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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 "lib/bitfield.h" | |
14 | #include "wrapper/vmalloc.h" /* for wrapper_vmalloc_sync_all() */ | |
15 | #include "wrapper/trace-clock.h" | |
16 | #include "ltt-events.h" | |
17 | #include "ltt-tracer.h" | |
18 | #include "wrapper/ringbuffer/frontend_types.h" | |
19 | ||
20 | /* | |
21 | * Keep the natural field alignment for _each field_ within this structure if | |
22 | * you ever add/remove a field from this header. Packed attribute is not used | |
23 | * because gcc generates poor code on at least powerpc and mips. Don't ever | |
24 | * let gcc add padding between the structure elements. | |
25 | */ | |
26 | ||
27 | struct packet_header { | |
28 | /* Trace packet header */ | |
29 | uint32_t magic; /* | |
30 | * Trace magic number. | |
31 | * contains endianness information. | |
32 | */ | |
33 | uint8_t uuid[16]; | |
34 | uint32_t stream_id; | |
35 | ||
36 | struct { | |
37 | /* Stream packet context */ | |
38 | uint64_t timestamp_begin; /* Cycle count at subbuffer start */ | |
39 | uint64_t timestamp_end; /* Cycle count at subbuffer end */ | |
40 | uint32_t events_discarded; /* | |
41 | * Events lost in this subbuffer since | |
42 | * the beginning of the trace. | |
43 | * (may overflow) | |
44 | */ | |
45 | uint32_t content_size; /* Size of data in subbuffer */ | |
46 | uint32_t packet_size; /* Subbuffer size (include padding) */ | |
47 | uint32_t cpu_id; /* CPU id associated with stream */ | |
48 | uint8_t header_end; /* End of header */ | |
49 | } ctx; | |
50 | }; | |
51 | ||
52 | ||
53 | static inline notrace u64 lib_ring_buffer_clock_read(struct channel *chan) | |
54 | { | |
55 | return trace_clock_read64(); | |
56 | } | |
57 | ||
58 | static inline | |
59 | size_t ctx_get_size(size_t offset, struct lttng_ctx *ctx) | |
60 | { | |
61 | int i; | |
62 | size_t orig_offset = offset; | |
63 | ||
64 | if (likely(!ctx)) | |
65 | return 0; | |
66 | for (i = 0; i < ctx->nr_fields; i++) | |
67 | offset += ctx->fields[i].get_size(offset); | |
68 | return offset - orig_offset; | |
69 | } | |
70 | ||
71 | static inline | |
72 | void ctx_record(struct lib_ring_buffer_ctx *bufctx, | |
73 | struct ltt_channel *chan, | |
74 | struct lttng_ctx *ctx) | |
75 | { | |
76 | int i; | |
77 | ||
78 | if (likely(!ctx)) | |
79 | return; | |
80 | for (i = 0; i < ctx->nr_fields; i++) | |
81 | ctx->fields[i].record(&ctx->fields[i], bufctx, chan); | |
82 | } | |
83 | ||
84 | /* | |
85 | * record_header_size - Calculate the header size and padding necessary. | |
86 | * @config: ring buffer instance configuration | |
87 | * @chan: channel | |
88 | * @offset: offset in the write buffer | |
89 | * @pre_header_padding: padding to add before the header (output) | |
90 | * @ctx: reservation context | |
91 | * | |
92 | * Returns the event header size (including padding). | |
93 | * | |
94 | * The payload must itself determine its own alignment from the biggest type it | |
95 | * contains. | |
96 | */ | |
97 | static __inline__ | |
98 | unsigned char record_header_size(const struct lib_ring_buffer_config *config, | |
99 | struct channel *chan, size_t offset, | |
