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
26enum stat_type {
27    /* Total time spent (in ns) between request dispatch to the driver and
28     * request completion for IOs doen by this cgroup. This may not be
29     * accurate when NCQ is turned on. */
30    BLKIO_STAT_SERVICE_TIME = 0,
31    /* Total bytes transferred */
32    BLKIO_STAT_SERVICE_BYTES,
33    /* Total IOs serviced, post merge */
34    BLKIO_STAT_SERVICED,
35    /* Total time spent waiting in scheduler queue in ns */
36    BLKIO_STAT_WAIT_TIME,
37    /* Number of IOs merged */
38    BLKIO_STAT_MERGED,
39    /* Number of IOs queued up */
40    BLKIO_STAT_QUEUED,
41    /* All the single valued stats go below this */
42    BLKIO_STAT_TIME,
43    BLKIO_STAT_SECTORS,
44#ifdef CONFIG_DEBUG_BLK_CGROUP
45    BLKIO_STAT_AVG_QUEUE_SIZE,
46    BLKIO_STAT_IDLE_TIME,
47    BLKIO_STAT_EMPTY_TIME,
48    BLKIO_STAT_GROUP_WAIT_TIME,
49    BLKIO_STAT_DEQUEUE
50#endif
51};
52
53enum stat_sub_type {
54    BLKIO_STAT_READ = 0,
55    BLKIO_STAT_WRITE,
56    BLKIO_STAT_SYNC,
57    BLKIO_STAT_ASYNC,
58    BLKIO_STAT_TOTAL
59};
60
61/* blkg state flags */
62enum blkg_state_flags {
63    BLKG_waiting = 0,
64    BLKG_idling,
65    BLKG_empty,
66};
67
68struct blkio_cgroup {
69    struct cgroup_subsys_state css;
70    unsigned int weight;
71    spinlock_t lock;
72    struct hlist_head blkg_list;
73    struct list_head policy_list; /* list of blkio_policy_node */
74};
75
76struct blkio_group_stats {
77    /* total disk time and nr sectors dispatched by this group */
78    uint64_t time;
79    uint64_t sectors;
80    uint64_t stat_arr[BLKIO_STAT_QUEUED + 1][BLKIO_STAT_TOTAL];
81#ifdef CONFIG_DEBUG_BLK_CGROUP
82    /* Sum of number of IOs queued across all samples */
83    uint64_t avg_queue_size_sum;
84    /* Count of samples taken for average */
85    uint64_t avg_queue_size_samples;
86    /* How many times this group has been removed from service tree */
87    unsigned long dequeue;
88
89    /* Total time spent waiting for it to be assigned a timeslice. */
90    uint64_t group_wait_time;
91    uint64_t start_group_wait_time;
92
93    /* Time spent idling for this blkio_group */
94    uint64_t idle_time;
95    uint64_t start_idle_time;
96    /*
97     * Total time when we have requests queued and do not contain the
98     * current active queue.
99     */
100    uint64_t empty_time;
101    uint64_t start_empty_time;
102    uint16_t flags;
103#endif
104};
105
106struct blkio_group {
107    /* An rcu protected unique identifier for the group */
108    void *key;
109    struct hlist_node blkcg_node;
110    unsigned short blkcg_id;
111    /* Store cgroup path */
112    char path[128];
113    /* The device MKDEV(major, minor), this group has been created for */
114    dev_t dev;
115
116    /* Need to serialize the stats in the case of reset/update */
117    spinlock_t stats_lock;
118    struct blkio_group_stats stats;
119};
120
121struct blkio_policy_node {
122    struct list_head node;
123    dev_t dev;
124    unsigned int weight;
125};
126
127extern unsigned int blkcg_get_weight(struct blkio_cgroup *blkcg,
128                     dev_t dev);
129
130typedef void (blkio_unlink_group_fn) (void *key, struct blkio_group *blkg);
131typedef void (blkio_update_group_weight_fn) (struct blkio_group *blkg,
132                        unsigned int weight);
133
134struct blkio_policy_ops {
135    blkio_unlink_group_fn *blkio_unlink_group_fn;
136    blkio_update_group_weight_fn *blkio_update_group_weight_fn;
137};
138
139struct blkio_policy_type {
140    struct list_head list;
141    struct blkio_policy_ops ops;
142};
143
144/* Blkio controller policy registration */
145extern void blkio_policy_register(struct blkio_policy_type *);
146extern void blkio_policy_unregister(struct blkio_policy_type *);
147
148static inline char *blkg_path(struct blkio_group *blkg)
149{
150    return blkg->path;
151}
152
153#else
154
155struct blkio_group {
156};
157
158struct blkio_policy_type {
159};
160
161static inline void blkio_policy_register(struct blkio_policy_type *blkiop) { }
162static inline void blkio_policy_unregister(struct blkio_policy_type *blkiop) { }
163
164static inline char *blkg_path(struct blkio_group *blkg) { return NULL; }
165
166#endif
167
168#define BLKIO_WEIGHT_MIN 100
169#define BLKIO_WEIGHT_MAX 1000
