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e92f3e28 MD |
1 | #ifndef _LTTNG_RING_BUFFER_CONFIG_H |
2 | #define _LTTNG_RING_BUFFER_CONFIG_H | |
a6352fd4 MD |
3 | |
4 | /* | |
e92f3e28 | 5 | * lttng/ringbuffer-config.h |
a6352fd4 MD |
6 | * |
7 | * Copyright (C) 2010 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
8 | * | |
9 | * Ring buffer configuration header. Note: after declaring the standard inline | |
10 | * functions, clients should also include linux/ringbuffer/api.h. | |
11 | * | |
e92f3e28 MD |
12 | * Permission is hereby granted, free of charge, to any person obtaining a copy |
13 | * of this software and associated documentation files (the "Software"), to deal | |
14 | * in the Software without restriction, including without limitation the rights | |
15 | * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell | |
16 | * copies of the Software, and to permit persons to whom the Software is | |
17 | * furnished to do so, subject to the following conditions: | |
a60d70e6 | 18 | * |
e92f3e28 MD |
19 | * The above copyright notice and this permission notice shall be included in |
20 | * all copies or substantial portions of the Software. | |
d2428e87 MD |
21 | * |
22 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
23 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | |
24 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE | |
25 | * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | |
26 | * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, | |
27 | * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE | |
28 | * SOFTWARE. | |
a6352fd4 MD |
29 | */ |
30 | ||
31 | #include <errno.h> | |
4318ae1b | 32 | #include "lttng/ust-tracer.h" |
b728d87e MD |
33 | #include <stdint.h> |
34 | #include <stddef.h> | |
35 | #include <urcu/arch.h> | |
2e707419 | 36 | #include <string.h> |
4318ae1b | 37 | #include "lttng/align.h" |
a8909ba5 | 38 | #include <lttng/ust-compiler.h> |
a6352fd4 | 39 | |
4cfec15c | 40 | struct lttng_ust_lib_ring_buffer; |
a6352fd4 | 41 | struct channel; |
4cfec15c MD |
42 | struct lttng_ust_lib_ring_buffer_config; |
43 | struct lttng_ust_lib_ring_buffer_ctx; | |
5a821cd6 | 44 | struct lttng_ust_shm_handle; |
a6352fd4 MD |
45 | |
46 | /* | |
47 | * Ring buffer client callbacks. Only used by slow path, never on fast path. | |
48 | * For the fast path, record_header_size(), ring_buffer_clock_read() should be | |
49 | * provided as inline functions too. These may simply return 0 if not used by | |
50 | * the client. | |
51 | */ | |
4cfec15c | 52 | struct lttng_ust_lib_ring_buffer_client_cb { |
a6352fd4 MD |
53 | /* Mandatory callbacks */ |
54 | ||
55 | /* A static inline version is also required for fast path */ | |
2fed87ae | 56 | uint64_t (*ring_buffer_clock_read) (struct channel *chan); |
4cfec15c | 57 | size_t (*record_header_size) (const struct lttng_ust_lib_ring_buffer_config *config, |
a6352fd4 MD |
58 | struct channel *chan, size_t offset, |
59 | size_t *pre_header_padding, | |
4cfec15c | 60 | struct lttng_ust_lib_ring_buffer_ctx *ctx); |
a6352fd4 MD |
61 | |
62 | /* Slow path only, at subbuffer switch */ | |
