Merge git://git.kernel.org/pub/scm/linux/kernel/git/wim/linux-2.6-watchdog
[pandora-kernel.git] / include / linux / ring_buffer.h
1 #ifndef _LINUX_RING_BUFFER_H
2 #define _LINUX_RING_BUFFER_H
3
4 #include <linux/kmemcheck.h>
5 #include <linux/mm.h>
6 #include <linux/seq_file.h>
7
8 struct ring_buffer;
9 struct ring_buffer_iter;
10
11 /*
12  * Don't refer to this struct directly, use functions below.
13  */
14 struct ring_buffer_event {
15         kmemcheck_bitfield_begin(bitfield);
16         u32             type_len:5, time_delta:27;
17         kmemcheck_bitfield_end(bitfield);
18
19         u32             array[];
20 };
21
22 /**
23  * enum ring_buffer_type - internal ring buffer types
24  *
25  * @RINGBUF_TYPE_PADDING:       Left over page padding or discarded event
26  *                               If time_delta is 0:
27  *                                array is ignored
28  *                                size is variable depending on how much
29  *                                padding is needed
30  *                               If time_delta is non zero:
31  *                                array[0] holds the actual length
32  *                                size = 4 + length (bytes)
33  *
34  * @RINGBUF_TYPE_TIME_EXTEND:   Extend the time delta
35  *                               array[0] = time delta (28 .. 59)
36  *                               size = 8 bytes
37  *
38  * @RINGBUF_TYPE_TIME_STAMP:    Sync time stamp with external clock
39  *                               array[0]    = tv_nsec
40  *                               array[1..2] = tv_sec
41  *                               size = 16 bytes
42  *
43  * <= @RINGBUF_TYPE_DATA_TYPE_LEN_MAX:
44  *                              Data record
45  *                               If type_len is zero:
46  *                                array[0] holds the actual length
47  *                                array[1..(length+3)/4] holds data
48  *                                size = 4 + length (bytes)
49  *                               else
50  *                                length = type_len << 2
51  *                                array[0..(length+3)/4-1] holds data
52  *                                size = 4 + length (bytes)
53  */
54 enum ring_buffer_type {
55         RINGBUF_TYPE_DATA_TYPE_LEN_MAX = 28,
56         RINGBUF_TYPE_PADDING,
57         RINGBUF_TYPE_TIME_EXTEND,
58         /* FIXME: RINGBUF_TYPE_TIME_STAMP not implemented */
59         RINGBUF_TYPE_TIME_STAMP,
60 };
61
62 unsigned ring_buffer_event_length(struct ring_buffer_event *event);
63 void *ring_buffer_event_data(struct ring_buffer_event *event);
64
65 /*
66  * ring_buffer_discard_commit will remove an event that has not
67  *   ben committed yet. If this is used, then ring_buffer_unlock_commit
68  *   must not be called on the discarded event. This function
69  *   will try to remove the event from the ring buffer completely
70  *   if another event has not been written after it.
71  *
72  * Example use:
73  *
74  *  if (some_condition)
75  *    ring_buffer_discard_commit(buffer, event);
76  *  else
77  *    ring_buffer_unlock_commit(buffer, event);
78  */
79 void ring_buffer_discard_commit(struct ring_buffer *buffer,
80                                 struct ring_buffer_event *event);
81
82 /*
83  * size is in bytes for each per CPU buffer.
84  */
85 struct ring_buffer *
86 __ring_buffer_alloc(unsigned long size, unsigned flags, struct lock_class_key *key);
87
88 /*
89  * Because the ring buffer is generic, if other users of the ring buffer get
90  * traced by ftrace, it can produce lockdep warnings. We need to keep each
91  * ring buffer's lock class separate.
