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b5b073e2 PMF |
1 | /* |
2 | * buffers.c | |
3 | * LTTng userspace tracer buffering system | |
4 | * | |
5 | * Copyright (C) 2009 - Pierre-Marc Fournier (pierre-marc dot fournier at polymtl dot ca) | |
6 | * Copyright (C) 2008 - Mathieu Desnoyers (mathieu.desnoyers@polymtl.ca) | |
7 | * | |
8 | * This library is free software; you can redistribute it and/or | |
9 | * modify it under the terms of the GNU Lesser General Public | |
10 | * License as published by the Free Software Foundation; either | |
11 | * version 2.1 of the License, or (at your option) any later version. | |
12 | * | |
13 | * This library is distributed in the hope that it will be useful, | |
14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
16 | * Lesser General Public License for more details. | |
17 | * | |
18 | * You should have received a copy of the GNU Lesser General Public | |
19 | * License along with this library; if not, write to the Free Software | |
20 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
21 | */ | |
22 | ||
204141ee | 23 | #include <unistd.h> |
b5b073e2 PMF |
24 | #include <sys/mman.h> |
25 | #include <sys/ipc.h> | |
26 | #include <sys/shm.h> | |
27 | #include <fcntl.h> | |
28 | #include <ust/kernelcompat.h> | |
29 | #include <kcompat/kref.h> | |
30 | #include "buffers.h" | |
31 | #include "channels.h" | |
32 | #include "tracer.h" | |
33 | #include "tracercore.h" | |
34 | #include "usterr.h" | |
35 | ||
b73a4c47 PMF |
36 | struct ltt_reserve_switch_offsets { |
37 | long begin, end, old; | |
38 | long begin_switch, end_switch_current, end_switch_old; | |
39 | size_t before_hdr_pad, size; | |
40 | }; | |
41 | ||
42 | ||
b5b073e2 PMF |
43 | static DEFINE_MUTEX(ust_buffers_channels_mutex); |
44 | static LIST_HEAD(ust_buffers_channels); | |
45 | ||
204141ee PMF |
46 | static int get_n_cpus(void) |
47 | { | |
48 | int result; | |
49 | static int n_cpus = 0; | |
50 | ||
51 | if(n_cpus) { | |
52 | return n_cpus; | |
53 | } | |
54 | ||
a0243ab1 PMF |
55 | /* On Linux, when some processors are offline |
56 | * _SC_NPROCESSORS_CONF counts the offline | |
57 | * processors, whereas _SC_NPROCESSORS_ONLN | |
58 | * does not. If we used _SC_NPROCESSORS_ONLN, | |
59 | * getcpu() could return a value greater than | |
60 | * this sysconf, in which case the arrays | |
61 | * indexed by processor would overflow. | |
62 | */ | |
63 | result = sysconf(_SC_NPROCESSORS_CONF); | |
204141ee PMF |
64 | if(result == -1) { |
65 | return -1; | |
66 | } | |
67 | ||
68 | n_cpus = result; | |
69 | ||
70 | return result; | |
71 | } | |
72 | ||
b73a4c47 PMF |
73 | /* _ust_buffers_write() |
74 | * | |
75 | * @buf: destination buffer | |
76 | * @offset: offset in destination | |
77 | * @src: source buffer | |
78 | * @len: length of source | |
79 | * @cpy: already copied | |
80 | */ | |
81 | ||
82 | void _ust_buffers_write(struct ust_buffer *buf, size_t offset, | |
83 | const void *src, size_t len, ssize_t cpy) | |
84 | { | |
85 | do { | |
86 | len -= cpy; | |
87 | src += cpy; | |
88 | offset += cpy; | |
89 | ||
90 | WARN_ON(offset >= buf->buf_size); | |
91 | ||
92 | cpy = min_t(size_t, len, buf->buf_size - offset); | |
93 | ust_buffers_do_copy(buf->buf_data + offset, src, cpy); | |
94 | } while (unlikely(len != cpy)); | |
95 | } | |
96 | ||
97 | static int ust_buffers_init_buffer(struct ust_trace *trace, | |
b5b073e2 PMF |
98 | struct ust_channel *ltt_chan, |
99 | struct ust_buffer *buf, | |
100 | unsigned int n_subbufs); | |
101 | ||
102 | static int ust_buffers_alloc_buf(struct ust_buffer *buf, size_t *size) | |
103 | { | |
104 | void *ptr; | |
105 | int result; | |
106 | ||
107 | *size = PAGE_ALIGN(*size); | |
108 | ||
109 | result = buf->shmid = shmget(getpid(), *size, IPC_CREAT | IPC_EXCL | 0700); | |
110 | if(result == -1 && errno == EINVAL) { | |
111 | ERR("shmget() returned EINVAL; maybe /proc/sys/kernel/shmmax should be increased."); | |
112 | return -1; | |
113 | } | |
114 | else if(result == -1) { | |
115 | PERROR("shmget"); | |
116 | return -1; | |
117 | } | |
118 | ||
204141ee | 119 | /* FIXME: should have matching call to shmdt */ |
b5b073e2 PMF |
120 | ptr = shmat(buf->shmid, NULL, 0); |
121 | if(ptr == (void *) -1) { | |
122 | perror("shmat"); | |
123 | goto destroy_shmem; | |
124 | } | |
125 | ||
126 | /* Already mark the shared memory for destruction. This will occur only | |
127 | * when all users have detached. | |
128 | */ | |
129 | result = shmctl(buf->shmid, IPC_RMID, NULL); | |
130 | if(result == -1) { | |
131 | perror("shmctl"); | |
132 | return -1; | |
133 | } | |
134 | ||
135 | buf->buf_data = ptr; | |
136 | buf->buf_size = *size; | |
137 | ||
138 | return 0; | |
139 | ||
140 | destroy_shmem: | |
141 | result = shmctl(buf->shmid, IPC_RMID, NULL); | |
142 | if(result == -1) { | |
143 | perror("shmctl"); | |
144 | } | |
145 | ||
146 | return -1; | |
147 | } | |
148 | ||
204141ee | 149 | int ust_buffers_create_buf(struct ust_channel *channel, int cpu) |
b5b073e2 PMF |
150 | { |
151 | int result; | |
204141ee | 152 | struct ust_buffer *buf = channel->buf[cpu]; |
b5b073e2 | 153 | |
204141ee PMF |
154 | buf->cpu = cpu; |
155 | result = ust_buffers_alloc_buf(buf, &channel->alloc_size); | |
b5b073e2 | 156 | if(result) |
204141ee | 157 | return -1; |
b5b073e2 | 158 | |
204141ee | 159 | buf->chan = channel; |
b5b073e2 | 160 | kref_get(&channel->kref); |
204141ee | 161 | return 0; |
b5b073e2 PMF |
162 | } |
163 | ||
164 | static void ust_buffers_destroy_channel(struct kref *kref) | |
165 | { | |
166 | struct ust_channel *chan = container_of(kref, struct ust_channel, kref); | |
167 | free(chan); | |
168 | } | |
169 | ||
170 | static void ust_buffers_destroy_buf(struct ust_buffer *buf) | |
171 | { | |
172 | struct ust_channel *chan = buf->chan; | |
173 | int result; | |
174 | ||
175 | result = munmap(buf->buf_data, buf->buf_size); | |
176 | if(result == -1) { | |
177 | PERROR("munmap"); | |
178 | } | |
179 | ||
204141ee | 180 | //ust// chan->buf[buf->cpu] = NULL; |
b5b073e2 PMF |
181 | free(buf); |
182 | kref_put(&chan->kref, ust_buffers_destroy_channel); | |
183 | } | |
184 | ||
185 | /* called from kref_put */ | |
186 | static void ust_buffers_remove_buf(struct kref *kref) | |
187 | { | |
188 | struct ust_buffer *buf = container_of(kref, struct ust_buffer, kref); | |
189 | ust_buffers_destroy_buf(buf); | |
190 | } | |
191 | ||
204141ee | 192 | int ust_buffers_open_buf(struct ust_channel *chan, int cpu) |
b5b073e2 | 193 | { |
204141ee | 194 | int result; |
b5b073e2 | 195 | |
204141ee PMF |
196 | result = ust_buffers_create_buf(chan, cpu); |
197 | if (result == -1) | |
198 | return -1; | |
b5b073e2 | 199 | |
204141ee | 200 | kref_init(&chan->buf[cpu]->kref); |
b5b073e2 | 201 | |
204141ee PMF |
202 | result = ust_buffers_init_buffer(chan->trace, chan, chan->buf[cpu], chan->subbuf_cnt); |
203 | if(result == -1) | |
204 | return -1; | |
b5b073e2 | 205 | |
204141ee | 206 | return 0; |
b5b073e2 PMF |
207 | |
208 | /* FIXME: decrementally destroy on error? */ | |
209 | } | |
210 | ||
211 | /** | |
212 | * ust_buffers_close_buf - close a channel buffer | |
213 | * @buf: buffer | |
214 | */ | |
215 | static void ust_buffers_close_buf(struct ust_buffer *buf) | |
216 | { | |
217 | kref_put(&buf->kref, ust_buffers_remove_buf); | |
218 | } | |
219 | ||
220 | int ust_buffers_channel_open(struct ust_channel *chan, size_t subbuf_size, size_t subbuf_cnt) | |
221 | { | |
204141ee PMF |
222 | int i; |
223 | int result; | |
224 | ||
b5b073e2 PMF |
225 | if(subbuf_size == 0 || subbuf_cnt == 0) |
226 | return -1; | |
227 | ||
b73a4c47 PMF |
228 | /* Check that the subbuffer size is larger than a page. */ |
229 | WARN_ON_ONCE(subbuf_size < PAGE_SIZE); | |
230 | ||
231 | /* | |
232 | * Make sure the number of subbuffers and subbuffer size are power of 2. | |
233 | */ | |
234 | WARN_ON_ONCE(hweight32(subbuf_size) != 1); | |
235 | WARN_ON(hweight32(subbuf_cnt) != 1); | |
236 | ||
b5b073e2 PMF |
237 | chan->version = UST_CHANNEL_VERSION; |
238 | chan->subbuf_cnt = subbuf_cnt; | |
239 | chan->subbuf_size = subbuf_size; | |
240 | chan->subbuf_size_order = get_count_order(subbuf_size); | |
b73a4c47 | 241 | chan->alloc_size = subbuf_size * subbuf_cnt; |
204141ee | 242 | |
b5b073e2 PMF |
243 | kref_init(&chan->kref); |
244 | ||
245 | mutex_lock(&ust_buffers_channels_mutex); | |
204141ee PMF |
246 | for(i=0; i<chan->n_cpus; i++) { |
247 | result = ust_buffers_open_buf(chan, i); | |
248 | if (result == -1) | |
249 | goto error; | |
250 | } | |
b5b073e2 PMF |
251 | list_add(&chan->list, &ust_buffers_channels); |
252 | mutex_unlock(&ust_buffers_channels_mutex); | |
253 | ||
254 | return 0; | |
255 | ||
204141ee PMF |
256 | /* Jump directly inside the loop to close the buffers that were already |
257 | * opened. */ | |
258 | for(; i>=0; i--) { | |
259 | ust_buffers_close_buf(chan->buf[i]); | |
260 | error: | |
120b0ec3 | 261 | do {} while(0); |
204141ee PMF |
262 | } |
263 | ||
b5b073e2 PMF |
264 | kref_put(&chan->kref, ust_buffers_destroy_channel); |
265 | mutex_unlock(&ust_buffers_channels_mutex); | |
266 | return -1; | |
267 | } | |
268 | ||
269 | void ust_buffers_channel_close(struct ust_channel *chan) | |
270 | { | |
204141ee PMF |
271 | int i; |
272 | if(!chan) | |
b5b073e2 PMF |
273 | return; |
274 | ||
275 | mutex_lock(&ust_buffers_channels_mutex); | |
204141ee PMF |
276 | for(i=0; i<chan->n_cpus; i++) { |
277 | /* FIXME: if we make it here, then all buffers were necessarily allocated. Moreover, we don't | |
278 | * initialize to NULL so we cannot use this check. Should we? */ | |
279 | //ust// if (chan->buf[i]) | |
