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 <errno.h>
  14
  15 #include "kernelcompat.h"
  16 #include "kref.h"
  17 #include "list.h"
  18
  19 #define EVENTS_PER_CHANNEL      65536
  20
  21 struct ltt_trace_struct;
  22 struct rchan_buf;
  23
  24 struct ltt_channel_struct {
  25         /* First 32 bytes cache-hot cacheline */
  26         struct ltt_trace_struct *trace;
  27         void *buf;
  28         void *trans_channel_data;
  29         int overwrite:1;
  30         int active:1;
  31         unsigned int n_subbufs_order;
  32         unsigned long commit_count_mask;        /*
  33                                                  * Commit count mask, removing
  34                                                  * the MSBs corresponding to
  35                                                  * bits used to represent the
  36                                                  * subbuffer index.
  37                                                  */
  38         /* End of first 32 bytes cacheline */
  39
  40         /*
  41          * buffer_begin - called on buffer-switch to a new sub-buffer
  42          * @buf: the channel buffer containing the new sub-buffer
  43          */
  44         void (*buffer_begin) (struct rchan_buf *buf,
  45                         u64 tsc, unsigned int subbuf_idx);
  46         /*
  47          * buffer_end - called on buffer-switch to a new sub-buffer
  48          * @buf: the channel buffer containing the previous sub-buffer
  49          */
  50         void (*buffer_end) (struct rchan_buf *buf,
  51                         u64 tsc, unsigned int offset, unsigned int subbuf_idx);
  52         struct kref kref;       /* Channel transport reference count */
  53         unsigned int subbuf_size;
  54         unsigned int subbuf_cnt;
  55         const char *channel_name;
  56
  57         int buf_shmid;
  58 } ____cacheline_aligned;
  59
  60 struct ltt_channel_setting {
  61         unsigned int subbuf_size;
  62         unsigned int subbuf_cnt;
  63         struct kref kref;       /* Number of references to structure content */
  64         struct list_head list;
  65         unsigned int index;     /* index of channel in trace channel array */
  66         u16 free_event_id;      /* Next event ID to allocate */
  67         char name[PATH_MAX];
  68 };
  69
  70 int ltt_channels_register(const char *name);
  71 int ltt_channels_unregister(const char *name);
  72 int ltt_channels_set_default(const char *name,
  73                              unsigned int subbuf_size,
  74                              unsigned int subbuf_cnt);
  75 const char *ltt_channels_get_name_from_index(unsigned int index);
  76 int ltt_channels_get_index_from_name(const char *name);
  77 struct ltt_channel_struct *ltt_channels_trace_alloc(unsigned int *nr_channels,
  78                                                     int overwrite,
  79                                                     int active);
  80 void ltt_channels_trace_free(struct ltt_channel_struct *channels);
  81 int _ltt_channels_get_event_id(const char *channel, const char *name);
  82 int ltt_channels_get_event_id(const char *channel, const char *name);
  83
  84 #endif /* _LTT_CHANNELS_H */