63 | size_t (*subbuffer_header_size) (void); | |
2fed87ae | 64 | void (*buffer_begin) (struct lttng_ust_lib_ring_buffer *buf, uint64_t tsc, |
1d498196 | 65 | unsigned int subbuf_idx, |
38fae1d3 | 66 | struct lttng_ust_shm_handle *handle); |
2fed87ae | 67 | void (*buffer_end) (struct lttng_ust_lib_ring_buffer *buf, uint64_t tsc, |
1d498196 | 68 | unsigned int subbuf_idx, unsigned long data_size, |
38fae1d3 | 69 | struct lttng_ust_shm_handle *handle); |
a6352fd4 MD |
70 | |
71 | /* Optional callbacks (can be set to NULL) */ | |
72 | ||
73 | /* Called at buffer creation/finalize */ | |
4cfec15c | 74 | int (*buffer_create) (struct lttng_ust_lib_ring_buffer *buf, void *priv, |
1d498196 | 75 | int cpu, const char *name, |
38fae1d3 | 76 | struct lttng_ust_shm_handle *handle); |
a6352fd4 MD |
77 | /* |
78 | * Clients should guarantee that no new reader handle can be opened | |
79 | * after finalize. | |
80 | */ | |
4cfec15c | 81 | void (*buffer_finalize) (struct lttng_ust_lib_ring_buffer *buf, |
1d498196 | 82 | void *priv, int cpu, |
38fae1d3 | 83 | struct lttng_ust_shm_handle *handle); |
a6352fd4 MD |
84 | |
85 | /* | |
86 | * Extract header length, payload length and timestamp from event | |
87 | * record. Used by buffer iterators. Timestamp is only used by channel | |
88 | * iterator. | |
89 | */ | |
4cfec15c MD |
90 | void (*record_get) (const struct lttng_ust_lib_ring_buffer_config *config, |
91 | struct channel *chan, struct lttng_ust_lib_ring_buffer *buf, | |
a6352fd4 | 92 | size_t offset, size_t *header_len, |
2fed87ae | 93 | size_t *payload_len, uint64_t *timestamp, |
38fae1d3 | 94 | struct lttng_ust_shm_handle *handle); |
a9ff648c MD |
95 | /* |
96 | * Offset and size of content size field in client. | |
97 | */ | |
98 | void (*content_size_field) (const struct lttng_ust_lib_ring_buffer_config *config, | |
99 | size_t *offset, size_t *length); | |
100 | void (*packet_size_field) (const struct lttng_ust_lib_ring_buffer_config *config, | |
101 | size_t *offset, size_t *length); | |
a6352fd4 MD |
102 | }; |
103 | ||
104 | /* | |
105 | * Ring buffer instance configuration. | |
106 | * | |
107 | * Declare as "static const" within the client object to ensure the inline fast | |
108 | * paths can be optimized. | |
109 | * | |
110 | * alloc/sync pairs: | |
111 | * | |
112 | * RING_BUFFER_ALLOC_PER_CPU and RING_BUFFER_SYNC_PER_CPU : | |
113 | * Per-cpu buffers with per-cpu synchronization. Tracing must be performed | |
114 | * with preemption disabled (lib_ring_buffer_get_cpu() and | |
115 | * lib_ring_buffer_put_cpu()). | |
116 | * | |
117 | * RING_BUFFER_ALLOC_PER_CPU and RING_BUFFER_SYNC_GLOBAL : | |
118 | * Per-cpu buffer with global synchronization. Tracing can be performed with | |
119 | * preemption enabled, statistically stays on the local buffers. | |
120 | * | |
121 | * RING_BUFFER_ALLOC_GLOBAL and RING_BUFFER_SYNC_PER_CPU : | |
122 | * Should only be used for buffers belonging to a single thread or protected | |
123 | * by mutual exclusion by the client. Note that periodical sub-buffer switch | |
124 | * should be disabled in this kind of configuration. | |
