1 #ifndef _LINUX_RING_BUFFER_H
2 #define _LINUX_RING_BUFFER_H
3
4 #include <linux/mm.h>
5 #include <linux/seq_file.h>
6
7 struct ring_buffer;
8 struct ring_buffer_iter;
9
10 /*
11 * Don't reference this struct directly, use functions below.
12 */
13 struct ring_buffer_event {
14 u32 type:2, len:3, time_delta:27;
15 u32 array[];
16 };
17
18 /**
19 * enum ring_buffer_type - internal ring buffer types
20 *
21 * @RINGBUF_TYPE_PADDING: Left over page padding
22 * array is ignored
23 * size is variable depending on how much
24 * padding is needed
25 *
26 * @RINGBUF_TYPE_TIME_EXTEND: Extend the time delta
27 * array[0] = time delta (28 .. 59)
28 * size = 8 bytes
29 *
30 * @RINGBUF_TYPE_TIME_STAMP: Sync time stamp with external clock
31 * array[0] = tv_nsec
32 * array[1..2] = tv_sec
33 * size = 16 bytes
34 *
35 * @RINGBUF_TYPE_DATA: Data record
36 * If len is zero:
37 * array[0] holds the actual length
38 * array[1..(length+3)/4] holds data
39 * size = 4 + 4 + length (bytes)
40 * else
41 * length = len << 2
42 * array[0..(length+3)/4-1] holds data
43 * size = 4 + length (bytes)
44 */
45 enum ring_buffer_type {
46 RINGBUF_TYPE_PADDING,
47 RINGBUF_TYPE_TIME_EXTEND,
48 /* FIXME: RINGBUF_TYPE_TIME_STAMP not implemented */
49 RINGBUF_TYPE_TIME_STAMP,
50 RINGBUF_TYPE_DATA,
51 };
52
53 unsigned ring_buffer_event_length(struct ring_buffer_event *event);
54 void *ring_buffer_event_data(struct ring_buffer_event *event);
55
56 /**
57 * ring_buffer_event_time_delta - return the delta timestamp of the event
58 * @event: the event to get the delta timestamp of
59 *
60 * The delta timestamp is the 27 bit timestamp since the last event.
61 */
62 static inline unsigned
ring_buffer_event_time_delta(struct ring_buffer_event * event)63 ring_buffer_event_time_delta(struct ring_buffer_event *event)
64 {
65 return event->time_delta;
66 }
67
68 /*
69 * size is in bytes for each per CPU buffer.
70 */
71 struct ring_buffer *
72 ring_buffer_alloc(unsigned long size, unsigned flags);
73 void ring_buffer_free(struct ring_buffer *buffer);
74
75 int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size);
76
77 struct ring_buffer_event *
78 ring_buffer_lock_reserve(struct ring_buffer *buffer,
79 unsigned long length,
80 unsigned long *flags);
81 int ring_buffer_unlock_commit(struct ring_buffer *buffer,
82 struct ring_buffer_event *event,
83 unsigned long flags);
84 int ring_buffer_write(struct ring_buffer *buffer,
85 unsigned long length, void *data);
86
87 struct ring_buffer_event *
88 ring_buffer_peek(struct ring_buffer *buffer, int cpu, u64 *ts);
89 struct ring_buffer_event *
90 ring_buffer_consume(struct ring_buffer *buffer, int cpu, u64 *ts);
91
92 struct ring_buffer_iter *
93 ring_buffer_read_start(struct ring_buffer *buffer, int cpu);
94 void ring_buffer_read_finish(struct ring_buffer_iter *iter);
95
96 struct ring_buffer_event *
97 ring_buffer_iter_peek(struct ring_buffer_iter *iter, u64 *ts);
98 struct ring_buffer_event *
99 ring_buffer_read(struct ring_buffer_iter *iter, u64 *ts);
100 void ring_buffer_iter_reset(struct ring_buffer_iter *iter);
101 int ring_buffer_iter_empty(struct ring_buffer_iter *iter);
102
103 unsigned long ring_buffer_size(struct ring_buffer *buffer);
104
105 void ring_buffer_reset_cpu(struct ring_buffer *buffer, int cpu);
106 void ring_buffer_reset(struct ring_buffer *buffer);
107
108 int ring_buffer_swap_cpu(struct ring_buffer *buffer_a,
109 struct ring_buffer *buffer_b, int cpu);
110
111 int ring_buffer_empty(struct ring_buffer *buffer);
112 int ring_buffer_empty_cpu(struct ring_buffer *buffer, int cpu);
113
114 void ring_buffer_record_disable(struct ring_buffer *buffer);
115 void ring_buffer_record_enable(struct ring_buffer *buffer);
116 void ring_buffer_record_disable_cpu(struct ring_buffer *buffer, int cpu);
117 void ring_buffer_record_enable_cpu(struct ring_buffer *buffer, int cpu);
118
119 unsigned long ring_buffer_entries(struct ring_buffer *buffer);
120 unsigned long ring_buffer_overruns(struct ring_buffer *buffer);
121 unsigned long ring_buffer_entries_cpu(struct ring_buffer *buffer, int cpu);
122 unsigned long ring_buffer_overrun_cpu(struct ring_buffer *buffer, int cpu);
123
124 u64 ring_buffer_time_stamp(int cpu);
125 void ring_buffer_normalize_time_stamp(int cpu, u64 *ts);
126
127 void tracing_on(void);
128 void tracing_off(void);
129 void tracing_off_permanent(void);
130
131 void *ring_buffer_alloc_read_page(struct ring_buffer *buffer);
132 void ring_buffer_free_read_page(struct ring_buffer *buffer, void *data);
133 int ring_buffer_read_page(struct ring_buffer *buffer,
134 void **data_page, int cpu, int full);
135
136 enum ring_buffer_flags {
137 RB_FL_OVERWRITE = 1 << 0,
138 };
139
140 #endif /* _LINUX_RING_BUFFER_H */
141