2 * Copyright (c) 2016 Cisco and/or its affiliates.
3 * Licensed under the Apache License, Version 2.0 (the "License");
4 * you may not use this file except in compliance with the License.
5 * You may obtain a copy of the License at:
7 * http://www.apache.org/licenses/LICENSE-2.0
9 * Unless required by applicable law or agreed to in writing, software
10 * distributed under the License is distributed on an "AS IS" BASIS,
11 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 * See the License for the specific language governing permissions and
13 * limitations under the License.
16 #include <svm/svm_fifo.h>
18 #define offset_lt(_a, _b) ((i32)((_a)-(_b)) < 0)
19 #define offset_leq(_a, _b) ((i32)((_a)-(_b)) <= 0)
22 format_ooo_segment (u8 * s, va_list * args)
24 ooo_segment_t *seg = va_arg (*args, ooo_segment_t *);
26 s = format (s, "pos %u, len %u, next %d, prev %d",
27 seg->start, seg->length, seg->next, seg->prev);
32 format_ooo_list (u8 * s, va_list * args)
34 svm_fifo_t *f = va_arg (*args, svm_fifo_t *);
35 u32 ooo_segment_index = f->ooos_list_head;
38 while (ooo_segment_index != OOO_SEGMENT_INVALID_INDEX)
40 seg = pool_elt_at_index (f->ooo_segments, ooo_segment_index);
41 s = format (s, "\n %U", format_ooo_segment, seg);
43 ooo_segment_index = seg->next;
48 /** create an svm fifo, in the current heap. Fails vs blow up the process */
50 svm_fifo_create (u32 data_size_in_bytes)
54 f = clib_mem_alloc_aligned_or_null (sizeof (*f) + data_size_in_bytes,
55 CLIB_CACHE_LINE_BYTES);
59 memset (f, 0, sizeof (*f) + data_size_in_bytes);
60 f->nitems = data_size_in_bytes;
61 f->ooos_list_head = OOO_SEGMENT_INVALID_INDEX;
67 svm_fifo_free (svm_fifo_t * f)
69 pool_free (f->ooo_segments);
73 always_inline ooo_segment_t *
74 ooo_segment_new (svm_fifo_t * f, u32 start, u32 length)
78 pool_get (f->ooo_segments, s);
83 s->prev = s->next = OOO_SEGMENT_INVALID_INDEX;
89 ooo_segment_del (svm_fifo_t * f, u32 index)
91 ooo_segment_t *cur, *prev = 0, *next = 0;
92 cur = pool_elt_at_index (f->ooo_segments, index);
94 if (cur->next != OOO_SEGMENT_INVALID_INDEX)
96 next = pool_elt_at_index (f->ooo_segments, cur->next);
97 next->prev = cur->prev;
100 if (cur->prev != OOO_SEGMENT_INVALID_INDEX)
102 prev = pool_elt_at_index (f->ooo_segments, cur->prev);
103 prev->next = cur->next;
107 f->ooos_list_head = cur->next;
110 pool_put (f->ooo_segments, cur);
114 * Add segment to fifo's out-of-order segment list. Takes care of merging
115 * adjacent segments and removing overlapping ones.
118 ooo_segment_add (svm_fifo_t * f, u32 offset, u32 length)
120 ooo_segment_t *s, *new_s, *prev, *next, *it;
121 u32 new_index, end_offset, s_sof, s_eof, s_index;
123 end_offset = offset + length;
125 if (f->ooos_list_head == OOO_SEGMENT_INVALID_INDEX)
127 s = ooo_segment_new (f, offset, length);
128 f->ooos_list_head = s - f->ooo_segments;
129 f->ooos_newest = f->ooos_list_head;
133 /* Find first segment that starts after new segment */
134 s = pool_elt_at_index (f->ooo_segments, f->ooos_list_head);
135 while (s->next != OOO_SEGMENT_INVALID_INDEX
136 && offset_leq (ooo_segment_offset (f, s), offset))
137 s = pool_elt_at_index (f->ooo_segments, s->next);
139 s_index = s - f->ooo_segments;
140 s_sof = ooo_segment_offset (f, s);
141 s_eof = ooo_segment_end_offset (f, s);
142 prev = ooo_segment_get_prev (f, s);
144 /* No overlap, add before current segment */
145 if (offset_lt (end_offset, s_sof)
146 && (!prev || offset_lt (prev->start + prev->length, offset)))
148 new_s = ooo_segment_new (f, offset, length);
149 new_index = new_s - f->ooo_segments;
151 /* Pool might've moved, get segment again */
152 s = pool_elt_at_index (f->ooo_segments, s_index);
153 if (s->prev != OOO_SEGMENT_INVALID_INDEX)
155 new_s->prev = s->prev;
156 prev = pool_elt_at_index (f->ooo_segments, new_s->prev);
157 prev->next = new_index;
162 f->ooos_list_head = new_index;
165 new_s->next = s - f->ooo_segments;
167 f->ooos_newest = new_index;
170 /* No overlap, add after current segment */
171 else if (offset_lt (s_eof, offset))
173 new_s = ooo_segment_new (f, offset, length);
174 new_index = new_s - f->ooo_segments;
176 /* Pool might've moved, get segment again */
177 s = pool_elt_at_index (f->ooo_segments, s_index);
179 if (s->next != OOO_SEGMENT_INVALID_INDEX)
181 new_s->next = s->next;
182 next = pool_elt_at_index (f->ooo_segments, new_s->next);
183 next->prev = new_index;
186 new_s->prev = s - f->ooo_segments;
188 f->ooos_newest = new_index;
198 if (offset_leq (offset, s_sof))
200 /* If we have a previous, check if we overlap */
201 if (s->prev != OOO_SEGMENT_INVALID_INDEX)
203 prev = pool_elt_at_index (f->ooo_segments, s->prev);
205 /* New segment merges prev and current. Remove previous and
206 * update position of current. */
207 if (offset_leq (offset, ooo_segment_end_offset (f, prev)))
209 s->start = prev->start;
210 s->length = s_eof - ooo_segment_offset (f, prev);
211 ooo_segment_del (f, s->prev);
216 s->length = s_eof - ooo_segment_offset (f, s);
222 s->length = s_eof - ooo_segment_offset (f, s);
225 /* The new segment's tail may cover multiple smaller ones */
226 if (offset_lt (s_eof, end_offset))
228 /* Remove segments completely covered */
229 it = (s->next != OOO_SEGMENT_INVALID_INDEX) ?
