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 refer to this struct directly, use functions below. 12 */ 13 struct ring_buffer_event { 14 u32 type_len:5, 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 * array[0] holds the actual length 28 * size = 4 + length (bytes) 29 * 30 * @RINGBUF_TYPE_TIME_EXTEND: Extend the time delta 31 * array[0] = time delta (28 .. 59) 32 * size = 8 bytes 33 * 34 * @RINGBUF_TYPE_TIME_STAMP: Sync time stamp with external clock 35 * array[0] = tv_nsec 36 * array[1..2] = tv_sec 37 * size = 16 bytes 38 * 39 * <= @RINGBUF_TYPE_DATA_TYPE_LEN_MAX: 40 * Data record 41 * If type_len is zero: 42 * array[0] holds the actual length 43 * array[1..(length+3)/4] holds data 44 * size = 4 + length (bytes) 45 * else 46 * length = type_len << 2 47 * array[0..(length+3)/4-1] holds data 48 * size = 4 + length (bytes) 49 */ 50 enum ring_buffer_type { 51 RINGBUF_TYPE_DATA_TYPE_LEN_MAX = 28, 52 RINGBUF_TYPE_PADDING, 53 RINGBUF_TYPE_TIME_EXTEND, 54 /* FIXME: RINGBUF_TYPE_TIME_STAMP not implemented */ 55 RINGBUF_TYPE_TIME_STAMP, 56 }; 57 58 unsigned ring_buffer_event_length(struct ring_buffer_event *event); 59 void *ring_buffer_event_data(struct ring_buffer_event *event); 60 61 /** 62 * ring_buffer_event_time_delta - return the delta timestamp of the event 63 * @event: the event to get the delta timestamp of 64 * 65 * The delta timestamp is the 27 bit timestamp since the last event. 66 */ 67 static inline unsigned 68 ring_buffer_event_time_delta(struct ring_buffer_event *event) 69 { 70 return event->time_delta; 71 } 72 73 /* 74 * ring_buffer_event_discard can discard any event in the ring buffer. 75 * it is up to the caller to protect against a reader from 76 * consuming it or a writer from wrapping and replacing it. 77 * 78 * No external protection is needed if this is called before 79 * the event is commited. But in that case it would be better to 80 * use ring_buffer_discard_commit. 81 * 82 * Note, if an event that has not been committed is discarded 83 * with ring_buffer_event_discard, it must still be committed. 84 */ 85 void ring_buffer_event_discard(struct ring_buffer_event *event); 86 87 /* 88 * ring_buffer_discard_commit will remove an event that has not 89 * ben committed yet. If this is used, then ring_buffer_unlock_commit 90 * must not be called on the discarded event. This function 91 * will try to remove the event from the ring buffer completely 92 * if another event has not been written after it. 93 * 94 * Example use: 95 * 96 * if (some_condition) 97 * ring_buffer_discard_commit(buffer, event); 98 * else 99 * ring_buffer_unlock_commit(buffer, event); 100 */ 101 void ring_buffer_discard_commit(struct ring_buffer *buffer, 102 struct ring_buffer_event *event); 103 104 /* 105 * size is in bytes for each per CPU buffer. 106 */ 107 struct ring_buffer * 108 __ring_buffer_alloc(unsigned long size, unsigned flags, struct lock_class_key *key); 109 110 /* 111 * Because the ring buffer is generic, if other users of the ring buffer get 112 * traced by ftrace, it can produce lockdep warnings. We need to keep each 113 * ring buffer's lock class separate. 114 */ 115 #define ring_buffer_alloc(size, flags) \ 116 ({ \ 117 static struct lock_class_key __key; \ 118 __ring_buffer_alloc((size), (flags), &__key); \ 119 }) 120 121 void ring_buffer_free(struct ring_buffer *buffer); 122 123 int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size); 124 125 struct ring_buffer_event *ring_buffer_lock_reserve(struct ring_buffer *buffer, 126 unsigned long length); 127 int ring_buffer_unlock_commit(struct ring_buffer *buffer, 128 struct ring_buffer_event *event); 129 int ring_buffer_write(struct ring_buffer *buffer, 130 unsigned long length, void *data); 131 132 struct ring_buffer_event * 133 ring_buffer_peek(struct ring_buffer *buffer, int cpu, u64 *ts); 134 struct ring_buffer_event * 135 ring_buffer_consume(struct ring_buffer *buffer, int cpu, u64 *ts); 136 137 struct ring_buffer_iter * 138 ring_buffer_read_start(struct ring_buffer *buffer, int cpu); 139 void ring_buffer_read_finish(struct ring_buffer_iter *iter); 140 141 struct ring_buffer_event * 142 ring_buffer_iter_peek(struct ring_buffer_iter *iter, u64 *ts); 143 struct ring_buffer_event * 144 ring_buffer_read(struct ring_buffer_iter *iter, u64 *ts); 145 void ring_buffer_iter_reset(struct ring_buffer_iter *iter); 146 int ring_buffer_iter_empty(struct ring_buffer_iter *iter); 147 148 unsigned long ring_buffer_size(struct ring_buffer *buffer); 149 150 void ring_buffer_reset_cpu(struct ring_buffer *buffer, int cpu); 151 void ring_buffer_reset(struct ring_buffer *buffer); 152 153 int ring_buffer_swap_cpu(struct ring_buffer *buffer_a, 154 struct ring_buffer *buffer_b, int cpu); 155 156 int ring_buffer_empty(struct ring_buffer *buffer); 157 int ring_buffer_empty_cpu(struct ring_buffer *buffer, int cpu); 158 159 void ring_buffer_record_disable(struct ring_buffer *buffer); 160 void ring_buffer_record_enable(struct ring_buffer *buffer); 161 void ring_buffer_record_disable_cpu(struct ring_buffer *buffer, int cpu); 162 void ring_buffer_record_enable_cpu(struct ring_buffer *buffer, int cpu); 163 164 unsigned long ring_buffer_entries(struct ring_buffer *buffer); 165 unsigned long ring_buffer_overruns(struct ring_buffer *buffer); 166 unsigned long ring_buffer_entries_cpu(struct ring_buffer *buffer, int cpu); 167 unsigned long ring_buffer_overrun_cpu(struct ring_buffer *buffer, int cpu); 168 unsigned long ring_buffer_commit_overrun_cpu(struct ring_buffer *buffer, int cpu); 169 unsigned long ring_buffer_nmi_dropped_cpu(struct ring_buffer *buffer, int cpu); 170 171 u64 ring_buffer_time_stamp(struct ring_buffer *buffer, int cpu); 172 void ring_buffer_normalize_time_stamp(struct ring_buffer *buffer, 173 int cpu, u64 *ts); 174 void ring_buffer_set_clock(struct ring_buffer *buffer, 175 u64 (*clock)(void)); 176 177 size_t ring_buffer_page_len(void *page); 178 179 180 void *ring_buffer_alloc_read_page(struct ring_buffer *buffer); 181 void ring_buffer_free_read_page(struct ring_buffer *buffer, void *data); 182 int ring_buffer_read_page(struct ring_buffer *buffer, void **data_page, 183 size_t len, int cpu, int full); 184 185 struct trace_seq; 186 187 int ring_buffer_print_entry_header(struct trace_seq *s); 188 int ring_buffer_print_page_header(struct trace_seq *s); 189 190 enum ring_buffer_flags { 191 RB_FL_OVERWRITE = 1 << 0, 192 }; 193 194 #endif /* _LINUX_RING_BUFFER_H */ 195