
 335  * @val: value to add
 336  *
 337  * Add @val to @rwstat.  The counters are chosen according to @rw.  The
 338  * caller is responsible for synchronizing calls to this function.
 339  */
 340 static inline void blkg_rwstat_add(struct blkg_rwstat *rwstat,
 341                                    int rw, uint64_t val)
 342 {
 343         u64_stats_update_begin(&rwstat->syncp);
 344
 345         if (rw & REQ_WRITE)
 346                 rwstat->cnt[BLKG_RWSTAT_WRITE] += val;
 347         else
 348                 rwstat->cnt[BLKG_RWSTAT_READ] += val;
 349         if (rw & REQ_SYNC)
 350                 rwstat->cnt[BLKG_RWSTAT_SYNC] += val;
 351         else
 352                 rwstat->cnt[BLKG_RWSTAT_ASYNC] += val;
 353
 354         u64_stats_update_end(&rwstat->syncp);
 355 }
 356
 357 /**
 358  * blkg_rwstat_read - read the current values of a blkg_rwstat
 359  * @rwstat: blkg_rwstat to read
 360  *
 361  * Read the current snapshot of @rwstat and return it as the return value.
 362  * This function can be called without synchronization and takes care of
 363  * u64 atomicity.
 364  */
 365 static struct blkg_rwstat blkg_rwstat_read(struct blkg_rwstat *rwstat)
 366 {
 367         unsigned int start;
 368         struct blkg_rwstat tmp;
 369
 370         do {
 371                 start = u64_stats_fetch_begin(&rwstat->syncp);
 372                 tmp = *rwstat;
 373         } while (u64_stats_fetch_retry(&rwstat->syncp, start));
 374
 375         return tmp;
 376 }
 377
 378 /**
 379  * blkg_rwstat_sum - read the total count of a blkg_rwstat
 380  * @rwstat: blkg_rwstat to read
 381  *
 382  * Return the total count of @rwstat regardless of the IO direction.  This
 383  * function can be called without synchronization and takes care of u64
 384  * atomicity.
 385  */
 386 static inline uint64_t blkg_rwstat_sum(struct blkg_rwstat *rwstat)
 387 {
 388         struct blkg_rwstat tmp = blkg_rwstat_read(rwstat);
 389
 390         return tmp.cnt[BLKG_RWSTAT_READ] + tmp.cnt[BLKG_RWSTAT_WRITE];
 391 }
 392
 393 /**
 394  * blkg_rwstat_reset - reset a blkg_rwstat
 395  * @rwstat: blkg_rwstat to reset
 396  */
 397 static inline void blkg_rwstat_reset(struct blkg_rwstat *rwstat)
 398 {
 399         memset(rwstat->cnt, 0, sizeof(rwstat->cnt));
 400 }
 401
 402 #else
 403
 404 struct blkio_group {
 405 };
 406
 407 struct blkio_policy_type {
 408 };
 409
 410 static inline int blkcg_init_queue(struct request_queue *q) { return 0; }
 411 static inline void blkcg_drain_queue(struct request_queue *q) { }
 412 static inline void blkcg_exit_queue(struct request_queue *q) { }
 413 static inline void blkio_policy_register(struct blkio_policy_type *blkiop) { }
 414 static inline void blkio_policy_unregister(struct blkio_policy_type *blkiop) { }
 415 static inline void blkg_destroy_all(struct request_queue *q,
 416                                     bool destory_root) { }
 417 static inline void update_root_blkg_pd(struct request_queue *q,
 418                                        enum blkio_policy_id plid) { }
 419
 420 static inline void *blkg_to_pdata(struct blkio_group *blkg,
 421                                 struct blkio_policy_type *pol) { return NULL; }
 422 static inline struct blkio_group *pdata_to_blkg(void *pdata,
 423                                 struct blkio_policy_type *pol) { return NULL; }
 424 static inline char *blkg_path(struct blkio_group *blkg) { return NULL; }
 425 static inline void blkg_get(struct blkio_group *blkg) { }
 426 static inline void blkg_put(struct blkio_group *blkg) { }
 427
 428 #endif
 429
 430 #define BLKIO_WEIGHT_MIN        10
 431 #define BLKIO_WEIGHT_MAX        1000
 432 #define BLKIO_WEIGHT_DEFAULT    500
 433
 434 #ifdef CONFIG_DEBUG_BLK_CGROUP
 435 void blkiocg_update_avg_queue_size_stats(struct blkio_group *blkg,
 436                                          struct blkio_policy_type *pol);
 437 void blkiocg_update_dequeue_stats(struct blkio_group *blkg,
 438                                   struct blkio_policy_type *pol,
 439                                   unsigned long dequeue);
 440 void blkiocg_update_set_idle_time_stats(struct blkio_group *blkg,
 441                                         struct blkio_policy_type *pol);
 442 void blkiocg_update_idle_time_stats(struct blkio_group *blkg,
 443                                     struct blkio_policy_type *pol);
 444 void blkiocg_set_start_empty_time(struct blkio_group *blkg,
 445                                   struct blkio_policy_type *pol);
 446
 447 #define BLKG_FLAG_FNS(name)                                             \
 448 static inline void blkio_mark_blkg_##name(                              \
 449                 struct blkio_group_stats *stats)                        \
 450 {                                                                       \
 451         stats->flags |= (1 << BLKG_##name);                             \
 452 }                                                                       \
 453 static inline void blkio_clear_blkg_##name(                             \
 454                 struct blkio_group_stats *stats)                        \
 455 {                                                                       \