280 | ust_buffers_close_buf(chan->buf[i]); | |
281 | } | |
b5b073e2 PMF |
282 | |
283 | list_del(&chan->list); | |
284 | kref_put(&chan->kref, ust_buffers_destroy_channel); | |
285 | mutex_unlock(&ust_buffers_channels_mutex); | |
286 | } | |
287 | ||
b5b073e2 PMF |
288 | /* |
289 | * ------- | |
290 | */ | |
291 | ||
204141ee | 292 | static void ust_buffers_destroy_buffer(struct ust_channel *ltt_chan, int cpu); |
b5b073e2 PMF |
293 | |
294 | static void ltt_force_switch(struct ust_buffer *buf, | |
295 | enum force_switch_mode mode); | |
296 | ||
297 | /* | |
298 | * Trace callbacks | |
299 | */ | |
b73a4c47 | 300 | static void ltt_buffer_begin(struct ust_buffer *buf, |
b5b073e2 PMF |
301 | u64 tsc, unsigned int subbuf_idx) |
302 | { | |
303 | struct ust_channel *channel = buf->chan; | |
304 | struct ltt_subbuffer_header *header = | |
305 | (struct ltt_subbuffer_header *) | |
b73a4c47 | 306 | ust_buffers_offset_address(buf, |
b5b073e2 PMF |
307 | subbuf_idx * buf->chan->subbuf_size); |
308 | ||
309 | header->cycle_count_begin = tsc; | |
02af3e60 PMF |
310 | header->data_size = 0xFFFFFFFF; /* for recognizing crashed buffers */ |
311 | header->sb_size = 0xFFFFFFFF; /* for recognizing crashed buffers */ | |
312 | /* FIXME: add memory barrier? */ | |
b5b073e2 PMF |
313 | ltt_write_trace_header(channel->trace, header); |
314 | } | |
315 | ||
316 | /* | |
317 | * offset is assumed to never be 0 here : never deliver a completely empty | |
318 | * subbuffer. The lost size is between 0 and subbuf_size-1. | |
319 | */ | |
b73a4c47 | 320 | static notrace void ltt_buffer_end(struct ust_buffer *buf, |
b5b073e2 PMF |
321 | u64 tsc, unsigned int offset, unsigned int subbuf_idx) |
322 | { | |
323 | struct ltt_subbuffer_header *header = | |
324 | (struct ltt_subbuffer_header *) | |
b73a4c47 | 325 | ust_buffers_offset_address(buf, |
b5b073e2 | 326 | subbuf_idx * buf->chan->subbuf_size); |
8c36d1ee | 327 | u32 data_size = SUBBUF_OFFSET(offset - 1, buf->chan) + 1; |
b5b073e2 | 328 | |
8c36d1ee PMF |
329 | header->data_size = data_size; |
330 | header->sb_size = PAGE_ALIGN(data_size); | |
b5b073e2 PMF |
331 | header->cycle_count_end = tsc; |
332 | header->events_lost = local_read(&buf->events_lost); | |
333 | header->subbuf_corrupt = local_read(&buf->corrupted_subbuffers); | |
b5b073e2 PMF |
334 | } |
335 | ||
336 | /* | |
337 | * This function should not be called from NMI interrupt context | |
338 | */ | |
339 | static notrace void ltt_buf_unfull(struct ust_buffer *buf, | |
340 | unsigned int subbuf_idx, | |
341 | long offset) | |
342 | { | |
b5b073e2 PMF |
343 | } |
344 | ||
b73a4c47 PMF |
345 | /* |
346 | * Promote compiler barrier to a smp_mb(). | |
347 | * For the specific LTTng case, this IPI call should be removed if the | |
348 | * architecture does not reorder writes. This should eventually be provided by | |
349 | * a separate architecture-specific infrastructure. | |
350 | */ | |
e17571a5 PMF |
351 | //ust// static void remote_mb(void *info) |
352 | //ust// { | |
353 | //ust// smp_mb(); | |
354 | //ust// } | |
b73a4c47 PMF |
355 | |
356 | int ust_buffers_get_subbuf(struct ust_buffer *buf, long *consumed) | |
b5b073e2 PMF |
357 | { |
358 | struct ust_channel *channel = buf->chan; | |
359 | long consumed_old, consumed_idx, commit_count, write_offset; | |
b73a4c47 PMF |
360 | //ust// int retval; |
361 | ||
b5b073e2 PMF |
362 | consumed_old = atomic_long_read(&buf->consumed); |
363 | consumed_idx = SUBBUF_INDEX(consumed_old, buf->chan); | |
b73a4c47 | 364 | commit_count = local_read(&buf->commit_count[consumed_idx].cc_sb); |
b5b073e2 PMF |
365 | /* |
366 | * Make sure we read the commit count before reading the buffer | |
367 | * data and the write offset. Correct consumed offset ordering | |
368 | * wrt commit count is insured by the use of cmpxchg to update | |
369 | * the consumed offset. | |
b73a4c47 PMF |
370 | * smp_call_function_single can fail if the remote CPU is offline, |
371 | * this is OK because then there is no wmb to execute there. | |
372 | * If our thread is executing on the same CPU as the on the buffers | |
373 | * belongs to, we don't have to synchronize it at all. If we are | |
374 | * migrated, the scheduler will take care of the memory barriers. | |
375 | * Normally, smp_call_function_single() should ensure program order when | |
376 | * executing the remote function, which implies that it surrounds the | |
377 | * function execution with : | |
378 | * smp_mb() | |
379 | * send IPI | |
380 | * csd_lock_wait | |
381 | * recv IPI | |
382 | * smp_mb() | |
383 | * exec. function | |
384 | * smp_mb() | |
385 | * csd unlock | |
386 | * smp_mb() | |
387 | * | |
388 | * However, smp_call_function_single() does not seem to clearly execute | |
389 | * such barriers. It depends on spinlock semantic to provide the barrier | |
390 | * before executing the IPI and, when busy-looping, csd_lock_wait only | |
391 | * executes smp_mb() when it has to wait for the other CPU. | |
392 | * | |
393 | * I don't trust this code. Therefore, let's add the smp_mb() sequence | |
394 | * required ourself, even if duplicated. It has no performance impact | |
395 | * anyway. | |
396 | * | |
397 | * smp_mb() is needed because smp_rmb() and smp_wmb() only order read vs | |
398 | * read and write vs write. They do not ensure core synchronization. We | |
399 | * really have to ensure total order between the 3 barriers running on | |
400 | * the 2 CPUs. | |
401 | */ | |
402 | //ust// #ifdef LTT_NO_IPI_BARRIER | |
403 | /* | |
404 | * Local rmb to match the remote wmb to read the commit count before the | |
405 | * buffer data and the write offset. | |
b5b073e2 PMF |
406 | */ |
407 | smp_rmb(); | |
b73a4c47 PMF |
408 | //ust// #else |
409 | //ust// if (raw_smp_processor_id() != buf->cpu) { | |
410 | //ust// smp_mb(); /* Total order with IPI handler smp_mb() */ | |
411 | //ust// smp_call_function_single(buf->cpu, remote_mb, NULL, 1); | |
412 | //ust// smp_mb(); /* Total order with IPI handler smp_mb() */ | |
413 | //ust// } | |
414 | //ust// #endif | |
415 | ||
b5b073e2 PMF |
416 | write_offset = local_read(&buf->offset); |
417 | /* | |
418 | * Check that the subbuffer we are trying to consume has been | |
419 | * already fully committed. | |
420 | */ | |
421 | if (((commit_count - buf->chan->subbuf_size) | |
422 | & channel->commit_count_mask) | |
423 | - (BUFFER_TRUNC(consumed_old, buf->chan) | |
424 | >> channel->n_subbufs_order) | |
425 | != 0) { | |
426 | return -EAGAIN; | |
427 | } | |
428 | /* | |
429 | * Check that we are not about to read the same subbuffer in | |
430 | * which the writer head is. | |
431 | */ | |
432 | if ((SUBBUF_TRUNC(write_offset, buf->chan) | |
433 | - SUBBUF_TRUNC(consumed_old, buf->chan)) | |
434 | == 0) { | |
435 | return -EAGAIN; | |
436 | } | |
437 | ||
b73a4c47 PMF |
438 | /* FIXME: is this ok to disable the reading feature? */ |
439 | //ust// retval = update_read_sb_index(buf, consumed_idx); | |
440 | //ust// if (retval) | |
441 | //ust// return retval; | |
442 | ||
443 | *consumed = consumed_old; | |
444 | ||
b5b073e2 PMF |
445 | return 0; |
446 | } | |
447 | ||
b73a4c47 | 448 | int ust_buffers_put_subbuf(struct ust_buffer *buf, unsigned long uconsumed_old) |
b5b073e2 PMF |
449 | { |
450 | long consumed_new, consumed_old; | |
451 | ||
452 | consumed_old = atomic_long_read(&buf->consumed); | |
453 | consumed_old = consumed_old & (~0xFFFFFFFFL); | |
454 | consumed_old = consumed_old | uconsumed_old; | |
455 | consumed_new = SUBBUF_ALIGN(consumed_old, buf->chan); | |
456 | ||
457 | //ust// spin_lock(<t_buf->full_lock); | |
458 | if (atomic_long_cmpxchg(&buf->consumed, consumed_old, | |
459 | consumed_new) | |
460 | != consumed_old) { | |
461 | /* We have been pushed by the writer : the last | |
462 | * buffer read _is_ corrupted! It can also | |
463 | * happen if this is a buffer we never got. */ | |
464 | //ust// spin_unlock(<t_buf->full_lock); | |
465 | return -EIO; | |
466 | } else { | |
467 | /* tell the client that buffer is now unfull */ | |
468 | int index; | |
469 | long data; | |
470 | index = SUBBUF_INDEX(consumed_old, buf->chan); | |
471 | data = BUFFER_OFFSET(consumed_old, buf->chan); | |
472 | ltt_buf_unfull(buf, index, data); | |
473 | //ust// spin_unlock(<t_buf->full_lock); | |
474 | } | |
475 | return 0; | |
476 | } | |
477 | ||
b73a4c47 PMF |
478 | //ust// static void switch_buffer(unsigned long data) |
479 | //ust// { | |
480 | //ust// struct ltt_channel_buf_struct *ltt_buf = | |
481 | //ust// (struct ltt_channel_buf_struct *)data; | |
482 | //ust// struct rchan_buf *buf = ltt_buf->rbuf; | |
483 | //ust// | |
484 | //ust// if (buf) | |
485 | //ust// ltt_force_switch(buf, FORCE_ACTIVE); | |
486 | //ust// | |
487 | //ust// ltt_buf->switch_timer.expires += ltt_buf->switch_timer_interval; | |
488 | //ust// add_timer_on(<t_buf->switch_timer, smp_processor_id()); | |
489 | //ust// } | |
490 | //ust// | |
491 | //ust// static void start_switch_timer(struct ltt_channel_struct *ltt_channel) | |
492 | //ust// { | |
493 | //ust// struct rchan *rchan = ltt_channel->trans_channel_data; | |
494 | //ust// int cpu; | |
495 | //ust// | |
496 | //ust// if (!ltt_channel->switch_timer_interval) | |
497 | //ust// return; | |
498 | //ust// | |
499 | //ust// // TODO : hotplug | |
500 | //ust// for_each_online_cpu(cpu) { | |
501 | //ust// struct ltt_channel_buf_struct *ltt_buf; | |
502 | //ust// struct rchan_buf *buf; | |
503 | //ust// | |
504 | //ust// buf = rchan->buf[cpu]; | |
505 | //ust// ltt_buf = buf->chan_private; | |
506 | //ust// buf->random_access = 1; | |
507 | //ust// ltt_buf->switch_timer_interval = | |
