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 io_type {
  27         IO_READ = 0,
  28         IO_WRITE,
  29         IO_SYNC,
  30         IO_ASYNC,
  31         IO_TYPE_MAX
  32 };
  33
  34 struct blkio_cgroup {
  35         struct cgroup_subsys_state css;
  36         unsigned int weight;
  37         spinlock_t lock;
  38         struct hlist_head blkg_list;
  39 };
  40
  41 struct blkio_group_stats {
  42         /* total disk time and nr sectors dispatched by this group */
  43         uint64_t time;
  44         uint64_t sectors;
  45         /* Total disk time used by IOs in ns */
  46         uint64_t io_service_time[IO_TYPE_MAX];
  47         uint64_t io_service_bytes[IO_TYPE_MAX]; /* Total bytes transferred */
  48         /* Total IOs serviced, post merge */
  49         uint64_t io_serviced[IO_TYPE_MAX];
  50         /* Total time spent waiting in scheduler queue in ns */
  51         uint64_t io_wait_time[IO_TYPE_MAX];
  52 #ifdef CONFIG_DEBUG_BLK_CGROUP
  53         /* How many times this group has been removed from service tree */
  54         unsigned long dequeue;
  55 #endif
  56 };
  57
  58 struct blkio_group {
  59         /* An rcu protected unique identifier for the group */
  60         void *key;
  61         struct hlist_node blkcg_node;
  62         unsigned short blkcg_id;
  63 #ifdef CONFIG_DEBUG_BLK_CGROUP
  64         /* Store cgroup path */
  65         char path[128];
  66 #endif
  67         /* The device MKDEV(major, minor), this group has been created for */
  68         dev_t   dev;
  69
  70         /* Need to serialize the stats in the case of reset/update */
  71         spinlock_t stats_lock;
  72         struct blkio_group_stats stats;
  73 };
  74
  75 typedef void (blkio_unlink_group_fn) (void *key, struct blkio_group *blkg);
  76 typedef void (blkio_update_group_weight_fn) (struct blkio_group *blkg,
  77                                                 unsigned int weight);
  78
  79 struct blkio_policy_ops {
  80         blkio_unlink_group_fn *blkio_unlink_group_fn;
  81         blkio_update_group_weight_fn *blkio_update_group_weight_fn;
  82 };
  83
  84 struct blkio_policy_type {
  85         struct list_head list;
  86         struct blkio_policy_ops ops;
  87 };
  88
  89 /* Blkio controller policy registration */
  90 extern void blkio_policy_register(struct blkio_policy_type *);
  91 extern void blkio_policy_unregister(struct blkio_policy_type *);
  92
  93 #else
  94
  95 struct blkio_group {
  96 };
  97
  98 struct blkio_policy_type {
  99 };
 100
 101 static inline void blkio_policy_register(struct blkio_policy_type *blkiop) { }
 102 static inline void blkio_policy_unregister(struct blkio_policy_type *blkiop) { }
 103
 104 #endif
 105
 106 #define BLKIO_WEIGHT_MIN        100
 107 #define BLKIO_WEIGHT_MAX        1000
 108 #define BLKIO_WEIGHT_DEFAULT    500
 109
 110 #ifdef CONFIG_DEBUG_BLK_CGROUP
 111 static inline char *blkg_path(struct blkio_group *blkg)
 112 {
 113         return blkg->path;
 114 }
 115 void blkiocg_update_blkio_group_dequeue_stats(struct blkio_group *blkg,
 116                                 unsigned long dequeue);
 117 #else
 118 static inline char *blkg_path(struct blkio_group *blkg) { return NULL; }
 119 static inline void blkiocg_update_blkio_group_dequeue_stats(
 120                         struct blkio_group *blkg, unsigned long dequeue) {}
 121 #endif
 122
 123 #if defined(CONFIG_BLK_CGROUP) || defined(CONFIG_BLK_CGROUP_MODULE)
 124 extern struct blkio_cgroup blkio_root_cgroup;
 125 extern struct blkio_cgroup *cgroup_to_blkio_cgroup(struct cgroup *cgroup);
 126 extern void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg,
 127                         struct blkio_group *blkg, void *key, dev_t dev);
 128 extern int blkiocg_del_blkio_group(struct blkio_group *blkg);
 129 extern struct blkio_group *blkiocg_lookup_group(struct blkio_cgroup *blkcg,
 130                                                 void *key);
 131 void blkiocg_update_timeslice_used(struct blkio_group *blkg,
 132                                         unsigned long time);
 133 #else
 134 struct cgroup;
 135 static inline struct blkio_cgroup *
 136 cgroup_to_blkio_cgroup(struct cgroup *cgroup) { return NULL; }
 137
 138 static inline void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg,
 139                         struct blkio_group *blkg, void *key, dev_t dev)
 140 {
 141 }
 142
 143 static inline int
 144 blkiocg_del_blkio_group(struct blkio_group *blkg) { return 0; }
 145
 146 static inline struct blkio_group *
 147 blkiocg_lookup_group(struct blkio_cgroup *blkcg, void *key) { return NULL; }
 148 static inline void blkiocg_update_timeslice_used(struct blkio_group *blkg,
 149                                                 unsigned long time) {}
 150 #endif
 151 #endif /* _BLK_CGROUP_H */