libtracing/channels.h

   1 #ifndef _LTT_CHANNELS_H
   2 #define _LTT_CHANNELS_H
   3
   4 /*
   5  * Copyright (C) 2008 Mathieu Desnoyers (mathieu.desnoyers@polymtl.ca)
   6  *
   7  * Dynamic tracer channel allocation.
   8  */
   9
  10 #include <linux/limits.h>
  11 //ust// #include <linux/kref.h>
  12 //ust// #include <linux/list.h>
  13 #include <kernelcompat.h>
  14
  15 #include <kref.h>
  16
  17 #define EVENTS_PER_CHANNEL      65536
  18
  19 struct ltt_trace_struct;
  20 struct rchan_buf;
  21
  22 struct ltt_channel_struct {
  23         /* First 32 bytes cache-hot cacheline */
  24         struct ltt_trace_struct *trace;
  25         void *buf;
  26         void *trans_channel_data;
  27         int overwrite:1;
  28         int active:1;
  29         unsigned int n_subbufs_order;
  30         unsigned long commit_count_mask;        /*
  31                                                  * Commit count mask, removing
  32                                                  * the MSBs corresponding to
  33                                                  * bits used to represent the
  34                                                  * subbuffer index.
  35                                                  */
  36         /* End of first 32 bytes cacheline */
  37
  38         /*
  39          * buffer_begin - called on buffer-switch to a new sub-buffer
  40          * @buf: the channel buffer containing the new sub-buffer
  41          */
  42         void (*buffer_begin) (struct rchan_buf *buf,
  43                         u64 tsc, unsigned int subbuf_idx);
  44         /*
  45          * buffer_end - called on buffer-switch to a new sub-buffer
  46          * @buf: the channel buffer containing the previous sub-buffer
  47          */
  48         void (*buffer_end) (struct rchan_buf *buf,
  49                         u64 tsc, unsigned int offset, unsigned int subbuf_idx);
  50         struct kref kref;       /* Channel transport reference count */
  51         unsigned int subbuf_size;
  52         unsigned int subbuf_cnt;
  53         const char *channel_name;
  54 } ____cacheline_aligned;
  55
  56 struct ltt_channel_setting {
  57         unsigned int subbuf_size;
  58         unsigned int subbuf_cnt;
  59         struct kref kref;       /* Number of references to structure content */
  60         struct list_head list;
  61         unsigned int index;     /* index of channel in trace channel array */
  62         u16 free_event_id;      /* Next event ID to allocate */
  63         char name[PATH_MAX];
  64 };
  65
  66 int ltt_channels_register(const char *name);
  67 int ltt_channels_unregister(const char *name);
  68 int ltt_channels_set_default(const char *name,
  69                              unsigned int subbuf_size,
  70                              unsigned int subbuf_cnt);
  71 const char *ltt_channels_get_name_from_index(unsigned int index);
  72 int ltt_channels_get_index_from_name(const char *name);
  73 struct ltt_channel_struct *ltt_channels_trace_alloc(unsigned int *nr_channels,
  74                                                     int overwrite,
  75                                                     int active);
  76 void ltt_channels_trace_free(struct ltt_channel_struct *channels);
  77 int _ltt_channels_get_event_id(const char *channel, const char *name);
  78 int ltt_channels_get_event_id(const char *channel, const char *name);
  79
  80 #endif /* _LTT_CHANNELS_H */