508 | //ust// ltt_channel->switch_timer_interval; | |
509 | //ust// init_timer(<t_buf->switch_timer); | |
510 | //ust// ltt_buf->switch_timer.function = switch_buffer; | |
511 | //ust// ltt_buf->switch_timer.expires = jiffies + | |
512 | //ust// ltt_buf->switch_timer_interval; | |
513 | //ust// ltt_buf->switch_timer.data = (unsigned long)ltt_buf; | |
514 | //ust// add_timer_on(<t_buf->switch_timer, cpu); | |
515 | //ust// } | |
516 | //ust// } | |
517 | //ust// | |
518 | //ust// /* | |
519 | //ust// * Cannot use del_timer_sync with add_timer_on, so use an IPI to locally | |
520 | //ust// * delete the timer. | |
521 | //ust// */ | |
522 | //ust// static void stop_switch_timer_ipi(void *info) | |
523 | //ust// { | |
524 | //ust// struct ltt_channel_buf_struct *ltt_buf = | |
525 | //ust// (struct ltt_channel_buf_struct *)info; | |
526 | //ust// | |
527 | //ust// del_timer(<t_buf->switch_timer); | |
528 | //ust// } | |
529 | //ust// | |
530 | //ust// static void stop_switch_timer(struct ltt_channel_struct *ltt_channel) | |
531 | //ust// { | |
532 | //ust// struct rchan *rchan = ltt_channel->trans_channel_data; | |
533 | //ust// int cpu; | |
534 | //ust// | |
535 | //ust// if (!ltt_channel->switch_timer_interval) | |
536 | //ust// return; | |
537 | //ust// | |
538 | //ust// // TODO : hotplug | |
539 | //ust// for_each_online_cpu(cpu) { | |
540 | //ust// struct ltt_channel_buf_struct *ltt_buf; | |
541 | //ust// struct rchan_buf *buf; | |
542 | //ust// | |
543 | //ust// buf = rchan->buf[cpu]; | |
544 | //ust// ltt_buf = buf->chan_private; | |
545 | //ust// smp_call_function(stop_switch_timer_ipi, ltt_buf, 1); | |
546 | //ust// buf->random_access = 0; | |
547 | //ust// } | |
548 | //ust// } | |
549 | ||
e17571a5 PMF |
550 | //ust// static void ust_buffers_print_written(struct ust_channel *chan, |
551 | //ust// long cons_off, unsigned int cpu) | |
552 | //ust// { | |
553 | //ust// struct ust_buffer *buf = chan->buf[cpu]; | |
554 | //ust// long cons_idx, events_count; | |
555 | //ust// | |
556 | //ust// cons_idx = SUBBUF_INDEX(cons_off, chan); | |
557 | //ust// events_count = local_read(&buf->commit_count[cons_idx].events); | |
558 | //ust// | |
559 | //ust// if (events_count) | |
560 | //ust// printk(KERN_INFO | |
561 | //ust// "channel %s: %lu events written (cpu %u, index %lu)\n", | |
562 | //ust// chan->channel_name, events_count, cpu, cons_idx); | |
563 | //ust// } | |
b73a4c47 | 564 | |
b5b073e2 PMF |
565 | static void ltt_relay_print_subbuffer_errors( |
566 | struct ust_channel *channel, | |
204141ee | 567 | long cons_off, int cpu) |
b5b073e2 | 568 | { |
204141ee | 569 | struct ust_buffer *ltt_buf = channel->buf[cpu]; |
b73a4c47 | 570 | long cons_idx, commit_count, commit_count_sb, write_offset; |
b5b073e2 PMF |
571 | |
572 | cons_idx = SUBBUF_INDEX(cons_off, channel); | |
b73a4c47 PMF |
573 | commit_count = local_read(<t_buf->commit_count[cons_idx].cc); |
574 | commit_count_sb = local_read(<t_buf->commit_count[cons_idx].cc_sb); | |
575 | ||
b5b073e2 PMF |
576 | /* |
577 | * No need to order commit_count and write_offset reads because we | |
578 | * execute after trace is stopped when there are no readers left. | |
579 | */ | |
580 | write_offset = local_read(<t_buf->offset); | |
581 | WARN( "LTT : unread channel %s offset is %ld " | |
b73a4c47 PMF |
582 | "and cons_off : %ld (cpu %d)\n", |
583 | channel->channel_name, write_offset, cons_off, cpu); | |
b5b073e2 PMF |
584 | /* Check each sub-buffer for non filled commit count */ |
585 | if (((commit_count - channel->subbuf_size) & channel->commit_count_mask) | |
586 | - (BUFFER_TRUNC(cons_off, channel) >> channel->n_subbufs_order) != 0) { | |
587 | ERR("LTT : %s : subbuffer %lu has non filled " | |
b73a4c47 PMF |
588 | "commit count [cc, cc_sb] [%lu,%lu].\n", |
589 | channel->channel_name, cons_idx, commit_count, commit_count_sb); | |
b5b073e2 PMF |
590 | } |
591 | ERR("LTT : %s : commit count : %lu, subbuf size %zd\n", | |
592 | channel->channel_name, commit_count, | |
593 | channel->subbuf_size); | |
594 | } | |
595 | ||
b73a4c47 | 596 | static void ltt_relay_print_errors(struct ust_trace *trace, |
204141ee | 597 | struct ust_channel *channel, int cpu) |
b5b073e2 | 598 | { |
204141ee | 599 | struct ust_buffer *ltt_buf = channel->buf[cpu]; |
b5b073e2 PMF |
600 | long cons_off; |
601 | ||
4292ed8a PMF |
602 | /* |
603 | * Can be called in the error path of allocation when | |
604 | * trans_channel_data is not yet set. | |
605 | */ | |
606 | if (!channel) | |
607 | return; | |
608 | ||
e17571a5 PMF |
609 | //ust// for (cons_off = 0; cons_off < rchan->alloc_size; |
610 | //ust// cons_off = SUBBUF_ALIGN(cons_off, rchan)) | |
611 | //ust// ust_buffers_print_written(ltt_chan, cons_off, cpu); | |
b5b073e2 PMF |
612 | for (cons_off = atomic_long_read(<t_buf->consumed); |
613 | (SUBBUF_TRUNC(local_read(<t_buf->offset), | |
614 | channel) | |
615 | - cons_off) > 0; | |
616 | cons_off = SUBBUF_ALIGN(cons_off, channel)) | |
204141ee | 617 | ltt_relay_print_subbuffer_errors(channel, cons_off, cpu); |
b5b073e2 PMF |
618 | } |
619 | ||
204141ee | 620 | static void ltt_relay_print_buffer_errors(struct ust_channel *channel, int cpu) |
b5b073e2 | 621 | { |
b73a4c47 | 622 | struct ust_trace *trace = channel->trace; |
204141ee | 623 | struct ust_buffer *ltt_buf = channel->buf[cpu]; |
b5b073e2 PMF |
624 | |
625 | if (local_read(<t_buf->events_lost)) | |
b73a4c47 | 626 | ERR("channel %s: %ld events lost (cpu %d)", |
b5b073e2 | 627 | channel->channel_name, |
b73a4c47 | 628 | local_read(<t_buf->events_lost), cpu); |
b5b073e2 | 629 | if (local_read(<t_buf->corrupted_subbuffers)) |
b73a4c47 | 630 | ERR("channel %s : %ld corrupted subbuffers (cpu %d)", |
b5b073e2 | 631 | channel->channel_name, |
b73a4c47 | 632 | local_read(<t_buf->corrupted_subbuffers), cpu); |
b5b073e2 | 633 | |
204141ee | 634 | ltt_relay_print_errors(trace, channel, cpu); |
b5b073e2 PMF |
635 | } |
636 | ||
637 | static void ltt_relay_release_channel(struct kref *kref) | |
638 | { | |
639 | struct ust_channel *ltt_chan = container_of(kref, | |
640 | struct ust_channel, kref); | |
641 | free(ltt_chan->buf); | |
642 | } | |
643 | ||
644 | /* | |
645 | * Create ltt buffer. | |
646 | */ | |
b73a4c47 | 647 | //ust// static int ltt_relay_create_buffer(struct ust_trace *trace, |
b5b073e2 PMF |
648 | //ust// struct ltt_channel_struct *ltt_chan, struct rchan_buf *buf, |
649 | //ust// unsigned int cpu, unsigned int n_subbufs) | |
650 | //ust// { | |
651 | //ust// struct ltt_channel_buf_struct *ltt_buf = | |
652 | //ust// percpu_ptr(ltt_chan->buf, cpu); | |
653 | //ust// unsigned int j; | |
b73a4c47 | 654 | //ust// |
b5b073e2 PMF |
655 | //ust// ltt_buf->commit_count = |
656 | //ust// kzalloc_node(sizeof(ltt_buf->commit_count) * n_subbufs, | |
657 | //ust// GFP_KERNEL, cpu_to_node(cpu)); | |
658 | //ust// if (!ltt_buf->commit_count) | |
659 | //ust// return -ENOMEM; | |
660 | //ust// kref_get(&trace->kref); | |
661 | //ust// kref_get(&trace->ltt_transport_kref); | |
662 | //ust// kref_get(<t_chan->kref); | |
663 | //ust// local_set(<t_buf->offset, ltt_subbuffer_header_size()); | |
664 | //ust// atomic_long_set(<t_buf->consumed, 0); | |
665 | //ust// atomic_long_set(<t_buf->active_readers, 0); | |
666 | //ust// for (j = 0; j < n_subbufs; j++) | |
667 | //ust// local_set(<t_buf->commit_count[j], 0); | |
668 | //ust// init_waitqueue_head(<t_buf->write_wait); | |
669 | //ust// atomic_set(<t_buf->wakeup_readers, 0); | |
670 | //ust// spin_lock_init(<t_buf->full_lock); | |
b73a4c47 | 671 | //ust// |
b5b073e2 PMF |
672 | //ust// ltt_buffer_begin_callback(buf, trace->start_tsc, 0); |
673 | //ust// /* atomic_add made on local variable on data that belongs to | |
674 | //ust// * various CPUs : ok because tracing not started (for this cpu). */ | |
675 | //ust// local_add(ltt_subbuffer_header_size(), <t_buf->commit_count[0]); | |
b73a4c47 | 676 | //ust// |
b5b073e2 PMF |
677 | //ust// local_set(<t_buf->events_lost, 0); |
678 | //ust// local_set(<t_buf->corrupted_subbuffers, 0); | |
b73a4c47 | 679 | //ust// |
b5b073e2 PMF |
680 | //ust// return 0; |
681 | //ust// } | |
682 | ||
b73a4c47 | 683 | static int ust_buffers_init_buffer(struct ust_trace *trace, |
b5b073e2 PMF |
684 | struct ust_channel *ltt_chan, struct ust_buffer *buf, |
685 | unsigned int n_subbufs) | |
686 | { | |
687 | unsigned int j; | |
688 | int fds[2]; | |
689 | int result; | |
690 | ||
691 | buf->commit_count = | |
b73a4c47 | 692 | zmalloc(sizeof(*buf->commit_count) * n_subbufs); |
b5b073e2 PMF |
693 | if (!buf->commit_count) |
694 | return -ENOMEM; | |
695 | kref_get(&trace->kref); | |
696 | kref_get(&trace->ltt_transport_kref); | |
697 | kref_get(<t_chan->kref); | |
698 | local_set(&buf->offset, ltt_subbuffer_header_size()); | |
699 | atomic_long_set(&buf->consumed, 0); | |
700 | atomic_long_set(&buf->active_readers, 0); | |
b73a4c47 PMF |
701 | for (j = 0; j < n_subbufs; j++) { |
702 | local_set(&buf->commit_count[j].cc, 0); | |
703 | local_set(&buf->commit_count[j].cc_sb, 0); | |
704 | } | |
b5b073e2 PMF |
705 | //ust// init_waitqueue_head(&buf->write_wait); |
706 | //ust// atomic_set(&buf->wakeup_readers, 0); | |
707 | //ust// spin_lock_init(&buf->full_lock); | |
708 | ||
b73a4c47 | 709 | ltt_buffer_begin(buf, trace->start_tsc, 0); |
b5b073e2 | 710 | |
b73a4c47 | 711 | local_add(ltt_subbuffer_header_size(), &buf->commit_count[0].cc); |
b5b073e2 PMF |
712 | |
713 | local_set(&buf->events_lost, 0); | |
714 | local_set(&buf->corrupted_subbuffers, 0); | |
715 | ||
716 | result = pipe(fds); | |
717 | if(result == -1) { | |
718 | PERROR("pipe"); | |
719 | return -1; | |
