ltt-ring-buffer-metadata-client.h

   1 /*
   2  * ltt-ring-buffer-client.h
   3  *
   4  * Copyright (C) 2010 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   5  *
   6  * LTTng lib ring buffer client template.
   7  *
   8  * Dual LGPL v2.1/GPL v2 license.
   9  */
  10
  11 #include <linux/module.h>
  12 #include <linux/types.h>
  13 #include "wrapper/vmalloc.h"    /* for wrapper_vmalloc_sync_all() */
  14 #include "ltt-events.h"
  15 #include "ltt-tracer.h"
  16
  17 struct metadata_packet_header {
  18         uint32_t magic;                 /* 0x75D11D57 */
  19         uint8_t  uuid[16];              /* Unique Universal Identifier */
  20         uint32_t checksum;              /* 0 if unused */
  21         uint32_t content_size;          /* in bits */
  22         uint32_t packet_size;           /* in bits */
  23         uint8_t  compression_scheme;    /* 0 if unused */
  24         uint8_t  encryption_scheme;     /* 0 if unused */
  25         uint8_t  checksum_scheme;       /* 0 if unused */
  26         uint8_t  header_end[0];
  27 };
  28
  29 struct metadata_record_header {
  30         uint8_t header_end[0];          /* End of header */
  31 };
  32
  33 static const struct lib_ring_buffer_config client_config;
  34
  35 static inline
  36 u64 lib_ring_buffer_clock_read(struct channel *chan)
  37 {
  38         return 0;
  39 }
  40
  41 static inline
  42 unsigned char record_header_size(const struct lib_ring_buffer_config *config,
  43                                  struct channel *chan, size_t offset,
  44                                  size_t *pre_header_padding,
  45                                  struct lib_ring_buffer_ctx *ctx)
  46 {
  47         return 0;
  48 }
  49
  50 #include "wrapper/ringbuffer/api.h"
  51
  52 static u64 client_ring_buffer_clock_read(struct channel *chan)
  53 {
  54         return 0;
  55 }
  56
  57 static
  58 size_t client_record_header_size(const struct lib_ring_buffer_config *config,
  59                                  struct channel *chan, size_t offset,
  60                                  size_t data_size,
  61                                  size_t *pre_header_padding,
  62                                  unsigned int rflags,
  63                                  struct lib_ring_buffer_ctx *ctx)
  64 {
  65         return 0;
  66 }
  67
  68 /**
  69  * client_packet_header_size - called on buffer-switch to a new sub-buffer
  70  *
  71  * Return header size without padding after the structure. Don't use packed
  72  * structure because gcc generates inefficient code on some architectures
  73  * (powerpc, mips..)
  74  */
  75 static size_t client_packet_header_size(void)
  76 {
  77         return offsetof(struct metadata_packet_header, header_end);
  78 }
  79
  80 static void client_buffer_begin(struct lib_ring_buffer *buf, u64 tsc,
  81                                 unsigned int subbuf_idx)
  82 {
  83         struct channel *chan = buf->backend.chan;
  84         struct metadata_packet_header *header =
  85                 (struct metadata_packet_header *)
  86                         lib_ring_buffer_offset_address(&buf->backend,
  87                                 subbuf_idx * chan->backend.subbuf_size);
  88         struct ltt_channel *ltt_chan = channel_get_private(chan);
  89         struct ltt_session *session = ltt_chan->session;
  90
  91         header->magic = TSDL_MAGIC_NUMBER;
  92         memcpy(header->uuid, session->uuid.b, sizeof(session->uuid));
  93         header->checksum = 0;           /* 0 if unused */
  94         header->content_size = 0xFFFFFFFF; /* in bits, for debugging */
  95         header->packet_size = 0xFFFFFFFF;  /* in bits, for debugging */
  96         header->compression_scheme = 0; /* 0 if unused */
  97         header->encryption_scheme = 0;  /* 0 if unused */
  98         header->checksum_scheme = 0;    /* 0 if unused */
  99 }
 100
 101 /*
 102  * offset is assumed to never be 0 here : never deliver a completely empty
 103  * subbuffer. data_size is between 1 and subbuf_size.
