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 *pre_header_padding,
  61                                  struct lib_ring_buffer_ctx *ctx)
  62 {
  63         return 0;
  64 }
  65
  66 /**
  67  * client_packet_header_size - called on buffer-switch to a new sub-buffer
  68  *
  69  * Return header size without padding after the structure. Don't use packed
  70  * structure because gcc generates inefficient code on some architectures
  71  * (powerpc, mips..)
  72  */
  73 static size_t client_packet_header_size(void)
  74 {
  75         return offsetof(struct metadata_packet_header, header_end);
  76 }
  77
  78 static void client_buffer_begin(struct lib_ring_buffer *buf, u64 tsc,
  79                                 unsigned int subbuf_idx)
  80 {
  81         struct channel *chan = buf->backend.chan;
  82         struct metadata_packet_header *header =
  83                 (struct metadata_packet_header *)
  84                         lib_ring_buffer_offset_address(&buf->backend,
  85                                 subbuf_idx * chan->backend.subbuf_size);
  86         struct ltt_channel *ltt_chan = channel_get_private(chan);
  87         struct ltt_session *session = ltt_chan->session;
  88
  89         header->magic = TSDL_MAGIC_NUMBER;
  90         memcpy(header->uuid, session->uuid.b, sizeof(session->uuid));
  91         header->checksum = 0;           /* 0 if unused */
  92         header->content_size = 0xFFFFFFFF; /* in bits, for debugging */
  93         header->packet_size = 0xFFFFFFFF;  /* in bits, for debugging */
  94         header->compression_scheme = 0; /* 0 if unused */
  95         header->encryption_scheme = 0;  /* 0 if unused */
  96         header->checksum_scheme = 0;    /* 0 if unused */
  97 }
  98
  99 /*
 100  * offset is assumed to never be 0 here : never deliver a completely empty
 101  * subbuffer. data_size is between 1 and subbuf_size.
 102  */
 103 static void client_buffer_end(struct lib_ring_buffer *buf, u64 tsc,
 104                               unsigned int subbuf_idx, unsigned long data_size)
 105 {
 106         struct channel *chan = buf->backend.chan;
 107         struct metadata_packet_header *header =
 108                 (struct metadata_packet_header *)
 109                         lib_ring_buffer_offset_address(&buf->backend,
 110                                 subbuf_idx * chan->backend.subbuf_size);
 111         unsigned long records_lost = 0;
 112
 113         header->content_size = data_size * CHAR_BIT;            /* in bits */
 114         header->packet_size = PAGE_ALIGN(data_size) * CHAR_BIT; /* in bits */
 115         records_lost += lib_ring_buffer_get_records_lost_full(&client_config, buf);
 116         records_lost += lib_ring_buffer_get_records_lost_wrap(&client_config, buf);
 117         records_lost += lib_ring_buffer_get_records_lost_big(&client_config, buf);
 118         WARN_ON_ONCE(records_lost != 0);
 119 }
 120
 121 static int client_buffer_create(struct lib_ring_buffer *buf, void *priv,
 122                                 int cpu, const char *name)
 123 {
 124         return 0;
 125 }
 126
 127 static void client_buffer_finalize(struct lib_ring_buffer *buf, void *priv, int cpu)
 128 {
 129 }
 130
 131 static const struct lib_ring_buffer_config client_config = {
 132         .cb.ring_buffer_clock_read = client_ring_buffer_clock_read,
 133         .cb.record_header_size = client_record_header_size,
 134         .cb.subbuffer_header_size = client_packet_header_size,
 135         .cb.buffer_begin = client_buffer_begin,
 136         .cb.buffer_end = client_buffer_end,
 137         .cb.buffer_create = client_buffer_create,
 138         .cb.buffer_finalize = client_buffer_finalize,
 139
 140         .tsc_bits = 0,
 141         .alloc = RING_BUFFER_ALLOC_GLOBAL,
 142         .sync = RING_BUFFER_SYNC_GLOBAL,
 143         .mode = RING_BUFFER_MODE_TEMPLATE,
 144         .backend = RING_BUFFER_PAGE,
 145         .output = RING_BUFFER_OUTPUT_TEMPLATE,
 146         .oops = RING_BUFFER_OOPS_CONSISTENCY,
 147         .ipi = RING_BUFFER_IPI_BARRIER,
 148         .wakeup = RING_BUFFER_WAKEUP_BY_TIMER,
 149 };
 150
 151 static
 152 struct channel *_channel_create(const char *name,
 153                                 struct ltt_channel *ltt_chan, void *buf_addr,
 154                                 size_t subbuf_size, size_t num_subbuf,
 155                                 unsigned int switch_timer_interval,
 156                                 unsigned int read_timer_interval)
 157 {
 158         return channel_create(&client_config, name, ltt_chan, buf_addr,
 159                               subbuf_size, num_subbuf, switch_timer_interval,