720 | } | |
721 | buf->data_ready_fd_read = fds[0]; | |
722 | buf->data_ready_fd_write = fds[1]; | |
723 | ||
724 | /* FIXME: do we actually need this? */ | |
725 | result = fcntl(fds[0], F_SETFL, O_NONBLOCK); | |
726 | if(result == -1) { | |
727 | PERROR("fcntl"); | |
728 | } | |
729 | ||
730 | //ust// buf->commit_seq = malloc(sizeof(buf->commit_seq) * n_subbufs); | |
731 | //ust// if(!ltt_buf->commit_seq) { | |
732 | //ust// return -1; | |
733 | //ust// } | |
37315729 | 734 | memset(buf->commit_seq, 0, sizeof(buf->commit_seq[0]) * n_subbufs); |
b5b073e2 PMF |
735 | |
736 | /* FIXME: decrementally destroy on error */ | |
737 | ||
738 | return 0; | |
739 | } | |
740 | ||
741 | /* FIXME: use this function */ | |
204141ee | 742 | static void ust_buffers_destroy_buffer(struct ust_channel *ltt_chan, int cpu) |
b5b073e2 | 743 | { |
b73a4c47 | 744 | struct ust_trace *trace = ltt_chan->trace; |
204141ee | 745 | struct ust_buffer *ltt_buf = ltt_chan->buf[cpu]; |
b5b073e2 PMF |
746 | |
747 | kref_put(<t_chan->trace->ltt_transport_kref, | |
748 | ltt_release_transport); | |
204141ee | 749 | ltt_relay_print_buffer_errors(ltt_chan, cpu); |
b5b073e2 PMF |
750 | //ust// free(ltt_buf->commit_seq); |
751 | kfree(ltt_buf->commit_count); | |
752 | ltt_buf->commit_count = NULL; | |
753 | kref_put(<t_chan->kref, ltt_relay_release_channel); | |
754 | kref_put(&trace->kref, ltt_release_trace); | |
755 | //ust// wake_up_interruptible(&trace->kref_wq); | |
756 | } | |
757 | ||
204141ee | 758 | static int ust_buffers_alloc_channel_buf_structs(struct ust_channel *chan) |
b5b073e2 PMF |
759 | { |
760 | void *ptr; | |
761 | int result; | |
204141ee PMF |
762 | size_t size; |
763 | int i; | |
b5b073e2 | 764 | |
204141ee | 765 | size = PAGE_ALIGN(1); |
b5b073e2 | 766 | |
204141ee | 767 | for(i=0; i<chan->n_cpus; i++) { |
b5b073e2 | 768 | |
204141ee PMF |
769 | result = chan->buf_struct_shmids[i] = shmget(getpid(), size, IPC_CREAT | IPC_EXCL | 0700); |
770 | if(result == -1) { | |
771 | PERROR("shmget"); | |
772 | goto destroy_previous; | |
773 | } | |
b5b073e2 | 774 | |
204141ee PMF |
775 | /* FIXME: should have matching call to shmdt */ |
776 | ptr = shmat(chan->buf_struct_shmids[i], NULL, 0); | |
777 | if(ptr == (void *) -1) { | |
778 | perror("shmat"); | |
779 | goto destroy_shm; | |
780 | } | |
781 | ||
782 | /* Already mark the shared memory for destruction. This will occur only | |
783 | * when all users have detached. | |
784 | */ | |
785 | result = shmctl(chan->buf_struct_shmids[i], IPC_RMID, NULL); | |
786 | if(result == -1) { | |
787 | perror("shmctl"); | |
788 | goto destroy_previous; | |
789 | } | |
790 | ||
791 | chan->buf[i] = ptr; | |
b5b073e2 PMF |
792 | } |
793 | ||
204141ee | 794 | return 0; |
b5b073e2 | 795 | |
204141ee PMF |
796 | /* Jumping inside this loop occurs from within the other loop above with i as |
797 | * counter, so it unallocates the structures for the cpu = current_i down to | |
798 | * zero. */ | |
799 | for(; i>=0; i--) { | |
800 | destroy_shm: | |
801 | result = shmctl(chan->buf_struct_shmids[i], IPC_RMID, NULL); | |
802 | if(result == -1) { | |
803 | perror("shmctl"); | |
804 | } | |
b5b073e2 | 805 | |
204141ee PMF |
806 | destroy_previous: |
807 | continue; | |
b5b073e2 PMF |
808 | } |
809 | ||
204141ee | 810 | return -1; |
b5b073e2 PMF |
811 | } |
812 | ||
813 | /* | |
814 | * Create channel. | |
815 | */ | |
b73a4c47 | 816 | static int ust_buffers_create_channel(const char *trace_name, struct ust_trace *trace, |
b5b073e2 PMF |
817 | const char *channel_name, struct ust_channel *ltt_chan, |
818 | unsigned int subbuf_size, unsigned int n_subbufs, int overwrite) | |
819 | { | |
b5b073e2 PMF |
820 | int result; |
821 | ||
822 | kref_init(<t_chan->kref); | |
823 | ||
824 | ltt_chan->trace = trace; | |
b5b073e2 PMF |
825 | ltt_chan->overwrite = overwrite; |
826 | ltt_chan->n_subbufs_order = get_count_order(n_subbufs); | |
827 | ltt_chan->commit_count_mask = (~0UL >> ltt_chan->n_subbufs_order); | |
204141ee | 828 | ltt_chan->n_cpus = get_n_cpus(); |
b5b073e2 | 829 | //ust// ltt_chan->buf = percpu_alloc_mask(sizeof(struct ltt_channel_buf_struct), GFP_KERNEL, cpu_possible_map); |
204141ee PMF |
830 | ltt_chan->buf = (void *) malloc(ltt_chan->n_cpus * sizeof(void *)); |
831 | if(ltt_chan->buf == NULL) { | |
832 | goto error; | |
833 | } | |
834 | ltt_chan->buf_struct_shmids = (int *) malloc(ltt_chan->n_cpus * sizeof(int)); | |
835 | if(ltt_chan->buf_struct_shmids == NULL) | |
836 | goto free_buf; | |
b5b073e2 | 837 | |
204141ee PMF |
838 | result = ust_buffers_alloc_channel_buf_structs(ltt_chan); |
839 | if(result != 0) { | |
840 | goto free_buf_struct_shmids; | |
841 | } | |
b5b073e2 | 842 | |
b5b073e2 | 843 | result = ust_buffers_channel_open(ltt_chan, subbuf_size, n_subbufs); |
204141ee | 844 | if (result != 0) { |
c1f20530 | 845 | ERR("Cannot open channel for trace %s", trace_name); |
204141ee | 846 | goto unalloc_buf_structs; |
b5b073e2 PMF |
847 | } |
848 | ||
204141ee PMF |
849 | return 0; |
850 | ||
851 | unalloc_buf_structs: | |
852 | /* FIXME: put a call here to unalloc the buf structs! */ | |
853 | ||
854 | free_buf_struct_shmids: | |
855 | free(ltt_chan->buf_struct_shmids); | |
b5b073e2 | 856 | |
204141ee PMF |
857 | free_buf: |
858 | free(ltt_chan->buf); | |
859 | ||
860 | error: | |
861 | return -1; | |
b5b073e2 PMF |
862 | } |
863 | ||
864 | /* | |
865 | * LTTng channel flush function. | |
866 | * | |
867 | * Must be called when no tracing is active in the channel, because of | |
868 | * accesses across CPUs. | |
869 | */ | |
870 | static notrace void ltt_relay_buffer_flush(struct ust_buffer *buf) | |
871 | { | |
872 | int result; | |
873 | ||
874 | //ust// buf->finalized = 1; | |
875 | ltt_force_switch(buf, FORCE_FLUSH); | |
876 | ||
877 | result = write(buf->data_ready_fd_write, "1", 1); | |
878 | if(result == -1) { | |
879 | PERROR("write (in ltt_relay_buffer_flush)"); | |
880 | ERR("this should never happen!"); | |
881 | } | |
882 | } | |
883 | ||
884 | static void ltt_relay_async_wakeup_chan(struct ust_channel *ltt_channel) | |
885 | { | |
886 | //ust// unsigned int i; | |
887 | //ust// struct rchan *rchan = ltt_channel->trans_channel_data; | |
888 | //ust// | |
889 | //ust// for_each_possible_cpu(i) { | |
890 | //ust// struct ltt_channel_buf_struct *ltt_buf = | |
891 | //ust// percpu_ptr(ltt_channel->buf, i); | |
892 | //ust// | |
893 | //ust// if (atomic_read(<t_buf->wakeup_readers) == 1) { | |
894 | //ust// atomic_set(<t_buf->wakeup_readers, 0); | |
895 | //ust// wake_up_interruptible(&rchan->buf[i]->read_wait); | |
896 | //ust// } | |
897 | //ust// } | |
898 | } | |
899 | ||
204141ee | 900 | static void ltt_relay_finish_buffer(struct ust_channel *channel, unsigned int cpu) |
b5b073e2 PMF |
901 | { |
902 | // int result; | |
903 | ||
204141ee PMF |
904 | if (channel->buf[cpu]) { |
905 | struct ust_buffer *buf = channel->buf[cpu]; | |
b5b073e2 PMF |
906 | ltt_relay_buffer_flush(buf); |
907 | //ust// ltt_relay_wake_writers(ltt_buf); | |
908 | /* closing the pipe tells the consumer the buffer is finished */ | |
909 | ||
910 | //result = write(ltt_buf->data_ready_fd_write, "D", 1); | |
911 | //if(result == -1) { | |
912 | // PERROR("write (in ltt_relay_finish_buffer)"); | |
913 | // ERR("this should never happen!"); | |
914 | //} | |
915 | close(buf->data_ready_fd_write); | |
916 | } | |
917 | } | |
918 | ||
919 | ||
920 | static void ltt_relay_finish_channel(struct ust_channel *channel) | |
921 | { | |
204141ee | 922 | unsigned int i; |
b5b073e2 | 923 | |
204141ee PMF |
924 | for(i=0; i<channel->n_cpus; i++) { |
925 | ltt_relay_finish_buffer(channel, i); | |
926 | } | |
b5b073e2 PMF |
927 | } |
928 | ||
929 | static void ltt_relay_remove_channel(struct ust_channel *channel) | |
930 | { | |
931 | ust_buffers_channel_close(channel); | |
932 | kref_put(&channel->kref, ltt_relay_release_channel); | |
933 | } | |
934 | ||
b73a4c47 PMF |
935 | //ust// /* |
936 | //ust// * Returns : | |
937 | //ust// * 0 if ok | |
938 | //ust// * !0 if execution must be aborted. | |
939 | //ust// */ | |
940 | //ust// static inline int ltt_relay_try_reserve( | |
941 | //ust// struct ust_channel *channel, struct ust_buffer *buf, | |
942 | //ust// struct ltt_reserve_switch_offsets *offsets, size_t data_size, | |
943 | //ust// u64 *tsc, unsigned int *rflags, int largest_align) | |
944 | //ust// { | |
945 | //ust// offsets->begin = local_read(&buf->offset); | |
946 | //ust// offsets->old = offsets->begin; | |
947 | //ust// offsets->begin_switch = 0; | |
948 | //ust// offsets->end_switch_current = 0; | |
949 | //ust// offsets->end_switch_old = 0; | |
950 | //ust// | |
951 | //ust// *tsc = trace_clock_read64(); | |
952 | //ust// if (last_tsc_overflow(buf, *tsc)) | |
953 | //ust// *rflags = LTT_RFLAG_ID_SIZE_TSC; | |
954 | //ust// | |
955 | //ust// if (SUBBUF_OFFSET(offsets->begin, buf->chan) == 0) { | |
956 | //ust// offsets->begin_switch = 1; /* For offsets->begin */ | |
957 | //ust// } else { | |
958 | //ust// offsets->size = ust_get_header_size(channel, | |
959 | //ust// offsets->begin, data_size, | |
960 | //ust// &offsets->before_hdr_pad, *rflags); | |
961 | //ust// offsets->size += ltt_align(offsets->begin + offsets->size, | |
962 | //ust// largest_align) | |
963 | //ust// + data_size; | |
964 | //ust// if ((SUBBUF_OFFSET(offsets->begin, buf->chan) + offsets->size) | |
965 | //ust// > buf->chan->subbuf_size) { | |
966 | //ust// offsets->end_switch_old = 1; /* For offsets->old */ | |
967 | //ust// offsets->begin_switch = 1; /* For offsets->begin */ | |
968 | //ust// } | |
969 | //ust// } | |
970 | //ust// if (offsets->begin_switch) { | |
