release/src-rt-6.x.4708/linux/linux-2.6.36/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         RINGBUF_TYPE_TIME_STAMP,
  59 };
  60
  61 unsigned ring_buffer_event_length(struct ring_buffer_event *event);
  62 void *ring_buffer_event_data(struct ring_buffer_event *event);
  63
  64 /**
  65  * ring_buffer_event_time_delta - return the delta timestamp of the event
  66  * @event: the event to get the delta timestamp of
  67  *
  68  * The delta timestamp is the 27 bit timestamp since the last event.
  69  */
  70 static inline unsigned
  71 ring_buffer_event_time_delta(struct ring_buffer_event *event)
  72 {
  73         return event->time_delta;
  74 }
  75
  76 /*
  77  * ring_buffer_discard_commit will remove an event that has not
  78  *   ben committed yet. If this is used, then ring_buffer_unlock_commit
  79  *   must not be called on the discarded event. This function
  80  *   will try to remove the event from the ring buffer completely
  81  *   if another event has not been written after it.
  82  *
  83  * Example use:
  84  *
  85  *  if (some_condition)
  86  *    ring_buffer_discard_commit(buffer, event);
  87  *  else
  88  *    ring_buffer_unlock_commit(buffer, event);
  89  */
  90 void ring_buffer_discard_commit(struct ring_buffer *buffer,
  91                                 struct ring_buffer_event *event);
  92
  93 /*
  94  * size is in bytes for each per CPU buffer.
  95  */
  96 struct ring_buffer *
  97 __ring_buffer_alloc(unsigned long size, unsigned flags, struct lock_class_key *key);
  98
  99 /*
 100  * Because the ring buffer is generic, if other users of the ring buffer get
 101  * traced by ftrace, it can produce lockdep warnings. We need to keep each
 102  * ring buffer's lock class separate.
 103  */
 104 #define ring_buffer_alloc(size, flags)                  \
 105 ({                                                      \
 106         static struct lock_class_key __key;             \
 107         __ring_buffer_alloc((size), (flags), &__key);   \
 108 })
 109
 110 void ring_buffer_free(struct ring_buffer *buffer);
 111
 112 int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size);
 113
 114 struct ring_buffer_event *ring_buffer_lock_reserve(struct ring_buffer *buffer,
 115                                                    unsigned long length);
 116 int ring_buffer_unlock_commit(struct ring_buffer *buffer,
 117                               struct ring_buffer_event *event);
 118 int ring_buffer_write(struct ring_buffer *buffer,
 119                       unsigned long length, void *data);
 120
 121 struct ring_buffer_event *
 122 ring_buffer_peek(struct ring_buffer *buffer, int cpu, u64 *ts,
 123                  unsigned long *lost_events);
 124 struct ring_buffer_event *
 125 ring_buffer_consume(struct ring_buffer *buffer, int cpu, u64 *ts,
 126                     unsigned long *lost_events);
 127
 128 struct ring_buffer_iter *
 129 ring_buffer_read_prepare(struct ring_buffer *buffer, int cpu);
 130 void ring_buffer_read_prepare_sync(void);
 131 void ring_buffer_read_start(struct ring_buffer_iter *iter);
 132 void ring_buffer_read_finish(struct ring_buffer_iter *iter);
 133
 134 struct ring_buffer_event *
 135 ring_buffer_iter_peek(struct ring_buffer_iter *iter, u64 *ts);
 136 struct ring_buffer_event *
 137 ring_buffer_read(struct ring_buffer_iter *iter, u64 *ts);
 138 void ring_buffer_iter_reset(struct ring_buffer_iter *iter);
 139 int ring_buffer_iter_empty(struct ring_buffer_iter *iter);
 140
 141 unsigned long ring_buffer_size(struct ring_buffer *buffer);
 142
 143 void ring_buffer_reset_cpu(struct ring_buffer *buffer, int cpu);
 144 void ring_buffer_reset(struct ring_buffer *buffer);
 145
 146 #ifdef CONFIG_RING_BUFFER_ALLOW_SWAP
 147 int ring_buffer_swap_cpu(struct ring_buffer *buffer_a,
 148                          struct ring_buffer *buffer_b, int cpu);
 149 #else
 150 static inline int
 151 ring_buffer_swap_cpu(struct ring_buffer *buffer_a,
 152                      struct ring_buffer *buffer_b, int cpu)
 153 {
 154         return -ENODEV;
 155 }
 156 #endif
 157
 158 int ring_buffer_empty(struct ring_buffer *buffer);
 159 int ring_buffer_empty_cpu(struct ring_buffer *buffer, int cpu);
 160
 161 void ring_buffer_record_disable(struct ring_buffer *buffer);
 162 void ring_buffer_record_enable(struct ring_buffer *buffer);
 163 void ring_buffer_record_disable_cpu(struct ring_buffer *buffer, int cpu);
 164 void ring_buffer_record_enable_cpu(struct ring_buffer *buffer, int cpu);
 165
 166 unsigned long ring_buffer_entries(struct ring_buffer *buffer);
 167 unsigned long ring_buffer_overruns(struct ring_buffer *buffer);
 168 unsigned long ring_buffer_entries_cpu(struct ring_buffer *buffer, int cpu);
 169 unsigned long ring_buffer_overrun_cpu(struct ring_buffer *buffer, int cpu);
 170 unsigned long ring_buffer_commit_overrun_cpu(struct ring_buffer *buffer, int cpu);
 171
 172 u64 ring_buffer_time_stamp(struct ring_buffer *buffer, int cpu);
 173 void ring_buffer_normalize_time_stamp(struct ring_buffer *buffer,
 174                                       int cpu, u64 *ts);
 175 void ring_buffer_set_clock(struct ring_buffer *buffer,
 176                            u64 (*clock)(void));
 177
 178 size_t ring_buffer_page_len(void *page);
 179
 180
 181 void *ring_buffer_alloc_read_page(struct ring_buffer *buffer);
 182 void ring_buffer_free_read_page(struct ring_buffer *buffer, void *data);
 183 int ring_buffer_read_page(struct ring_buffer *buffer, void **data_page,
 184                           size_t len, int cpu, int full);
 185
 186 struct trace_seq;
 187
 188 int ring_buffer_print_entry_header(struct trace_seq *s);
 189 int ring_buffer_print_page_header(struct trace_seq *s);
 190
 191 enum ring_buffer_flags {
 192         RB_FL_OVERWRITE         = 1 << 0,
 193 };
 194
 195 #endif /* _LINUX_RING_BUFFER_H */