xref: /dpdk/lib/reorder/rte_reorder.c (revision 3178e37c65a676366f33f0bc56f49d9b26a06448)
1 /* SPDX-License-Identifier: BSD-3-Clause
2  * Copyright(c) 2010-2014 Intel Corporation
3  */
4 
5 #include <string.h>
6 #include <sys/queue.h>
7 
8 #include <rte_string_fns.h>
9 #include <rte_log.h>
10 #include <rte_mbuf.h>
11 #include <rte_mbuf_dyn.h>
12 #include <rte_eal_memconfig.h>
13 #include <rte_errno.h>
14 #include <rte_malloc.h>
15 #include <rte_tailq.h>
16 
17 #include "rte_reorder.h"
18 
19 RTE_LOG_REGISTER_DEFAULT(reorder_logtype, INFO);
20 #define RTE_LOGTYPE_REORDER reorder_logtype
21 #define REORDER_LOG(level, ...) \
22 	RTE_LOG_LINE(level, REORDER, "" __VA_ARGS__)
23 
24 TAILQ_HEAD(rte_reorder_list, rte_tailq_entry);
25 
26 static struct rte_tailq_elem rte_reorder_tailq = {
27 	.name = "RTE_REORDER",
28 };
29 EAL_REGISTER_TAILQ(rte_reorder_tailq)
30 
31 #define NO_FLAGS 0
32 #define RTE_REORDER_PREFIX "RO_"
33 #define RTE_REORDER_NAMESIZE 32
34 
35 #define RTE_REORDER_SEQN_DYNFIELD_NAME "rte_reorder_seqn_dynfield"
36 int rte_reorder_seqn_dynfield_offset = -1;
37 
38 /* A generic circular buffer */
39 struct cir_buffer {
40 	unsigned int size;   /**< Number of entries that can be stored */
41 	unsigned int mask;   /**< [buffer_size - 1]: used for wrap-around */
42 	unsigned int head;   /**< insertion point in buffer */
43 	unsigned int tail;   /**< extraction point in buffer */
44 	struct rte_mbuf **entries;
45 } __rte_cache_aligned;
46 
47 /* The reorder buffer data structure itself */
48 struct rte_reorder_buffer {
49 	char name[RTE_REORDER_NAMESIZE];
50 	uint32_t min_seqn;  /**< Lowest seq. number that can be in the buffer */
51 	unsigned int memsize; /**< memory area size of reorder buffer */
52 	bool is_initialized; /**< flag indicates that buffer was initialized */
53 
54 	struct cir_buffer ready_buf; /**< temp buffer for dequeued entries */
55 	struct cir_buffer order_buf; /**< buffer used to reorder entries */
56 } __rte_cache_aligned;
57 
58 static void
59 rte_reorder_free_mbufs(struct rte_reorder_buffer *b);
60 
61 unsigned int
62 rte_reorder_memory_footprint_get(unsigned int size)
63 {
64 	return sizeof(struct rte_reorder_buffer) + (2 * size * sizeof(struct rte_mbuf *));
65 }
66 
67 struct rte_reorder_buffer *
68 rte_reorder_init(struct rte_reorder_buffer *b, unsigned int bufsize,
69 		const char *name, unsigned int size)
70 {
71 	const unsigned int min_bufsize = rte_reorder_memory_footprint_get(size);
72 	static const struct rte_mbuf_dynfield reorder_seqn_dynfield_desc = {
73 		.name = RTE_REORDER_SEQN_DYNFIELD_NAME,
74 		.size = sizeof(rte_reorder_seqn_t),
75 		.align = __alignof__(rte_reorder_seqn_t),
76 	};
77 
78 	if (b == NULL) {
79 		REORDER_LOG(ERR, "Invalid reorder buffer parameter:"
80 					" NULL");
81 		rte_errno = EINVAL;
82 		return NULL;
83 	}
84 	if (!rte_is_power_of_2(size)) {
85 		REORDER_LOG(ERR, "Invalid reorder buffer size"
86 				" - Not a power of 2");
87 		rte_errno = EINVAL;
88 		return NULL;
89 	}
90 	if (name == NULL) {
91 		REORDER_LOG(ERR, "Invalid reorder buffer name ptr:"
92 					" NULL");
93 		rte_errno = EINVAL;
94 		return NULL;
95 	}
96 	if (bufsize < min_bufsize) {
97 		REORDER_LOG(ERR, "Invalid reorder buffer memory size: %u, "
98 			"minimum required: %u", bufsize, min_bufsize);
99 		rte_errno = EINVAL;
100 		return NULL;
101 	}
102 
103 	rte_reorder_seqn_dynfield_offset = rte_mbuf_dynfield_register(&reorder_seqn_dynfield_desc);
104 	if (rte_reorder_seqn_dynfield_offset < 0) {
105 		REORDER_LOG(ERR,
106 			"Failed to register mbuf field for reorder sequence number, rte_errno: %i",
107 			rte_errno);
108 		rte_errno = ENOMEM;
109 		return NULL;
110 	}
111 
112 	memset(b, 0, bufsize);
113 	strlcpy(b->name, name, sizeof(b->name));
114 	b->memsize = bufsize;
115 	b->order_buf.size = b->ready_buf.size = size;
116 	b->order_buf.mask = b->ready_buf.mask = size - 1;
117 	b->ready_buf.entries = (void *)&b[1];
118 	b->order_buf.entries = RTE_PTR_ADD(&b[1],
119 			size * sizeof(b->ready_buf.entries[0]));
120 
121 	return b;
122 }
123 
124 /*
125  * Insert new entry into global list.