100 | size_t *pre_header_padding, | |
101 | struct lib_ring_buffer_ctx *ctx) | |
102 | { | |
103 | struct ltt_channel *ltt_chan = channel_get_private(chan); | |
104 | struct ltt_event *event = ctx->priv; | |
105 | size_t orig_offset = offset; | |
106 | size_t padding; | |
107 | ||
108 | switch (ltt_chan->header_type) { | |
109 | case 1: /* compact */ | |
110 | padding = lib_ring_buffer_align(offset, ltt_alignof(uint32_t)); | |
111 | offset += padding; | |
112 | if (!(ctx->rflags & (RING_BUFFER_RFLAG_FULL_TSC | LTT_RFLAG_EXTENDED))) { | |
113 | offset += sizeof(uint32_t); /* id and timestamp */ | |
114 | } else { | |
115 | /* Minimum space taken by 5-bit id */ | |
116 | offset += sizeof(uint8_t); | |
117 | /* Align extended struct on largest member */ | |
118 | offset += lib_ring_buffer_align(offset, ltt_alignof(uint64_t)); | |
119 | offset += sizeof(uint32_t); /* id */ | |
120 | offset += lib_ring_buffer_align(offset, ltt_alignof(uint64_t)); | |
121 | offset += sizeof(uint64_t); /* timestamp */ | |
122 | } | |
123 | break; | |
124 | case 2: /* large */ | |
125 | padding = lib_ring_buffer_align(offset, ltt_alignof(uint16_t)); | |
126 | offset += padding; | |
127 | offset += sizeof(uint16_t); | |
128 | if (!(ctx->rflags & (RING_BUFFER_RFLAG_FULL_TSC | LTT_RFLAG_EXTENDED))) { | |
129 | offset += lib_ring_buffer_align(offset, ltt_alignof(uint32_t)); | |
130 | offset += sizeof(uint32_t); /* timestamp */ | |
131 | } else { | |
132 | /* Align extended struct on largest member */ | |
133 | offset += lib_ring_buffer_align(offset, ltt_alignof(uint64_t)); | |
134 | offset += sizeof(uint32_t); /* id */ | |
135 | offset += lib_ring_buffer_align(offset, ltt_alignof(uint64_t)); | |
136 | offset += sizeof(uint64_t); /* timestamp */ | |
137 | } | |
138 | break; | |
139 | default: | |
140 | WARN_ON_ONCE(1); | |
141 | } | |
142 | offset += ctx_get_size(offset, event->ctx); | |
143 | offset += ctx_get_size(offset, ltt_chan->ctx); | |
144 | ||
145 | *pre_header_padding = padding; | |
146 | return offset - orig_offset; | |
147 | } | |
148 | ||
149 | #include "wrapper/ringbuffer/api.h" | |
150 | ||
151 | extern | |
152 | void ltt_write_event_header_slow(const struct lib_ring_buffer_config *config, | |
153 | struct lib_ring_buffer_ctx *ctx, | |
154 | uint32_t event_id); | |
155 | ||
156 | /* | |
157 | * ltt_write_event_header | |
158 | * | |
159 | * Writes the event header to the offset (already aligned on 32-bits). | |
160 | * | |
161 | * @config: ring buffer instance configuration | |
162 | * @ctx: reservation context | |
163 | * @event_id: event ID | |
164 | */ | |
165 | static __inline__ | |
166 | void ltt_write_event_header(const struct lib_ring_buffer_config *config, | |
167 | struct lib_ring_buffer_ctx *ctx, | |
168 | uint32_t event_id) | |
169 | { | |
170 | struct ltt_channel *ltt_chan = channel_get_private(ctx->chan); | |
171 | struct ltt_event *event = ctx->priv; | |
172 | ||
173 | if (unlikely(ctx->rflags)) | |
174 | goto slow_path; | |
175 | ||
176 | switch (ltt_chan->header_type) { | |
177 | case 1: /* compact */ | |
178 | { | |
179 | uint32_t id_time = 0; | |
180 | ||
181 | bt_bitfield_write(&id_time, uint32_t, 0, 5, event_id); | |