 456         stats->flags &= ~(1 << BLKG_##name);                            \
 457 }                                                                       \
 458 static inline int blkio_blkg_##name(struct blkio_group_stats *stats)    \
 459 {                                                                       \
 460         return (stats->flags & (1 << BLKG_##name)) != 0;                \
 461 }                                                                       \
 462
 463 BLKG_FLAG_FNS(waiting)
 464 BLKG_FLAG_FNS(idling)
 465 BLKG_FLAG_FNS(empty)
 466 #undef BLKG_FLAG_FNS
 467 #else
 468 static inline void blkiocg_update_avg_queue_size_stats(struct blkio_group *blkg,
 469                         struct blkio_policy_type *pol) { }
 470 static inline void blkiocg_update_dequeue_stats(struct blkio_group *blkg,
 471                         struct blkio_policy_type *pol, unsigned long dequeue) { }
 472 static inline void blkiocg_update_set_idle_time_stats(struct blkio_group *blkg,
 473                         struct blkio_policy_type *pol) { }
 474 static inline void blkiocg_update_idle_time_stats(struct blkio_group *blkg,
 475                         struct blkio_policy_type *pol) { }
 476 static inline void blkiocg_set_start_empty_time(struct blkio_group *blkg,
 477                         struct blkio_policy_type *pol) { }
 478 #endif
 479
 480 #ifdef CONFIG_BLK_CGROUP
 481 extern struct blkio_cgroup blkio_root_cgroup;
 482 extern struct blkio_cgroup *cgroup_to_blkio_cgroup(struct cgroup *cgroup);
 483 extern struct blkio_cgroup *bio_blkio_cgroup(struct bio *bio);
 484 extern struct blkio_group *blkg_lookup(struct blkio_cgroup *blkcg,
 485                                        struct request_queue *q);
 486 struct blkio_group *blkg_lookup_create(struct blkio_cgroup *blkcg,
 487                                        struct request_queue *q,
 488                                        bool for_root);
 489 void blkiocg_update_timeslice_used(struct blkio_group *blkg,
 490                                    struct blkio_policy_type *pol,
 491                                    unsigned long time,
 492                                    unsigned long unaccounted_time);
 493 void blkiocg_update_dispatch_stats(struct blkio_group *blkg,
 494                                    struct blkio_policy_type *pol,
 495                                    uint64_t bytes, bool direction, bool sync);
 496 void blkiocg_update_completion_stats(struct blkio_group *blkg,
 497                                      struct blkio_policy_type *pol,
 498                                      uint64_t start_time,
 499                                      uint64_t io_start_time, bool direction,
 500                                      bool sync);
 501 void blkiocg_update_io_merged_stats(struct blkio_group *blkg,
 502                                     struct blkio_policy_type *pol,
 503                                     bool direction, bool sync);
 504 void blkiocg_update_io_add_stats(struct blkio_group *blkg,
 505                                  struct blkio_policy_type *pol,
 506                                  struct blkio_group *curr_blkg, bool direction,
 507                                  bool sync);
 508 void blkiocg_update_io_remove_stats(struct blkio_group *blkg,
 509                                     struct blkio_policy_type *pol,
 510                                     bool direction, bool sync);
 511 #else
 512 struct cgroup;
 513 static inline struct blkio_cgroup *
 514 cgroup_to_blkio_cgroup(struct cgroup *cgroup) { return NULL; }
 515 static inline struct blkio_cgroup *
 516 bio_blkio_cgroup(struct bio *bio) { return NULL; }
 517
 518 static inline struct blkio_group *blkg_lookup(struct blkio_cgroup *blkcg,
 519                                               void *key) { return NULL; }
 520 static inline void blkiocg_update_timeslice_used(struct blkio_group *blkg,
 521                         struct blkio_policy_type *pol, unsigned long time,
 522                         unsigned long unaccounted_time) { }
 523 static inline void blkiocg_update_dispatch_stats(struct blkio_group *blkg,
 524                         struct blkio_policy_type *pol, uint64_t bytes,
 525                         bool direction, bool sync) { }
 526 static inline void blkiocg_update_completion_stats(struct blkio_group *blkg,
 527                         struct blkio_policy_type *pol, uint64_t start_time,
 528                         uint64_t io_start_time, bool direction, bool sync) { }
 529 static inline void blkiocg_update_io_merged_stats(struct blkio_group *blkg,
 530                         struct blkio_policy_type *pol, bool direction,
 531                         bool sync) { }
 532 static inline void blkiocg_update_io_add_stats(struct blkio_group *blkg,
 533                         struct blkio_policy_type *pol,
 534                         struct blkio_group *curr_blkg, bool direction,
 535                         bool sync) { }
 536 static inline void blkiocg_update_io_remove_stats(struct blkio_group *blkg,
 537                         struct blkio_policy_type *pol, bool direction,
 538                         bool sync) { }
 539 #endif
 540 #endif /* _BLK_CGROUP_H */