971 | //ust// long subbuf_index; | |
972 | //ust// | |
973 | //ust// if (offsets->end_switch_old) | |
974 | //ust// offsets->begin = SUBBUF_ALIGN(offsets->begin, | |
975 | //ust// buf->chan); | |
976 | //ust// offsets->begin = offsets->begin + ltt_subbuffer_header_size(); | |
977 | //ust// /* Test new buffer integrity */ | |
978 | //ust// subbuf_index = SUBBUF_INDEX(offsets->begin, buf->chan); | |
979 | //ust// offsets->reserve_commit_diff = | |
980 | //ust// (BUFFER_TRUNC(offsets->begin, buf->chan) | |
981 | //ust// >> channel->n_subbufs_order) | |
982 | //ust// - (local_read(&buf->commit_count[subbuf_index]) | |
983 | //ust// & channel->commit_count_mask); | |
984 | //ust// if (offsets->reserve_commit_diff == 0) { | |
985 | //ust// long consumed; | |
986 | //ust// | |
987 | //ust// consumed = atomic_long_read(&buf->consumed); | |
988 | //ust// | |
989 | //ust// /* Next buffer not corrupted. */ | |
990 | //ust// if (!channel->overwrite && | |
991 | //ust// (SUBBUF_TRUNC(offsets->begin, buf->chan) | |
992 | //ust// - SUBBUF_TRUNC(consumed, buf->chan)) | |
993 | //ust// >= channel->alloc_size) { | |
994 | //ust// | |
995 | //ust// long consumed_idx = SUBBUF_INDEX(consumed, buf->chan); | |
996 | //ust// long commit_count = local_read(&buf->commit_count[consumed_idx]); | |
997 | //ust// if(((commit_count - buf->chan->subbuf_size) & channel->commit_count_mask) - (BUFFER_TRUNC(consumed, buf->chan) >> channel->n_subbufs_order) != 0) { | |
998 | //ust// WARN("Event dropped. Caused by non-committed event."); | |
999 | //ust// } | |
1000 | //ust// else { | |
1001 | //ust// WARN("Event dropped. Caused by non-consumed buffer."); | |
1002 | //ust// } | |
1003 | //ust// /* | |
1004 | //ust// * We do not overwrite non consumed buffers | |
1005 | //ust// * and we are full : event is lost. | |
1006 | //ust// */ | |
1007 | //ust// local_inc(&buf->events_lost); | |
1008 | //ust// return -1; | |
1009 | //ust// } else { | |
1010 | //ust// /* | |
1011 | //ust// * next buffer not corrupted, we are either in | |
1012 | //ust// * overwrite mode or the buffer is not full. | |
1013 | //ust// * It's safe to write in this new subbuffer. | |
1014 | //ust// */ | |
1015 | //ust// } | |
1016 | //ust// } else { | |
1017 | //ust// /* | |
1018 | //ust// * Next subbuffer corrupted. Force pushing reader even | |
1019 | //ust// * in normal mode. It's safe to write in this new | |
1020 | //ust// * subbuffer. | |
1021 | //ust// */ | |
1022 | //ust// } | |
1023 | //ust// offsets->size = ust_get_header_size(channel, | |
1024 | //ust// offsets->begin, data_size, | |
1025 | //ust// &offsets->before_hdr_pad, *rflags); | |
1026 | //ust// offsets->size += ltt_align(offsets->begin + offsets->size, | |
1027 | //ust// largest_align) | |
1028 | //ust// + data_size; | |
1029 | //ust// if ((SUBBUF_OFFSET(offsets->begin, buf->chan) + offsets->size) | |
1030 | //ust// > buf->chan->subbuf_size) { | |
1031 | //ust// /* | |
1032 | //ust// * Event too big for subbuffers, report error, don't | |
1033 | //ust// * complete the sub-buffer switch. | |
1034 | //ust// */ | |
1035 | //ust// local_inc(&buf->events_lost); | |
1036 | //ust// return -1; | |
1037 | //ust// } else { | |
1038 | //ust// /* | |
1039 | //ust// * We just made a successful buffer switch and the event | |
1040 | //ust// * fits in the new subbuffer. Let's write. | |
1041 | //ust// */ | |
1042 | //ust// } | |
1043 | //ust// } else { | |
1044 | //ust// /* | |
1045 | //ust// * Event fits in the current buffer and we are not on a switch | |
1046 | //ust// * boundary. It's safe to write. | |
1047 | //ust// */ | |
1048 | //ust// } | |
1049 | //ust// offsets->end = offsets->begin + offsets->size; | |
1050 | //ust// | |
1051 | //ust// if ((SUBBUF_OFFSET(offsets->end, buf->chan)) == 0) { | |
1052 | //ust// /* | |
1053 | //ust// * The offset_end will fall at the very beginning of the next | |
1054 | //ust// * subbuffer. | |
1055 | //ust// */ | |
1056 | //ust// offsets->end_switch_current = 1; /* For offsets->begin */ | |
1057 | //ust// } | |
1058 | //ust// return 0; | |
1059 | //ust// } | |
1060 | //ust// | |
1061 | //ust// /* | |
1062 | //ust// * Returns : | |
1063 | //ust// * 0 if ok | |
1064 | //ust// * !0 if execution must be aborted. | |
1065 | //ust// */ | |
1066 | //ust// static inline int ltt_relay_try_switch( | |
1067 | //ust// enum force_switch_mode mode, | |
1068 | //ust// struct ust_channel *channel, | |
1069 | //ust// struct ust_buffer *buf, | |
1070 | //ust// struct ltt_reserve_switch_offsets *offsets, | |
1071 | //ust// u64 *tsc) | |
1072 | //ust// { | |
1073 | //ust// long subbuf_index; | |
1074 | //ust// | |
1075 | //ust// offsets->begin = local_read(&buf->offset); | |
1076 | //ust// offsets->old = offsets->begin; | |
1077 | //ust// offsets->begin_switch = 0; | |
1078 | //ust// offsets->end_switch_old = 0; | |
1079 | //ust// | |
1080 | //ust// *tsc = trace_clock_read64(); | |
1081 | //ust// | |
1082 | //ust// if (SUBBUF_OFFSET(offsets->begin, buf->chan) != 0) { | |
1083 | //ust// offsets->begin = SUBBUF_ALIGN(offsets->begin, buf->chan); | |
1084 | //ust// offsets->end_switch_old = 1; | |
1085 | //ust// } else { | |
1086 | //ust// /* we do not have to switch : buffer is empty */ | |
1087 | //ust// return -1; | |
1088 | //ust// } | |
1089 | //ust// if (mode == FORCE_ACTIVE) | |
1090 | //ust// offsets->begin += ltt_subbuffer_header_size(); | |
1091 | //ust// /* | |
1092 | //ust// * Always begin_switch in FORCE_ACTIVE mode. | |
1093 | //ust// * Test new buffer integrity | |
1094 | //ust// */ | |
1095 | //ust// subbuf_index = SUBBUF_INDEX(offsets->begin, buf->chan); | |
1096 | //ust// offsets->reserve_commit_diff = | |
1097 | //ust// (BUFFER_TRUNC(offsets->begin, buf->chan) | |
1098 | //ust// >> channel->n_subbufs_order) | |
1099 | //ust// - (local_read(&buf->commit_count[subbuf_index]) | |
1100 | //ust// & channel->commit_count_mask); | |
1101 | //ust// if (offsets->reserve_commit_diff == 0) { | |
1102 | //ust// /* Next buffer not corrupted. */ | |
1103 | //ust// if (mode == FORCE_ACTIVE | |
1104 | //ust// && !channel->overwrite | |
1105 | //ust// && offsets->begin - atomic_long_read(&buf->consumed) | |
1106 | //ust// >= channel->alloc_size) { | |
1107 | //ust// /* | |
1108 | //ust// * We do not overwrite non consumed buffers and we are | |
1109 | //ust// * full : ignore switch while tracing is active. | |
1110 | //ust// */ | |
1111 | //ust// return -1; | |
1112 | //ust// } | |
1113 | //ust// } else { | |
1114 | //ust// /* | |
1115 | //ust// * Next subbuffer corrupted. Force pushing reader even in normal | |
1116 | //ust// * mode | |
1117 | //ust// */ | |
1118 | //ust// } | |
1119 | //ust// offsets->end = offsets->begin; | |
1120 | //ust// return 0; | |
1121 | //ust// } | |
1122 | //ust// | |
1123 | //ust// static inline void ltt_reserve_push_reader( | |
1124 | //ust// struct ust_channel *channel, | |
1125 | //ust// struct ust_buffer *buf, | |
1126 | //ust// struct ltt_reserve_switch_offsets *offsets) | |
1127 | //ust// { | |
1128 | //ust// long consumed_old, consumed_new; | |
1129 | //ust// | |
1130 | //ust// do { | |
1131 | //ust// consumed_old = atomic_long_read(&buf->consumed); | |
1132 | //ust// /* | |
1133 | //ust// * If buffer is in overwrite mode, push the reader consumed | |
1134 | //ust// * count if the write position has reached it and we are not | |
1135 | //ust// * at the first iteration (don't push the reader farther than | |
1136 | //ust// * the writer). This operation can be done concurrently by many | |
1137 | //ust// * writers in the same buffer, the writer being at the farthest | |
1138 | //ust// * write position sub-buffer index in the buffer being the one | |
1139 | //ust// * which will win this loop. | |
1140 | //ust// * If the buffer is not in overwrite mode, pushing the reader | |
1141 | //ust// * only happens if a sub-buffer is corrupted. | |
1142 | //ust// */ | |
1143 | //ust// if ((SUBBUF_TRUNC(offsets->end-1, buf->chan) | |
1144 | //ust// - SUBBUF_TRUNC(consumed_old, buf->chan)) | |
1145 | //ust// >= channel->alloc_size) | |
1146 | //ust// consumed_new = SUBBUF_ALIGN(consumed_old, buf->chan); | |
1147 | //ust// else { | |
1148 | //ust// consumed_new = consumed_old; | |
1149 | //ust// break; | |
1150 | //ust// } | |
1151 | //ust// } while (atomic_long_cmpxchg(&buf->consumed, consumed_old, | |
1152 | //ust// consumed_new) != consumed_old); | |
1153 | //ust// | |
1154 | //ust// if (consumed_old != consumed_new) { | |
1155 | //ust// /* | |
1156 | //ust// * Reader pushed : we are the winner of the push, we can | |
1157 | //ust// * therefore reequilibrate reserve and commit. Atomic increment | |
1158 | //ust// * of the commit count permits other writers to play around | |
1159 | //ust// * with this variable before us. We keep track of | |
1160 | //ust// * corrupted_subbuffers even in overwrite mode : | |
1161 | //ust// * we never want to write over a non completely committed | |
1162 | //ust// * sub-buffer : possible causes : the buffer size is too low | |
1163 | //ust// * compared to the unordered data input, or there is a writer | |
1164 | //ust// * that died between the reserve and the commit. | |
1165 | //ust// */ | |
1166 | //ust// if (offsets->reserve_commit_diff) { | |
1167 | //ust// /* | |
1168 | //ust// * We have to alter the sub-buffer commit count. | |
1169 | //ust// * We do not deliver the previous subbuffer, given it | |
1170 | //ust// * was either corrupted or not consumed (overwrite | |
1171 | //ust// * mode). | |
1172 | //ust// */ | |
1173 | //ust// local_add(offsets->reserve_commit_diff, | |
1174 | //ust// &buf->commit_count[ | |
