1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
|
#ifndef _LINUX_RING_BUFFER_H
#define _LINUX_RING_BUFFER_H
#include <linux/mm.h>
#include <linux/seq_file.h>
struct ring_buffer;
struct ring_buffer_iter;
/*
* Don't refer to this struct directly, use functions below.
*/
struct ring_buffer_event {
u32 type:2, len:3, time_delta:27;
u32 array[];
};
/**
* enum ring_buffer_type - internal ring buffer types
*
* @RINGBUF_TYPE_PADDING: Left over page padding or discarded event
* If time_delta is 0:
* array is ignored
* size is variable depending on how much
* padding is needed
* If time_delta is non zero:
* everything else same as RINGBUF_TYPE_DATA
*
* @RINGBUF_TYPE_TIME_EXTEND: Extend the time delta
* array[0] = time delta (28 .. 59)
* size = 8 bytes
*
* @RINGBUF_TYPE_TIME_STAMP: Sync time stamp with external clock
* array[0] = tv_nsec
* array[1..2] = tv_sec
* size = 16 bytes
*
* @RINGBUF_TYPE_DATA: Data record
* If len is zero:
* array[0] holds the actual length
* array[1..(length+3)/4] holds data
* size = 4 + 4 + length (bytes)
* else
* length = len << 2
* array[0..(length+3)/4-1] holds data
* size = 4 + length (bytes)
*/
enum ring_buffer_type {
RINGBUF_TYPE_PADDING,
RINGBUF_TYPE_TIME_EXTEND,
/* FIXME: RINGBUF_TYPE_TIME_STAMP not implemented */
RINGBUF_TYPE_TIME_STAMP,
RINGBUF_TYPE_DATA,
};
unsigned ring_buffer_event_length(struct ring_buffer_event *event);
void *ring_buffer_event_data(struct ring_buffer_event *event);
/**
* ring_buffer_event_time_delta - return the delta timestamp of the event
* @event: the event to get the delta timestamp of
*
* The delta timestamp is the 27 bit timestamp since the last event.
*/
static inline unsigned
ring_buffer_event_time_delta(struct ring_buffer_event *event)
{
return event->time_delta;
}
/*
* ring_buffer_event_discard can discard any event in the ring buffer.
* it is up to the caller to protect against a reader from
* consuming it or a writer from wrapping and replacing it.
*
* No external protection is needed if this is called before
* the event is commited. But in that case it would be better to
* use ring_buffer_discard_commit.
*
* Note, if an event that has not been committed is discarded
* with ring_buffer_event_discard, it must still be committed.
*/
void ring_buffer_event_discard(struct ring_buffer_event *event);
/*
* ring_buffer_discard_commit will remove an event that has not
* ben committed yet. If this is used, then ring_buffer_unlock_commit
* must not be called on the discarded event. This function
* will try to remove the event from the ring buffer completely
* if another event has not been written after it.
*
* Example use:
*
* if (some_condition)
* ring_buffer_discard_commit(buffer, event);
* else
* ring_buffer_unlock_commit(buffer, event);
*/
void ring_buffer_discard_commit(struct ring_buffer *buffer,
struct ring_buffer_event *event);
/*
* size is in bytes for each per CPU buffer.
*/
struct ring_buffer *
ring_buffer_alloc(unsigned long size, unsigned flags);
void ring_buffer_free(struct ring_buffer *buffer);
int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size);
struct ring_buffer_event *ring_buffer_lock_reserve(struct ring_buffer *buffer,
unsigned long length);
int ring_buffer_unlock_commit(struct ring_buffer *buffer,
struct ring_buffer_event *event);
int ring_buffer_write(struct ring_buffer *buffer,
unsigned long length, void *data);
struct ring_buffer_event *
ring_buffer_peek(struct ring_buffer *buffer, int cpu, u64 *ts);
struct ring_buffer_event *
ring_buffer_consume(struct ring_buffer *buffer, int cpu, u64 *ts);
struct ring_buffer_iter *
ring_buffer_read_start(struct ring_buffer *buffer, int cpu);
void ring_buffer_read_finish(struct ring_buffer_iter *iter);
struct ring_buffer_event *
ring_buffer_iter_peek(struct ring_buffer_iter *iter, u64 *ts);
struct ring_buffer_event *
ring_buffer_read(struct ring_buffer_iter *iter, u64 *ts);
void ring_buffer_iter_reset(struct ring_buffer_iter *iter);
int ring_buffer_iter_empty(struct ring_buffer_iter *iter);
unsigned long ring_buffer_size(struct ring_buffer *buffer);
void ring_buffer_reset_cpu(struct ring_buffer *buffer, int cpu);
void ring_buffer_reset(struct ring_buffer *buffer);
int ring_buffer_swap_cpu(struct ring_buffer *buffer_a,
struct ring_buffer *buffer_b, int cpu);
int ring_buffer_empty(struct ring_buffer *buffer);
int ring_buffer_empty_cpu(struct ring_buffer *buffer, int cpu);
void ring_buffer_record_disable(struct ring_buffer *buffer);
void ring_buffer_record_enable(struct ring_buffer *buffer);
void ring_buffer_record_disable_cpu(struct ring_buffer *buffer, int cpu);
void ring_buffer_record_enable_cpu(struct ring_buffer *buffer, int cpu);
unsigned long ring_buffer_entries(struct ring_buffer *buffer);
unsigned long ring_buffer_overruns(struct ring_buffer *buffer);
unsigned long ring_buffer_entries_cpu(struct ring_buffer *buffer, int cpu);
unsigned long ring_buffer_overrun_cpu(struct ring_buffer *buffer, int cpu);
u64 ring_buffer_time_stamp(struct ring_buffer *buffer, int cpu);
void ring_buffer_normalize_time_stamp(struct ring_buffer *buffer,
int cpu, u64 *ts);
void ring_buffer_set_clock(struct ring_buffer *buffer,
u64 (*clock)(void));
size_t ring_buffer_page_len(void *page);
void *ring_buffer_alloc_read_page(struct ring_buffer *buffer);
void ring_buffer_free_read_page(struct ring_buffer *buffer, void *data);
int ring_buffer_read_page(struct ring_buffer *buffer, void **data_page,
size_t len, int cpu, int full);
enum ring_buffer_flags {
RB_FL_OVERWRITE = 1 << 0,
};
#endif /* _LINUX_RING_BUFFER_H */
|