170#define BLKIO_WEIGHT_DEFAULT 500
171
172#ifdef CONFIG_DEBUG_BLK_CGROUP
173void blkiocg_update_avg_queue_size_stats(struct blkio_group *blkg);
174void blkiocg_update_dequeue_stats(struct blkio_group *blkg,
175                unsigned long dequeue);
176void blkiocg_update_set_idle_time_stats(struct blkio_group *blkg);
177void blkiocg_update_idle_time_stats(struct blkio_group *blkg);
178void blkiocg_set_start_empty_time(struct blkio_group *blkg);
179
180#define BLKG_FLAG_FNS(name) \
181static inline void blkio_mark_blkg_##name( \
182        struct blkio_group_stats *stats) \
183{ \
184    stats->flags |= (1 << BLKG_##name); \
185} \
186static inline void blkio_clear_blkg_##name( \
187        struct blkio_group_stats *stats) \
188{ \
189    stats->flags &= ~(1 << BLKG_##name); \
190} \
191static inline int blkio_blkg_##name(struct blkio_group_stats *stats) \
192{ \
193    return (stats->flags & (1 << BLKG_##name)) != 0; \
194} \
195
196BLKG_FLAG_FNS(waiting)
197BLKG_FLAG_FNS(idling)
198BLKG_FLAG_FNS(empty)
199#undef BLKG_FLAG_FNS
200#else
201static inline void blkiocg_update_avg_queue_size_stats(
202                        struct blkio_group *blkg) {}
203static inline void blkiocg_update_dequeue_stats(struct blkio_group *blkg,
204                        unsigned long dequeue) {}
205static inline void blkiocg_update_set_idle_time_stats(struct blkio_group *blkg)
206{}
207static inline void blkiocg_update_idle_time_stats(struct blkio_group *blkg) {}
208static inline void blkiocg_set_start_empty_time(struct blkio_group *blkg) {}
209#endif
210
211#if defined(CONFIG_BLK_CGROUP) || defined(CONFIG_BLK_CGROUP_MODULE)
212extern struct blkio_cgroup blkio_root_cgroup;
213extern struct blkio_cgroup *cgroup_to_blkio_cgroup(struct cgroup *cgroup);
214extern void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg,
215            struct blkio_group *blkg, void *key, dev_t dev);
216extern int blkiocg_del_blkio_group(struct blkio_group *blkg);
217extern struct blkio_group *blkiocg_lookup_group(struct blkio_cgroup *blkcg,
218                        void *key);
219void blkiocg_update_timeslice_used(struct blkio_group *blkg,
220                    unsigned long time);
221void blkiocg_update_dispatch_stats(struct blkio_group *blkg, uint64_t bytes,
222                        bool direction, bool sync);
223void blkiocg_update_completion_stats(struct blkio_group *blkg,
224    uint64_t start_time, uint64_t io_start_time, bool direction, bool sync);
225void blkiocg_update_io_merged_stats(struct blkio_group *blkg, bool direction,
226                    bool sync);
227void blkiocg_update_io_add_stats(struct blkio_group *blkg,
228        struct blkio_group *curr_blkg, bool direction, bool sync);
229void blkiocg_update_io_remove_stats(struct blkio_group *blkg,
230                    bool direction, bool sync);
231#else
232struct cgroup;
233static inline struct blkio_cgroup *
234cgroup_to_blkio_cgroup(struct cgroup *cgroup) { return NULL; }
235
236static inline void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg,
237            struct blkio_group *blkg, void *key, dev_t dev) {}
238
239static inline int
240blkiocg_del_blkio_group(struct blkio_group *blkg) { return 0; }
241
242static inline struct blkio_group *
243blkiocg_lookup_group(struct blkio_cgroup *blkcg, void *key) { return NULL; }
244static inline void blkiocg_update_timeslice_used(struct blkio_group *blkg,
245                        unsigned long time) {}
246static inline void blkiocg_update_dispatch_stats(struct blkio_group *blkg,
247                uint64_t bytes, bool direction, bool sync) {}
248static inline void blkiocg_update_completion_stats(struct blkio_group *blkg,
249        uint64_t start_time, uint64_t io_start_time, bool direction,
250        bool sync) {}
251static inline void blkiocg_update_io_merged_stats(struct blkio_group *blkg,
252                        bool direction, bool sync) {}
253static inline void blkiocg_update_io_add_stats(struct blkio_group *blkg,
254        struct blkio_group *curr_blkg, bool direction, bool sync) {}
255static inline void blkiocg_update_io_remove_stats(struct blkio_group *blkg,
256                        bool direction, bool sync) {}
257#endif
258#endif /* _BLK_CGROUP_H */
259

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