libringbuffer/backend_types.h

   1 #ifndef _LINUX_RING_BUFFER_BACKEND_TYPES_H
   2 #define _LINUX_RING_BUFFER_BACKEND_TYPES_H
   3
   4 /*
   5  * linux/ringbuffer/backend_types.h
   6  *
   7  * Copyright (C) 2008-2010 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   8  *
   9  * Ring buffer backend (types).
  10  *
  11  * Dual LGPL v2.1/GPL v2 license.
  12  */
  13
  14 #include "shm_internal.h"
  15
  16 struct lttng_ust_lib_ring_buffer_backend_pages {
  17         unsigned long mmap_offset;      /* offset of the subbuffer in mmap */
  18         union v_atomic records_commit;  /* current records committed count */
  19         union v_atomic records_unread;  /* records to read */
  20         unsigned long data_size;        /* Amount of data to read from subbuf */
  21         DECLARE_SHMP(char, p);          /* Backing memory map */
  22 };
  23
  24 struct lttng_ust_lib_ring_buffer_backend_subbuffer {
  25         /* Identifier for subbuf backend pages. Exchanged atomically. */
  26         unsigned long id;               /* backend subbuffer identifier */
  27 };
  28
  29 /*
  30  * Forward declaration of frontend-specific channel and ring_buffer.
  31  */
  32 struct channel;
  33 struct lttng_ust_lib_ring_buffer;
  34
  35 struct lttng_ust_lib_ring_buffer_backend_pages_shmp {
  36         DECLARE_SHMP(struct lttng_ust_lib_ring_buffer_backend_pages, shmp);
  37 };
  38
  39 struct lttng_ust_lib_ring_buffer_backend {
  40         /* Array of ring_buffer_backend_subbuffer for writer */
  41         DECLARE_SHMP(struct lttng_ust_lib_ring_buffer_backend_subbuffer, buf_wsb);
  42         /* ring_buffer_backend_subbuffer for reader */
  43         struct lttng_ust_lib_ring_buffer_backend_subbuffer buf_rsb;
  44         /*
  45          * Pointer array of backend pages, for whole buffer.
  46          * Indexed by ring_buffer_backend_subbuffer identifier (id) index.
  47          */
  48         DECLARE_SHMP(struct lttng_ust_lib_ring_buffer_backend_pages_shmp, array);
  49         DECLARE_SHMP(char, memory_map); /* memory mapping */
  50
  51         DECLARE_SHMP(struct channel, chan);     /* Associated channel */
  52         int cpu;                        /* This buffer's cpu. -1 if global. */
  53         union v_atomic records_read;    /* Number of records read */
  54         unsigned int allocated:1;       /* Bool: is buffer allocated ? */
  55 };
  56
  57 struct lttng_ust_lib_ring_buffer_shmp {
  58         DECLARE_SHMP(struct lttng_ust_lib_ring_buffer, shmp); /* Channel per-cpu buffers */
  59 };
  60
  61 struct channel_backend {
  62         unsigned long buf_size;         /* Size of the buffer */
  63         unsigned long subbuf_size;      /* Sub-buffer size */
  64         unsigned int subbuf_size_order; /* Order of sub-buffer size */
  65         unsigned int num_subbuf_order;  /*
  66                                          * Order of number of sub-buffers/buffer
  67                                          * for writer.
  68                                          */
  69         unsigned int buf_size_order;    /* Order of buffer size */
  70         int extra_reader_sb:1;          /* Bool: has extra reader subbuffer */
  71         unsigned long num_subbuf;       /* Number of sub-buffers for writer */
  72         u64 start_tsc;                  /* Channel creation TSC value */
  73         void *priv;                     /* Client-specific information */
  74         struct lttng_ust_lib_ring_buffer_config config; /* Ring buffer configuration */
  75         char name[NAME_MAX];            /* Channel name */
  76         struct lttng_ust_lib_ring_buffer_shmp buf[];
  77 };
  78
  79 #endif /* _LINUX_RING_BUFFER_BACKEND_TYPES_H */