diff options
Diffstat (limited to 'include/linux/ring_buffer.h')
| -rw-r--r-- | include/linux/ring_buffer.h | 186 |
1 files changed, 186 insertions, 0 deletions
diff --git a/include/linux/ring_buffer.h b/include/linux/ring_buffer.h new file mode 100644 index 00000000..ab38ac80 --- /dev/null +++ b/include/linux/ring_buffer.h @@ -0,0 +1,186 @@ +#ifndef _LINUX_RING_BUFFER_H +#define _LINUX_RING_BUFFER_H + +#include <linux/kmemcheck.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 { + kmemcheck_bitfield_begin(bitfield); + u32 type_len:5, time_delta:27; + kmemcheck_bitfield_end(bitfield); + + 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: + * array[0] holds the actual length + * size = 4 + length (bytes) + * + * @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_TYPE_LEN_MAX: + * Data record + * If type_len is zero: + * array[0] holds the actual length + * array[1..(length+3)/4] holds data + * size = 4 + length (bytes) + * else + * length = type_len << 2 + * array[0..(length+3)/4-1] holds data + * size = 4 + length (bytes) + */ +enum ring_buffer_type { + RINGBUF_TYPE_DATA_TYPE_LEN_MAX = 28, + RINGBUF_TYPE_PADDING, + RINGBUF_TYPE_TIME_EXTEND, + /* FIXME: RINGBUF_TYPE_TIME_STAMP not implemented */ + RINGBUF_TYPE_TIME_STAMP, +}; + +unsigned ring_buffer_event_length(struct ring_buffer_event *event); +void *ring_buffer_event_data(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, struct lock_class_key *key); + +/* + * Because the ring buffer is generic, if other users of the ring buffer get + * traced by ftrace, it can produce lockdep warnings. We need to keep each + * ring buffer's lock class separate. + */ +#define ring_buffer_alloc(size, flags) \ +({ \ + static struct lock_class_key __key; \ + __ring_buffer_alloc((size), (flags), &__key); \ +}) + +void ring_buffer_free(struct ring_buffer *buffer); + +int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size); + +void ring_buffer_change_overwrite(struct ring_buffer *buffer, int val); + +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, + unsigned long *lost_events); +struct ring_buffer_event * +ring_buffer_consume(struct ring_buffer *buffer, int cpu, u64 *ts, + unsigned long *lost_events); + +struct ring_buffer_iter * +ring_buffer_read_prepare(struct ring_buffer *buffer, int cpu); +void ring_buffer_read_prepare_sync(void); +void ring_buffer_read_start(struct ring_buffer_iter *iter); +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); + +#ifdef CONFIG_RING_BUFFER_ALLOW_SWAP +int ring_buffer_swap_cpu(struct ring_buffer *buffer_a, + struct ring_buffer *buffer_b, int cpu); +#else +static inline int +ring_buffer_swap_cpu(struct ring_buffer *buffer_a, + struct ring_buffer *buffer_b, int cpu) +{ + return -ENODEV; +} +#endif + +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); +unsigned long ring_buffer_commit_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); + +struct trace_seq; + +int ring_buffer_print_entry_header(struct trace_seq *s); +int ring_buffer_print_page_header(struct trace_seq *s); + +enum ring_buffer_flags { + RB_FL_OVERWRITE = 1 << 0, +}; + +#endif /* _LINUX_RING_BUFFER_H */ |