ltt-ring-buffer-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/symbols.h"    /* for wrapper_vmalloc_sync_all() */
  14 #include "wrapper/trace-clock.h"
  15 #include "ltt-events.h"
  16 #include "ltt-tracer.h"
  17
  18 static const struct lib_ring_buffer_config client_config;
  19
  20 static u64 client_ring_buffer_clock_read(struct channel *chan)
  21 {
  22         return lib_ring_buffer_clock_read(chan);
  23 }
  24
  25 static
  26 size_t client_record_header_size(const struct lib_ring_buffer_config *config,
  27                                  struct channel *chan, size_t offset,
  28                                  size_t data_size,
  29                                  size_t *pre_header_padding,
  30                                  unsigned int rflags,
  31                                  struct lib_ring_buffer_ctx *ctx)
  32 {
  33         return record_header_size(config, chan, offset, data_size,
  34                                   pre_header_padding, rflags, ctx);
  35 }
  36
  37 /**
  38  * client_packet_header_size - called on buffer-switch to a new sub-buffer
  39  *
  40  * Return header size without padding after the structure. Don't use packed
  41  * structure because gcc generates inefficient code on some architectures
  42  * (powerpc, mips..)
  43  */
  44 static size_t client_packet_header_size(void)
  45 {
  46         return offsetof(struct packet_header, header_end);
  47 }
  48
  49 static void client_buffer_begin(struct lib_ring_buffer *buf, u64 tsc,
  50                                 unsigned int subbuf_idx)
  51 {
  52         struct channel *chan = buf->backend.chan;
  53         struct packet_header *header =
  54                 (struct packet_header *)
  55                         lib_ring_buffer_offset_address(&buf->backend,
  56                                 subbuf_idx * chan->backend.subbuf_size);
  57
  58         header->timestamp_begin = tsc;
  59         header->content_size = 0xFFFFFFFF; /* for debugging */
  60         write_trace_header(&client_config, header);
  61 }
  62
  63 /*
  64  * offset is assumed to never be 0 here : never deliver a completely empty
  65  * subbuffer. data_size is between 1 and subbuf_size.
  66  */
  67 static void client_buffer_end(struct lib_ring_buffer *buf, u64 tsc,
  68                               unsigned int subbuf_idx, unsigned long data_size)
  69 {
  70         struct channel *chan = buf->backend.chan;
  71         struct packet_header *header =
  72                 (struct packet_header *)
  73                         lib_ring_buffer_offset_address(&buf->backend,
  74                                 subbuf_idx * chan->backend.subbuf_size);
  75         unsigned long records_lost = 0;
  76
  77         header->content_size = data_size;
  78         header->packet_size = PAGE_ALIGN(data_size);
  79         header->timestamp_end = tsc;
  80         records_lost += lib_ring_buffer_get_records_lost_full(&client_config, buf);
  81         records_lost += lib_ring_buffer_get_records_lost_wrap(&client_config, buf);
  82         records_lost += lib_ring_buffer_get_records_lost_big(&client_config, buf);
  83         header->events_lost = records_lost;
  84 }
  85
  86 static int client_buffer_create(struct lib_ring_buffer *buf, void *priv,
  87                                 int cpu, const char *name)
  88 {
  89         return 0;
  90 }
  91
  92 static void client_buffer_finalize(struct lib_ring_buffer *buf, void *priv, int cpu)
  93 {
  94 }
  95
  96 static const struct lib_ring_buffer_config client_config = {
  97         .cb.ring_buffer_clock_read = client_ring_buffer_clock_read,
  98         .cb.record_header_size = client_record_header_size,
  99         .cb.subbuffer_header_size = client_packet_header_size,
 100         .cb.buffer_begin = client_buffer_begin,
 101         .cb.buffer_end = client_buffer_end,
 102         .cb.buffer_create = client_buffer_create,
 103         .cb.buffer_finalize = client_buffer_finalize,
 104
 105         .tsc_bits = 32,
 106         .alloc = RING_BUFFER_ALLOC_PER_CPU,
 107         .sync = RING_BUFFER_SYNC_PER_CPU,
