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  major;                 /* CTF spec major version number */
  27         uint8_t  minor;                 /* CTF spec minor version number */
  28         uint8_t  header_end[0];
  29 };
  30
  31 struct metadata_record_header {
  32         uint8_t header_end[0];          /* End of header */
  33 };
  34
  35 static const struct lib_ring_buffer_config client_config;
  36
  37 static inline
  38 u64 lib_ring_buffer_clock_read(struct channel *chan)
  39 {
  40         return 0;
  41 }
  42
  43 static inline
  44 unsigned char record_header_size(const struct lib_ring_buffer_config *config,
  45                                  struct channel *chan, size_t offset,
  46                                  size_t *pre_header_padding,
  47                                  struct lib_ring_buffer_ctx *ctx)
  48 {
  49         return 0;
  50 }
  51
  52 #include "wrapper/ringbuffer/api.h"
  53
  54 static u64 client_ring_buffer_clock_read(struct channel *chan)
  55 {
  56         return 0;
  57 }
  58
  59 static
  60 size_t client_record_header_size(const struct lib_ring_buffer_config *config,
  61                                  struct channel *chan, size_t offset,
  62                                  size_t *pre_header_padding,
  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         header->major = CTF_SPEC_MAJOR;
 100         header->minor = CTF_SPEC_MINOR;
 101 }
 102
 103 /*
 104  * offset is assumed to never be 0 here : never deliver a completely empty
 105  * subbuffer. data_size is between 1 and subbuf_size.
 106  */
 107 static void client_buffer_end(struct lib_ring_buffer *buf, u64 tsc,
 108                               unsigned int subbuf_idx, unsigned long data_size)
 109 {
 110         struct channel *chan = buf->backend.chan;
 111         struct metadata_packet_header *header =
 112                 (struct metadata_packet_header *)
 113                         lib_ring_buffer_offset_address(&buf->backend,
 114                                 subbuf_idx * chan->backend.subbuf_size);
 115         unsigned long records_lost = 0;
 116
 117         header->content_size = data_size * CHAR_BIT;            /* in bits */
 118         header->packet_size = PAGE_ALIGN(data_size) * CHAR_BIT; /* in bits */
 119         records_lost += lib_ring_buffer_get_records_lost_full(&client_config, buf);
 120         records_lost += lib_ring_buffer_get_records_lost_wrap(&client_config, buf);
 121         records_lost += lib_ring_buffer_get_records_lost_big(&client_config, buf);
 122         WARN_ON_ONCE(records_lost != 0);
 123 }
 124
 125 static int client_buffer_create(struct lib_ring_buffer *buf, void *priv,
 126                                 int cpu, const char *name)
 127 {
 128         return 0;
 129 }
 130
 131 static void client_buffer_finalize(struct lib_ring_buffer *buf, void *priv, int cpu)
 132 {
 133 }
 134
 135 static const struct lib_ring_buffer_config client_config = {
 136         .cb.ring_buffer_clock_read = client_ring_buffer_clock_read,
 137         .cb.record_header_size = client_record_header_size,
 138         .cb.subbuffer_header_size = client_packet_header_size,
 139         .cb.buffer_begin = client_buffer_begin,
 140         .cb.buffer_end = client_buffer_end,
 141         .cb.buffer_create = client_buffer_create,
 142         .cb.buffer_finalize = client_buffer_finalize,
 143
 144         .tsc_bits = 0,
 145         .alloc = RING_BUFFER_ALLOC_GLOBAL,
 146         .sync = RING_BUFFER_SYNC_GLOBAL,
 147         .mode = RING_BUFFER_MODE_TEMPLATE,
 148         .backend = RING_BUFFER_PAGE,
 149         .output = RING_BUFFER_OUTPUT_TEMPLATE,
 150         .oops = RING_BUFFER_OOPS_CONSISTENCY,
 151         .ipi = RING_BUFFER_IPI_BARRIER,
 152         .wakeup = RING_BUFFER_WAKEUP_BY_TIMER,
 153 };
 154
 155 static
 156 struct channel *_channel_create(const char *name,
 157                                 struct ltt_channel *ltt_chan, void *buf_addr,
 158                                 size_t subbuf_size, size_t num_subbuf,
 159                                 unsigned int switch_timer_interval,
 160                                 unsigned int read_timer_interval)
 161 {
 162         return channel_create(&client_config, name, ltt_chan, buf_addr,
 163                               subbuf_size, num_subbuf, switch_timer_interval,
 164                               read_timer_interval);
 165 }
 166
 167 static
 168 void ltt_channel_destroy(struct channel *chan)
 169 {
 170         channel_destroy(chan);