126  * Returns pointer to already inserted entry if such exists, or to newly inserted one.
127  */
128 static struct rte_tailq_entry *
129 rte_reorder_entry_insert(struct rte_tailq_entry *new_te)
130 {
131 	struct rte_reorder_list *reorder_list;
132 	struct rte_reorder_buffer *b, *nb;
133 	struct rte_tailq_entry *te;
134 
135 	rte_mcfg_tailq_write_lock();
136 
137 	reorder_list = RTE_TAILQ_CAST(rte_reorder_tailq.head, rte_reorder_list);
138 	/* guarantee there's no existing */
139 	TAILQ_FOREACH(te, reorder_list, next) {
140 		b = (struct rte_reorder_buffer *) te->data;
141 		nb = (struct rte_reorder_buffer *) new_te->data;
142 		if (strncmp(nb->name, b->name, RTE_REORDER_NAMESIZE) == 0)
143 			break;
144 	}
145 
146 	if (te == NULL) {
147 		TAILQ_INSERT_TAIL(reorder_list, new_te, next);
148 		te = new_te;
149 	}
150 
151 	rte_mcfg_tailq_write_unlock();
152 
153 	return te;
154 }
155 
156 struct rte_reorder_buffer*
157 rte_reorder_create(const char *name, unsigned socket_id, unsigned int size)
158 {
159 	struct rte_reorder_buffer *b = NULL;
160 	struct rte_tailq_entry *te, *te_inserted;
161 
162 	const unsigned int bufsize = rte_reorder_memory_footprint_get(size);
163 
164 	/* Check user arguments. */
165 	if (!rte_is_power_of_2(size)) {
166 		REORDER_LOG(ERR, "Invalid reorder buffer size"
167 				" - Not a power of 2");
168 		rte_errno = EINVAL;
169 		return NULL;
170 	}
171 	if (name == NULL) {
172 		REORDER_LOG(ERR, "Invalid reorder buffer name ptr:"
173 					" NULL");
174 		rte_errno = EINVAL;
175 		return NULL;
176 	}
177 
178 	/* allocate tailq entry */
179 	te = rte_zmalloc("REORDER_TAILQ_ENTRY", sizeof(*te), 0);
180 	if (te == NULL) {
181 		REORDER_LOG(ERR, "Failed to allocate tailq entry");
182 		rte_errno = ENOMEM;
183 		return NULL;
184 	}
185 
186 	/* Allocate memory to store the reorder buffer structure. */
187 	b = rte_zmalloc_socket("REORDER_BUFFER", bufsize, 0, socket_id);
188 	if (b == NULL) {
189 		REORDER_LOG(ERR, "Memzone allocation failed");
190 		rte_errno = ENOMEM;
191 		rte_free(te);
192 		return NULL;
193 	} else {
194 		if (rte_reorder_init(b, bufsize, name, size) == NULL) {
195 			rte_free(b);
196 			rte_free(te);
197 			return NULL;
198 		}
199 		te->data = (void *)b;
200 	}
201 
202 	te_inserted = rte_reorder_entry_insert(te);
203 	if (te_inserted != te) {
204 		rte_free(b);
205 		rte_free(te);
206 		return te_inserted->data;
207 	}
208 
209 	return b;
210 }
211 
212 void
213 rte_reorder_reset(struct rte_reorder_buffer *b)
214 {
215 	char name[RTE_REORDER_NAMESIZE];
216 
217 	rte_reorder_free_mbufs(b);
218 	strlcpy(name, b->name, sizeof(name));
219 	/* No error checking as current values should be valid */
220 	rte_reorder_init(b, b->memsize, name, b->order_buf.size);
221 }
222 
223 static void
224 rte_reorder_free_mbufs(struct rte_reorder_buffer *b)
225 {
226 	unsigned i;
227 
228 	/* Free up the mbufs of order buffer & ready buffer */
229 	for (i = 0; i < b->order_buf.size; i++) {
230 		rte_pktmbuf_free(b->order_buf.entries[i]);
231 		rte_pktmbuf_free(b->ready_buf.entries[i]);
232 	}
233 }
234 
235 void
236 rte_reorder_free(struct rte_reorder_buffer *b)
237 {
238 	struct rte_reorder_list *reorder_list;
239 	struct rte_tailq_entry *te;
240 
241 	/* Check user arguments. */
242 	if (b == NULL)
243 		return;
244 
245 	reorder_list = RTE_TAILQ_CAST(rte_reorder_tailq.head, rte_reorder_list);