 108         .mode = RING_BUFFER_MODE_TEMPLATE,
 109         .backend = RING_BUFFER_PAGE,
 110         .output = RING_BUFFER_SPLICE,
 111         .oops = RING_BUFFER_OOPS_CONSISTENCY,
 112         .ipi = RING_BUFFER_IPI_BARRIER,
 113         .wakeup = RING_BUFFER_WAKEUP_BY_TIMER,
 114 };
 115
 116 static
 117 struct channel *_channel_create(const char *name,
 118                                 struct ltt_session *session, void *buf_addr,
 119                                 size_t subbuf_size, size_t num_subbuf,
 120                                 unsigned int switch_timer_interval,
 121                                 unsigned int read_timer_interval)
 122 {
 123         return channel_create(&client_config, name, session, buf_addr,
 124                               subbuf_size, num_subbuf, switch_timer_interval,
 125                               read_timer_interval);
 126 }
 127
 128 static
 129 void ltt_channel_destroy(struct channel *chan)
 130 {
 131         channel_destroy(chan);
 132 }
 133
 134 static
 135 struct lib_ring_buffer *ltt_buffer_read_open(struct channel *chan)
 136 {
 137         struct lib_ring_buffer *buf;
 138         int cpu;
 139
 140         for_each_channel_cpu(cpu, chan) {
 141                 buf = channel_get_ring_buffer(&client_config, chan, cpu);
 142                 if (!lib_ring_buffer_open_read(buf))
 143                         return buf;
 144         }
 145         return NULL;
 146 }
 147
 148 static
 149 void ltt_buffer_read_close(struct lib_ring_buffer *buf)
 150 {
 151         lib_ring_buffer_release_read(buf);
 152
 153 }
 154
 155 int ltt_event_reserve(struct lib_ring_buffer_ctx *ctx)
 156 {
 157         int ret, cpu;
 158
 159         cpu = lib_ring_buffer_get_cpu(&client_config);
 160         if (cpu < 0)
 161                 return -EPERM;
 162         ctx->cpu = cpu;
 163
 164         ret = lib_ring_buffer_reserve(&client_config, ctx);
 165         if (ret)
 166                 goto put;
 167         return ret;
 168
 169 put:
 170         lib_ring_buffer_put_cpu(&client_config);
 171         return ret;
 172 }
 173
 174 void ltt_event_commit(struct lib_ring_buffer_ctx *ctx)
 175 {
 176         lib_ring_buffer_commit(&client_config, ctx);
 177         lib_ring_buffer_put_cpu(&client_config);
 178 }
 179
 180 void ltt_event_write(struct lib_ring_buffer_ctx *ctx, const void *src,
 181                      size_t len)
 182 {
 183         lib_ring_buffer_write(&client_config, ctx, src, len);
 184 }
 185
 186 static struct ltt_transport ltt_relay_transport = {
 187         .name = "relay-" RING_BUFFER_MODE_TEMPLATE_STRING,
 188         .owner = THIS_MODULE,
 189         .ops = {
 190                 .channel_create = _channel_create,
 191                 .channel_destroy = ltt_channel_destroy,
 192                 .buffer_read_open = ltt_buffer_read_open,
 193                 .buffer_read_close = ltt_buffer_read_close,
 194                 .event_reserve = ltt_event_reserve,
 195                 .event_commit = ltt_event_commit,
 196                 .event_write = ltt_event_write,
 197         },
 198 };
 199
 200 static int __init ltt_ring_buffer_client_init(void)
 201 {
 202         /*
 203          * This vmalloc sync all also takes care of the lib ring buffer
 204          * vmalloc'd module pages when it is built as a module into LTTng.
 205          */
 206         wrapper_vmalloc_sync_all();
 207         printk(KERN_INFO "LTT : ltt ring buffer client init\n");
 208         ltt_transport_register(&ltt_relay_transport);
 209         return 0;
 210 }
 211
 212 module_init(ltt_ring_buffer_client_init);
 213
 214 static void __exit ltt_ring_buffer_client_exit(void)
 215 {
 216         printk(KERN_INFO "LTT : ltt ring buffer client exit\n");
 217         ltt_transport_unregister(&ltt_relay_transport);
 218 }
 219
 220 module_exit(ltt_ring_buffer_client_exit);
 221
 222 MODULE_LICENSE("GPL and additional rights");
 223 MODULE_AUTHOR("Mathieu Desnoyers");
 224 MODULE_DESCRIPTION("LTTng ring buffer " RING_BUFFER_MODE_TEMPLATE_STRING
 225                    " client");