Commit | Line | Data |
---|---|---|
852c2936 MD |
1 | /* |
2 | * ring_buffer_backend.c | |
3 | * | |
4 | * Copyright (C) 2005-2010 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
5 | * | |
6 | * Dual LGPL v2.1/GPL v2 license. | |
7 | */ | |
8 | ||
14641deb MD |
9 | #include <urcu/arch.h> |
10 | ||
11 | #include "ust/core.h" | |
12 | ||
8d8a24c8 | 13 | #include <ust/ringbuffer-config.h> |
4931a13e MD |
14 | #include "backend.h" |
15 | #include "frontend.h" | |
a6352fd4 | 16 | #include "smp.h" |
431d5cf0 | 17 | #include "shm.h" |
852c2936 MD |
18 | |
19 | /** | |
20 | * lib_ring_buffer_backend_allocate - allocate a channel buffer | |
21 | * @config: ring buffer instance configuration | |
22 | * @buf: the buffer struct | |
23 | * @size: total size of the buffer | |
24 | * @num_subbuf: number of subbuffers | |
25 | * @extra_reader_sb: need extra subbuffer for reader | |
26 | */ | |
27 | static | |
28 | int lib_ring_buffer_backend_allocate(const struct lib_ring_buffer_config *config, | |
29 | struct lib_ring_buffer_backend *bufb, | |
30 | size_t size, size_t num_subbuf, | |
a6352fd4 MD |
31 | int extra_reader_sb, |
32 | struct shm_header *shm_header) | |
852c2936 | 33 | { |
a6352fd4 | 34 | struct channel_backend *chanb = &shmp(bufb->chan)->backend; |
852c2936 MD |
35 | unsigned long subbuf_size, mmap_offset = 0; |
36 | unsigned long num_subbuf_alloc; | |
852c2936 MD |
37 | unsigned long i; |
38 | ||
852c2936 MD |
39 | subbuf_size = chanb->subbuf_size; |
40 | num_subbuf_alloc = num_subbuf; | |
41 | ||
a6352fd4 | 42 | if (extra_reader_sb) |
852c2936 | 43 | num_subbuf_alloc++; |
852c2936 | 44 | |
431d5cf0 MD |
45 | /* Align the entire buffer backend data on PAGE_SIZE */ |
46 | align_shm(shm_header, PAGE_SIZE); | |
a6352fd4 MD |
47 | set_shmp(bufb->array, zalloc_shm(shm_header, |
48 | sizeof(*bufb->array) * num_subbuf_alloc)); | |
49 | if (unlikely(!shmp(bufb->array))) | |
852c2936 MD |
50 | goto array_error; |
51 | ||
431d5cf0 MD |
52 | /* |
53 | * This is the largest element (the buffer pages) which needs to | |
54 | * be aligned on PAGE_SIZE. | |
55 | */ | |
56 | align_shm(shm_header, PAGE_SIZE); | |
a6352fd4 MD |
57 | set_shmp(bufb->memory_map, zalloc_shm(shm_header, |
58 | subbuf_size * num_subbuf_alloc)); | |
59 | if (unlikely(!shmp(bufb->memory_map))) | |
60 | goto memory_map_error; | |
852c2936 MD |
61 | |
62 | /* Allocate backend pages array elements */ | |
63 | for (i = 0; i < num_subbuf_alloc; i++) { | |
431d5cf0 | 64 | align_shm(shm_header, __alignof__(struct lib_ring_buffer_backend_pages)); |
a6352fd4 MD |
65 | set_shmp(bufb->array[i], |
66 | zalloc_shm(shm_header, | |
431d5cf0 | 67 | sizeof(struct lib_ring_buffer_backend_pages))); |
a6352fd4 | 68 | if (!shmp(bufb->array[i])) |
852c2936 MD |
69 | goto free_array; |
70 | } | |
71 | ||
72 | /* Allocate write-side subbuffer table */ | |
431d5cf0 | 73 | align_shm(shm_header, __alignof__(struct lib_ring_buffer_backend_subbuffer)); |
a6352fd4 | 74 | bufb->buf_wsb = zalloc_shm(shm_header, |
852c2936 | 75 | sizeof(struct lib_ring_buffer_backend_subbuffer) |
14641deb | 76 | * num_subbuf); |
a6352fd4 | 77 | if (unlikely(!shmp(bufb->buf_wsb))) |
852c2936 MD |
78 | goto free_array; |
79 | ||
80 | for (i = 0; i < num_subbuf; i++) | |