246 
247 	rte_mcfg_tailq_write_lock();
248 
249 	/* find our tailq entry */
250 	TAILQ_FOREACH(te, reorder_list, next) {
251 		if (te->data == (void *) b)
252 			break;
253 	}
254 	if (te == NULL) {
255 		rte_mcfg_tailq_write_unlock();
256 		return;
257 	}
258 
259 	TAILQ_REMOVE(reorder_list, te, next);
260 
261 	rte_mcfg_tailq_write_unlock();
262 
263 	rte_reorder_free_mbufs(b);
264 
265 	rte_free(b);
266 	rte_free(te);
267 }
268 
269 struct rte_reorder_buffer *
270 rte_reorder_find_existing(const char *name)
271 {
272 	struct rte_reorder_buffer *b = NULL;
273 	struct rte_tailq_entry *te;
274 	struct rte_reorder_list *reorder_list;
275 
276 	if (name == NULL) {
277 		rte_errno = EINVAL;
278 		return NULL;
279 	}
280 
281 	reorder_list = RTE_TAILQ_CAST(rte_reorder_tailq.head, rte_reorder_list);
282 
283 	rte_mcfg_tailq_read_lock();
284 	TAILQ_FOREACH(te, reorder_list, next) {
285 		b = (struct rte_reorder_buffer *) te->data;
286 		if (strncmp(name, b->name, RTE_REORDER_NAMESIZE) == 0)
287 			break;
288 	}
289 	rte_mcfg_tailq_read_unlock();
290 
291 	if (te == NULL) {
292 		rte_errno = ENOENT;
293 		return NULL;
294 	}
295 
296 	return b;
297 }
298 
299 static unsigned
300 rte_reorder_fill_overflow(struct rte_reorder_buffer *b, unsigned n)
301 {
302 	/*
303 	 * 1. Move all ready entries that fit to the ready_buf
304 	 * 2. check if we meet the minimum needed (n).
305 	 * 3. If not, then skip any gaps and keep moving.
306 	 * 4. If at any point the ready buffer is full, stop
307 	 * 5. Return the number of positions the order_buf head has moved
308 	 */
309 
310 	struct cir_buffer *order_buf = &b->order_buf,
311 			*ready_buf = &b->ready_buf;
312 
313 	unsigned int order_head_adv = 0;
314 
315 	/*
316 	 * move at least n packets to ready buffer, assuming ready buffer
317 	 * has room for those packets.
318 	 */
319 	while (order_head_adv < n &&
320 			((ready_buf->head + 1) & ready_buf->mask) != ready_buf->tail) {
321 
322 		/* if we are blocked waiting on a packet, skip it */
323 		if (order_buf->entries[order_buf->head] == NULL) {
324 			order_buf->head = (order_buf->head + 1) & order_buf->mask;
325 			order_head_adv++;
326 		}
327 
328 		/* Move all ready entries that fit to the ready_buf */
329 		while (order_buf->entries[order_buf->head] != NULL) {
330 			ready_buf->entries[ready_buf->head] =
331 					order_buf->entries[order_buf->head];
332 
333 			order_buf->entries[order_buf->head] = NULL;
334 			order_head_adv++;
335 
336 			order_buf->head = (order_buf->head + 1) & order_buf->mask;
337 
338 			if (((ready_buf->head + 1) & ready_buf->mask) == ready_buf->tail)
339 				break;
340 
341 			ready_buf->head = (ready_buf->head + 1) & ready_buf->mask;
342 		}
343 	}
344 
345 	b->min_seqn += order_head_adv;
346 	/* Return the number of positions the order_buf head has moved */
347 	return order_head_adv;
348 }
349 
350 int
351 rte_reorder_insert(struct rte_reorder_buffer *b, struct rte_mbuf *mbuf)
352 {
353 	uint32_t offset, position;
354 	struct cir_buffer *order_buf;
355 
356 	if (b == NULL || mbuf == NULL) {
357 		rte_errno = EINVAL;
358 		return -1;
359 	}
360 
361 	order_buf = &b->order_buf;
362 	if (!b->is_initialized) {
363 		b->min_seqn = *rte_reorder_seqn(mbuf);
364 		b->is_initialized = 1;
365 	}
366 
367 	/*
368 	 * calculate the offset from the head pointer we need to go.