 160                               read_timer_interval);
 161 }
 162
 163 static
 164 void ltt_channel_destroy(struct channel *chan)
 165 {
 166         channel_destroy(chan);
 167 }
 168
 169 static
 170 struct lib_ring_buffer *ltt_buffer_read_open(struct channel *chan)
 171 {
 172         struct lib_ring_buffer *buf;
 173
 174         buf = channel_get_ring_buffer(&client_config, chan, 0);
 175         if (!lib_ring_buffer_open_read(buf))
 176                 return buf;
 177         return NULL;
 178 }
 179
 180 static
 181 int ltt_buffer_has_read_closed_stream(struct channel *chan)
 182 {
 183         struct lib_ring_buffer *buf;
 184         int cpu;
 185
 186         for_each_channel_cpu(cpu, chan) {
 187                 buf = channel_get_ring_buffer(&client_config, chan, cpu);
 188                 if (!atomic_long_read(&buf->active_readers))
 189                         return 1;
 190         }
 191         return 0;
 192 }
 193
 194 static
 195 void ltt_buffer_read_close(struct lib_ring_buffer *buf)
 196 {
 197         lib_ring_buffer_release_read(buf);
 198 }
 199
 200 static
 201 int ltt_event_reserve(struct lib_ring_buffer_ctx *ctx, uint32_t event_id)
 202 {
 203         return lib_ring_buffer_reserve(&client_config, ctx);
 204 }
 205
 206 static
 207 void ltt_event_commit(struct lib_ring_buffer_ctx *ctx)
 208 {
 209         lib_ring_buffer_commit(&client_config, ctx);
 210 }
 211
 212 static
 213 void ltt_event_write(struct lib_ring_buffer_ctx *ctx, const void *src,
 214                      size_t len)
 215 {
 216         lib_ring_buffer_write(&client_config, ctx, src, len);
 217 }
 218
 219 static
 220 size_t ltt_packet_avail_size(struct channel *chan)
 221
 222 {
 223         unsigned long o_begin;
 224         struct lib_ring_buffer *buf;
 225
 226         buf = chan->backend.buf;        /* Only for global buffer ! */
 227         o_begin = v_read(&client_config, &buf->offset);
 228         if (subbuf_offset(o_begin, chan) != 0) {
 229                 return chan->backend.subbuf_size - subbuf_offset(o_begin, chan);
 230         } else {
 231                 return chan->backend.subbuf_size - subbuf_offset(o_begin, chan)
 232                         - sizeof(struct metadata_packet_header);
 233         }
 234 }
 235
 236 static
 237 wait_queue_head_t *ltt_get_reader_wait_queue(struct channel *chan)
 238 {
 239         return &chan->read_wait;
 240 }
 241
 242 static
 243 wait_queue_head_t *ltt_get_hp_wait_queue(struct channel *chan)
 244 {
 245         return &chan->hp_wait;
 246 }
 247
 248 static
 249 int ltt_is_finalized(struct channel *chan)
 250 {
 251         return lib_ring_buffer_channel_is_finalized(chan);
 252 }
 253
 254 static
 255 int ltt_is_disabled(struct channel *chan)
 256 {
 257         return lib_ring_buffer_channel_is_disabled(chan);
 258 }
 259
 260 static struct ltt_transport ltt_relay_transport = {
 261         .name = "relay-" RING_BUFFER_MODE_TEMPLATE_STRING,
 262         .owner = THIS_MODULE,
 263         .ops = {
 264                 .channel_create = _channel_create,
 265                 .channel_destroy = ltt_channel_destroy,
 266                 .buffer_read_open = ltt_buffer_read_open,
 267                 .buffer_has_read_closed_stream =
 268                         ltt_buffer_has_read_closed_stream,
 269                 .buffer_read_close = ltt_buffer_read_close,
 270                 .event_reserve = ltt_event_reserve,
 271                 .event_commit = ltt_event_commit,
 272                 .event_write = ltt_event_write,
 273                 .packet_avail_size = ltt_packet_avail_size,
 274                 .get_reader_wait_queue = ltt_get_reader_wait_queue,
 275                 .get_hp_wait_queue = ltt_get_hp_wait_queue,
 276                 .is_finalized = ltt_is_finalized,
 277                 .is_disabled = ltt_is_disabled,
 278         },
 279 };
 280
 281 static int __init ltt_ring_buffer_client_init(void)
 282 {
 283         /*
 284          * This vmalloc sync all also takes care of the lib ring buffer
 285          * vmalloc'd module pages when it is built as a module into LTTng.
 286          */
 287         wrapper_vmalloc_sync_all();
 288         ltt_transport_register(&ltt_relay_transport);
 289         return 0;
 290 }
 291
 292 module_init(ltt_ring_buffer_client_init);
 293
 294 static void __exit ltt_ring_buffer_client_exit(void)
 295 {
 296         ltt_transport_unregister(&ltt_relay_transport);
 297 }
 298
 299 module_exit(ltt_ring_buffer_client_exit);
 300
 301 MODULE_LICENSE("GPL and additional rights");
 302 MODULE_AUTHOR("Mathieu Desnoyers");
 303 MODULE_DESCRIPTION("LTTng ring buffer " RING_BUFFER_MODE_TEMPLATE_STRING
 304                    " client");