Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
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
7struct ring_buffer;
8struct ring_buffer_iter;
9
10/*
11 * Don't refer to this struct directly, use functions below.
12 */
13struct 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 or discarded event
22 * If time_delta is 0:
23 * array is ignored
24 * size is variable depending on how much
25 * padding is needed
26 * If time_delta is non zero:
27 * everything else same as RINGBUF_TYPE_DATA
28 *
29 * @RINGBUF_TYPE_TIME_EXTEND: Extend the time delta
30 * array[0] = time delta (28 .. 59)
31 * size = 8 bytes
32 *
33 * @RINGBUF_TYPE_TIME_STAMP: Sync time stamp with external clock
34 * array[0] = tv_nsec
35 * array[1..2] = tv_sec
36 * size = 16 bytes
37 *
38 * @RINGBUF_TYPE_DATA: Data record
39 * If len is zero:
40 * array[0] holds the actual length
41 * array[1..(length+3)/4] holds data
42 * size = 4 + 4 + length (bytes)
43 * else
44 * length = len << 2
45 * array[0..(length+3)/4-1] holds data
46 * size = 4 + length (bytes)
47 */
48enum ring_buffer_type {
49 RINGBUF_TYPE_PADDING,
50 RINGBUF_TYPE_TIME_EXTEND,
51 /* FIXME: RINGBUF_TYPE_TIME_STAMP not implemented */
52 RINGBUF_TYPE_TIME_STAMP,
53 RINGBUF_TYPE_DATA,
54};
55
56unsigned ring_buffer_event_length(struct ring_buffer_event *event);
57void *ring_buffer_event_data(struct ring_buffer_event *event);
58
59/**
60 * ring_buffer_event_time_delta - return the delta timestamp of the event
61 * @event: the event to get the delta timestamp of
62 *
63 * The delta timestamp is the 27 bit timestamp since the last event.
64 */
65static inline unsigned
66ring_buffer_event_time_delta(struct ring_buffer_event *event)
67{
68 return event->time_delta;
69}
70
71void ring_buffer_event_discard(struct ring_buffer_event *event);
72
73/*
74 * size is in bytes for each per CPU buffer.
75 */
76struct ring_buffer *
77ring_buffer_alloc(unsigned long size, unsigned flags);
78void ring_buffer_free(struct ring_buffer *buffer);
79
80int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size);
81
82struct ring_buffer_event *ring_buffer_lock_reserve(struct ring_buffer *buffer,
83 unsigned long length);
84int ring_buffer_unlock_commit(struct ring_buffer *buffer,
85 struct ring_buffer_event *event);
86int ring_buffer_write(struct ring_buffer *buffer,
87 unsigned long length, void *data);
88
89struct ring_buffer_event *
90ring_buffer_peek(struct ring_buffer *buffer, int cpu, u64 *ts);
91struct ring_buffer_event *
92ring_buffer_consume(struct ring_buffer *buffer, int cpu, u64 *ts);
93
94struct ring_buffer_iter *
95ring_buffer_read_start(struct ring_buffer *buffer, int cpu);
96void ring_buffer_read_finish(struct ring_buffer_iter *iter);
97
98struct ring_buffer_event *
99ring_buffer_iter_peek(struct ring_buffer_iter *iter, u64 *ts);
100struct ring_buffer_event *
101ring_buffer_read(struct ring_buffer_iter *iter, u64 *ts);
102void ring_buffer_iter_reset(struct ring_buffer_iter *iter);
103int ring_buffer_iter_empty(struct ring_buffer_iter *iter);
104
105unsigned long ring_buffer_size(struct ring_buffer *buffer);
106
107void ring_buffer_reset_cpu(struct ring_buffer *buffer, int cpu);
108void ring_buffer_reset(struct ring_buffer *buffer);
109
110int ring_buffer_swap_cpu(struct ring_buffer *buffer_a,
111 struct ring_buffer *buffer_b, int cpu);
112
113int ring_buffer_empty(struct ring_buffer *buffer);
114int ring_buffer_empty_cpu(struct ring_buffer *buffer, int cpu);
115
116void ring_buffer_record_disable(struct ring_buffer *buffer);
117void ring_buffer_record_enable(struct ring_buffer *buffer);
118void ring_buffer_record_disable_cpu(struct ring_buffer *buffer, int cpu);
119void ring_buffer_record_enable_cpu(struct ring_buffer *buffer, int cpu);
120
121unsigned long ring_buffer_entries(struct ring_buffer *buffer);
122unsigned long ring_buffer_overruns(struct ring_buffer *buffer);
123unsigned long ring_buffer_entries_cpu(struct ring_buffer *buffer, int cpu);
124unsigned long ring_buffer_overrun_cpu(struct ring_buffer *buffer, int cpu);
125
126u64 ring_buffer_time_stamp(struct ring_buffer *buffer, int cpu);
127void ring_buffer_normalize_time_stamp(struct ring_buffer *buffer,
128 int cpu, u64 *ts);
129void ring_buffer_set_clock(struct ring_buffer *buffer,
130 u64 (*clock)(void));
131
132size_t ring_buffer_page_len(void *page);
133
134
135void *ring_buffer_alloc_read_page(struct ring_buffer *buffer);
136void ring_buffer_free_read_page(struct ring_buffer *buffer, void *data);
137int ring_buffer_read_page(struct ring_buffer *buffer, void **data_page,
138 size_t len, int cpu, int full);
139
140enum ring_buffer_flags {
141 RB_FL_OVERWRITE = 1 << 0,
142};
143
144#endif /* _LINUX_RING_BUFFER_H */