1175 | //ust// SUBBUF_INDEX(offsets->begin, | |
1176 | //ust// buf->chan)]); | |
1177 | //ust// if (!channel->overwrite | |
1178 | //ust// || offsets->reserve_commit_diff | |
1179 | //ust// != channel->subbuf_size) { | |
1180 | //ust// /* | |
1181 | //ust// * The reserve commit diff was not subbuf_size : | |
1182 | //ust// * it means the subbuffer was partly written to | |
1183 | //ust// * and is therefore corrupted. If it is multiple | |
1184 | //ust// * of subbuffer size and we are in flight | |
1185 | //ust// * recorder mode, we are skipping over a whole | |
1186 | //ust// * subbuffer. | |
1187 | //ust// */ | |
1188 | //ust// local_inc(&buf->corrupted_subbuffers); | |
1189 | //ust// } | |
1190 | //ust// } | |
1191 | //ust// } | |
1192 | //ust// } | |
1193 | //ust// | |
1194 | //ust// /** | |
1195 | //ust// * ltt_relay_reserve_slot - Atomic slot reservation in a LTTng buffer. | |
1196 | //ust// * @trace: the trace structure to log to. | |
1197 | //ust// * @ltt_channel: channel structure | |
1198 | //ust// * @transport_data: data structure specific to ltt relay | |
1199 | //ust// * @data_size: size of the variable length data to log. | |
1200 | //ust// * @slot_size: pointer to total size of the slot (out) | |
1201 | //ust// * @buf_offset : pointer to reserved buffer offset (out) | |
1202 | //ust// * @tsc: pointer to the tsc at the slot reservation (out) | |
1203 | //ust// * @cpu: cpuid | |
1204 | //ust// * | |
1205 | //ust// * Return : -ENOSPC if not enough space, else returns 0. | |
1206 | //ust// * It will take care of sub-buffer switching. | |
1207 | //ust// */ | |
1208 | //ust// static notrace int ltt_relay_reserve_slot(struct ust_trace *trace, | |
1209 | //ust// struct ust_channel *channel, void **transport_data, | |
1210 | //ust// size_t data_size, size_t *slot_size, long *buf_offset, u64 *tsc, | |
1211 | //ust// unsigned int *rflags, int largest_align, int cpu) | |
1212 | //ust// { | |
1213 | //ust// struct ust_buffer *buf = *transport_data = channel->buf[cpu]; | |
1214 | //ust// struct ltt_reserve_switch_offsets offsets; | |
1215 | //ust// | |
1216 | //ust// offsets.reserve_commit_diff = 0; | |
1217 | //ust// offsets.size = 0; | |
1218 | //ust// | |
1219 | //ust// /* | |
1220 | //ust// * Perform retryable operations. | |
1221 | //ust// */ | |
1222 | //ust// if (ltt_nesting > 4) { | |
1223 | //ust// local_inc(&buf->events_lost); | |
1224 | //ust// return -EPERM; | |
1225 | //ust// } | |
1226 | //ust// do { | |
1227 | //ust// if (ltt_relay_try_reserve(channel, buf, &offsets, data_size, tsc, rflags, | |
1228 | //ust// largest_align)) | |
1229 | //ust// return -ENOSPC; | |
1230 | //ust// } while (local_cmpxchg(&buf->offset, offsets.old, | |
1231 | //ust// offsets.end) != offsets.old); | |
1232 | //ust// | |
1233 | //ust// /* | |
1234 | //ust// * Atomically update last_tsc. This update races against concurrent | |
1235 | //ust// * atomic updates, but the race will always cause supplementary full TSC | |
1236 | //ust// * events, never the opposite (missing a full TSC event when it would be | |
1237 | //ust// * needed). | |
1238 | //ust// */ | |
1239 | //ust// save_last_tsc(buf, *tsc); | |
1240 | //ust// | |
1241 | //ust// /* | |
1242 | //ust// * Push the reader if necessary | |
1243 | //ust// */ | |
1244 | //ust// ltt_reserve_push_reader(channel, buf, &offsets); | |
1245 | //ust// | |
1246 | //ust// /* | |
1247 | //ust// * Switch old subbuffer if needed. | |
1248 | //ust// */ | |
1249 | //ust// if (offsets.end_switch_old) | |
1250 | //ust// ltt_reserve_switch_old_subbuf(channel, buf, &offsets, tsc); | |
1251 | //ust// | |
1252 | //ust// /* | |
1253 | //ust// * Populate new subbuffer. | |
1254 | //ust// */ | |
1255 | //ust// if (offsets.begin_switch) | |
1256 | //ust// ltt_reserve_switch_new_subbuf(channel, buf, &offsets, tsc); | |
1257 | //ust// | |
1258 | //ust// if (offsets.end_switch_current) | |
1259 | //ust// ltt_reserve_end_switch_current(channel, buf, &offsets, tsc); | |
1260 | //ust// | |
1261 | //ust// *slot_size = offsets.size; | |
1262 | //ust// *buf_offset = offsets.begin + offsets.before_hdr_pad; | |
1263 | //ust// return 0; | |
1264 | //ust// } | |
1265 | //ust// | |
1266 | //ust// /* | |
1267 | //ust// * Force a sub-buffer switch for a per-cpu buffer. This operation is | |
1268 | //ust// * completely reentrant : can be called while tracing is active with | |
1269 | //ust// * absolutely no lock held. | |
1270 | //ust// * | |
1271 | //ust// * Note, however, that as a local_cmpxchg is used for some atomic | |
1272 | //ust// * operations, this function must be called from the CPU which owns the buffer | |
1273 | //ust// * for a ACTIVE flush. | |
1274 | //ust// */ | |
1275 | //ust// static notrace void ltt_force_switch(struct ust_buffer *buf, | |
1276 | //ust// enum force_switch_mode mode) | |
1277 | //ust// { | |
1278 | //ust// struct ust_channel *channel = buf->chan; | |
1279 | //ust// struct ltt_reserve_switch_offsets offsets; | |
1280 | //ust// u64 tsc; | |
1281 | //ust// | |
1282 | //ust// offsets.reserve_commit_diff = 0; | |
1283 | //ust// offsets.size = 0; | |
1284 | //ust// | |
1285 | //ust// /* | |
1286 | //ust// * Perform retryable operations. | |
1287 | //ust// */ | |
1288 | //ust// do { | |
1289 | //ust// if (ltt_relay_try_switch(mode, channel, buf, &offsets, &tsc)) | |
1290 | //ust// return; | |
1291 | //ust// } while (local_cmpxchg(&buf->offset, offsets.old, | |
1292 | //ust// offsets.end) != offsets.old); | |
1293 | //ust// | |
1294 | //ust// /* | |
1295 | //ust// * Atomically update last_tsc. This update races against concurrent | |
1296 | //ust// * atomic updates, but the race will always cause supplementary full TSC | |
1297 | //ust// * events, never the opposite (missing a full TSC event when it would be | |
1298 | //ust// * needed). | |
1299 | //ust// */ | |
1300 | //ust// save_last_tsc(buf, tsc); | |
1301 | //ust// | |
1302 | //ust// /* | |
1303 | //ust// * Push the reader if necessary | |
1304 | //ust// */ | |
1305 | //ust// if (mode == FORCE_ACTIVE) | |
1306 | //ust// ltt_reserve_push_reader(channel, buf, &offsets); | |
1307 | //ust// | |
1308 | //ust// /* | |
1309 | //ust// * Switch old subbuffer if needed. | |
1310 | //ust// */ | |
1311 | //ust// if (offsets.end_switch_old) | |
1312 | //ust// ltt_reserve_switch_old_subbuf(channel, buf, &offsets, &tsc); | |
1313 | //ust// | |
1314 | //ust// /* | |
1315 | //ust// * Populate new subbuffer. | |
1316 | //ust// */ | |
1317 | //ust// if (mode == FORCE_ACTIVE) | |
1318 | //ust// ltt_reserve_switch_new_subbuf(channel, buf, &offsets, &tsc); | |
1319 | //ust// } | |
b5b073e2 PMF |
1320 | |
1321 | /* | |
b73a4c47 PMF |
1322 | * ltt_reserve_switch_old_subbuf: switch old subbuffer |
1323 | * | |
1324 | * Concurrency safe because we are the last and only thread to alter this | |
1325 | * sub-buffer. As long as it is not delivered and read, no other thread can | |
1326 | * alter the offset, alter the reserve_count or call the | |
1327 | * client_buffer_end_callback on this sub-buffer. | |
1328 | * | |
1329 | * The only remaining threads could be the ones with pending commits. They will | |
1330 | * have to do the deliver themselves. Not concurrency safe in overwrite mode. | |
1331 | * We detect corrupted subbuffers with commit and reserve counts. We keep a | |
1332 | * corrupted sub-buffers count and push the readers across these sub-buffers. | |
1333 | * | |
1334 | * Not concurrency safe if a writer is stalled in a subbuffer and another writer | |
1335 | * switches in, finding out it's corrupted. The result will be than the old | |
1336 | * (uncommited) subbuffer will be declared corrupted, and that the new subbuffer | |
1337 | * will be declared corrupted too because of the commit count adjustment. | |
1338 | * | |
1339 | * Note : offset_old should never be 0 here. | |
b5b073e2 | 1340 | */ |
b73a4c47 PMF |
1341 | static void ltt_reserve_switch_old_subbuf( |
1342 | struct ust_channel *chan, struct ust_buffer *buf, | |
1343 | struct ltt_reserve_switch_offsets *offsets, u64 *tsc) | |
b5b073e2 | 1344 | { |
b73a4c47 PMF |
1345 | long oldidx = SUBBUF_INDEX(offsets->old - 1, chan); |
1346 | long commit_count, padding_size; | |
b5b073e2 | 1347 | |
b73a4c47 PMF |
1348 | padding_size = chan->subbuf_size |
1349 | - (SUBBUF_OFFSET(offsets->old - 1, chan) + 1); | |
1350 | ltt_buffer_end(buf, *tsc, offsets->old, oldidx); | |
b5b073e2 | 1351 | |
b73a4c47 PMF |
1352 | /* |
1353 | * Must write slot data before incrementing commit count. | |
1354 | * This compiler barrier is upgraded into a smp_wmb() by the IPI | |
1355 | * sent by get_subbuf() when it does its smp_rmb(). | |
1356 | */ | |
1357 | barrier(); | |
1358 | local_add(padding_size, | |
1359 | &buf->commit_count[oldidx].cc); | |
1360 | commit_count = local_read(&buf->commit_count[oldidx].cc); | |
1361 | ltt_check_deliver(chan, buf, offsets->old - 1, commit_count, oldidx); | |
1e8c9e7b | 1362 | ltt_write_commit_counter(chan, buf, oldidx, |
b73a4c47 PMF |
1363 | offsets->old, commit_count, padding_size); |
1364 | } | |
b5b073e2 | 1365 | |
b73a4c47 PMF |
1366 | /* |
1367 | * ltt_reserve_switch_new_subbuf: Populate new subbuffer. | |
1368 | * | |
1369 | * This code can be executed unordered : writers may already have written to the | |
1370 | * sub-buffer before this code gets executed, caution. The commit makes sure | |
1371 | * that this code is executed before the deliver of this sub-buffer. | |
1372 | */ | |
1373 | static void ltt_reserve_switch_new_subbuf( | |
1374 | struct ust_channel *chan, struct ust_buffer *buf, | |
1375 | struct ltt_reserve_switch_offsets *offsets, u64 *tsc) | |
1376 | { | |