182 | bt_bitfield_write(&id_time, uint32_t, 5, 27, ctx->tsc); | |
183 | lib_ring_buffer_write(config, ctx, &id_time, sizeof(id_time)); | |
184 | break; | |
185 | } | |
186 | case 2: /* large */ | |
187 | { | |
188 | uint32_t timestamp = (uint32_t) ctx->tsc; | |
189 | uint16_t id = event_id; | |
190 | ||
191 | lib_ring_buffer_write(config, ctx, &id, sizeof(id)); | |
192 | lib_ring_buffer_align_ctx(ctx, ltt_alignof(uint32_t)); | |
193 | lib_ring_buffer_write(config, ctx, ×tamp, sizeof(timestamp)); | |
194 | break; | |
195 | } | |
196 | default: | |
197 | WARN_ON_ONCE(1); | |
198 | } | |
199 | ||
200 | ctx_record(ctx, ltt_chan, event->ctx); | |
201 | ctx_record(ctx, ltt_chan, ltt_chan->ctx); | |
202 | ||
203 | return; | |
204 | ||
205 | slow_path: | |
206 | ltt_write_event_header_slow(config, ctx, event_id); | |
207 | } | |
208 | ||
209 | void ltt_write_event_header_slow(const struct lib_ring_buffer_config *config, | |
210 | struct lib_ring_buffer_ctx *ctx, | |
211 | uint32_t event_id) | |
212 | { | |
213 | struct ltt_channel *ltt_chan = channel_get_private(ctx->chan); | |
214 | struct ltt_event *event = ctx->priv; | |
215 | ||
216 | switch (ltt_chan->header_type) { | |
217 | case 1: /* compact */ | |
218 | if (!(ctx->rflags & (RING_BUFFER_RFLAG_FULL_TSC | LTT_RFLAG_EXTENDED))) { | |
219 | uint32_t id_time = 0; | |
220 | ||
221 | bt_bitfield_write(&id_time, uint32_t, 0, 5, event_id); | |
222 | bt_bitfield_write(&id_time, uint32_t, 5, 27, ctx->tsc); | |
223 | lib_ring_buffer_write(config, ctx, &id_time, sizeof(id_time)); | |
224 | } else { | |
225 | uint8_t id = 0; | |
226 | uint64_t timestamp = ctx->tsc; | |
227 | ||
228 | bt_bitfield_write(&id, uint8_t, 0, 5, 31); | |
229 | lib_ring_buffer_write(config, ctx, &id, sizeof(id)); | |
230 | /* Align extended struct on largest member */ | |
231 | lib_ring_buffer_align_ctx(ctx, ltt_alignof(uint64_t)); | |
232 | lib_ring_buffer_write(config, ctx, &event_id, sizeof(event_id)); | |
233 | lib_ring_buffer_align_ctx(ctx, ltt_alignof(uint64_t)); | |
234 | lib_ring_buffer_write(config, ctx, ×tamp, sizeof(timestamp)); | |
235 | } | |
236 | break; | |
237 | case 2: /* large */ | |
238 | { | |
239 | if (!(ctx->rflags & (RING_BUFFER_RFLAG_FULL_TSC | LTT_RFLAG_EXTENDED))) { | |
240 | uint32_t timestamp = (uint32_t) ctx->tsc; | |
241 | uint16_t id = event_id; | |
242 | ||
243 | lib_ring_buffer_write(config, ctx, &id, sizeof(id)); | |
244 | lib_ring_buffer_align_ctx(ctx, ltt_alignof(uint32_t)); | |
245 | lib_ring_buffer_write(config, ctx, ×tamp, sizeof(timestamp)); | |
246 | } else { | |
247 | uint16_t id = 65535; | |
248 | uint64_t timestamp = ctx->tsc; | |
249 | ||
250 | lib_ring_buffer_write(config, ctx, &id, sizeof(id)); | |
251 | /* Align extended struct on largest member */ | |
252 | lib_ring_buffer_align_ctx(ctx, ltt_alignof(uint64_t)); | |
253 | lib_ring_buffer_write(config, ctx, &event_id, sizeof(event_id)); | |
254 | lib_ring_buffer_align_ctx(ctx, ltt_alignof(uint64_t)); | |
255 | lib_ring_buffer_write(config, ctx, ×tamp, sizeof(timestamp)); | |
256 | } | |
257 | break; | |
258 | } | |
259 | default: | |
260 | WARN_ON_ONCE(1); | |
261 | } | |
262 | ctx_record(ctx, ltt_chan, event->ctx); | |