 104  */
 105 static void client_buffer_end(struct lib_ring_buffer *buf, u64 tsc,
 106                               unsigned int subbuf_idx, unsigned long data_size)
 107 {
 108         struct channel *chan = buf->backend.chan;
 109         struct metadata_packet_header *header =
 110                 (struct metadata_packet_header *)
 111                         lib_ring_buffer_offset_address(&buf->backend,
 112                                 subbuf_idx * chan->backend.subbuf_size);
 113         unsigned long records_lost = 0;
 114
 115         header->content_size = data_size * CHAR_BIT;            /* in bits */
 116         header->packet_size = PAGE_ALIGN(data_size) * CHAR_BIT; /* in bits */
 117         records_lost += lib_ring_buffer_get_records_lost_full(&client_config, buf);
 118         records_lost += lib_ring_buffer_get_records_lost_wrap(&client_config, buf);
 119         records_lost += lib_ring_buffer_get_records_lost_big(&client_config, buf);
 120         WARN_ON_ONCE(records_lost != 0);
 121 }
 122
 123 static int client_buffer_create(struct lib_ring_buffer *buf, void *priv,
 124                                 int cpu, const char *name)
 125 {
 126         return 0;
 127 }
 128
 129 static void client_buffer_finalize(struct lib_ring_buffer *buf, void *priv, int cpu)
 130 {
 131 }
 132
 133 static const struct lib_ring_buffer_config client_config = {
 134         .cb.ring_buffer_clock_read = client_ring_buffer_clock_read,
 135         .cb.record_header_size = client_record_header_size,
 136         .cb.subbuffer_header_size = client_packet_header_size,
 137         .cb.buffer_begin = client_buffer_begin,
 138         .cb.buffer_end = client_buffer_end,
 139         .cb.buffer_create = client_buffer_create,
 140         .cb.buffer_finalize = client_buffer_finalize,
 141
 142         .tsc_bits = 0,
 143         .alloc = RING_BUFFER_ALLOC_GLOBAL,
 144         .sync = RING_BUFFER_SYNC_GLOBAL,
 145         .mode = RING_BUFFER_MODE_TEMPLATE,
 146         .backend = RING_BUFFER_PAGE,
 147         .output = RING_BUFFER_SPLICE,
 148         .oops = RING_BUFFER_OOPS_CONSISTENCY,
 149         .ipi = RING_BUFFER_IPI_BARRIER,
 150         .wakeup = RING_BUFFER_WAKEUP_BY_TIMER,
 151 };
 152
 153 static
 154 struct channel *_channel_create(const char *name,
 155                                 struct ltt_channel *ltt_chan, void *buf_addr,
 156                                 size_t subbuf_size, size_t num_subbuf,
 157                                 unsigned int switch_timer_interval,
 158                                 unsigned int read_timer_interval)
 159 {
 160         return channel_create(&client_config, name, ltt_chan, buf_addr,
 161                               subbuf_size, num_subbuf, switch_timer_interval,
 162                               read_timer_interval);
 163 }
 164
 165 static
 166 void ltt_channel_destroy(struct channel *chan)
 167 {
 168         channel_destroy(chan);
 169 }
 170
 171 static
 172 struct lib_ring_buffer *ltt_buffer_read_open(struct channel *chan)
 173 {
 174         struct lib_ring_buffer *buf;
 175
 176         buf = channel_get_ring_buffer(&client_config, chan, 0);
 177         if (!lib_ring_buffer_open_read(buf))
 178                 return buf;
 179         return NULL;
 180 }
 181
 182 static
 183 void ltt_buffer_read_close(struct lib_ring_buffer *buf)
 184 {
 185         lib_ring_buffer_release_read(buf);
 186 }
 187
 188 static
 189 int ltt_event_reserve(struct lib_ring_buffer_ctx *ctx, uint32_t event_id)
 190 {
 191         return lib_ring_buffer_reserve(&client_config, ctx);
 192 }
 193
 194 static
 195 void ltt_event_commit(struct lib_ring_buffer_ctx *ctx)
 196 {
 197         lib_ring_buffer_commit(&client_config, ctx);
 198 }
 199
 200 static
 201 void ltt_event_write(struct lib_ring_buffer_ctx *ctx, const void *src,
 202                      size_t len)
 203 {
 204         lib_ring_buffer_write(&client_config, ctx, src, len);
 205 }
 206
 207 static
 208 size_t ltt_packet_avail_size(struct channel *chan)
 209
 210 {
 211         unsigned long o_begin;
 212         struct lib_ring_buffer *buf;
 213
 214         buf = chan->backend.buf;        /* Only for global buffer ! */
 215         o_begin = v_read(&client_config, &buf->offset);
 216         if (subbuf_offset(o_begin, chan) != 0) {
 217                 return chan->backend.subbuf_size - subbuf_offset(o_begin, chan);
 218         } else {
 219                 return chan->backend.subbuf_size - subbuf_offset(o_begin, chan)
 220                         - sizeof(struct metadata_packet_header);
 221         }
 222 }
 223
 224 static
 225 wait_queue_head_t *ltt_get_reader_wait_queue(struct ltt_channel *chan)
 226 {
 227         return &chan->chan->read_wait;
 228 }
 229
 230 static struct ltt_transport ltt_relay_transport = {
 231         .name = "relay-" RING_BUFFER_MODE_TEMPLATE_STRING,
 232         .owner = THIS_MODULE,
 233         .ops = {
 234                 .channel_create = _channel_create,
 235                 .channel_destroy = ltt_channel_destroy,
 236                 .buffer_read_open = ltt_buffer_read_open,
 237                 .buffer_read_close = ltt_buffer_read_close,
 238                 .event_reserve = ltt_event_reserve,
 239                 .event_commit = ltt_event_commit,
 240                 .event_write = ltt_event_write,
 241                 .packet_avail_size = ltt_packet_avail_size,
 242                 .get_reader_wait_queue = ltt_get_reader_wait_queue,
 243         },
 244 };
 245
 246 static int __init ltt_ring_buffer_client_init(void)
 247 {
 248         /*
 249          * This vmalloc sync all also takes care of the lib ring buffer
 250          * vmalloc'd module pages when it is built as a module into LTTng.
 251          */
 252         wrapper_vmalloc_sync_all();
 253         printk(KERN_INFO "LTT : ltt ring buffer metadata client init\n");
 254         ltt_transport_register(&ltt_relay_transport);
 255         return 0;
 256 }
 257
 258 module_init(ltt_ring_buffer_client_init);
 259
 260 static void __exit ltt_ring_buffer_client_exit(void)
 261 {
 262         printk(KERN_INFO "LTT : ltt ring buffer metadata client exit\n");
 263         ltt_transport_unregister(&ltt_relay_transport);
 264 }
 265
 266 module_exit(ltt_ring_buffer_client_exit);
 267
 268 MODULE_LICENSE("GPL and additional rights");
 269 MODULE_AUTHOR("Mathieu Desnoyers");
 270 MODULE_DESCRIPTION("LTTng ring buffer " RING_BUFFER_MODE_TEMPLATE_STRING
 271                    " client");