a6352fd4 | 81 | shmp(bufb->buf_wsb)[i].id = subbuffer_id(config, 0, 1, i); |
852c2936 MD |
82 | |
83 | /* Assign read-side subbuffer table */ | |
84 | if (extra_reader_sb) | |
85 | bufb->buf_rsb.id = subbuffer_id(config, 0, 1, | |
86 | num_subbuf_alloc - 1); | |
87 | else | |
88 | bufb->buf_rsb.id = subbuffer_id(config, 0, 1, 0); | |
89 | ||
90 | /* Assign pages to page index */ | |
91 | for (i = 0; i < num_subbuf_alloc; i++) { | |
a6352fd4 MD |
92 | set_shmp(shmp(bufb->array)[i]->p, |
93 | &shmp(bufb->memory_map)[i * subbuf_size]); | |
852c2936 | 94 | if (config->output == RING_BUFFER_MMAP) { |
a6352fd4 | 95 | shmp(bufb->array)[i]->mmap_offset = mmap_offset; |
852c2936 MD |
96 | mmap_offset += subbuf_size; |
97 | } | |
98 | } | |
431d5cf0 MD |
99 | /* |
100 | * Align the end of each buffer backend data on PAGE_SIZE, to | |
101 | * behave like an array which contains elements that need to be | |
102 | * aligned on PAGE_SIZE. | |
103 | */ | |
104 | align_shm(shm_header, PAGE_SIZE); | |
852c2936 | 105 | |
852c2936 MD |
106 | return 0; |
107 | ||
108 | free_array: | |
a6352fd4 MD |
109 | /* bufb->array[i] will be freed by shm teardown */ |
110 | memory_map_error: | |
111 | /* bufb->array will be freed by shm teardown */ | |
852c2936 | 112 | array_error: |
852c2936 MD |
113 | return -ENOMEM; |
114 | } | |
115 | ||
116 | int lib_ring_buffer_backend_create(struct lib_ring_buffer_backend *bufb, | |
a6352fd4 MD |
117 | struct channel_backend *chanb, int cpu, |
118 | struct shm_header *shm_header) | |
852c2936 MD |
119 | { |
120 | const struct lib_ring_buffer_config *config = chanb->config; | |
121 | ||
a6352fd4 | 122 | set_shmp(&bufb->chan, caa_container_of(chanb, struct channel, backend)); |
852c2936 MD |
123 | bufb->cpu = cpu; |
124 | ||
125 | return lib_ring_buffer_backend_allocate(config, bufb, chanb->buf_size, | |
126 | chanb->num_subbuf, | |
a6352fd4 MD |
127 | chanb->extra_reader_sb, |
128 | shm_header); | |
852c2936 MD |
129 | } |
130 | ||
131 | void lib_ring_buffer_backend_free(struct lib_ring_buffer_backend *bufb) | |
132 | { | |
a6352fd4 MD |
133 | /* bufb->buf_wsb will be freed by shm teardown */ |
134 | /* bufb->array[i] will be freed by shm teardown */ | |
135 | /* bufb->array will be freed by shm teardown */ | |
852c2936 MD |
136 | bufb->allocated = 0; |
137 | } | |
138 | ||
139 | void lib_ring_buffer_backend_reset(struct lib_ring_buffer_backend *bufb) | |
140 | { | |
a6352fd4 | 141 | struct channel_backend *chanb = &shmp(bufb->chan)->backend; |
852c2936 MD |
142 | const struct lib_ring_buffer_config *config = chanb->config; |
143 | unsigned long num_subbuf_alloc; | |
144 | unsigned int i; | |
145 | ||
146 | num_subbuf_alloc = chanb->num_subbuf; | |
147 | if (chanb->extra_reader_sb) | |
148 | num_subbuf_alloc++; | |
149 | ||
150 | for (i = 0; i < chanb->num_subbuf; i++) | |
a6352fd4 | 151 | shmp(bufb->buf_wsb)[i].id = subbuffer_id(config, 0, 1, i); |
852c2936 MD |
152 | if (chanb->extra_reader_sb) |
153 | bufb->buf_rsb.id = subbuffer_id(config, 0, 1, | |
154 | num_subbuf_alloc - 1); | |
155 | else | |
156 | bufb->buf_rsb.id = subbuffer_id(config, 0, 1, 0); | |
157 | ||
158 | for (i = 0; i < num_subbuf_alloc; i++) { | |
159 | /* Don't reset mmap_offset */ | |
a6352fd4 MD |