125 | * | |
126 | * RING_BUFFER_ALLOC_GLOBAL and RING_BUFFER_SYNC_GLOBAL : | |
127 | * Global shared buffer with global synchronization. | |
128 | * | |
129 | * wakeup: | |
130 | * | |
131 | * RING_BUFFER_WAKEUP_BY_TIMER uses per-cpu deferrable timers to poll the | |
132 | * buffers and wake up readers if data is ready. Mainly useful for tracers which | |
133 | * don't want to call into the wakeup code on the tracing path. Use in | |
134 | * combination with "read_timer_interval" channel_create() argument. | |
135 | * | |
136 | * RING_BUFFER_WAKEUP_BY_WRITER directly wakes up readers when a subbuffer is | |
137 | * ready to read. Lower latencies before the reader is woken up. Mainly suitable | |
138 | * for drivers. | |
139 | * | |
140 | * RING_BUFFER_WAKEUP_NONE does not perform any wakeup whatsoever. The client | |
141 | * has the responsibility to perform wakeups. | |
142 | */ | |
82b9bde8 | 143 | #define LTTNG_UST_RING_BUFFER_CONFIG_PADDING 20 |
46d52200 ZT |
144 | |
145 | enum lttng_ust_lib_ring_buffer_alloc_types { | |
146 | RING_BUFFER_ALLOC_PER_CPU, | |
147 | RING_BUFFER_ALLOC_GLOBAL, | |
148 | }; | |
149 | ||
150 | enum lttng_ust_lib_ring_buffer_sync_types { | |
151 | RING_BUFFER_SYNC_PER_CPU, /* Wait-free */ | |
152 | RING_BUFFER_SYNC_GLOBAL, /* Lock-free */ | |
153 | }; | |
154 | ||
155 | enum lttng_ust_lib_ring_buffer_mode_types { | |
a9ff648c MD |
156 | RING_BUFFER_OVERWRITE = 0, /* Overwrite when buffer full */ |
157 | RING_BUFFER_DISCARD = 1, /* Discard when buffer full */ | |
46d52200 ZT |
158 | }; |
159 | ||
160 | enum lttng_ust_lib_ring_buffer_output_types { | |
161 | RING_BUFFER_SPLICE, | |
162 | RING_BUFFER_MMAP, | |
163 | RING_BUFFER_READ, /* TODO */ | |
164 | RING_BUFFER_ITERATOR, | |
165 | RING_BUFFER_NONE, | |
166 | }; | |
167 | ||
168 | enum lttng_ust_lib_ring_buffer_backend_types { | |
169 | RING_BUFFER_PAGE, | |
170 | RING_BUFFER_VMAP, /* TODO */ | |
171 | RING_BUFFER_STATIC, /* TODO */ | |
172 | }; | |
173 | ||
174 | enum lttng_ust_lib_ring_buffer_oops_types { | |
175 | RING_BUFFER_NO_OOPS_CONSISTENCY, | |
176 | RING_BUFFER_OOPS_CONSISTENCY, | |
177 | }; | |
178 | ||
179 | enum lttng_ust_lib_ring_buffer_ipi_types { | |
180 | RING_BUFFER_IPI_BARRIER, | |
181 | RING_BUFFER_NO_IPI_BARRIER, | |
182 | }; | |
183 | ||
184 | enum lttng_ust_lib_ring_buffer_wakeup_types { | |
185 | RING_BUFFER_WAKEUP_BY_TIMER, /* wake up performed by timer */ | |
186 | RING_BUFFER_WAKEUP_BY_WRITER, /* | |
187 | * writer wakes up reader, | |
188 | * not lock-free | |
189 | * (takes spinlock). | |
190 | */ | |
191 | }; | |
192 | ||
4cfec15c | 193 | struct lttng_ust_lib_ring_buffer_config { |
46d52200 ZT |
194 | enum lttng_ust_lib_ring_buffer_alloc_types alloc; |
195 | enum lttng_ust_lib_ring_buffer_sync_types sync; | |
196 | enum lttng_ust_lib_ring_buffer_mode_types mode; | |
197 | enum lttng_ust_lib_ring_buffer_output_types output; | |
198 | enum lttng_ust_lib_ring_buffer_backend_types backend; | |
199 | enum lttng_ust_lib_ring_buffer_oops_types oops; | |
200 | enum lttng_ust_lib_ring_buffer_ipi_types ipi; | |
201 | enum lttng_ust_lib_ring_buffer_wakeup_types wakeup; | |
