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 #ifdef CONFIG_BLK_CGROUP
  19
  20 struct blkio_cgroup {
  21         struct cgroup_subsys_state css;
  22         unsigned int weight;
  23         spinlock_t lock;
  24         struct hlist_head blkg_list;
  25 };
  26
  27 struct blkio_group {
  28         /* An rcu protected unique identifier for the group */
  29         void *key;
  30         struct hlist_node blkcg_node;
  31         unsigned short blkcg_id;
  32 #ifdef CONFIG_DEBUG_BLK_CGROUP
  33         /* Store cgroup path */
  34         char path[128];
  35         /* How many times this group has been removed from service tree */
  36         unsigned long dequeue;
  37 #endif
  38         /* The device MKDEV(major, minor), this group has been created for */
  39         dev_t   dev;
  40
  41         /* total disk time and nr sectors dispatched by this group */
  42         unsigned long time;
  43         unsigned long sectors;
  44 };
  45
  46 extern bool blkiocg_css_tryget(struct blkio_cgroup *blkcg);
  47 extern void blkiocg_css_put(struct blkio_cgroup *blkcg);
  48
  49 typedef void (blkio_unlink_group_fn) (void *key, struct blkio_group *blkg);
  50 typedef void (blkio_update_group_weight_fn) (struct blkio_group *blkg,
  51                                                 unsigned int weight);
  52
  53 struct blkio_policy_ops {
  54         blkio_unlink_group_fn *blkio_unlink_group_fn;
  55         blkio_update_group_weight_fn *blkio_update_group_weight_fn;
  56 };
  57
  58 struct blkio_policy_type {
  59         struct list_head list;
  60         struct blkio_policy_ops ops;
  61 };
  62
  63 /* Blkio controller policy registration */
  64 extern void blkio_policy_register(struct blkio_policy_type *);
  65 extern void blkio_policy_unregister(struct blkio_policy_type *);
  66
  67 #else
  68
  69 struct blkio_group {
  70 };
  71
  72 struct blkio_policy_type {
  73 };
  74
  75 static inline void blkio_policy_register(struct blkio_policy_type *blkiop) { }
  76 static inline void blkio_policy_unregister(struct blkio_policy_type *blkiop) { }
  77
  78 #endif
  79
  80 #define BLKIO_WEIGHT_MIN        100
  81 #define BLKIO_WEIGHT_MAX        1000
  82 #define BLKIO_WEIGHT_DEFAULT    500
  83
  84 #ifdef CONFIG_DEBUG_BLK_CGROUP
  85 static inline char *blkg_path(struct blkio_group *blkg)
  86 {
  87         return blkg->path;
  88 }
  89 void blkiocg_update_blkio_group_dequeue_stats(struct blkio_group *blkg,
  90                                 unsigned long dequeue);
  91 #else
  92 static inline char *blkg_path(struct blkio_group *blkg) { return NULL; }
  93 static inline void blkiocg_update_blkio_group_dequeue_stats(
  94                         struct blkio_group *blkg, unsigned long dequeue) {}
  95 #endif
  96
  97 #ifdef CONFIG_BLK_CGROUP
  98 extern struct blkio_cgroup blkio_root_cgroup;
  99 extern struct blkio_cgroup *cgroup_to_blkio_cgroup(struct cgroup *cgroup);
 100 extern void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg,
 101                         struct blkio_group *blkg, void *key, dev_t dev);
 102 extern int blkiocg_del_blkio_group(struct blkio_group *blkg);
 103 extern struct blkio_group *blkiocg_lookup_group(struct blkio_cgroup *blkcg,
 104                                                 void *key);
 105 void blkiocg_update_blkio_group_stats(struct blkio_group *blkg,
 106                         unsigned long time, unsigned long sectors);
 107 #else
 108 struct cgroup;
 109 static inline struct blkio_cgroup *
 110 cgroup_to_blkio_cgroup(struct cgroup *cgroup) { return NULL; }
 111
 112 static inline void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg,
 113                         struct blkio_group *blkg, void *key, dev_t dev)
 114 {
 115 }
 116
 117 static inline int
 118 blkiocg_del_blkio_group(struct blkio_group *blkg) { return 0; }
 119
 120 static inline struct blkio_group *
 121 blkiocg_lookup_group(struct blkio_cgroup *blkcg, void *key) { return NULL; }
 122 static inline void blkiocg_update_blkio_group_stats(struct blkio_group *blkg,
 123                         unsigned long time, unsigned long sectors)
 124 {
 125 }
 126 #endif
 127 #endif /* _BLK_CGROUP_H */