160 | v_set(config, &shmp(bufb->array)[i]->records_commit, 0); |
161 | v_set(config, &shmp(bufb->array)[i]->records_unread, 0); | |
162 | shmp(bufb->array)[i]->data_size = 0; | |
852c2936 MD |
163 | /* Don't reset backend page and virt addresses */ |
164 | } | |
165 | /* Don't reset num_pages_per_subbuf, cpu, allocated */ | |
166 | v_set(config, &bufb->records_read, 0); | |
167 | } | |
168 | ||
169 | /* | |
170 | * The frontend is responsible for also calling ring_buffer_backend_reset for | |
171 | * each buffer when calling channel_backend_reset. | |
172 | */ | |
173 | void channel_backend_reset(struct channel_backend *chanb) | |
174 | { | |
14641deb | 175 | struct channel *chan = caa_container_of(chanb, struct channel, backend); |
852c2936 MD |
176 | const struct lib_ring_buffer_config *config = chanb->config; |
177 | ||
178 | /* | |
179 | * Don't reset buf_size, subbuf_size, subbuf_size_order, | |
180 | * num_subbuf_order, buf_size_order, extra_reader_sb, num_subbuf, | |
181 | * priv, notifiers, config, cpumask and name. | |
182 | */ | |
183 | chanb->start_tsc = config->cb.ring_buffer_clock_read(chan); | |
184 | } | |
185 | ||
852c2936 MD |
186 | /** |
187 | * channel_backend_init - initialize a channel backend | |
188 | * @chanb: channel backend | |
189 | * @name: channel name | |
190 | * @config: client ring buffer configuration | |
191 | * @priv: client private data | |
192 | * @parent: dentry of parent directory, %NULL for root directory | |
193 | * @subbuf_size: size of sub-buffers (> PAGE_SIZE, power of 2) | |
194 | * @num_subbuf: number of sub-buffers (power of 2) | |
a6352fd4 | 195 | * @shm_header: shared memory header |
852c2936 MD |
196 | * |
197 | * Returns channel pointer if successful, %NULL otherwise. | |
198 | * | |
199 | * Creates per-cpu channel buffers using the sizes and attributes | |
200 | * specified. The created channel buffer files will be named | |
201 | * name_0...name_N-1. File permissions will be %S_IRUSR. | |
202 | * | |
203 | * Called with CPU hotplug disabled. | |
204 | */ | |
205 | int channel_backend_init(struct channel_backend *chanb, | |
206 | const char *name, | |
207 | const struct lib_ring_buffer_config *config, | |
a6352fd4 MD |
208 | void *priv, size_t subbuf_size, size_t num_subbuf, |
209 | struct shm_header *shm_header) | |
852c2936 | 210 | { |
14641deb | 211 | struct channel *chan = caa_container_of(chanb, struct channel, backend); |
852c2936 MD |
212 | unsigned int i; |
213 | int ret; | |
214 | ||
215 | if (!name) | |
216 | return -EPERM; | |
217 | ||
218 | if (!(subbuf_size && num_subbuf)) | |
219 | return -EPERM; | |
220 | ||
221 | /* Check that the subbuffer size is larger than a page. */ | |
222 | if (subbuf_size < PAGE_SIZE) | |
223 | return -EINVAL; | |
224 | ||
225 | /* | |
226 | * Make sure the number of subbuffers and subbuffer size are power of 2. | |
227 | */ | |
228 | CHAN_WARN_ON(chanb, hweight32(subbuf_size) != 1); | |
229 | CHAN_WARN_ON(chanb, hweight32(num_subbuf) != 1); | |
230 | ||
231 | ret = subbuffer_id_check_index(config, num_subbuf); | |
232 | if (ret) | |
233 | return ret; | |
234 | ||
235 | chanb->priv = priv; | |
236 | chanb->buf_size = num_subbuf * subbuf_size; | |
237 | chanb->subbuf_size = subbuf_size; | |
