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C/C++ Source or Header  |  2008-12-24  |  3.8 KB  |  131 lines
  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 reference this struct directly, use functions below.
  12.  */
  13. struct 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
  22.  *                 array is ignored
  23.  *                 size is variable depending on how much
  24.  *                  padding is needed
  25.  *
  26.  * @RINGBUF_TYPE_TIME_EXTEND:    Extend the time delta
  27.  *                 array[0] = time delta (28 .. 59)
  28.  *                 size = 8 bytes
  29.  *
  30.  * @RINGBUF_TYPE_TIME_STAMP:    Sync time stamp with external clock
  31.  *                 array[0] = tv_nsec
  32.  *                 array[1] = tv_sec
  33.  *                 size = 16 bytes
  34.  *
  35.  * @RINGBUF_TYPE_DATA:        Data record
  36.  *                 If len is zero:
  37.  *                  array[0] holds the actual length
  38.  *                  array[1..(length+3)/4-1] holds data
  39.  *                 else
  40.  *                  length = len << 2
  41.  *                  array[0..(length+3)/4] holds data
  42.  */
  43. enum ring_buffer_type {
  44.     RINGBUF_TYPE_PADDING,
  45.     RINGBUF_TYPE_TIME_EXTEND,
  46.     /* FIXME: RINGBUF_TYPE_TIME_STAMP not implemented */
  47.     RINGBUF_TYPE_TIME_STAMP,
  48.     RINGBUF_TYPE_DATA,
  49. };
  50.  
  51. unsigned ring_buffer_event_length(struct ring_buffer_event *event);
  52. void *ring_buffer_event_data(struct ring_buffer_event *event);
  53.  
  54. /**
  55.  * ring_buffer_event_time_delta - return the delta timestamp of the event
  56.  * @event: the event to get the delta timestamp of
  57.  *
  58.  * The delta timestamp is the 27 bit timestamp since the last event.
  59.  */
  60. static inline unsigned
  61. ring_buffer_event_time_delta(struct ring_buffer_event *event)
  62. {
  63.     return event->time_delta;
  64. }
  65.  
  66. /*
  67.  * size is in bytes for each per CPU buffer.
  68.  */
  69. struct ring_buffer *
  70. ring_buffer_alloc(unsigned long size, unsigned flags);
  71. void ring_buffer_free(struct ring_buffer *buffer);
  72.  
  73. int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size);
  74.  
  75. struct ring_buffer_event *
  76. ring_buffer_lock_reserve(struct ring_buffer *buffer,
  77.              unsigned long length,
  78.              unsigned long *flags);
  79. int ring_buffer_unlock_commit(struct ring_buffer *buffer,
  80.                   struct ring_buffer_event *event,
  81.                   unsigned long flags);
  82. int ring_buffer_write(struct ring_buffer *buffer,
  83.               unsigned long length, void *data);
  84.  
  85. struct ring_buffer_event *
  86. ring_buffer_peek(struct ring_buffer *buffer, int cpu, u64 *ts);
  87. struct ring_buffer_event *
  88. ring_buffer_consume(struct ring_buffer *buffer, int cpu, u64 *ts);
  89.  
  90. struct ring_buffer_iter *
  91. ring_buffer_read_start(struct ring_buffer *buffer, int cpu);
  92. void ring_buffer_read_finish(struct ring_buffer_iter *iter);
  93.  
  94. struct ring_buffer_event *
  95. ring_buffer_iter_peek(struct ring_buffer_iter *iter, u64 *ts);
  96. struct ring_buffer_event *
  97. ring_buffer_read(struct ring_buffer_iter *iter, u64 *ts);
  98. void ring_buffer_iter_reset(struct ring_buffer_iter *iter);
  99. int ring_buffer_iter_empty(struct ring_buffer_iter *iter);
  100.  
  101. unsigned long ring_buffer_size(struct ring_buffer *buffer);
  102.  
  103. void ring_buffer_reset_cpu(struct ring_buffer *buffer, int cpu);
  104. void ring_buffer_reset(struct ring_buffer *buffer);
  105.  
  106. int ring_buffer_swap_cpu(struct ring_buffer *buffer_a,
  107.              struct ring_buffer *buffer_b, int cpu);
  108.  
  109. int ring_buffer_empty(struct ring_buffer *buffer);
  110. int ring_buffer_empty_cpu(struct ring_buffer *buffer, int cpu);
  111.  
  112. void ring_buffer_record_disable(struct ring_buffer *buffer);
  113. void ring_buffer_record_enable(struct ring_buffer *buffer);
  114. void ring_buffer_record_disable_cpu(struct ring_buffer *buffer, int cpu);
  115. void ring_buffer_record_enable_cpu(struct ring_buffer *buffer, int cpu);
  116.  
  117. unsigned long ring_buffer_entries(struct ring_buffer *buffer);
  118. unsigned long ring_buffer_overruns(struct ring_buffer *buffer);
  119.  
  120. u64 ring_buffer_time_stamp(int cpu);
  121. void ring_buffer_normalize_time_stamp(int cpu, u64 *ts);
  122.  
  123. void tracing_on(void);
  124. void tracing_off(void);
  125.  
  126. enum ring_buffer_flags {
  127.     RB_FL_OVERWRITE        = 1 << 0,
  128. };
  129.  
  130. #endif /* _LINUX_RING_BUFFER_H */
  131.