263 | ctx_record(ctx, ltt_chan, ltt_chan->ctx); | |
264 | } | |
265 | ||
266 | static const struct lib_ring_buffer_config client_config; | |
267 | ||
268 | static u64 client_ring_buffer_clock_read(struct channel *chan) | |
269 | { | |
270 | return lib_ring_buffer_clock_read(chan); | |
271 | } | |
272 | ||
273 | static | |
274 | size_t client_record_header_size(const struct lib_ring_buffer_config *config, | |
275 | struct channel *chan, size_t offset, | |
276 | size_t *pre_header_padding, | |
277 | struct lib_ring_buffer_ctx *ctx) | |
278 | { | |
279 | return record_header_size(config, chan, offset, | |
280 | pre_header_padding, ctx); | |
281 | } | |
282 | ||
283 | /** | |
284 | * client_packet_header_size - called on buffer-switch to a new sub-buffer | |
285 | * | |
286 | * Return header size without padding after the structure. Don't use packed | |
287 | * structure because gcc generates inefficient code on some architectures | |
288 | * (powerpc, mips..) | |
289 | */ | |
290 | static size_t client_packet_header_size(void) | |
291 | { | |
292 | return offsetof(struct packet_header, ctx.header_end); | |
293 | } | |
294 | ||
295 | static void client_buffer_begin(struct lib_ring_buffer *buf, u64 tsc, | |
296 | unsigned int subbuf_idx) | |
297 | { | |
298 | struct channel *chan = buf->backend.chan; | |
299 | struct packet_header *header = | |
300 | (struct packet_header *) | |
301 | lib_ring_buffer_offset_address(&buf->backend, | |
302 | subbuf_idx * chan->backend.subbuf_size); | |
303 | struct ltt_channel *ltt_chan = channel_get_private(chan); | |
304 | struct ltt_session *session = ltt_chan->session; | |
305 | ||
306 | header->magic = CTF_MAGIC_NUMBER; | |
307 | memcpy(header->uuid, session->uuid.b, sizeof(session->uuid)); | |
308 | header->stream_id = ltt_chan->id; | |
309 | header->ctx.timestamp_begin = tsc; | |
310 | header->ctx.timestamp_end = 0; | |
311 | header->ctx.events_discarded = 0; | |
312 | header->ctx.content_size = 0xFFFFFFFF; /* for debugging */ | |
313 | header->ctx.packet_size = 0xFFFFFFFF; | |
314 | header->ctx.cpu_id = buf->backend.cpu; | |
315 | } | |
316 | ||
317 | /* | |
318 | * offset is assumed to never be 0 here : never deliver a completely empty | |
319 | * subbuffer. data_size is between 1 and subbuf_size. | |
320 | */ | |
321 | static void client_buffer_end(struct lib_ring_buffer *buf, u64 tsc, | |
322 | unsigned int subbuf_idx, unsigned long data_size) | |
323 | { | |
324 | struct channel *chan = buf->backend.chan; | |
325 | struct packet_header *header = | |
326 | (struct packet_header *) | |
327 | lib_ring_buffer_offset_address(&buf->backend, | |
328 | subbuf_idx * chan->backend.subbuf_size); | |
329 | unsigned long records_lost = 0; | |
330 | ||
331 | header->ctx.timestamp_end = tsc; | |
332 | header->ctx.content_size = data_size * CHAR_BIT; /* in bits */ | |
333 | header->ctx.packet_size = PAGE_ALIGN(data_size) * CHAR_BIT; /* in bits */ | |
334 | records_lost += lib_ring_buffer_get_records_lost_full(&client_config, buf); | |
335 | records_lost += lib_ring_buffer_get_records_lost_wrap(&client_config, buf); | |
336 | records_lost += lib_ring_buffer_get_records_lost_big(&client_config, buf); | |
