libringbuffer/backend_types.h

   1 #ifndef _LTTNG_RING_BUFFER_BACKEND_TYPES_H
   2 #define _LTTNG_RING_BUFFER_BACKEND_TYPES_H
   3
   4 /*
   5  * linux/ringbuffer/backend_types.h
   6  *
   7  * Ring buffer backend (types).
   8  *
   9  * Copyright (C) 2008-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
  10  *
  11  * This library is free software; you can redistribute it and/or
  12  * modify it under the terms of the GNU Lesser General Public
  13  * License as published by the Free Software Foundation; only
  14  * version 2.1 of the License.
  15  *
  16  * This library is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  19  * Lesser General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU Lesser General Public
  22  * License along with this library; if not, write to the Free Software
  23  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  24  */
  25
  26 #include <limits.h>
  27 #include "shm_internal.h"
  28 #include "vatomic.h"
  29
  30 #define RB_BACKEND_PAGES_PADDING        16
  31 struct lttng_ust_lib_ring_buffer_backend_pages {
  32         unsigned long mmap_offset;      /* offset of the subbuffer in mmap */
  33         union v_atomic records_commit;  /* current records committed count */
  34         union v_atomic records_unread;  /* records to read */
  35         unsigned long data_size;        /* Amount of data to read from subbuf */
  36         DECLARE_SHMP(char, p);          /* Backing memory map */
  37         char padding[RB_BACKEND_PAGES_PADDING];
  38 };
  39
  40 struct lttng_ust_lib_ring_buffer_backend_subbuffer {
  41         /* Identifier for subbuf backend pages. Exchanged atomically. */
  42         unsigned long id;               /* backend subbuffer identifier */
  43 };
  44
  45 /*
  46  * Forward declaration of frontend-specific channel and ring_buffer.
  47  */
  48 struct channel;
  49 struct lttng_ust_lib_ring_buffer;
  50
  51 struct lttng_ust_lib_ring_buffer_backend_pages_shmp {
  52         DECLARE_SHMP(struct lttng_ust_lib_ring_buffer_backend_pages, shmp);
  53 };
  54
  55 #define RB_BACKEND_RING_BUFFER_PADDING          64
  56 struct lttng_ust_lib_ring_buffer_backend {
  57         /* Array of ring_buffer_backend_subbuffer for writer */
  58         DECLARE_SHMP(struct lttng_ust_lib_ring_buffer_backend_subbuffer, buf_wsb);
  59         /* ring_buffer_backend_subbuffer for reader */
  60         struct lttng_ust_lib_ring_buffer_backend_subbuffer buf_rsb;
  61         /*
  62          * Pointer array of backend pages, for whole buffer.
  63          * Indexed by ring_buffer_backend_subbuffer identifier (id) index.
  64          */
  65         DECLARE_SHMP(struct lttng_ust_lib_ring_buffer_backend_pages_shmp, array);
  66         DECLARE_SHMP(char, memory_map); /* memory mapping */
  67
  68         DECLARE_SHMP(struct channel, chan);     /* Associated channel */
  69         int cpu;                        /* This buffer's cpu. -1 if global. */
  70         union v_atomic records_read;    /* Number of records read */
  71         unsigned int allocated:1;       /* is buffer allocated ? */
  72         char padding[RB_BACKEND_RING_BUFFER_PADDING];
  73 };
  74
  75 struct lttng_ust_lib_ring_buffer_shmp {
  76         DECLARE_SHMP(struct lttng_ust_lib_ring_buffer, shmp); /* Channel per-cpu buffers */
  77 };
  78
  79 #define RB_BACKEND_CHANNEL_PADDING      64
  80 struct channel_backend {
  81         unsigned long buf_size;         /* Size of the buffer */
  82         unsigned long subbuf_size;      /* Sub-buffer size */
  83         unsigned int subbuf_size_order; /* Order of sub-buffer size */
  84         unsigned int num_subbuf_order;  /*
  85                                          * Order of number of sub-buffers/buffer
  86                                          * for writer.
  87                                          */
  88         unsigned int buf_size_order;    /* Order of buffer size */
  89         unsigned int extra_reader_sb:1; /* has extra reader subbuffer ? */
  90         unsigned long num_subbuf;       /* Number of sub-buffers for writer */
  91         uint64_t start_tsc;             /* Channel creation TSC value */
  92         DECLARE_SHMP(void *, priv_data);/* Client-specific information */
  93         struct lttng_ust_lib_ring_buffer_config config; /* Ring buffer configuration */
  94         char name[NAME_MAX];            /* Channel name */
  95         char padding[RB_BACKEND_CHANNEL_PADDING];
  96         struct lttng_ust_lib_ring_buffer_shmp buf[];
  97 };
  98
  99 #endif /* _LTTNG_RING_BUFFER_BACKEND_TYPES_H */