1377 | long beginidx = SUBBUF_INDEX(offsets->begin, chan); | |
1378 | long commit_count; | |
b5b073e2 | 1379 | |
b73a4c47 | 1380 | ltt_buffer_begin(buf, *tsc, beginidx); |
b5b073e2 | 1381 | |
b73a4c47 PMF |
1382 | /* |
1383 | * Must write slot data before incrementing commit count. | |
1384 | * This compiler barrier is upgraded into a smp_wmb() by the IPI | |
1385 | * sent by get_subbuf() when it does its smp_rmb(). | |
1386 | */ | |
1387 | barrier(); | |
1388 | local_add(ltt_subbuffer_header_size(), | |
1389 | &buf->commit_count[beginidx].cc); | |
1390 | commit_count = local_read(&buf->commit_count[beginidx].cc); | |
1391 | /* Check if the written buffer has to be delivered */ | |
1392 | ltt_check_deliver(chan, buf, offsets->begin, commit_count, beginidx); | |
1e8c9e7b | 1393 | ltt_write_commit_counter(chan, buf, beginidx, |
b73a4c47 PMF |
1394 | offsets->begin, commit_count, ltt_subbuffer_header_size()); |
1395 | } | |
b5b073e2 | 1396 | |
b73a4c47 PMF |
1397 | /* |
1398 | * ltt_reserve_end_switch_current: finish switching current subbuffer | |
1399 | * | |
1400 | * Concurrency safe because we are the last and only thread to alter this | |
1401 | * sub-buffer. As long as it is not delivered and read, no other thread can | |
1402 | * alter the offset, alter the reserve_count or call the | |
1403 | * client_buffer_end_callback on this sub-buffer. | |
1404 | * | |
1405 | * The only remaining threads could be the ones with pending commits. They will | |
1406 | * have to do the deliver themselves. Not concurrency safe in overwrite mode. | |
1407 | * We detect corrupted subbuffers with commit and reserve counts. We keep a | |
1408 | * corrupted sub-buffers count and push the readers across these sub-buffers. | |
1409 | * | |
1410 | * Not concurrency safe if a writer is stalled in a subbuffer and another writer | |
1411 | * switches in, finding out it's corrupted. The result will be than the old | |
1412 | * (uncommited) subbuffer will be declared corrupted, and that the new subbuffer | |
1413 | * will be declared corrupted too because of the commit count adjustment. | |
1414 | */ | |
1415 | static void ltt_reserve_end_switch_current( | |
1416 | struct ust_channel *chan, | |
1417 | struct ust_buffer *buf, | |
1418 | struct ltt_reserve_switch_offsets *offsets, u64 *tsc) | |
1419 | { | |
1420 | long endidx = SUBBUF_INDEX(offsets->end - 1, chan); | |
1421 | long commit_count, padding_size; | |
1422 | ||
1423 | padding_size = chan->subbuf_size | |
1424 | - (SUBBUF_OFFSET(offsets->end - 1, chan) + 1); | |
1425 | ||
1426 | ltt_buffer_end(buf, *tsc, offsets->end, endidx); | |
1427 | ||
1428 | /* | |
1429 | * Must write slot data before incrementing commit count. | |
1430 | * This compiler barrier is upgraded into a smp_wmb() by the IPI | |
1431 | * sent by get_subbuf() when it does its smp_rmb(). | |
1432 | */ | |
1433 | barrier(); | |
1434 | local_add(padding_size, | |
1435 | &buf->commit_count[endidx].cc); | |
1436 | commit_count = local_read(&buf->commit_count[endidx].cc); | |
1437 | ltt_check_deliver(chan, buf, | |
1438 | offsets->end - 1, commit_count, endidx); | |
1e8c9e7b | 1439 | ltt_write_commit_counter(chan, buf, endidx, |
b73a4c47 | 1440 | offsets->end, commit_count, padding_size); |
b5b073e2 PMF |
1441 | } |
1442 | ||
1443 | /* | |
1444 | * Returns : | |
1445 | * 0 if ok | |
1446 | * !0 if execution must be aborted. | |
1447 | */ | |
b73a4c47 | 1448 | static int ltt_relay_try_switch_slow( |
b5b073e2 | 1449 | enum force_switch_mode mode, |
b73a4c47 | 1450 | struct ust_channel *chan, |
b5b073e2 PMF |
1451 | struct ust_buffer *buf, |
1452 | struct ltt_reserve_switch_offsets *offsets, | |
1453 | u64 *tsc) | |
1454 | { | |
1455 | long subbuf_index; | |
b73a4c47 | 1456 | long reserve_commit_diff; |
b5b073e2 PMF |
1457 | |
1458 | offsets->begin = local_read(&buf->offset); | |
1459 | offsets->old = offsets->begin; | |
1460 | offsets->begin_switch = 0; | |
1461 | offsets->end_switch_old = 0; | |
1462 | ||
1463 | *tsc = trace_clock_read64(); | |
1464 | ||
1465 | if (SUBBUF_OFFSET(offsets->begin, buf->chan) != 0) { | |
1466 | offsets->begin = SUBBUF_ALIGN(offsets->begin, buf->chan); | |
1467 | offsets->end_switch_old = 1; | |
1468 | } else { | |
1469 | /* we do not have to switch : buffer is empty */ | |
1470 | return -1; | |
1471 | } | |
1472 | if (mode == FORCE_ACTIVE) | |
1473 | offsets->begin += ltt_subbuffer_header_size(); | |
1474 | /* | |
1475 | * Always begin_switch in FORCE_ACTIVE mode. | |
1476 | * Test new buffer integrity | |
1477 | */ | |
1478 | subbuf_index = SUBBUF_INDEX(offsets->begin, buf->chan); | |
b73a4c47 | 1479 | reserve_commit_diff = |
b5b073e2 | 1480 | (BUFFER_TRUNC(offsets->begin, buf->chan) |
b73a4c47 PMF |
1481 | >> chan->n_subbufs_order) |
1482 | - (local_read(&buf->commit_count[subbuf_index].cc_sb) | |
1483 | & chan->commit_count_mask); | |
1484 | if (reserve_commit_diff == 0) { | |
b5b073e2 PMF |
1485 | /* Next buffer not corrupted. */ |
1486 | if (mode == FORCE_ACTIVE | |
b73a4c47 | 1487 | && !chan->overwrite |
b5b073e2 | 1488 | && offsets->begin - atomic_long_read(&buf->consumed) |
b73a4c47 | 1489 | >= chan->alloc_size) { |
b5b073e2 PMF |
1490 | /* |
1491 | * We do not overwrite non consumed buffers and we are | |
1492 | * full : ignore switch while tracing is active. | |
1493 | */ | |
1494 | return -1; | |
1495 | } | |
1496 | } else { | |
1497 | /* | |
1498 | * Next subbuffer corrupted. Force pushing reader even in normal | |
1499 | * mode | |
1500 | */ | |
1501 | } | |
1502 | offsets->end = offsets->begin; | |
1503 | return 0; | |
1504 | } | |
1505 | ||
b5b073e2 | 1506 | /* |
b73a4c47 PMF |
1507 | * Force a sub-buffer switch for a per-cpu buffer. This operation is |
1508 | * completely reentrant : can be called while tracing is active with | |
1509 | * absolutely no lock held. | |
b5b073e2 | 1510 | * |
b73a4c47 PMF |
1511 | * Note, however, that as a local_cmpxchg is used for some atomic |
1512 | * operations, this function must be called from the CPU which owns the buffer | |
1513 | * for a ACTIVE flush. | |
b5b073e2 | 1514 | */ |
b73a4c47 PMF |
1515 | void ltt_force_switch_lockless_slow(struct ust_buffer *buf, |
1516 | enum force_switch_mode mode) | |
b5b073e2 | 1517 | { |
b73a4c47 | 1518 | struct ust_channel *chan = buf->chan; |
b5b073e2 | 1519 | struct ltt_reserve_switch_offsets offsets; |
b73a4c47 | 1520 | u64 tsc; |
b5b073e2 | 1521 | |
b5b073e2 PMF |
1522 | offsets.size = 0; |
1523 | ||
10dd3941 | 1524 | DBG("Switching (forced) %s_%d", chan->channel_name, buf->cpu); |
b5b073e2 PMF |
1525 | /* |
1526 | * Perform retryable operations. | |
1527 | */ | |
b5b073e2 | 1528 | do { |
b73a4c47 PMF |
1529 | if (ltt_relay_try_switch_slow(mode, chan, buf, |
1530 | &offsets, &tsc)) | |
1531 | return; | |
b5b073e2 PMF |
1532 | } while (local_cmpxchg(&buf->offset, offsets.old, |
1533 | offsets.end) != offsets.old); | |
1534 | ||
1535 | /* | |
1536 | * Atomically update last_tsc. This update races against concurrent | |
1537 | * atomic updates, but the race will always cause supplementary full TSC | |
1538 | * events, never the opposite (missing a full TSC event when it would be | |
1539 | * needed). | |
1540 | */ | |
b73a4c47 | 1541 | save_last_tsc(buf, tsc); |
b5b073e2 PMF |
1542 | |
1543 | /* | |
1544 | * Push the reader if necessary | |
1545 | */ | |
b73a4c47 PMF |
1546 | if (mode == FORCE_ACTIVE) { |
1547 | ltt_reserve_push_reader(chan, buf, offsets.end - 1); | |
1548 | //ust// ltt_clear_noref_flag(chan, buf, SUBBUF_INDEX(offsets.end - 1, chan)); | |
1549 | } | |
b5b073e2 PMF |
1550 | |
1551 | /* | |
1552 | * Switch old subbuffer if needed. | |
1553 | */ | |
b73a4c47 PMF |
1554 | if (offsets.end_switch_old) { |
1555 | //ust// ltt_clear_noref_flag(rchan, buf, SUBBUF_INDEX(offsets.old - 1, rchan)); | |
1556 | ltt_reserve_switch_old_subbuf(chan, buf, &offsets, &tsc); | |
1557 | } | |
b5b073e2 PMF |
1558 | |
1559 | /* | |
1560 | * Populate new subbuffer. | |
1561 | */ | |
b73a4c47 PMF |
1562 | if (mode == FORCE_ACTIVE) |
1563 | ltt_reserve_switch_new_subbuf(chan, buf, &offsets, &tsc); | |
1564 | } | |
b5b073e2 | 1565 | |
b73a4c47 PMF |
1566 | /* |
1567 | * Returns : | |
1568 | * 0 if ok | |
1569 | * !0 if execution must be aborted. | |
1570 | */ | |
1571 | static int ltt_relay_try_reserve_slow(struct ust_channel *chan, struct ust_buffer *buf, | |
1572 | struct ltt_reserve_switch_offsets *offsets, size_t data_size, | |
1573 | u64 *tsc, unsigned int *rflags, int largest_align) | |
1574 | { | |
1575 | long reserve_commit_diff; | |
b5b073e2 | 1576 | |
b73a4c47 PMF |
1577 | offsets->begin = local_read(&buf->offset); |
1578 | offsets->old = offsets->begin; | |
1579 | offsets->begin_switch = 0; | |
1580 | offsets->end_switch_current = 0; | |
1581 | offsets->end_switch_old = 0; | |
1582 | ||
1583 | *tsc = trace_clock_read64(); | |
1584 | if (last_tsc_overflow(buf, *tsc)) | |
1585 | *rflags = LTT_RFLAG_ID_SIZE_TSC; | |
1586 | ||
1587 | if (unlikely(SUBBUF_OFFSET(offsets->begin, buf->chan) == 0)) { | |
1588 | offsets->begin_switch = 1; /* For offsets->begin */ | |
1589 | } else { | |
1590 | offsets->size = ust_get_header_size(chan, | |
1591 | offsets->begin, data_size, | |
1592 | &offsets->before_hdr_pad, *rflags); | |
1593 | offsets->size += ltt_align(offsets->begin + offsets->size, | |
1594 | largest_align) | |
1595 | + data_size; | |
1596 | if (unlikely((SUBBUF_OFFSET(offsets->begin, buf->chan) + | |
1597 | offsets->size) > buf->chan->subbuf_size)) { | |
1598 | offsets->end_switch_old = 1; /* For offsets->old */ | |
1599 | offsets->begin_switch = 1; /* For offsets->begin */ | |
1600 | } | |
1601 | } | |
1602 | if (unlikely(offsets->begin_switch)) { | |
