kernel/2.6.29.6-aldebaran-rt/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_define_bitfield(bitfield, {
  16                 u32             type:2, len:3, time_delta:27;
  17         });
  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  *                                everything else same as RINGBUF_TYPE_DATA
  32  *
  33  * @RINGBUF_TYPE_TIME_EXTEND:   Extend the time delta
  34  *                               array[0] = time delta (28 .. 59)
  35  *                               size = 8 bytes
  36  *
  37  * @RINGBUF_TYPE_TIME_STAMP:    Sync time stamp with external clock
  38  *                               array[0]    = tv_nsec
  39  *                               array[1..2] = tv_sec
  40  *                               size = 16 bytes
  41  *
  42  * @RINGBUF_TYPE_DATA:          Data record
  43  *                               If len is zero:
  44  *                                array[0] holds the actual length
  45  *                                array[1..(length+3)/4] holds data
  46  *                                size = 4 + 4 + length (bytes)
  47  *                               else
  48  *                                length = len << 2
  49  *                                array[0..(length+3)/4-1] holds data
  50  *                                size = 4 + length (bytes)
  51  */
  52 enum ring_buffer_type {
  53         RINGBUF_TYPE_PADDING,
  54         RINGBUF_TYPE_TIME_EXTEND,
  55         /* FIXME: RINGBUF_TYPE_TIME_STAMP not implemented */
  56         RINGBUF_TYPE_TIME_STAMP,
  57         RINGBUF_TYPE_DATA,
  58 };
  59
  60 unsigned ring_buffer_event_length(struct ring_buffer_event *event);
  61 void *ring_buffer_event_data(struct ring_buffer_event *event);
  62
  63 /**
  64  * ring_buffer_event_time_delta - return the delta timestamp of the event
  65  * @event: the event to get the delta timestamp of
  66  *
  67  * The delta timestamp is the 27 bit timestamp since the last event.
  68  */
  69 static inline unsigned
  70 ring_buffer_event_time_delta(struct ring_buffer_event *event)
  71 {
  72         return event->time_delta;
  73 }
  74
  75 void ring_buffer_event_discard(struct ring_buffer_event *event);
  76
  77 /*
  78  * size is in bytes for each per CPU buffer.
  79  */
  80 struct ring_buffer *
  81 ring_buffer_alloc(unsigned long size, unsigned flags);
  82 void ring_buffer_free(struct ring_buffer *buffer);
  83
  84 int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size);
  85
  86 struct ring_buffer_event *ring_buffer_lock_reserve(struct ring_buffer *buffer,
  87                                                    unsigned long length);
  88 int ring_buffer_unlock_commit(struct ring_buffer *buffer,
  89                               struct ring_buffer_event *event);
  90 int ring_buffer_write(struct ring_buffer *buffer,
  91                       unsigned long length, void *data);
  92
  93 struct ring_buffer_event *
  94 ring_buffer_peek(struct ring_buffer *buffer, int cpu, u64 *ts);
  95 struct ring_buffer_event *
  96 ring_buffer_consume(struct ring_buffer *buffer, int cpu, u64 *ts);
  97
  98 struct ring_buffer_iter *
  99 ring_buffer_read_start(struct ring_buffer *buffer, int cpu);
 100 void ring_buffer_read_finish(struct ring_buffer_iter *iter);
 101
 102 struct ring_buffer_event *
 103 ring_buffer_iter_peek(struct ring_buffer_iter *iter, u64 *ts);
 104 struct ring_buffer_event *
 105 ring_buffer_read(struct ring_buffer_iter *iter, u64 *ts);
 106 void ring_buffer_iter_reset(struct ring_buffer_iter *iter);
 107 int ring_buffer_iter_empty(struct ring_buffer_iter *iter);
 108
 109 unsigned long ring_buffer_size(struct ring_buffer *buffer);
 110
 111 void ring_buffer_reset_cpu(struct ring_buffer *buffer, int cpu);
 112 void ring_buffer_reset(struct ring_buffer *buffer);
 113
 114 int ring_buffer_swap_cpu(struct ring_buffer *buffer_a,
 115                          struct ring_buffer *buffer_b, int cpu);
 116
 117 int ring_buffer_empty(struct ring_buffer *buffer);
 118 int ring_buffer_empty_cpu(struct ring_buffer *buffer, int cpu);
 119
 120 void ring_buffer_record_disable(struct ring_buffer *buffer);
 121 void ring_buffer_record_enable(struct ring_buffer *buffer);
 122 void ring_buffer_record_disable_cpu(struct ring_buffer *buffer, int cpu);
 123 void ring_buffer_record_enable_cpu(struct ring_buffer *buffer, int cpu);
 124
 125 unsigned long ring_buffer_entries(struct ring_buffer *buffer);
 126 unsigned long ring_buffer_overruns(struct ring_buffer *buffer);
 127 unsigned long ring_buffer_entries_cpu(struct ring_buffer *buffer, int cpu);
 128 unsigned long ring_buffer_overrun_cpu(struct ring_buffer *buffer, int cpu);
 129
 130 u64 ring_buffer_time_stamp(struct ring_buffer *buffer, int cpu);
 131 void ring_buffer_normalize_time_stamp(struct ring_buffer *buffer,
 132                                       int cpu, u64 *ts);
 133 void ring_buffer_set_clock(struct ring_buffer *buffer,
 134                            u64 (*clock)(void));
 135
 136 size_t ring_buffer_page_len(void *page);
 137
 138
 139 void *ring_buffer_alloc_read_page(struct ring_buffer *buffer);
 140 void ring_buffer_free_read_page(struct ring_buffer *buffer, void *data);
 141 int ring_buffer_read_page(struct ring_buffer *buffer, void **data_page,
 142                           size_t len, int cpu, int full);
 143
 144 enum ring_buffer_flags {
 145         RB_FL_OVERWRITE         = 1 << 0,
 146 };
 147
 148 #endif /* _LINUX_RING_BUFFER_H */