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 struct blkio_cgroup {
  27         struct cgroup_subsys_state css;
  28         unsigned int weight;
  29         spinlock_t lock;
  30         struct hlist_head blkg_list;
  31 };
  32
  33 struct blkio_group {
  34         /* An rcu protected unique identifier for the group */
  35         void *key;
  36         struct hlist_node blkcg_node;
  37         unsigned short blkcg_id;
  38 #ifdef CONFIG_DEBUG_BLK_CGROUP
  39         /* Store cgroup path */
  40         char path[128];
  41         /* How many times this group has been removed from service tree */
  42         unsigned long dequeue;
  43 #endif
  44         /* The device MKDEV(major, minor), this group has been created for */
  45         dev_t   dev;
  46
  47         /* total disk time and nr sectors dispatched by this group */
  48         unsigned long time;
  49         unsigned long sectors;
  50 };
  51
  52 typedef void (blkio_unlink_group_fn) (void *key, struct blkio_group *blkg);
  53 typedef void (blkio_update_group_weight_fn) (struct blkio_group *blkg,
  54                                                 unsigned int weight);
  55
  56 struct blkio_policy_ops {
  57         blkio_unlink_group_fn *blkio_unlink_group_fn;
  58         blkio_update_group_weight_fn *blkio_update_group_weight_fn;
  59 };
  60
  61 struct blkio_policy_type {
  62         struct list_head list;
  63         struct blkio_policy_ops ops;
  64 };
  65
  66 /* Blkio controller policy registration */
  67 extern void blkio_policy_register(struct blkio_policy_type *);
  68 extern void blkio_policy_unregister(struct blkio_policy_type *);
  69
  70 #else
  71
  72 struct blkio_group {
  73 };
  74
  75 struct blkio_policy_type {
  76 };
  77
  78 static inline void blkio_policy_register(struct blkio_policy_type *blkiop) { }
  79 static inline void blkio_policy_unregister(struct blkio_policy_type *blkiop) { }
  80
  81 #endif
  82
  83 #define BLKIO_WEIGHT_MIN        100
  84 #define BLKIO_WEIGHT_MAX        1000
  85 #define BLKIO_WEIGHT_DEFAULT    500
  86
  87 #ifdef CONFIG_DEBUG_BLK_CGROUP
  88 static inline char *blkg_path(struct blkio_group *blkg)
  89 {
  90         return blkg->path;
  91 }
  92 void blkiocg_update_blkio_group_dequeue_stats(struct blkio_group *blkg,
  93                                 unsigned long dequeue);
  94 #else
  95 static inline char *blkg_path(struct blkio_group *blkg) { return NULL; }
  96 static inline void blkiocg_update_blkio_group_dequeue_stats(
  97                         struct blkio_group *blkg, unsigned long dequeue) {}
  98 #endif
  99
 100 #if defined(CONFIG_BLK_CGROUP) || defined(CONFIG_BLK_CGROUP_MODULE)
 101 extern struct blkio_cgroup blkio_root_cgroup;
 102 extern struct blkio_cgroup *cgroup_to_blkio_cgroup(struct cgroup *cgroup);
 103 extern void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg,
 104                         struct blkio_group *blkg, void *key, dev_t dev);
 105 extern int blkiocg_del_blkio_group(struct blkio_group *blkg);
 106 extern struct blkio_group *blkiocg_lookup_group(struct blkio_cgroup *blkcg,
 107                                                 void *key);
 108 void blkiocg_update_blkio_group_stats(struct blkio_group *blkg,
 109                         unsigned long time, unsigned long sectors);
 110 #else
 111 struct cgroup;
 112 static inline struct blkio_cgroup *
 113 cgroup_to_blkio_cgroup(struct cgroup *cgroup) { return NULL; }
 114
 115 static inline void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg,
 116                         struct blkio_group *blkg, void *key, dev_t dev)
 117 {
 118 }
 119
 120 static inline int
 121 blkiocg_del_blkio_group(struct blkio_group *blkg) { return 0; }
 122
 123 static inline struct blkio_group *
 124 blkiocg_lookup_group(struct blkio_cgroup *blkcg, void *key) { return NULL; }
 125 static inline void blkiocg_update_blkio_group_stats(struct blkio_group *blkg,
 126                         unsigned long time, unsigned long sectors)
 127 {
 128 }
 129 #endif
 130 #endif /* _BLK_CGROUP_H */