369 	 * The subtraction takes care of the sequence number wrapping.
370 	 * For example (using 16-bit for brevity):
371 	 *	min_seqn  = 0xFFFD
372 	 *	mbuf_seqn = 0x0010
373 	 *	offset    = 0x0010 - 0xFFFD = 0x13
374 	 */
375 	offset = *rte_reorder_seqn(mbuf) - b->min_seqn;
376 
377 	/*
378 	 * action to take depends on offset.
379 	 * offset < buffer->size: the mbuf fits within the current window of
380 	 *    sequence numbers we can reorder. EXPECTED CASE.
381 	 * offset > buffer->size: the mbuf is outside the current window. There
382 	 *    are a number of cases to consider:
383 	 *    1. The packet sequence is just outside the window, then we need
384 	 *       to see about shifting the head pointer and taking any ready
385 	 *       to return packets out of the ring. If there was a delayed
386 	 *       or dropped packet preventing drains from shifting the window
387 	 *       this case will skip over the dropped packet instead, and any
388 	 *       packets dequeued here will be returned on the next drain call.
389 	 *    2. The packet sequence number is vastly outside our window, taken
390 	 *       here as having offset greater than twice the buffer size. In
391 	 *       this case, the packet is probably an old or late packet that
392 	 *       was previously skipped, so just enqueue the packet for
393 	 *       immediate return on the next drain call, or else return error.
394 	 */
395 	if (offset < b->order_buf.size) {
396 		position = (order_buf->head + offset) & order_buf->mask;
397 		order_buf->entries[position] = mbuf;
398 	} else if (offset < 2 * b->order_buf.size) {
399 		if (rte_reorder_fill_overflow(b, offset + 1 - order_buf->size)
400 				< (offset + 1 - order_buf->size)) {
401 			/* Put in handling for enqueue straight to output */
402 			rte_errno = ENOSPC;
403 			return -1;
404 		}
405 		offset = *rte_reorder_seqn(mbuf) - b->min_seqn;
406 		position = (order_buf->head + offset) & order_buf->mask;
407 		order_buf->entries[position] = mbuf;
408 	} else {
409 		/* Put in handling for enqueue straight to output */
410 		rte_errno = ERANGE;
411 		return -1;
412 	}
413 	return 0;
414 }
415 
416 unsigned int
417 rte_reorder_drain(struct rte_reorder_buffer *b, struct rte_mbuf **mbufs,
418 		unsigned max_mbufs)
419 {
420 	unsigned int drain_cnt = 0;
421 
422 	struct cir_buffer *order_buf = &b->order_buf,
423 			*ready_buf = &b->ready_buf;
424 
425 	/* Try to fetch requested number of mbufs from ready buffer */
426 	while ((drain_cnt < max_mbufs) && (ready_buf->tail != ready_buf->head)) {
427 		mbufs[drain_cnt++] = ready_buf->entries[ready_buf->tail];
428 		ready_buf->entries[ready_buf->tail] = NULL;
429 		ready_buf->tail = (ready_buf->tail + 1) & ready_buf->mask;
430 	}
431 
432 	/*
433 	 * If requested number of buffers not fetched from ready buffer, fetch
434 	 * remaining buffers from order buffer
435 	 */
436 	while ((drain_cnt < max_mbufs) &&
437 			(order_buf->entries[order_buf->head] != NULL)) {
438 		mbufs[drain_cnt++] = order_buf->entries[order_buf->head];
439 		order_buf->entries[order_buf->head] = NULL;
440 		b->min_seqn++;
441 		order_buf->head = (order_buf->head + 1) & order_buf->mask;
442 	}
443 
444 	return drain_cnt;
445 }
446 
447 /* Binary search seqn in ready buffer */
448 static inline uint32_t