238 | chanb->buf_size_order = get_count_order(chanb->buf_size); | |
239 | chanb->subbuf_size_order = get_count_order(subbuf_size); | |
240 | chanb->num_subbuf_order = get_count_order(num_subbuf); | |
241 | chanb->extra_reader_sb = | |
242 | (config->mode == RING_BUFFER_OVERWRITE) ? 1 : 0; | |
243 | chanb->num_subbuf = num_subbuf; | |
a6352fd4 MD |
244 | strncpy(chanb->name, name, NAME_MAX); |
245 | chanb->name[NAME_MAX - 1] = '\0'; | |
852c2936 MD |
246 | chanb->config = config; |
247 | ||
248 | if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) { | |
a6352fd4 MD |
249 | struct lib_ring_buffer *buf; |
250 | size_t alloc_size; | |
852c2936 | 251 | |
852c2936 | 252 | /* Allocating the buffer per-cpu structures */ |
431d5cf0 | 253 | align_shm(shm_header, __alignof__(struct lib_ring_buffer)); |
a6352fd4 MD |
254 | alloc_size = sizeof(struct lib_ring_buffer); |
255 | buf = zalloc_shm(shm_header, alloc_size * num_possible_cpus()); | |
256 | if (!buf) | |
257 | goto end; | |
258 | set_shmp(chanb->buf, buf); | |
852c2936 MD |
259 | |
260 | /* | |
a6352fd4 | 261 | * We need to allocate for all possible cpus. |
852c2936 | 262 | */ |
852c2936 | 263 | for_each_possible_cpu(i) { |
a6352fd4 MD |
264 | ret = lib_ring_buffer_create(&shmp(chanb->buf)[i], |
265 | chanb, i, shm_header); | |
852c2936 MD |
266 | if (ret) |
267 | goto free_bufs; /* cpu hotplug locked */ | |
268 | } | |
852c2936 | 269 | } else { |
a6352fd4 MD |
270 | struct lib_ring_buffer *buf; |
271 | size_t alloc_size; | |
272 | ||
431d5cf0 | 273 | align_shm(shm_header, __alignof__(struct lib_ring_buffer)); |
a6352fd4 | 274 | alloc_size = sizeof(struct lib_ring_buffer); |
a6352fd4 MD |
275 | buf = zalloc_shm(shm_header, alloc_size); |
276 | if (!buf) | |
277 | goto end; | |
278 | set_shmp(chanb->buf, buf); | |
279 | ret = lib_ring_buffer_create(shmp(chanb->buf), chanb, -1, | |
280 | shm_header); | |
852c2936 MD |
281 | if (ret) |
282 | goto free_bufs; | |
283 | } | |
284 | chanb->start_tsc = config->cb.ring_buffer_clock_read(chan); | |
285 | ||
286 | return 0; | |
287 | ||
288 | free_bufs: | |
289 | if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) { | |
290 | for_each_possible_cpu(i) { | |
a6352fd4 | 291 | struct lib_ring_buffer *buf = &shmp(chanb->buf)[i]; |
852c2936 MD |
292 | |
293 | if (!buf->backend.allocated) | |
294 | continue; | |
295 | lib_ring_buffer_free(buf); | |
296 | } | |
a6352fd4 MD |
297 | } |
298 | /* We only free the buffer data upon shm teardown */ | |
299 | end: | |
852c2936 MD |
300 | return -ENOMEM; |
301 | } | |
302 | ||
852c2936 MD |
303 | /** |
304 | * channel_backend_free - destroy the channel | |
305 | * @chan: the channel | |
306 | * | |
307 | * Destroy all channel buffers and frees the channel. | |
308 | */ | |
309 | void channel_backend_free(struct channel_backend *chanb) | |
310 | { | |
311 | const struct lib_ring_buffer_config *config = chanb->config; | |
312 | unsigned int i; | |
313 | ||
314 | if (config->alloc == RING_BUFFER_ALLOC_PER_CPU) { | |
315 | for_each_possible_cpu(i) { | |
a6352fd4 | 316 | struct lib_ring_buffer *buf = &shmp(chanb->buf)[i]; |
852c2936 MD |
317 | |
318 | if (!buf->backend.allocated) | |
319 | continue; | |
320 | lib_ring_buffer_free(buf); | |
321 | } | |