 171 }
 172
 173 static
 174 struct lib_ring_buffer *ltt_buffer_read_open(struct channel *chan)
 175 {
 176         struct lib_ring_buffer *buf;
 177
 178         buf = channel_get_ring_buffer(&client_config, chan, 0);
 179         if (!lib_ring_buffer_open_read(buf))
 180                 return buf;
 181         return NULL;
 182 }
 183
 184 static
 185 int ltt_buffer_has_read_closed_stream(struct channel *chan)
 186 {
 187         struct lib_ring_buffer *buf;
 188         int cpu;
 189
 190         for_each_channel_cpu(cpu, chan) {
 191                 buf = channel_get_ring_buffer(&client_config, chan, cpu);
 192                 if (!atomic_long_read(&buf->active_readers))
 193                         return 1;
 194         }
 195         return 0;
 196 }
 197
 198 static
 199 void ltt_buffer_read_close(struct lib_ring_buffer *buf)
 200 {
 201         lib_ring_buffer_release_read(buf);
 202 }
 203
 204 static
 205 int ltt_event_reserve(struct lib_ring_buffer_ctx *ctx, uint32_t event_id)
 206 {
 207         return lib_ring_buffer_reserve(&client_config, ctx);
 208 }
 209
 210 static
 211 void ltt_event_commit(struct lib_ring_buffer_ctx *ctx)
 212 {
 213         lib_ring_buffer_commit(&client_config, ctx);
 214 }
 215
 216 static
 217 void ltt_event_write(struct lib_ring_buffer_ctx *ctx, const void *src,
 218                      size_t len)
 219 {
 220         lib_ring_buffer_write(&client_config, ctx, src, len);
 221 }
 222
 223 static
 224 size_t ltt_packet_avail_size(struct channel *chan)
 225
 226 {
 227         unsigned long o_begin;
 228         struct lib_ring_buffer *buf;
 229
 230         buf = chan->backend.buf;        /* Only for global buffer ! */
 231         o_begin = v_read(&client_config, &buf->offset);
 232         if (subbuf_offset(o_begin, chan) != 0) {
 233                 return chan->backend.subbuf_size - subbuf_offset(o_begin, chan);
 234         } else {
 235                 return chan->backend.subbuf_size - subbuf_offset(o_begin, chan)
 236                         - sizeof(struct metadata_packet_header);
 237         }
 238 }
 239
 240 static
 241 wait_queue_head_t *ltt_get_reader_wait_queue(struct channel *chan)
 242 {
 243         return &chan->read_wait;
 244 }
 245
 246 static
 247 wait_queue_head_t *ltt_get_hp_wait_queue(struct channel *chan)
 248 {
 249         return &chan->hp_wait;
 250 }
 251
 252 static
 253 int ltt_is_finalized(struct channel *chan)
 254 {
 255         return lib_ring_buffer_channel_is_finalized(chan);
 256 }
 257
 258 static
 259 int ltt_is_disabled(struct channel *chan)
 260 {
 261         return lib_ring_buffer_channel_is_disabled(chan);
 262 }
 263
 264 static struct ltt_transport ltt_relay_transport = {
 265         .name = "relay-" RING_BUFFER_MODE_TEMPLATE_STRING,
 266         .owner = THIS_MODULE,
 267         .ops = {
 268                 .channel_create = _channel_create,
 269                 .channel_destroy = ltt_channel_destroy,
 270                 .buffer_read_open = ltt_buffer_read_open,
 271                 .buffer_has_read_closed_stream =
 272                         ltt_buffer_has_read_closed_stream,
 273                 .buffer_read_close = ltt_buffer_read_close,
 274                 .event_reserve = ltt_event_reserve,
 275                 .event_commit = ltt_event_commit,
 276                 .event_write = ltt_event_write,
 277                 .packet_avail_size = ltt_packet_avail_size,
 278                 .get_reader_wait_queue = ltt_get_reader_wait_queue,
 279                 .get_hp_wait_queue = ltt_get_hp_wait_queue,
 280                 .is_finalized = ltt_is_finalized,
 281                 .is_disabled = ltt_is_disabled,
 282         },
 283 };
 284
 285 static int __init ltt_ring_buffer_client_init(void)
 286 {
 287         /*
 288          * This vmalloc sync all also takes care of the lib ring buffer
 289          * vmalloc'd module pages when it is built as a module into LTTng.
 290          */
 291         wrapper_vmalloc_sync_all();
 292         ltt_transport_register(&ltt_relay_transport);
 293         return 0;
 294 }
 295
 296 module_init(ltt_ring_buffer_client_init);
 297
 298 static void __exit ltt_ring_buffer_client_exit(void)
 299 {
 300         ltt_transport_unregister(&ltt_relay_transport);
 301 }
 302
 303 module_exit(ltt_ring_buffer_client_exit);
 304
 305 MODULE_LICENSE("GPL and additional rights");
 306 MODULE_AUTHOR("Mathieu Desnoyers");
 307 MODULE_DESCRIPTION("LTTng ring buffer " RING_BUFFER_MODE_TEMPLATE_STRING
 308                    " client");