a6352fd4 MD |
202 | /* |
203 | * tsc_bits: timestamp bits saved at each record. | |
204 | * 0 and 64 disable the timestamp compression scheme. | |
205 | */ | |
206 | unsigned int tsc_bits; | |
4cfec15c | 207 | struct lttng_ust_lib_ring_buffer_client_cb cb; |
c1fca457 MD |
208 | /* |
209 | * client_type is used by the consumer process (which is in a | |
210 | * different address space) to lookup the appropriate client | |
211 | * callbacks and update the cb pointers. | |
212 | */ | |
213 | int client_type; | |
82b9bde8 JD |
214 | int _unused1; |
215 | const struct lttng_ust_lib_ring_buffer_client_cb *cb_ptr; | |
2e707419 | 216 | char padding[LTTNG_UST_RING_BUFFER_CONFIG_PADDING]; |
a6352fd4 MD |
217 | }; |
218 | ||
26cc635c MD |
219 | /* State returned by rseq_start, passed as argument to rseq_finish. */ |
220 | struct lttng_rseq_state { | |
221 | volatile struct rseq *rseqp; | |
222 | int32_t cpu_id; /* cpu_id at start. */ | |
223 | uint32_t event_counter; /* event_counter at start. */ | |
224 | }; | |
225 | ||
a6352fd4 MD |
226 | /* |
227 | * ring buffer context | |
228 | * | |
229 | * Context passed to lib_ring_buffer_reserve(), lib_ring_buffer_commit(), | |
230 | * lib_ring_buffer_try_discard_reserve(), lib_ring_buffer_align_ctx() and | |
231 | * lib_ring_buffer_write(). | |
180901e6 MD |
232 | * |
233 | * IMPORTANT: this structure is part of the ABI between the probe and | |
234 | * UST. Fields need to be only added at the end, never reordered, never | |
235 | * removed. | |
a6352fd4 | 236 | */ |
96f85541 | 237 | #define LTTNG_UST_RING_BUFFER_CTX_PADDING \ |
53569322 | 238 | (24 - sizeof(int) - sizeof(void *) - sizeof(void *)) |
4cfec15c | 239 | struct lttng_ust_lib_ring_buffer_ctx { |
a6352fd4 MD |
240 | /* input received by lib_ring_buffer_reserve(), saved here. */ |
241 | struct channel *chan; /* channel */ | |
242 | void *priv; /* client private data */ | |
38fae1d3 | 243 | struct lttng_ust_shm_handle *handle; /* shared-memory handle */ |
a6352fd4 MD |
244 | size_t data_size; /* size of payload */ |
245 | int largest_align; /* | |
246 | * alignment of the largest element | |
247 | * in the payload | |
248 | */ | |
249 | int cpu; /* processor id */ | |
250 | ||
251 | /* output from lib_ring_buffer_reserve() */ | |
4cfec15c | 252 | struct lttng_ust_lib_ring_buffer *buf; /* |
a6352fd4 MD |
253 | * buffer corresponding to processor id |
254 | * for this channel | |
255 | */ | |
256 | size_t slot_size; /* size of the reserved slot */ | |
257 | unsigned long buf_offset; /* offset following the record header */ | |
258 | unsigned long pre_offset; /* | |
259 | * Initial offset position _before_ | |
260 | * the record is written. Positioned | |
261 | * prior to record header alignment | |
262 | * padding. | |
263 | */ | |
2fed87ae | 264 | uint64_t tsc; /* time-stamp counter value */ |
a6352fd4 | 265 | unsigned int rflags; /* reservation flags */ |
82cd0cfd MD |
266 | /* |
267 | * The field ctx_len is the length of struct | |
268 | * lttng_ust_lib_ring_buffer_ctx as known by the user of | |
269 | * lib_ring_buffer_ctx_init. | |