852c2936 | 322 | } else { |
a6352fd4 | 323 | struct lib_ring_buffer *buf = shmp(chanb->buf); |
852c2936 MD |
324 | |
325 | CHAN_WARN_ON(chanb, !buf->backend.allocated); | |
326 | lib_ring_buffer_free(buf); | |
852c2936 | 327 | } |
a6352fd4 | 328 | /* We only free the buffer data upon shm teardown */ |
852c2936 MD |
329 | } |
330 | ||
852c2936 MD |
331 | /** |
332 | * lib_ring_buffer_read - read data from ring_buffer_buffer. | |
333 | * @bufb : buffer backend | |
334 | * @offset : offset within the buffer | |
335 | * @dest : destination address | |
336 | * @len : length to copy to destination | |
337 | * | |
338 | * Should be protected by get_subbuf/put_subbuf. | |
339 | * Returns the length copied. | |
340 | */ | |
341 | size_t lib_ring_buffer_read(struct lib_ring_buffer_backend *bufb, size_t offset, | |
342 | void *dest, size_t len) | |
343 | { | |
a6352fd4 | 344 | struct channel_backend *chanb = &shmp(bufb->chan)->backend; |
852c2936 | 345 | const struct lib_ring_buffer_config *config = chanb->config; |
a6352fd4 | 346 | ssize_t orig_len; |
852c2936 MD |
347 | struct lib_ring_buffer_backend_pages *rpages; |
348 | unsigned long sb_bindex, id; | |
349 | ||
350 | orig_len = len; | |
351 | offset &= chanb->buf_size - 1; | |
a6352fd4 | 352 | |
852c2936 MD |
353 | if (unlikely(!len)) |
354 | return 0; | |
a6352fd4 MD |
355 | id = bufb->buf_rsb.id; |
356 | sb_bindex = subbuffer_id_get_index(config, id); | |
357 | rpages = shmp(bufb->array)[sb_bindex]; | |
358 | /* | |
359 | * Underlying layer should never ask for reads across | |
360 | * subbuffers. | |
361 | */ | |
362 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
363 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE | |
364 | && subbuffer_id_is_noref(config, id)); | |
365 | memcpy(dest, shmp(rpages->p) + (offset & ~(chanb->subbuf_size - 1)), len); | |
852c2936 MD |
366 | return orig_len; |
367 | } | |
852c2936 | 368 | |
852c2936 MD |
369 | /** |
370 | * lib_ring_buffer_read_cstr - read a C-style string from ring_buffer. | |
371 | * @bufb : buffer backend | |
372 | * @offset : offset within the buffer | |
373 | * @dest : destination address | |
374 | * @len : destination's length | |
375 | * | |
376 | * return string's length | |
377 | * Should be protected by get_subbuf/put_subbuf. | |
378 | */ | |
379 | int lib_ring_buffer_read_cstr(struct lib_ring_buffer_backend *bufb, size_t offset, | |
380 | void *dest, size_t len) | |
381 | { | |
a6352fd4 | 382 | struct channel_backend *chanb = &shmp(bufb->chan)->backend; |
852c2936 | 383 | const struct lib_ring_buffer_config *config = chanb->config; |
a6352fd4 | 384 | ssize_t string_len, orig_offset; |
852c2936 MD |
385 | char *str; |
386 | struct lib_ring_buffer_backend_pages *rpages; | |
387 | unsigned long sb_bindex, id; | |
388 | ||
389 | offset &= chanb->buf_size - 1; | |
852c2936 | 390 | orig_offset = offset; |
852c2936 MD |
391 | id = bufb->buf_rsb.id; |
392 | sb_bindex = subbuffer_id_get_index(config, id); | |
a6352fd4 MD |
393 | rpages = shmp(bufb->array)[sb_bindex]; |
394 | /* | |
395 | * Underlying layer should never ask for reads across | |
396 | * subbuffers. | |
397 | */ | |
398 | CHAN_WARN_ON(chanb, offset >= chanb->buf_size); | |
852c2936 MD |
399 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE |
