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  trace_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 data_size, size_t *pre_header_padding,
  45                                  unsigned int rflags,
  46                                  struct lib_ring_buffer_ctx *ctx)
  47 {
  48         return 0;
  49 }
  50
  51 #include "wrapper/ringbuffer/api.h"
  52
  53 static u64 client_ring_buffer_clock_read(struct channel *chan)
  54 {
  55         return 0;
  56 }
  57
  58 static
  59 size_t client_record_header_size(const struct lib_ring_buffer_config *config,
  60                                  struct channel *chan, size_t offset,
  61                                  size_t data_size,
  62                                  size_t *pre_header_padding,
  63                                  unsigned int rflags,
  64                                  struct lib_ring_buffer_ctx *ctx)
  65 {
  66         return 0;
  67 }
  68
  69 /**
  70  * client_packet_header_size - called on buffer-switch to a new sub-buffer
  71  *
  72  * Return header size without padding after the structure. Don't use packed
  73  * structure because gcc generates inefficient code on some architectures
  74  * (powerpc, mips..)
  75  */
  76 static size_t client_packet_header_size(void)
  77 {
  78         return offsetof(struct metadata_packet_header, header_end);
  79 }
  80
  81 static void client_buffer_begin(struct lib_ring_buffer *buf, u64 tsc,
  82                                 unsigned int subbuf_idx)
  83 {
  84         struct channel *chan = buf->backend.chan;
  85         struct metadata_packet_header *header =
  86                 (struct metadata_packet_header *)
  87                         lib_ring_buffer_offset_address(&buf->backend,
  88                                 subbuf_idx * chan->backend.subbuf_size);
  89
  90         header->magic = TSDL_MAGIC_NUMBER;
  91         /* TODO */
  92         //header->trace_uuid = ;        /* Unique Universal Identifier */
  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 packet_header *header =
 110                 (struct 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_session *session, 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, session, 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)
 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 wait_queue_head_t *ltt_get_reader_wait_queue(struct ltt_channel *chan)
 209 {
 210         return &chan->chan->read_wait;
 211 }
 212
 213 static struct ltt_transport ltt_relay_transport = {
 214         .name = "relay-" RING_BUFFER_MODE_TEMPLATE_STRING,
 215         .owner = THIS_MODULE,
 216         .ops = {
 217                 .channel_create = _channel_create,
 218                 .channel_destroy = ltt_channel_destroy,
 219                 .buffer_read_open = ltt_buffer_read_open,
 220                 .buffer_read_close = ltt_buffer_read_close,
 221                 .event_reserve = ltt_event_reserve,
 222                 .event_commit = ltt_event_commit,
 223                 .event_write = ltt_event_write,
 224                 .get_reader_wait_queue = ltt_get_reader_wait_queue,
 225         },
 226 };
 227
 228 static int __init ltt_ring_buffer_client_init(void)
 229 {
 230         /*
 231          * This vmalloc sync all also takes care of the lib ring buffer
 232          * vmalloc'd module pages when it is built as a module into LTTng.
 233          */
 234         wrapper_vmalloc_sync_all();
 235         printk(KERN_INFO "LTT : ltt ring buffer metadata client init\n");
 236         ltt_transport_register(&ltt_relay_transport);
 237         return 0;
 238 }
 239
 240 module_init(ltt_ring_buffer_client_init);
 241
 242 static void __exit ltt_ring_buffer_client_exit(void)
 243 {
 244         printk(KERN_INFO "LTT : ltt ring buffer metadata client exit\n");
 245         ltt_transport_unregister(&ltt_relay_transport);
 246 }
 247
 248 module_exit(ltt_ring_buffer_client_exit);
 249
 250 MODULE_LICENSE("GPL and additional rights");
 251 MODULE_AUTHOR("Mathieu Desnoyers");
 252 MODULE_DESCRIPTION("LTTng ring buffer " RING_BUFFER_MODE_TEMPLATE_STRING
 253                    " client");