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
  18 #if defined(CONFIG_BLK_CGROUP) || defined(CONFIG_BLK_CGROUP_MODULE)
  19
  20 #ifndef CONFIG_BLK_CGROUP
  21 /* When blk-cgroup is a module, its subsys_id isn't a compile-time constant */
  22 extern struct cgroup_subsys blkio_subsys;
  23 #define blkio_subsys_id blkio_subsys.subsys_id
  24 #endif
  25
  26 enum stat_type {
  27         /* Total time spent (in ns) between request dispatch to the driver and
  28          * request completion for IOs doen by this cgroup. This may not be
  29          * accurate when NCQ is turned on. */
  30         BLKIO_STAT_SERVICE_TIME = 0,
  31         /* Total bytes transferred */
  32         BLKIO_STAT_SERVICE_BYTES,
  33         /* Total IOs serviced, post merge */
  34         BLKIO_STAT_SERVICED,
  35         /* Total time spent waiting in scheduler queue in ns */
  36         BLKIO_STAT_WAIT_TIME,
  37         /* Number of IOs merged */
  38         BLKIO_STAT_MERGED,
  39         /* Number of IOs queued up */
  40         BLKIO_STAT_QUEUED,
  41         /* All the single valued stats go below this */
  42         BLKIO_STAT_TIME,
  43         BLKIO_STAT_SECTORS,
  44 #ifdef CONFIG_DEBUG_BLK_CGROUP
  45         BLKIO_STAT_AVG_QUEUE_SIZE,
  46         BLKIO_STAT_IDLE_TIME,
  47         BLKIO_STAT_EMPTY_TIME,
  48         BLKIO_STAT_GROUP_WAIT_TIME,
  49         BLKIO_STAT_DEQUEUE
  50 #endif
  51 };
  52
  53 enum stat_sub_type {
  54         BLKIO_STAT_READ = 0,
  55         BLKIO_STAT_WRITE,
  56         BLKIO_STAT_SYNC,
  57         BLKIO_STAT_ASYNC,
  58         BLKIO_STAT_TOTAL
  59 };
  60
  61 /* blkg state flags */
  62 enum blkg_state_flags {
  63         BLKG_waiting = 0,
  64         BLKG_idling,
  65         BLKG_empty,
  66 };
  67
  68 struct blkio_cgroup {
  69         struct cgroup_subsys_state css;
  70         unsigned int weight;
  71         spinlock_t lock;
  72         struct hlist_head blkg_list;
  73         struct list_head policy_list; /* list of blkio_policy_node */
  74 };
  75
  76 struct blkio_group_stats {
  77         /* total disk time and nr sectors dispatched by this group */
  78         uint64_t time;
  79         uint64_t sectors;
  80         uint64_t stat_arr[BLKIO_STAT_QUEUED + 1][BLKIO_STAT_TOTAL];
  81 #ifdef CONFIG_DEBUG_BLK_CGROUP
  82         /* Sum of number of IOs queued across all samples */
  83         uint64_t avg_queue_size_sum;
  84         /* Count of samples taken for average */
  85         uint64_t avg_queue_size_samples;
  86         /* How many times this group has been removed from service tree */
  87         unsigned long dequeue;
  88
  89         /* Total time spent waiting for it to be assigned a timeslice. */
  90         uint64_t group_wait_time;
  91         uint64_t start_group_wait_time;
  92
  93         /* Time spent idling for this blkio_group */
  94         uint64_t idle_time;
  95         uint64_t start_idle_time;
  96         /*
  97          * Total time when we have requests queued and do not contain the
  98          * current active queue.
  99          */
 100         uint64_t empty_time;
 101         uint64_t start_empty_time;
 102         uint16_t flags;
 103 #endif
 104 };
 105
 106 struct blkio_group {
 107         /* An rcu protected unique identifier for the group */
 108         void *key;
 109         struct hlist_node blkcg_node;
 110         unsigned short blkcg_id;
 111         /* Store cgroup path */
 112         char path[128];
 113         /* The device MKDEV(major, minor), this group has been created for */
 114         dev_t dev;
 115
 116         /* Need to serialize the stats in the case of reset/update */
 117         spinlock_t stats_lock;
 118         struct blkio_group_stats stats;
 119 };
 120
 121 struct blkio_policy_node {
 122         struct list_head node;
 123         dev_t dev;
 124         unsigned int weight;
 125 };
 126
 127 extern unsigned int blkcg_get_weight(struct blkio_cgroup *blkcg,
 128                                      dev_t dev);
 129
 130 typedef void (blkio_unlink_group_fn) (void *key, struct blkio_group *blkg);
 131 typedef void (blkio_update_group_weight_fn) (struct blkio_group *blkg,
 132                                                 unsigned int weight);
 133
 134 struct blkio_policy_ops {
 135         blkio_unlink_group_fn *blkio_unlink_group_fn;
 136         blkio_update_group_weight_fn *blkio_update_group_weight_fn;
 137 };
 138
 139 struct blkio_policy_type {
 140         struct list_head list;
 141         struct blkio_policy_ops ops;
 142 };
 143
 144 /* Blkio controller policy registration */
 145 extern void blkio_policy_register(struct blkio_policy_type *);
 146 extern void blkio_policy_unregister(struct blkio_policy_type *);
 147
 148 static inline char *blkg_path(struct blkio_group *blkg)
 149 {
 150         return blkg->path;
 151 }
 152
 153 #else
 154
 155 struct blkio_group {
 156 };
 157
 158 struct blkio_policy_type {
 159 };
 160
 161 static inline void blkio_policy_register(struct blkio_policy_type *blkiop) { }
 162 static inline void blkio_policy_unregister(struct blkio_policy_type *blkiop) { }
 163
 164 static inline char *blkg_path(struct blkio_group *blkg) { return NULL; }
 165
 166 #endif
 167
 168 #define BLKIO_WEIGHT_MIN        100
 169 #define BLKIO_WEIGHT_MAX        1000
 170 #define BLKIO_WEIGHT_DEFAULT    500
