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 struct blkio_cgroup {
  19         struct cgroup_subsys_state css;
  20         unsigned int weight;
  21         spinlock_t lock;
  22         struct hlist_head blkg_list;
  23 };
  24
  25 struct blkio_group {
  26         /* An rcu protected unique identifier for the group */
  27         void *key;
  28         struct hlist_node blkcg_node;
  29         unsigned short blkcg_id;
  30 };
  31
  32 #define BLKIO_WEIGHT_MIN        100
  33 #define BLKIO_WEIGHT_MAX        1000
  34 #define BLKIO_WEIGHT_DEFAULT    500
  35
  36 #ifdef CONFIG_BLK_CGROUP
  37 extern struct blkio_cgroup blkio_root_cgroup;
  38 extern struct blkio_cgroup *cgroup_to_blkio_cgroup(struct cgroup *cgroup);
  39 extern void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg,
  40                                 struct blkio_group *blkg, void *key);
  41 extern int blkiocg_del_blkio_group(struct blkio_group *blkg);
  42 extern struct blkio_group *blkiocg_lookup_group(struct blkio_cgroup *blkcg,
  43                                                 void *key);
  44 #else
  45 static inline struct blkio_cgroup *
  46 cgroup_to_blkio_cgroup(struct cgroup *cgroup) { return NULL; }
  47
  48 static inline void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg,
  49                         struct blkio_group *blkg, void *key)
  50 {
  51 }
  52
  53 static inline int
  54 blkiocg_del_blkio_group(struct blkio_group *blkg) { return 0; }
  55
  56 static inline struct blkio_group *
  57 blkiocg_lookup_group(struct blkio_cgroup *blkcg, void *key) { return NULL; }
  58 #endif
  59 #endif /* _BLK_CGROUP_H */