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 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         struct ltt_channel *ltt_chan = channel_get_private(chan);
  90         struct ltt_session *session = ltt_chan->session;
  91
  92         header->magic = TSDL_MAGIC_NUMBER;
  93         memcpy(header->uuid, session->uuid.b, sizeof(session->uuid));
  94         header->checksum = 0;           /* 0 if unused */
  95         header->content_size = 0xFFFFFFFF; /* in bits, for debugging */
  96         header->packet_size = 0xFFFFFFFF;  /* in bits, for debugging */
  97         header->compression_scheme = 0; /* 0 if unused */
  98         header->encryption_scheme = 0;  /* 0 if unused */
  99         header->checksum_scheme = 0;    /* 0 if unused */
 100 }
 101
 102 /*
 103  * offset is assumed to never be 0 here : never deliver a completely empty
 104  * subbuffer. data_size is between 1 and subbuf_size.
 105  */
 106 static void client_buffer_end(struct lib_ring_buffer *buf, u64 tsc,
 107                               unsigned int subbuf_idx, unsigned long data_size)
 108 {
 109         struct channel *chan = buf->backend.chan;
 110         struct metadata_packet_header *header =
 111                 (struct metadata_packet_header *)
 112                         lib_ring_buffer_offset_address(&buf->backend,
 113                                 subbuf_idx * chan->backend.subbuf_size);
 114         unsigned long records_lost = 0;
 115
 116         header->content_size = data_size * CHAR_BIT;            /* in bits */
 117         header->packet_size = PAGE_ALIGN(data_size) * CHAR_BIT; /* in bits */
 118         records_lost += lib_ring_buffer_get_records_lost_full(&client_config, buf);
 119         records_lost += lib_ring_buffer_get_records_lost_wrap(&client_config, buf);
 120         records_lost += lib_ring_buffer_get_records_lost_big(&client_config, buf);
 121         WARN_ON_ONCE(records_lost != 0);
 122 }
 123
 124 static int client_buffer_create(struct lib_ring_buffer *buf, void *priv,
 125                                 int cpu, const char *name)
 126 {
 127         return 0;
 128 }
 129
 130 static void client_buffer_finalize(struct lib_ring_buffer *buf, void *priv, int cpu)
 131 {
 132 }
 133
 134 static const struct lib_ring_buffer_config client_config = {
 135         .cb.ring_buffer_clock_read = client_ring_buffer_clock_read,
 136         .cb.record_header_size = client_record_header_size,
 137         .cb.subbuffer_header_size = client_packet_header_size,
 138         .cb.buffer_begin = client_buffer_begin,
 139         .cb.buffer_end = client_buffer_end,
 140         .cb.buffer_create = client_buffer_create,
 141         .cb.buffer_finalize = client_buffer_finalize,
 142
 143         .tsc_bits = 0,
 144         .alloc = RING_BUFFER_ALLOC_GLOBAL,
 145         .sync = RING_BUFFER_SYNC_GLOBAL,
 146         .mode = RING_BUFFER_MODE_TEMPLATE,
 147         .backend = RING_BUFFER_PAGE,
 148         .output = RING_BUFFER_SPLICE,
 149         .oops = RING_BUFFER_OOPS_CONSISTENCY,
 150         .ipi = RING_BUFFER_IPI_BARRIER,
 151         .wakeup = RING_BUFFER_WAKEUP_BY_TIMER,
 152 };
 153
 154 static
 155 struct channel *_channel_create(const char *name,
 156                                 struct ltt_channel *ltt_chan, void *buf_addr,
 157                                 size_t subbuf_size, size_t num_subbuf,
 158                                 unsigned int switch_timer_interval,
 159                                 unsigned int read_timer_interval)
 160 {
 161         return channel_create(&client_config, name, ltt_chan, buf_addr,
 162                               subbuf_size, num_subbuf, switch_timer_interval,