 171
 172 #ifdef CONFIG_DEBUG_BLK_CGROUP
 173 void blkiocg_update_avg_queue_size_stats(struct blkio_group *blkg);
 174 void blkiocg_update_dequeue_stats(struct blkio_group *blkg,
 175                                 unsigned long dequeue);
 176 void blkiocg_update_set_idle_time_stats(struct blkio_group *blkg);
 177 void blkiocg_update_idle_time_stats(struct blkio_group *blkg);
 178 void blkiocg_set_start_empty_time(struct blkio_group *blkg);
 179
 180 #define BLKG_FLAG_FNS(name)                                             \
 181 static inline void blkio_mark_blkg_##name(                              \
 182                 struct blkio_group_stats *stats)                        \
 183 {                                                                       \
 184         stats->flags |= (1 << BLKG_##name);                             \
 185 }                                                                       \
 186 static inline void blkio_clear_blkg_##name(                             \
 187                 struct blkio_group_stats *stats)                        \
 188 {                                                                       \
 189         stats->flags &= ~(1 << BLKG_##name);                            \
 190 }                                                                       \
 191 static inline int blkio_blkg_##name(struct blkio_group_stats *stats)    \
 192 {                                                                       \
 193         return (stats->flags & (1 << BLKG_##name)) != 0;                \
 194 }                                                                       \
 195
 196 BLKG_FLAG_FNS(waiting)
 197 BLKG_FLAG_FNS(idling)
 198 BLKG_FLAG_FNS(empty)
 199 #undef BLKG_FLAG_FNS
 200 #else
 201 static inline void blkiocg_update_avg_queue_size_stats(
 202                                                 struct blkio_group *blkg) {}
 203 static inline void blkiocg_update_dequeue_stats(struct blkio_group *blkg,
 204                                                 unsigned long dequeue) {}
 205 static inline void blkiocg_update_set_idle_time_stats(struct blkio_group *blkg)
 206 {}
 207 static inline void blkiocg_update_idle_time_stats(struct blkio_group *blkg) {}
 208 static inline void blkiocg_set_start_empty_time(struct blkio_group *blkg) {}
 209 #endif
 210
 211 #if defined(CONFIG_BLK_CGROUP) || defined(CONFIG_BLK_CGROUP_MODULE)
 212 extern struct blkio_cgroup blkio_root_cgroup;
 213 extern struct blkio_cgroup *cgroup_to_blkio_cgroup(struct cgroup *cgroup);
 214 extern void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg,
 215                         struct blkio_group *blkg, void *key, dev_t dev);
 216 extern int blkiocg_del_blkio_group(struct blkio_group *blkg);
 217 extern struct blkio_group *blkiocg_lookup_group(struct blkio_cgroup *blkcg,
 218                                                 void *key);
 219 void blkiocg_update_timeslice_used(struct blkio_group *blkg,
 220                                         unsigned long time);
 221 void blkiocg_update_dispatch_stats(struct blkio_group *blkg, uint64_t bytes,
 222                                                 bool direction, bool sync);
 223 void blkiocg_update_completion_stats(struct blkio_group *blkg,
 224         uint64_t start_time, uint64_t io_start_time, bool direction, bool sync);
 225 void blkiocg_update_io_merged_stats(struct blkio_group *blkg, bool direction,
 226                                         bool sync);
 227 void blkiocg_update_io_add_stats(struct blkio_group *blkg,
 228                 struct blkio_group *curr_blkg, bool direction, bool sync);
 229 void blkiocg_update_io_remove_stats(struct blkio_group *blkg,
 230                                         bool direction, bool sync);
 231 #else
 232 struct cgroup;
 233 static inline struct blkio_cgroup *
 234 cgroup_to_blkio_cgroup(struct cgroup *cgroup) { return NULL; }
 235
 236 static inline void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg,
 237                         struct blkio_group *blkg, void *key, dev_t dev) {}
 238
 239 static inline int
 240 blkiocg_del_blkio_group(struct blkio_group *blkg) { return 0; }
 241
 242 static inline struct blkio_group *
 243 blkiocg_lookup_group(struct blkio_cgroup *blkcg, void *key) { return NULL; }
 244 static inline void blkiocg_update_timeslice_used(struct blkio_group *blkg,
 245                                                 unsigned long time) {}
 246 static inline void blkiocg_update_dispatch_stats(struct blkio_group *blkg,
 247                                 uint64_t bytes, bool direction, bool sync) {}
 248 static inline void blkiocg_update_completion_stats(struct blkio_group *blkg,
 249                 uint64_t start_time, uint64_t io_start_time, bool direction,
 250                 bool sync) {}
 251 static inline void blkiocg_update_io_merged_stats(struct blkio_group *blkg,
 252                                                 bool direction, bool sync) {}
 253 static inline void blkiocg_update_io_add_stats(struct blkio_group *blkg,
 254                 struct blkio_group *curr_blkg, bool direction, bool sync) {}
 255 static inline void blkiocg_update_io_remove_stats(struct blkio_group *blkg,
 256                                                 bool direction, bool sync) {}
 257 #endif
 258 #endif /* _BLK_CGROUP_H */