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.h"
  15
  16 struct 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 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 lib_ring_buffer;
  34
  35 struct lib_ring_buffer_backend {
  36         /* Array of ring_buffer_backend_subbuffer for writer */
  37         DECLARE_SHMP(struct lib_ring_buffer_backend_subbuffer, buf_wsb);
  38         /* ring_buffer_backend_subbuffer for reader */
  39         struct lib_ring_buffer_backend_subbuffer buf_rsb;
  40         /*
  41          * Pointer array of backend pages, for whole buffer.
  42          * Indexed by ring_buffer_backend_subbuffer identifier (id) index.
  43          */
  44         DECLARE_SHMP(struct lib_ring_buffer_backend_pages *, array);
  45         DECLARE_SHMP(char, memory_map); /* memory mapping */
  46
  47         DECLARE_SHMP(struct channel, chan);     /* Associated channel */
  48         int cpu;                        /* This buffer's cpu. -1 if global. */
  49         union v_atomic records_read;    /* Number of records read */
  50         unsigned int allocated:1;       /* Bool: is buffer allocated ? */
  51 };
  52
  53 struct channel_backend {
  54         unsigned long buf_size;         /* Size of the buffer */
  55         unsigned long subbuf_size;      /* Sub-buffer size */
  56         unsigned int subbuf_size_order; /* Order of sub-buffer size */
  57         unsigned int num_subbuf_order;  /*
  58                                          * Order of number of sub-buffers/buffer
  59                                          * for writer.
  60                                          */
  61         unsigned int buf_size_order;    /* Order of buffer size */
  62         int extra_reader_sb:1;          /* Bool: has extra reader subbuffer */
  63         DECLARE_SHMP(struct lib_ring_buffer, buf); /* Channel per-cpu buffers */
  64         unsigned long num_subbuf;       /* Number of sub-buffers for writer */
  65         u64 start_tsc;                  /* Channel creation TSC value */
  66         void *priv;                     /* Client-specific information */
  67         const struct lib_ring_buffer_config *config; /* Ring buffer configuration */
  68         char name[NAME_MAX];            /* Channel name */
  69 };
  70
  71 #endif /* _LINUX_RING_BUFFER_BACKEND_TYPES_H */