337 | header->ctx.events_discarded = records_lost; | |
338 | } | |
339 | ||
340 | static int client_buffer_create(struct lib_ring_buffer *buf, void *priv, | |
341 | int cpu, const char *name) | |
342 | { | |
343 | return 0; | |
344 | } | |
345 | ||
346 | static void client_buffer_finalize(struct lib_ring_buffer *buf, void *priv, int cpu) | |
347 | { | |
348 | } | |
349 | ||
350 | static const struct lib_ring_buffer_config client_config = { | |
351 | .cb.ring_buffer_clock_read = client_ring_buffer_clock_read, | |
352 | .cb.record_header_size = client_record_header_size, | |
353 | .cb.subbuffer_header_size = client_packet_header_size, | |
354 | .cb.buffer_begin = client_buffer_begin, | |
355 | .cb.buffer_end = client_buffer_end, | |
356 | .cb.buffer_create = client_buffer_create, | |
357 | .cb.buffer_finalize = client_buffer_finalize, | |
358 | ||
359 | .tsc_bits = 32, | |
360 | .alloc = RING_BUFFER_ALLOC_PER_CPU, | |
361 | .sync = RING_BUFFER_SYNC_PER_CPU, | |
362 | .mode = RING_BUFFER_MODE_TEMPLATE, | |
363 | .backend = RING_BUFFER_PAGE, | |
364 | .output = RING_BUFFER_SPLICE, | |
365 | .oops = RING_BUFFER_OOPS_CONSISTENCY, | |
366 | .ipi = RING_BUFFER_IPI_BARRIER, | |
367 | .wakeup = RING_BUFFER_WAKEUP_BY_TIMER, | |
368 | }; | |
369 | ||
370 | static | |
371 | struct channel *_channel_create(const char *name, | |
372 | struct ltt_channel *ltt_chan, void *buf_addr, | |
373 | size_t subbuf_size, size_t num_subbuf, | |
374 | unsigned int switch_timer_interval, | |
375 | unsigned int read_timer_interval) | |
376 | { | |
377 | return channel_create(&client_config, name, ltt_chan, buf_addr, | |
378 | subbuf_size, num_subbuf, switch_timer_interval, | |
379 | read_timer_interval); | |
380 | } | |
381 | ||
382 | static | |
383 | void ltt_channel_destroy(struct channel *chan) | |
384 | { | |
385 | channel_destroy(chan); | |
386 | } | |
387 | ||
388 | static | |
389 | struct lib_ring_buffer *ltt_buffer_read_open(struct channel *chan) | |
390 | { | |
391 | struct lib_ring_buffer *buf; | |
392 | int cpu; | |
393 | ||
394 | for_each_channel_cpu(cpu, chan) { | |
395 | buf = channel_get_ring_buffer(&client_config, chan, cpu); | |
396 | if (!lib_ring_buffer_open_read(buf)) | |
397 | return buf; | |
398 | } | |
399 | return NULL; | |
400 | } | |
401 | ||
402 | static | |
403 | void ltt_buffer_read_close(struct lib_ring_buffer *buf) | |
404 | { | |
405 | lib_ring_buffer_release_read(buf); | |
406 | } | |
407 | ||
408 | static | |
409 | int ltt_event_reserve(struct lib_ring_buffer_ctx *ctx, | |
410 | uint32_t event_id) | |
411 | { | |
412 | struct ltt_channel *ltt_chan = channel_get_private(ctx->chan); | |
413 | int ret, cpu; | |
414 | ||
415 | cpu = lib_ring_buffer_get_cpu(&client_config); | |
416 | if (cpu < 0) | |
417 | return -EPERM; | |
418 | ctx->cpu = cpu; | |
419 | ||
420 | switch (ltt_chan->header_type) { | |
421 | case 1: /* compact */ | |
422 | if (event_id > 30) | |
423 | ctx->rflags |= LTT_RFLAG_EXTENDED; | |
424 | break; | |
425 | case 2: /* large */ | |
426 | if (event_id > 65534) | |
427 | ctx->rflags |= LTT_RFLAG_EXTENDED; | |
428 | break; | |
429 | default: | |
430 | WARN_ON_ONCE(1); | |
431 | } | |
432 | ||