400 | && subbuffer_id_is_noref(config, id)); | |
a6352fd4 MD |
401 | str = (char *)shmp(rpages->p) + (offset & ~(chanb->subbuf_size - 1)); |
402 | string_len = strnlen(str, len); | |
403 | if (dest && len) { | |
404 | memcpy(dest, str, string_len); | |
405 | ((char *)dest)[0] = 0; | |
406 | } | |
407 | return offset - orig_offset; | |
852c2936 | 408 | } |
852c2936 MD |
409 | |
410 | /** | |
411 | * lib_ring_buffer_read_offset_address - get address of a buffer location | |
412 | * @bufb : buffer backend | |
413 | * @offset : offset within the buffer. | |
414 | * | |
415 | * Return the address where a given offset is located (for read). | |
416 | * Should be used to get the current subbuffer header pointer. Given we know | |
417 | * it's never on a page boundary, it's safe to write directly to this address, | |
418 | * as long as the write is never bigger than a page size. | |
419 | */ | |
420 | void *lib_ring_buffer_read_offset_address(struct lib_ring_buffer_backend *bufb, | |
421 | size_t offset) | |
422 | { | |
852c2936 | 423 | struct lib_ring_buffer_backend_pages *rpages; |
a6352fd4 | 424 | struct channel_backend *chanb = &shmp(bufb->chan)->backend; |
852c2936 MD |
425 | const struct lib_ring_buffer_config *config = chanb->config; |
426 | unsigned long sb_bindex, id; | |
427 | ||
428 | offset &= chanb->buf_size - 1; | |
852c2936 MD |
429 | id = bufb->buf_rsb.id; |
430 | sb_bindex = subbuffer_id_get_index(config, id); | |
a6352fd4 | 431 | rpages = shmp(bufb->array)[sb_bindex]; |
852c2936 MD |
432 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE |
433 | && subbuffer_id_is_noref(config, id)); | |
a6352fd4 | 434 | return shmp(rpages->p) + (offset & ~(chanb->subbuf_size - 1)); |
852c2936 | 435 | } |
852c2936 MD |
436 | |
437 | /** | |
438 | * lib_ring_buffer_offset_address - get address of a location within the buffer | |
439 | * @bufb : buffer backend | |
440 | * @offset : offset within the buffer. | |
441 | * | |
442 | * Return the address where a given offset is located. | |
443 | * Should be used to get the current subbuffer header pointer. Given we know | |
444 | * it's always at the beginning of a page, it's safe to write directly to this | |
445 | * address, as long as the write is never bigger than a page size. | |
446 | */ | |
447 | void *lib_ring_buffer_offset_address(struct lib_ring_buffer_backend *bufb, | |
448 | size_t offset) | |
449 | { | |
a6352fd4 | 450 | size_t sbidx; |
852c2936 | 451 | struct lib_ring_buffer_backend_pages *rpages; |
a6352fd4 | 452 | struct channel_backend *chanb = &shmp(bufb->chan)->backend; |
852c2936 MD |
453 | const struct lib_ring_buffer_config *config = chanb->config; |
454 | unsigned long sb_bindex, id; | |
455 | ||
456 | offset &= chanb->buf_size - 1; | |
457 | sbidx = offset >> chanb->subbuf_size_order; | |
a6352fd4 | 458 | id = shmp(bufb->buf_wsb)[sbidx].id; |
852c2936 | 459 | sb_bindex = subbuffer_id_get_index(config, id); |
a6352fd4 | 460 | rpages = shmp(bufb->array)[sb_bindex]; |
852c2936 MD |
461 | CHAN_WARN_ON(chanb, config->mode == RING_BUFFER_OVERWRITE |
462 | && subbuffer_id_is_noref(config, id)); | |
a6352fd4 | 463 | return shmp(rpages->p) + (offset & ~(chanb->subbuf_size - 1)); |
852c2936 | 464 | } |