 163                               read_timer_interval);
 164 }
 165
 166 static
 167 void ltt_channel_destroy(struct channel *chan)
 168 {
 169         channel_destroy(chan);
 170 }
 171
 172 static
 173 struct lib_ring_buffer *ltt_buffer_read_open(struct channel *chan)
 174 {
 175         struct lib_ring_buffer *buf;
 176
 177         buf = channel_get_ring_buffer(&client_config, chan, 0);
 178         if (!lib_ring_buffer_open_read(buf))
 179                 return buf;
 180         return NULL;
 181 }
 182
 183 static
 184 void ltt_buffer_read_close(struct lib_ring_buffer *buf)
 185 {
 186         lib_ring_buffer_release_read(buf);
 187 }
 188
 189 static
 190 int ltt_event_reserve(struct lib_ring_buffer_ctx *ctx, uint16_t event_id)
 191 {
 192         return lib_ring_buffer_reserve(&client_config, ctx);
 193 }
 194
 195 static
 196 void ltt_event_commit(struct lib_ring_buffer_ctx *ctx)
 197 {
 198         lib_ring_buffer_commit(&client_config, ctx);
 199 }
 200
 201 static
 202 void ltt_event_write(struct lib_ring_buffer_ctx *ctx, const void *src,
 203                      size_t len)
 204 {
 205         lib_ring_buffer_write(&client_config, ctx, src, len);
 206 }
 207
 208 static
 209 size_t ltt_packet_avail_size(struct channel *chan)
 210
 211 {
 212         unsigned long o_begin;
 213         struct lib_ring_buffer *buf;
 214
 215         buf = chan->backend.buf;        /* Only for global buffer ! */
 216         o_begin = v_read(&client_config, &buf->offset);
 217         if (subbuf_offset(o_begin, chan) != 0) {
 218                 return chan->backend.subbuf_size - subbuf_offset(o_begin, chan);
 219         } else {
 220                 return chan->backend.subbuf_size - subbuf_offset(o_begin, chan)
 221                         - sizeof(struct metadata_packet_header);
 222         }
 223 }
 224
 225 static
 226 wait_queue_head_t *ltt_get_reader_wait_queue(struct ltt_channel *chan)
 227 {
 228         return &chan->chan->read_wait;
 229 }
 230
 231 static struct ltt_transport ltt_relay_transport = {
 232         .name = "relay-" RING_BUFFER_MODE_TEMPLATE_STRING,
 233         .owner = THIS_MODULE,
 234         .ops = {
 235                 .channel_create = _channel_create,
 236                 .channel_destroy = ltt_channel_destroy,
 237                 .buffer_read_open = ltt_buffer_read_open,
 238                 .buffer_read_close = ltt_buffer_read_close,
 239                 .event_reserve = ltt_event_reserve,
 240                 .event_commit = ltt_event_commit,
 241                 .event_write = ltt_event_write,
 242                 .packet_avail_size = ltt_packet_avail_size,
 243                 .get_reader_wait_queue = ltt_get_reader_wait_queue,
 244         },
 245 };
 246
 247 static int __init ltt_ring_buffer_client_init(void)
 248 {
 249         /*
 250          * This vmalloc sync all also takes care of the lib ring buffer
 251          * vmalloc'd module pages when it is built as a module into LTTng.
 252          */
 253         wrapper_vmalloc_sync_all();
 254         printk(KERN_INFO "LTT : ltt ring buffer metadata client init\n");
 255         ltt_transport_register(&ltt_relay_transport);
 256         return 0;
 257 }
 258
 259 module_init(ltt_ring_buffer_client_init);
 260
 261 static void __exit ltt_ring_buffer_client_exit(void)
 262 {
 263         printk(KERN_INFO "LTT : ltt ring buffer metadata client exit\n");
 264         ltt_transport_unregister(&ltt_relay_transport);
 265 }
 266
 267 module_exit(ltt_ring_buffer_client_exit);
 268
 269 MODULE_LICENSE("GPL and additional rights");
 270 MODULE_AUTHOR("Mathieu Desnoyers");
 271 MODULE_DESCRIPTION("LTTng ring buffer " RING_BUFFER_MODE_TEMPLATE_STRING
 272                    " client");