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Merge branch 'writeback-for-2.6.34' into nfs-for-2.6.34
[net-next-2.6.git] / block / blk-cgroup.h
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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
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18#ifdef CONFIG_BLK_CGROUP
19
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20struct blkio_cgroup {
21 struct cgroup_subsys_state css;
22 unsigned int weight;
23 spinlock_t lock;
24 struct hlist_head blkg_list;
25};
26
27struct blkio_group {
28 /* An rcu protected unique identifier for the group */
29 void *key;
30 struct hlist_node blkcg_node;
b1c35769 31 unsigned short blkcg_id;
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32#ifdef CONFIG_DEBUG_BLK_CGROUP
33 /* Store cgroup path */
34 char path[128];
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35 /* How many times this group has been removed from service tree */
36 unsigned long dequeue;
2868ef7b 37#endif
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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;
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44};
45
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46typedef void (blkio_unlink_group_fn) (void *key, struct blkio_group *blkg);
47typedef void (blkio_update_group_weight_fn) (struct blkio_group *blkg,
48 unsigned int weight);
49
50struct blkio_policy_ops {
51 blkio_unlink_group_fn *blkio_unlink_group_fn;
52 blkio_update_group_weight_fn *blkio_update_group_weight_fn;
53};
54
55struct blkio_policy_type {
56 struct list_head list;
57 struct blkio_policy_ops ops;
58};
59
60/* Blkio controller policy registration */
61extern void blkio_policy_register(struct blkio_policy_type *);
62extern void blkio_policy_unregister(struct blkio_policy_type *);
63
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64#else
65
66struct blkio_group {
67};
68
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69struct blkio_policy_type {
70};
71
72static inline void blkio_policy_register(struct blkio_policy_type *blkiop) { }
73static inline void blkio_policy_unregister(struct blkio_policy_type *blkiop) { }
74
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75#endif
76
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77#define BLKIO_WEIGHT_MIN 100
78#define BLKIO_WEIGHT_MAX 1000
79#define BLKIO_WEIGHT_DEFAULT 500
80
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81#ifdef CONFIG_DEBUG_BLK_CGROUP
82static inline char *blkg_path(struct blkio_group *blkg)
83{
84 return blkg->path;
85}
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86void blkiocg_update_blkio_group_dequeue_stats(struct blkio_group *blkg,
87 unsigned long dequeue);
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88#else
89static inline char *blkg_path(struct blkio_group *blkg) { return NULL; }
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90static inline void blkiocg_update_blkio_group_dequeue_stats(
91 struct blkio_group *blkg, unsigned long dequeue) {}
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92#endif
93
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94#ifdef CONFIG_BLK_CGROUP
95extern struct blkio_cgroup blkio_root_cgroup;
96extern struct blkio_cgroup *cgroup_to_blkio_cgroup(struct cgroup *cgroup);
97extern void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg,
22084190 98 struct blkio_group *blkg, void *key, dev_t dev);
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99extern int blkiocg_del_blkio_group(struct blkio_group *blkg);
100extern struct blkio_group *blkiocg_lookup_group(struct blkio_cgroup *blkcg,
101 void *key);
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102void blkiocg_update_blkio_group_stats(struct blkio_group *blkg,
103 unsigned long time, unsigned long sectors);
31e4c28d 104#else
2f5ea477 105struct cgroup;
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106static inline struct blkio_cgroup *
107cgroup_to_blkio_cgroup(struct cgroup *cgroup) { return NULL; }
108
109static inline void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg,
22084190 110 struct blkio_group *blkg, void *key, dev_t dev)
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111{
112}
113
114static inline int
115blkiocg_del_blkio_group(struct blkio_group *blkg) { return 0; }
116
117static inline struct blkio_group *
118blkiocg_lookup_group(struct blkio_cgroup *blkcg, void *key) { return NULL; }
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119static inline void blkiocg_update_blkio_group_stats(struct blkio_group *blkg,
120 unsigned long time, unsigned long sectors)
121{
122}
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123#endif
124#endif /* _BLK_CGROUP_H */