449 ready_buffer_seqn_find(const struct cir_buffer *ready_buf, const uint32_t seqn)
450 {
451 	uint32_t mid, value, position, high;
452 	uint32_t low = 0;
453 
454 	if (ready_buf->tail > ready_buf->head)
455 		high = ready_buf->tail - ready_buf->head;
456 	else
457 		high = ready_buf->head - ready_buf->tail;
458 
459 	while (low <= high) {
460 		mid = low + (high - low) / 2;
461 		position = (ready_buf->tail + mid) & ready_buf->mask;
462 		value = *rte_reorder_seqn(ready_buf->entries[position]);
463 		if (seqn == value)
464 			return mid;
465 		else if (seqn > value)
466 			low = mid + 1;
467 		else
468 			high = mid - 1;
469 	}
470 
471 	return low;
472 }
473 
474 unsigned int
475 rte_reorder_drain_up_to_seqn(struct rte_reorder_buffer *b, struct rte_mbuf **mbufs,
476 		const unsigned int max_mbufs, const rte_reorder_seqn_t seqn)
477 {
478 	uint32_t i, position, offset;
479 	unsigned int drain_cnt = 0;
480 
481 	struct cir_buffer *order_buf = &b->order_buf,
482 			*ready_buf = &b->ready_buf;
483 
484 	/* Seqn in Ready buffer */
485 	if (seqn < b->min_seqn) {
486 		/* All sequence numbers are higher then given */
487 		if ((ready_buf->tail == ready_buf->head) ||
488 		    (*rte_reorder_seqn(ready_buf->entries[ready_buf->tail]) > seqn))
489 			return 0;
490 
491 		offset = ready_buffer_seqn_find(ready_buf, seqn);
492 
493 		for (i = 0; (i < offset) && (drain_cnt < max_mbufs); i++) {
494 			position = (ready_buf->tail + i) & ready_buf->mask;
495 			mbufs[drain_cnt++] = ready_buf->entries[position];
496 			ready_buf->entries[position] = NULL;
497 		}
498 		ready_buf->tail = (ready_buf->tail + i) & ready_buf->mask;
499 
500 		return drain_cnt;
501 	}
502 
503 	/* Seqn in Order buffer, add all buffers from Ready buffer */
504 	while ((drain_cnt < max_mbufs) && (ready_buf->tail != ready_buf->head)) {
505 		mbufs[drain_cnt++] = ready_buf->entries[ready_buf->tail];
506 		ready_buf->entries[ready_buf->tail] = NULL;
507 		ready_buf->tail = (ready_buf->tail + 1) & ready_buf->mask;
508 	}
509 
510 	/* Fetch buffers from Order buffer up to given sequence number (exclusive) */
511 	offset = RTE_MIN(seqn - b->min_seqn, b->order_buf.size);
512 	for (i = 0; (i < offset) && (drain_cnt < max_mbufs); i++) {
513 		position = (order_buf->head + i) & order_buf->mask;
514 		if (order_buf->entries[position] == NULL)
515 			continue;
516 		mbufs[drain_cnt++] = order_buf->entries[position];
517 		order_buf->entries[position] = NULL;
518 	}
519 	b->min_seqn += i;
520 	order_buf->head = (order_buf->head + i) & order_buf->mask;
521 
522 	return drain_cnt;
523 }
524 
525 static bool
526 rte_reorder_is_empty(const struct rte_reorder_buffer *b)
527 {
528 	const struct cir_buffer *order_buf = &b->order_buf, *ready_buf = &b->ready_buf;
529 	unsigned int i;
530 
531 	/* Ready buffer does not have gaps */
532 	if (ready_buf->tail != ready_buf->head)
533 		return false;
534 
535 	/* Order buffer could have gaps, iterate */
536 	for (i = 0; i < order_buf->size; i++) {
537 		if (order_buf->entries[i] != NULL)
538 			return false;
539 	}
540 
541 	return true;
542 }
543 
544 unsigned int
545 rte_reorder_min_seqn_set(struct rte_reorder_buffer *b, rte_reorder_seqn_t min_seqn)
546 {
547 	if (!rte_reorder_is_empty(b))
548 		return -ENOTEMPTY;
549 
550 	b->min_seqn = min_seqn;
551 	b->is_initialized = true;
552 
553 	return 0;
554 }
555