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 <limits.h>
  15 #include "shm_internal.h"
  16 #include "vatomic.h"
  17
  18 struct lttng_ust_lib_ring_buffer_backend_pages {
  19         unsigned long mmap_offset;      /* offset of the subbuffer in mmap */
  20         union v_atomic records_commit;  /* current records committed count */
  21         union v_atomic records_unread;  /* records to read */
  22         unsigned long data_size;        /* Amount of data to read from subbuf */
  23         DECLARE_SHMP(char, p);          /* Backing memory map */
  24 };
  25
  26 struct lttng_ust_lib_ring_buffer_backend_subbuffer {
  27         /* Identifier for subbuf backend pages. Exchanged atomically. */
  28         unsigned long id;               /* backend subbuffer identifier */
  29 };
  30
  31 /*
  32  * Forward declaration of frontend-specific channel and ring_buffer.
  33  */
  34 struct channel;
  35 struct lttng_ust_lib_ring_buffer;
  36
  37 struct lttng_ust_lib_ring_buffer_backend_pages_shmp {
  38         DECLARE_SHMP(struct lttng_ust_lib_ring_buffer_backend_pages, shmp);
  39 };
  40
  41 struct lttng_ust_lib_ring_buffer_backend {
  42         /* Array of ring_buffer_backend_subbuffer for writer */
  43         DECLARE_SHMP(struct lttng_ust_lib_ring_buffer_backend_subbuffer, buf_wsb);
  44         /* ring_buffer_backend_subbuffer for reader */
  45         struct lttng_ust_lib_ring_buffer_backend_subbuffer buf_rsb;
  46         /*
  47          * Pointer array of backend pages, for whole buffer.
  48          * Indexed by ring_buffer_backend_subbuffer identifier (id) index.
  49          */
  50         DECLARE_SHMP(struct lttng_ust_lib_ring_buffer_backend_pages_shmp, array);
  51         DECLARE_SHMP(char, memory_map); /* memory mapping */
  52
  53         DECLARE_SHMP(struct channel, chan);     /* Associated channel */
  54         int cpu;                        /* This buffer's cpu. -1 if global. */
  55         union v_atomic records_read;    /* Number of records read */
  56         unsigned int allocated:1;       /* is buffer allocated ? */
  57 };
  58
  59 struct lttng_ust_lib_ring_buffer_shmp {
  60         DECLARE_SHMP(struct lttng_ust_lib_ring_buffer, shmp); /* Channel per-cpu buffers */
  61 };
  62
  63 struct channel_backend {
  64         unsigned long buf_size;         /* Size of the buffer */
  65         unsigned long subbuf_size;      /* Sub-buffer size */
  66         unsigned int subbuf_size_order; /* Order of sub-buffer size */
  67         unsigned int num_subbuf_order;  /*
  68                                          * Order of number of sub-buffers/buffer
  69                                          * for writer.
  70                                          */
  71         unsigned int buf_size_order;    /* Order of buffer size */
  72         unsigned int extra_reader_sb:1; /* has extra reader subbuffer ? */
  73         unsigned long num_subbuf;       /* Number of sub-buffers for writer */
  74         uint64_t start_tsc;             /* Channel creation TSC value */
  75         DECLARE_SHMP(void *, priv_data);/* Client-specific information */
  76         struct lttng_ust_lib_ring_buffer_config config; /* Ring buffer configuration */
  77         char name[NAME_MAX];            /* Channel name */
  78         struct lttng_ust_lib_ring_buffer_shmp buf[];
  79 };
  80
  81 #endif /* _LINUX_RING_BUFFER_BACKEND_TYPES_H */