libust/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  * This library is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU Lesser General Public
  11  * License as published by the Free Software Foundation; either
  12  * version 2.1 of the License, or (at your option) any later version.
  13  *
  14  * This library is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17  * Lesser General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU Lesser General Public
  20  * License along with this library; if not, write to the Free Software
  21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
  22  */
  23
  24 #include <linux/limits.h>
  25 #include <errno.h>
  26
  27 #include <ust/kernelcompat.h>
  28 #include <kcompat/kref.h>
  29
  30 #define EVENTS_PER_CHANNEL      65536
  31
  32 struct ltt_trace_struct;
  33
  34 struct ust_buffer;
  35
  36 struct ust_channel {
  37         /* First 32 bytes cache-hot cacheline */
  38         struct ltt_trace_struct *trace;
  39         void *buf;
  40         int overwrite:1;
  41         int active:1;
  42         unsigned int n_subbufs_order;
  43         unsigned long commit_count_mask;        /*
  44                                                  * Commit count mask, removing
  45                                                  * the MSBs corresponding to
  46                                                  * bits used to represent the
  47                                                  * subbuffer index.
  48                                                  */
  49         /* End of first 32 bytes cacheline */
  50
  51         /*
  52          * buffer_begin - called on buffer-switch to a new sub-buffer
  53          * @buf: the channel buffer containing the new sub-buffer
  54          */
  55         void (*buffer_begin) (struct ust_buffer *buf,
  56                         u64 tsc, unsigned int subbuf_idx);
  57         /*
  58          * buffer_end - called on buffer-switch to a new sub-buffer
  59          * @buf: the channel buffer containing the previous sub-buffer
  60          */
  61         void (*buffer_end) (struct ust_buffer *buf,
  62                         u64 tsc, unsigned int offset, unsigned int subbuf_idx);
  63         struct kref kref;       /* Channel transport reference count */
  64         size_t subbuf_size;
  65         int subbuf_size_order;
  66         unsigned int subbuf_cnt;
  67         const char *channel_name;
  68
  69         int buf_shmid;
  70
  71         u32 version;
  72         size_t alloc_size;
  73         struct list_head list;
  74 } ____cacheline_aligned;
  75
  76 struct ltt_channel_setting {
  77         unsigned int subbuf_size;
  78         unsigned int subbuf_cnt;
  79         struct kref kref;       /* Number of references to structure content */
  80         struct list_head list;
  81         unsigned int index;     /* index of channel in trace channel array */
  82         u16 free_event_id;      /* Next event ID to allocate */
  83         char name[PATH_MAX];
  84 };
  85
  86 extern int ltt_channels_register(const char *name);
  87 extern int ltt_channels_unregister(const char *name);
  88 extern int ltt_channels_set_default(const char *name,
  89                              unsigned int subbuf_size,
  90                              unsigned int subbuf_cnt);
  91 extern const char *ltt_channels_get_name_from_index(unsigned int index);
  92 extern int ltt_channels_get_index_from_name(const char *name);
  93 extern struct ust_channel *ltt_channels_trace_alloc(unsigned int *nr_channels,
  94                                                     int overwrite,
  95                                                     int active);
  96 extern void ltt_channels_trace_free(struct ust_channel *channels);
  97 extern int _ltt_channels_get_event_id(const char *channel, const char *name);
  98 extern int ltt_channels_get_event_id(const char *channel, const char *name);
  99
 100 #endif /* _LTT_CHANNELS_H */