270 | */ | |
271 | unsigned int ctx_len; | |
96f85541 | 272 | void *ip; /* caller ip address */ |
53569322 | 273 | void *priv2; /* 2nd priv data */ |
96f85541 | 274 | char padding2[LTTNG_UST_RING_BUFFER_CTX_PADDING]; |
82cd0cfd MD |
275 | /* |
276 | * This is the end of the initial fields expected by the original ABI | |
277 | * between probes and UST. Only the fields above can be used if | |
278 | * ctx_len is 0. Use the value of ctx_len to find out which of the | |
279 | * following fields may be used. | |
280 | */ | |
a3492932 | 281 | struct lttng_ust_lib_ring_buffer_backend_pages *backend_pages; |
3ea36dea | 282 | struct lttng_rseq_state rseq_state; |
a6352fd4 MD |
283 | }; |
284 | ||
285 | /** | |
286 | * lib_ring_buffer_ctx_init - initialize ring buffer context | |
287 | * @ctx: ring buffer context to initialize | |
288 | * @chan: channel | |
289 | * @priv: client private data | |
290 | * @data_size: size of record data payload | |
291 | * @largest_align: largest alignment within data payload types | |
292 | * @cpu: processor id | |
293 | */ | |
a8909ba5 PW |
294 | static inline lttng_ust_notrace |
295 | void lib_ring_buffer_ctx_init(struct lttng_ust_lib_ring_buffer_ctx *ctx, | |
296 | struct channel *chan, void *priv, | |
297 | size_t data_size, int largest_align, | |
53569322 MD |
298 | int cpu, struct lttng_ust_shm_handle *handle, |
299 | void *priv2); | |
a6352fd4 | 300 | static inline |
4cfec15c | 301 | void lib_ring_buffer_ctx_init(struct lttng_ust_lib_ring_buffer_ctx *ctx, |
a6352fd4 MD |
302 | struct channel *chan, void *priv, |
303 | size_t data_size, int largest_align, | |
53569322 MD |
304 | int cpu, struct lttng_ust_shm_handle *handle, |
305 | void *priv2) | |
a6352fd4 MD |
306 | { |
307 | ctx->chan = chan; | |
308 | ctx->priv = priv; | |
309 | ctx->data_size = data_size; | |
310 | ctx->largest_align = largest_align; | |
311 | ctx->cpu = cpu; | |
312 | ctx->rflags = 0; | |
1d498196 | 313 | ctx->handle = handle; |
82cd0cfd | 314 | ctx->ctx_len = sizeof(struct lttng_ust_lib_ring_buffer_ctx); |
96f85541 | 315 | ctx->ip = 0; |
53569322 | 316 | ctx->priv2 = priv2; |
96f85541 | 317 | memset(ctx->padding2, 0, LTTNG_UST_RING_BUFFER_CTX_PADDING); |
3ea36dea MD |
318 | ctx->rseq_state.rseqp = NULL; |
319 | ctx->rseq_state.cpu_id = -1; | |
320 | ctx->rseq_state.event_counter = 0; | |
a6352fd4 MD |
321 | } |
322 | ||
323 | /* | |
324 | * Reservation flags. | |
325 | * | |
326 | * RING_BUFFER_RFLAG_FULL_TSC | |
327 | * | |
328 | * This flag is passed to record_header_size() and to the primitive used to | |
329 | * write the record header. It indicates that the full 64-bit time value is | |
330 | * needed in the record header. If this flag is not set, the record header needs | |
331 | * only to contain "tsc_bits" bit of time value. | |
332 | * | |
333 | * Reservation flags can be added by the client, starting from | |
334 | * "(RING_BUFFER_FLAGS_END << 0)". It can be used to pass information from | |
335 | * record_header_size() to lib_ring_buffer_write_record_header(). | |
336 | */ | |
337 | #define RING_BUFFER_RFLAG_FULL_TSC (1U << 0) | |
