Root/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 */
22extern struct cgroup_subsys blkio_subsys;
23#define blkio_subsys_id blkio_subsys.subsys_id
24#endif
25
26struct blkio_cgroup {
27    struct cgroup_subsys_state css;
28    unsigned int weight;
29    spinlock_t lock;
30    struct hlist_head blkg_list;
31};
32
33struct 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
52typedef void (blkio_unlink_group_fn) (void *key, struct blkio_group *blkg);
53typedef void (blkio_update_group_weight_fn) (struct blkio_group *blkg,
54                        unsigned int weight);
55
56struct 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
61struct blkio_policy_type {
62    struct list_head list;
63    struct blkio_policy_ops ops;
64};
65
66/* Blkio controller policy registration */
67extern void blkio_policy_register(struct blkio_policy_type *);
68extern void blkio_policy_unregister(struct blkio_policy_type *);
69
70#else
71
72struct blkio_group {
73};
74
75struct blkio_policy_type {
76};
77
78static inline void blkio_policy_register(struct blkio_policy_type *blkiop) { }
79static 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
88static inline char *blkg_path(struct blkio_group *blkg)
89{
90    return blkg->path;
91}
92void blkiocg_update_blkio_group_dequeue_stats(struct blkio_group *blkg,
93                unsigned long dequeue);
94#else
95static inline char *blkg_path(struct blkio_group *blkg) { return NULL; }
96static 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)
101extern struct blkio_cgroup blkio_root_cgroup;
102extern struct blkio_cgroup *cgroup_to_blkio_cgroup(struct cgroup *cgroup);
103extern void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg,
104            struct blkio_group *blkg, void *key, dev_t dev);
105extern int blkiocg_del_blkio_group(struct blkio_group *blkg);
106extern struct blkio_group *blkiocg_lookup_group(struct blkio_cgroup *blkcg,
107                        void *key);
108void blkiocg_update_blkio_group_stats(struct blkio_group *blkg,
109            unsigned long time, unsigned long sectors);
110#else
111struct cgroup;
112static inline struct blkio_cgroup *
113cgroup_to_blkio_cgroup(struct cgroup *cgroup) { return NULL; }
114
115static inline void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg,
116            struct blkio_group *blkg, void *key, dev_t dev)
117{
118}
119
120static inline int
121blkiocg_del_blkio_group(struct blkio_group *blkg) { return 0; }
122
123static inline struct blkio_group *
124blkiocg_lookup_group(struct blkio_cgroup *blkcg, void *key) { return NULL; }
125static 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 */
131

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