433 | ret = lib_ring_buffer_reserve(&client_config, ctx); | |
434 | if (ret) | |
435 | goto put; | |
436 | ltt_write_event_header(&client_config, ctx, event_id); | |
437 | return 0; | |
438 | put: | |
439 | lib_ring_buffer_put_cpu(&client_config); | |
440 | return ret; | |
441 | } | |
442 | ||
443 | static | |
444 | void ltt_event_commit(struct lib_ring_buffer_ctx *ctx) | |
445 | { | |
446 | lib_ring_buffer_commit(&client_config, ctx); | |
447 | lib_ring_buffer_put_cpu(&client_config); | |
448 | } | |
449 | ||
450 | static | |
451 | void ltt_event_write(struct lib_ring_buffer_ctx *ctx, const void *src, | |
452 | size_t len) | |
453 | { | |
454 | lib_ring_buffer_write(&client_config, ctx, src, len); | |
455 | } | |
456 | ||
457 | static | |
458 | wait_queue_head_t *ltt_get_reader_wait_queue(struct channel *chan) | |
459 | { | |
460 | return &chan->read_wait; | |
461 | } | |
462 | ||
463 | static | |
464 | wait_queue_head_t *ltt_get_hp_wait_queue(struct channel *chan) | |
465 | { | |
466 | return &chan->hp_wait; | |
467 | } | |
468 | ||
469 | static | |
470 | int ltt_is_finalized(struct channel *chan) | |
471 | { | |
472 | return lib_ring_buffer_channel_is_finalized(chan); | |
473 | } | |
474 | ||
475 | static | |
476 | int ltt_is_disabled(struct channel *chan) | |
477 | { | |
478 | return lib_ring_buffer_channel_is_disabled(chan); | |
479 | } | |
480 | ||
481 | static struct ltt_transport ltt_relay_transport = { | |
482 | .name = "relay-" RING_BUFFER_MODE_TEMPLATE_STRING, | |
483 | .owner = THIS_MODULE, | |
484 | .ops = { | |
485 | .channel_create = _channel_create, | |
486 | .channel_destroy = ltt_channel_destroy, | |
487 | .buffer_read_open = ltt_buffer_read_open, | |
488 | .buffer_read_close = ltt_buffer_read_close, | |
489 | .event_reserve = ltt_event_reserve, | |
490 | .event_commit = ltt_event_commit, | |
491 | .event_write = ltt_event_write, | |
492 | .packet_avail_size = NULL, /* Would be racy anyway */ | |
493 | .get_reader_wait_queue = ltt_get_reader_wait_queue, | |
494 | .get_hp_wait_queue = ltt_get_hp_wait_queue, | |
495 | .is_finalized = ltt_is_finalized, | |
496 | .is_disabled = ltt_is_disabled, | |
497 | }, | |
498 | }; | |
499 | ||
500 | static int __init ltt_ring_buffer_client_init(void) | |
501 | { | |
502 | /* | |
503 | * This vmalloc sync all also takes care of the lib ring buffer | |
504 | * vmalloc'd module pages when it is built as a module into LTTng. | |
505 | */ | |
506 | wrapper_vmalloc_sync_all(); | |
507 | printk(KERN_INFO "LTT : ltt ring buffer client init\n"); | |
508 | ltt_transport_register(<t_relay_transport); | |
509 | return 0; | |
510 | } | |
511 | ||
512 | module_init(ltt_ring_buffer_client_init); | |
513 | ||
514 | static void __exit ltt_ring_buffer_client_exit(void) | |
515 | { | |
516 | printk(KERN_INFO "LTT : ltt ring buffer client exit\n"); | |
517 | ltt_transport_unregister(<t_relay_transport); | |
518 | } | |
519 | ||
520 | module_exit(ltt_ring_buffer_client_exit); | |
521 | ||
522 | MODULE_LICENSE("GPL and additional rights"); | |
523 | MODULE_AUTHOR("Mathieu Desnoyers"); | |
524 | MODULE_DESCRIPTION("LTTng ring buffer " RING_BUFFER_MODE_TEMPLATE_STRING | |
525 | " client"); |