92  */
93 #define ring_buffer_alloc(size, flags)                  \
94 ({                                                      \
95         static struct lock_class_key __key;             \
96         __ring_buffer_alloc((size), (flags), &__key);   \
97 })
98
99 void ring_buffer_free(struct ring_buffer *buffer);
100
101 int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size);
102
103 void ring_buffer_change_overwrite(struct ring_buffer *buffer, int val);
104
105 struct ring_buffer_event *ring_buffer_lock_reserve(struct ring_buffer *buffer,
106                                                    unsigned long length);
107 int ring_buffer_unlock_commit(struct ring_buffer *buffer,
108                               struct ring_buffer_event *event);
109 int ring_buffer_write(struct ring_buffer *buffer,
110                       unsigned long length, void *data);
111
112 struct ring_buffer_event *
113 ring_buffer_peek(struct ring_buffer *buffer, int cpu, u64 *ts,
114                  unsigned long *lost_events);
115 struct ring_buffer_event *
116 ring_buffer_consume(struct ring_buffer *buffer, int cpu, u64 *ts,
117                     unsigned long *lost_events);
118
119 struct ring_buffer_iter *
120 ring_buffer_read_prepare(struct ring_buffer *buffer, int cpu);
121 void ring_buffer_read_prepare_sync(void);
122 void ring_buffer_read_start(struct ring_buffer_iter *iter);
123 void ring_buffer_read_finish(struct ring_buffer_iter *iter);
124
125 struct ring_buffer_event *
126 ring_buffer_iter_peek(struct ring_buffer_iter *iter, u64 *ts);
127 struct ring_buffer_event *
128 ring_buffer_read(struct ring_buffer_iter *iter, u64 *ts);
129 void ring_buffer_iter_reset(struct ring_buffer_iter *iter);
130 int ring_buffer_iter_empty(struct ring_buffer_iter *iter);
131
132 unsigned long ring_buffer_size(struct ring_buffer *buffer);
133
134 void ring_buffer_reset_cpu(struct ring_buffer *buffer, int cpu);
135 void ring_buffer_reset(struct ring_buffer *buffer);
136
137 #ifdef CONFIG_RING_BUFFER_ALLOW_SWAP
138 int ring_buffer_swap_cpu(struct ring_buffer *buffer_a,
139                          struct ring_buffer *buffer_b, int cpu);
140 #else
141 static inline int
142 ring_buffer_swap_cpu(struct ring_buffer *buffer_a,
143                      struct ring_buffer *buffer_b, int cpu)
144 {
145         return -ENODEV;
146 }
147 #endif
148
149 int ring_buffer_empty(struct ring_buffer *buffer);
150 int ring_buffer_empty_cpu(struct ring_buffer *buffer, int cpu);
151
152 void ring_buffer_record_disable(struct ring_buffer *buffer);
153 void ring_buffer_record_enable(struct ring_buffer *buffer);
154 void ring_buffer_record_disable_cpu(struct ring_buffer *buffer, int cpu);
155 void ring_buffer_record_enable_cpu(struct ring_buffer *buffer, int cpu);
156
157 unsigned long ring_buffer_entries(struct ring_buffer *buffer);
158 unsigned long ring_buffer_overruns(struct ring_buffer *buffer);
159 unsigned long ring_buffer_entries_cpu(struct ring_buffer *buffer, int cpu);
160 unsigned long ring_buffer_overrun_cpu(struct ring_buffer *buffer, int cpu);
161 unsigned long ring_buffer_commit_overrun_cpu(struct ring_buffer *buffer, int cpu);
162
163 u64 ring_buffer_time_stamp(struct ring_buffer *buffer, int cpu);
164 void ring_buffer_normalize_time_stamp(struct ring_buffer *buffer,
165                                       int cpu, u64 *ts);
166 void ring_buffer_set_clock(struct ring_buffer *buffer,
167                            u64 (*clock)(void));
168
169 size_t ring_buffer_page_len(void *page);
170
171
172 void *ring_buffer_alloc_read_page(struct ring_buffer *buffer);
173 void ring_buffer_free_read_page(struct ring_buffer *buffer, void *data);
174 int ring_buffer_read_page(struct ring_buffer *buffer, void **data_page,
175                           size_t len, int cpu, int full);
176
177 struct trace_seq;
178
179 int ring_buffer_print_entry_header(struct trace_seq *s);
180 int ring_buffer_print_page_header(struct trace_seq *s);
181
182 enum ring_buffer_flags {
183         RB_FL_OVERWRITE         = 1 << 0,
184 };
185
186 #endif /* _LINUX_RING_BUFFER_H */