338 | #define RING_BUFFER_RFLAG_END (1U << 1) | |
339 | ||
340 | /* | |
341 | * We need to define RING_BUFFER_ALIGN_ATTR so it is known early at | |
342 | * compile-time. We have to duplicate the "config->align" information and the | |
343 | * definition here because config->align is used both in the slow and fast | |
344 | * paths, but RING_BUFFER_ALIGN_ATTR is only available for the client code. | |
345 | */ | |
346 | #ifdef RING_BUFFER_ALIGN | |
347 | ||
348 | # define RING_BUFFER_ALIGN_ATTR /* Default arch alignment */ | |
349 | ||
350 | /* | |
351 | * Calculate the offset needed to align the type. | |
352 | * size_of_type must be non-zero. | |
353 | */ | |
a8909ba5 PW |
354 | static inline lttng_ust_notrace |
355 | unsigned int lib_ring_buffer_align(size_t align_drift, size_t size_of_type); | |
a6352fd4 MD |
356 | static inline |
357 | unsigned int lib_ring_buffer_align(size_t align_drift, size_t size_of_type) | |
358 | { | |
359 | return offset_align(align_drift, size_of_type); | |
360 | } | |
361 | ||
362 | #else | |
363 | ||
364 | # define RING_BUFFER_ALIGN_ATTR __attribute__((packed)) | |
365 | ||
366 | /* | |
367 | * Calculate the offset needed to align the type. | |
368 | * size_of_type must be non-zero. | |
369 | */ | |
a8909ba5 PW |
370 | static inline lttng_ust_notrace |
371 | unsigned int lib_ring_buffer_align(size_t align_drift, size_t size_of_type); | |
a6352fd4 MD |
372 | static inline |
373 | unsigned int lib_ring_buffer_align(size_t align_drift, size_t size_of_type) | |
374 | { | |
375 | return 0; | |
376 | } | |
377 | ||
378 | #endif | |
379 | ||
380 | /** | |
381 | * lib_ring_buffer_align_ctx - Align context offset on "alignment" | |
382 | * @ctx: ring buffer context. | |
383 | */ | |
a8909ba5 PW |
384 | static inline lttng_ust_notrace |
385 | void lib_ring_buffer_align_ctx(struct lttng_ust_lib_ring_buffer_ctx *ctx, | |
386 | size_t alignment); | |
a6352fd4 | 387 | static inline |
4cfec15c | 388 | void lib_ring_buffer_align_ctx(struct lttng_ust_lib_ring_buffer_ctx *ctx, |
a6352fd4 MD |
389 | size_t alignment) |
390 | { | |
391 | ctx->buf_offset += lib_ring_buffer_align(ctx->buf_offset, | |
392 | alignment); | |
393 | } | |
394 | ||
395 | /* | |
396 | * lib_ring_buffer_check_config() returns 0 on success. | |
397 | * Used internally to check for valid configurations at channel creation. | |
398 | */ | |
a8909ba5 PW |
399 | static inline lttng_ust_notrace |
400 | int lib_ring_buffer_check_config(const struct lttng_ust_lib_ring_buffer_config *config, | |
401 | unsigned int switch_timer_interval, | |
402 | unsigned int read_timer_interval); | |
a6352fd4 | 403 | static inline |
4cfec15c | 404 | int lib_ring_buffer_check_config(const struct lttng_ust_lib_ring_buffer_config *config, |
a6352fd4 MD |
405 | unsigned int switch_timer_interval, |
406 | unsigned int read_timer_interval) | |
407 | { | |
408 | if (config->alloc == RING_BUFFER_ALLOC_GLOBAL | |
409 | && config->sync == RING_BUFFER_SYNC_PER_CPU | |
410 | && switch_timer_interval) | |
411 | return -EINVAL; | |
412 | return 0; | |
413 | } | |
414 | ||
e92f3e28 | 415 | #endif /* _LTTNG_RING_BUFFER_CONFIG_H */ |