1603 | long subbuf_index; | |
1604 | ||
1605 | /* | |
1606 | * We are typically not filling the previous buffer completely. | |
1607 | */ | |
1608 | if (likely(offsets->end_switch_old)) | |
1609 | offsets->begin = SUBBUF_ALIGN(offsets->begin, | |
1610 | buf->chan); | |
1611 | offsets->begin = offsets->begin + ltt_subbuffer_header_size(); | |
1612 | /* Test new buffer integrity */ | |
1613 | subbuf_index = SUBBUF_INDEX(offsets->begin, buf->chan); | |
1614 | reserve_commit_diff = | |
1615 | (BUFFER_TRUNC(offsets->begin, buf->chan) | |
1616 | >> chan->n_subbufs_order) | |
1617 | - (local_read(&buf->commit_count[subbuf_index].cc_sb) | |
1618 | & chan->commit_count_mask); | |
1619 | if (likely(reserve_commit_diff == 0)) { | |
1620 | /* Next buffer not corrupted. */ | |
1621 | if (unlikely(!chan->overwrite && | |
1622 | (SUBBUF_TRUNC(offsets->begin, buf->chan) | |
1623 | - SUBBUF_TRUNC(atomic_long_read( | |
1624 | &buf->consumed), | |
1625 | buf->chan)) | |
1626 | >= chan->alloc_size)) { | |
1627 | /* | |
1628 | * We do not overwrite non consumed buffers | |
1629 | * and we are full : event is lost. | |
1630 | */ | |
1631 | local_inc(&buf->events_lost); | |
1632 | return -1; | |
1633 | } else { | |
1634 | /* | |
1635 | * next buffer not corrupted, we are either in | |
1636 | * overwrite mode or the buffer is not full. | |
1637 | * It's safe to write in this new subbuffer. | |
1638 | */ | |
1639 | } | |
1640 | } else { | |
1641 | /* | |
1642 | * Next subbuffer corrupted. Drop event in normal and | |
1643 | * overwrite mode. Caused by either a writer OOPS or | |
1644 | * too many nested writes over a reserve/commit pair. | |
1645 | */ | |
1646 | local_inc(&buf->events_lost); | |
1647 | return -1; | |
1648 | } | |
1649 | offsets->size = ust_get_header_size(chan, | |
1650 | offsets->begin, data_size, | |
1651 | &offsets->before_hdr_pad, *rflags); | |
1652 | offsets->size += ltt_align(offsets->begin + offsets->size, | |
1653 | largest_align) | |
1654 | + data_size; | |
1655 | if (unlikely((SUBBUF_OFFSET(offsets->begin, buf->chan) | |
1656 | + offsets->size) > buf->chan->subbuf_size)) { | |
1657 | /* | |
1658 | * Event too big for subbuffers, report error, don't | |
1659 | * complete the sub-buffer switch. | |
1660 | */ | |
1661 | local_inc(&buf->events_lost); | |
1662 | return -1; | |
1663 | } else { | |
1664 | /* | |
1665 | * We just made a successful buffer switch and the event | |
1666 | * fits in the new subbuffer. Let's write. | |
1667 | */ | |
1668 | } | |
1669 | } else { | |
1670 | /* | |
1671 | * Event fits in the current buffer and we are not on a switch | |
1672 | * boundary. It's safe to write. | |
1673 | */ | |
1674 | } | |
1675 | offsets->end = offsets->begin + offsets->size; | |
1676 | ||
1677 | if (unlikely((SUBBUF_OFFSET(offsets->end, buf->chan)) == 0)) { | |
1678 | /* | |
1679 | * The offset_end will fall at the very beginning of the next | |
1680 | * subbuffer. | |
1681 | */ | |
1682 | offsets->end_switch_current = 1; /* For offsets->begin */ | |
1683 | } | |
b5b073e2 PMF |
1684 | return 0; |
1685 | } | |
1686 | ||
b73a4c47 PMF |
1687 | /** |
1688 | * ltt_relay_reserve_slot_lockless_slow - Atomic slot reservation in a buffer. | |
1689 | * @trace: the trace structure to log to. | |
1690 | * @ltt_channel: channel structure | |
1691 | * @transport_data: data structure specific to ltt relay | |
1692 | * @data_size: size of the variable length data to log. | |
1693 | * @slot_size: pointer to total size of the slot (out) | |
1694 | * @buf_offset : pointer to reserved buffer offset (out) | |
1695 | * @tsc: pointer to the tsc at the slot reservation (out) | |
1696 | * @cpu: cpuid | |
b5b073e2 | 1697 | * |
b73a4c47 PMF |
1698 | * Return : -ENOSPC if not enough space, else returns 0. |
1699 | * It will take care of sub-buffer switching. | |
b5b073e2 | 1700 | */ |
b73a4c47 PMF |
1701 | int ltt_reserve_slot_lockless_slow(struct ust_trace *trace, |
1702 | struct ust_channel *chan, void **transport_data, | |
1703 | size_t data_size, size_t *slot_size, long *buf_offset, u64 *tsc, | |
1704 | unsigned int *rflags, int largest_align, int cpu) | |
b5b073e2 | 1705 | { |
b73a4c47 | 1706 | struct ust_buffer *buf = chan->buf[cpu]; |
b5b073e2 | 1707 | struct ltt_reserve_switch_offsets offsets; |
b5b073e2 | 1708 | |
b5b073e2 PMF |
1709 | offsets.size = 0; |
1710 | ||
b5b073e2 | 1711 | do { |
b73a4c47 PMF |
1712 | if (unlikely(ltt_relay_try_reserve_slow(chan, buf, &offsets, |
1713 | data_size, tsc, rflags, largest_align))) | |
1714 | return -ENOSPC; | |
1715 | } while (unlikely(local_cmpxchg(&buf->offset, offsets.old, | |
1716 | offsets.end) != offsets.old)); | |
b5b073e2 PMF |
1717 | |
1718 | /* | |
1719 | * Atomically update last_tsc. This update races against concurrent | |
1720 | * atomic updates, but the race will always cause supplementary full TSC | |
1721 | * events, never the opposite (missing a full TSC event when it would be | |
1722 | * needed). | |
1723 | */ | |
b73a4c47 | 1724 | save_last_tsc(buf, *tsc); |
b5b073e2 PMF |
1725 | |
1726 | /* | |
1727 | * Push the reader if necessary | |
1728 | */ | |
b73a4c47 PMF |
1729 | ltt_reserve_push_reader(chan, buf, offsets.end - 1); |
1730 | ||
1731 | /* | |
1732 | * Clear noref flag for this subbuffer. | |
1733 | */ | |
1734 | //ust// ltt_clear_noref_flag(chan, buf, SUBBUF_INDEX(offsets.end - 1, chan)); | |
b5b073e2 PMF |
1735 | |
1736 | /* | |
1737 | * Switch old subbuffer if needed. | |
1738 | */ | |
b73a4c47 PMF |
1739 | if (unlikely(offsets.end_switch_old)) { |
1740 | //ust// ltt_clear_noref_flag(chan, buf, SUBBUF_INDEX(offsets.old - 1, chan)); | |
1741 | ltt_reserve_switch_old_subbuf(chan, buf, &offsets, tsc); | |
10dd3941 | 1742 | DBG("Switching %s_%d", chan->channel_name, cpu); |
b73a4c47 | 1743 | } |
b5b073e2 PMF |
1744 | |
1745 | /* | |
1746 | * Populate new subbuffer. | |
1747 | */ | |
b73a4c47 PMF |
1748 | if (unlikely(offsets.begin_switch)) |
1749 | ltt_reserve_switch_new_subbuf(chan, buf, &offsets, tsc); | |
1750 | ||
1751 | if (unlikely(offsets.end_switch_current)) | |
1752 | ltt_reserve_end_switch_current(chan, buf, &offsets, tsc); | |
1753 | ||
1754 | *slot_size = offsets.size; | |
1755 | *buf_offset = offsets.begin + offsets.before_hdr_pad; | |
1756 | return 0; | |
b5b073e2 PMF |
1757 | } |
1758 | ||
b5b073e2 PMF |
1759 | static struct ltt_transport ust_relay_transport = { |
1760 | .name = "ustrelay", | |
1761 | .ops = { | |
1762 | .create_channel = ust_buffers_create_channel, | |
1763 | .finish_channel = ltt_relay_finish_channel, | |
1764 | .remove_channel = ltt_relay_remove_channel, | |
1765 | .wakeup_channel = ltt_relay_async_wakeup_chan, | |
b5b073e2 PMF |
1766 | }, |
1767 | }; | |
1768 | ||
b5b073e2 PMF |
1769 | static char initialized = 0; |
1770 | ||
1771 | void __attribute__((constructor)) init_ustrelay_transport(void) | |
1772 | { | |
1773 | if(!initialized) { | |
1774 | ltt_transport_register(&ust_relay_transport); | |
1775 | initialized = 1; | |
1776 | } | |
1777 | } | |
1778 | ||
b73a4c47 | 1779 | static void __attribute__((destructor)) ust_buffers_exit(void) |
b5b073e2 PMF |
1780 | { |
1781 | ltt_transport_unregister(&ust_relay_transport); | |
1782 | } | |
b73a4c47 PMF |
1783 | |
1784 | size_t ltt_write_event_header_slow(struct ust_trace *trace, | |
1785 | struct ust_channel *channel, | |
1786 | struct ust_buffer *buf, long buf_offset, | |
1787 | u16 eID, u32 event_size, | |
1788 | u64 tsc, unsigned int rflags) | |
1789 | { | |
1790 | struct ltt_event_header header; | |
1791 | u16 small_size; | |
1792 | ||
1793 | switch (rflags) { | |
1794 | case LTT_RFLAG_ID_SIZE_TSC: | |
1795 | header.id_time = 29 << LTT_TSC_BITS; | |
1796 | break; | |
1797 | case LTT_RFLAG_ID_SIZE: | |
1798 | header.id_time = 30 << LTT_TSC_BITS; | |
1799 | break; | |
1800 | case LTT_RFLAG_ID: | |
1801 | header.id_time = 31 << LTT_TSC_BITS; | |
1802 | break; | |
1803 | } | |
1804 | ||
1805 | header.id_time |= (u32)tsc & LTT_TSC_MASK; | |
1806 | ust_buffers_write(buf, buf_offset, &header, sizeof(header)); | |
1807 | buf_offset += sizeof(header); | |
1808 | ||
1809 | switch (rflags) { | |
1810 | case LTT_RFLAG_ID_SIZE_TSC: | |
1811 | small_size = (u16)min_t(u32, event_size, LTT_MAX_SMALL_SIZE); | |
1812 | ust_buffers_write(buf, buf_offset, | |
1813 | &eID, sizeof(u16)); | |
1814 | buf_offset += sizeof(u16); | |
1815 | ust_buffers_write(buf, buf_offset, | |
1816 | &small_size, sizeof(u16)); | |
1817 | buf_offset += sizeof(u16); | |
1818 | if (small_size == LTT_MAX_SMALL_SIZE) { | |
1819 | ust_buffers_write(buf, buf_offset, | |
1820 | &event_size, sizeof(u32)); | |
1821 | buf_offset += sizeof(u32); | |
1822 | } | |
1823 | buf_offset += ltt_align(buf_offset, sizeof(u64)); | |
1824 | ust_buffers_write(buf, buf_offset, | |
1825 | &tsc, sizeof(u64)); | |
1826 | buf_offset += sizeof(u64); | |
1827 | break; | |
1828 | case LTT_RFLAG_ID_SIZE: | |
1829 | small_size = (u16)min_t(u32, event_size, LTT_MAX_SMALL_SIZE); | |
1830 | ust_buffers_write(buf, buf_offset, | |
1831 | &eID, sizeof(u16)); | |
1832 | buf_offset += sizeof(u16); | |
1833 | ust_buffers_write(buf, buf_offset, | |
1834 | &small_size, sizeof(u16)); | |
1835 | buf_offset += sizeof(u16); | |
1836 | if (small_size == LTT_MAX_SMALL_SIZE) { | |
1837 | ust_buffers_write(buf, buf_offset, | |
1838 | &event_size, sizeof(u32)); | |
1839 | buf_offset += sizeof(u32); | |
1840 | } | |
1841 | break; | |
1842 | case LTT_RFLAG_ID: | |
1843 | ust_buffers_write(buf, buf_offset, | |
1844 | &eID, sizeof(u16)); | |
1845 | buf_offset += sizeof(u16); | |
1846 | break; | |
1847 | } | |
1848 | ||
1849 | return buf_offset; | |
1850 | } |