230 pool_elt_at_index (f->ooo_segments, s->next) : 0;
231 while (it && offset_lt (ooo_segment_end_offset (f, it), end_offset))
233 next = (it->next != OOO_SEGMENT_INVALID_INDEX) ?
234 pool_elt_at_index (f->ooo_segments, it->next) : 0;
235 ooo_segment_del (f, it - f->ooo_segments);
239 /* Update length. Segment's start might have changed. */
240 s->length = end_offset - ooo_segment_offset (f, s);
242 /* If partial overlap with last, merge */
243 if (it && offset_lt (ooo_segment_offset (f, it), end_offset))
246 it->length - (ooo_segment_offset (f, it) - end_offset);
247 ooo_segment_del (f, it - f->ooo_segments);
251 /* Last but overlapping previous */
252 else if (offset_leq (s_eof, end_offset))
254 s->length = end_offset - ooo_segment_offset (f, s);
256 /* New segment completely covered by current one */
262 /* Most recently updated segment */
263 f->ooos_newest = s - f->ooo_segments;
267 * Removes segments that can now be enqueued because the fifo's tail has
268 * advanced. Returns the number of bytes added to tail.
271 ooo_segment_try_collect (svm_fifo_t * f, u32 n_bytes_enqueued)
274 u32 index, bytes = 0, diff;
277 /* read cursize, which can only increase while we're working */
278 cursize = svm_fifo_max_dequeue (f);
280 s = pool_elt_at_index (f->ooo_segments, f->ooos_list_head);
282 /* If last tail update overlaps one/multiple ooo segments, remove them */
283 diff = (f->nitems + ((int) s->start - f->tail)) % f->nitems;
284 while (0 < diff && diff < n_bytes_enqueued)
286 /* Segment end is beyond the tail. Advance tail and be done */
287 if (diff < s->length)
289 f->tail += s->length - diff;
290 f->tail %= f->nitems;
293 /* If we have next go on */
294 else if (s->next != OOO_SEGMENT_INVALID_INDEX)
296 index = s - f->ooo_segments;
297 s = pool_elt_at_index (f->ooo_segments, s->next);
298 diff = (f->nitems + ((int) s->start - f->tail)) % f->nitems;
299 ooo_segment_del (f, index);
308 /* If tail is adjacent to an ooo segment, 'consume' it */
311 bytes = ((f->nitems - cursize) >= s->length) ? s->length :
315 f->tail %= f->nitems;
317 ooo_segment_del (f, s - f->ooo_segments);
324 svm_fifo_enqueue_internal (svm_fifo_t * f,
325 int pid, u32 max_bytes, u8 * copy_from_here)
327 u32 total_copy_bytes, first_copy_bytes, second_copy_bytes;
330 /* read cursize, which can only increase while we're working */
331 cursize = svm_fifo_max_dequeue (f);
333 if (PREDICT_FALSE (cursize == f->nitems))
334 return -2; /* fifo stuffed */
338 /* Number of bytes we're going to copy */
339 total_copy_bytes = (nitems - cursize) < max_bytes ?
340 (nitems - cursize) : max_bytes;
342 if (PREDICT_TRUE (copy_from_here != 0))
344 /* Number of bytes in first copy segment */
345 first_copy_bytes = ((nitems - f->tail) < total_copy_bytes)
346 ? (nitems - f->tail) : total_copy_bytes;
348 clib_memcpy (&f->data[f->tail], copy_from_here, first_copy_bytes);
349 f->tail += first_copy_bytes;
350 f->tail = (f->tail == nitems) ? 0 : f->tail;
352 /* Number of bytes in second copy segment, if any */
353 second_copy_bytes = total_copy_bytes - first_copy_bytes;
354 if (second_copy_bytes)
356 clib_memcpy (&f->data[f->tail], copy_from_here + first_copy_bytes,
358 f->tail += second_copy_bytes;
359 f->tail = (f->tail == nitems) ? 0 : f->tail;
364 /* Account for a zero-copy enqueue done elsewhere */
365 ASSERT (max_bytes <= (nitems - cursize));
366 f->tail += max_bytes;
367 f->tail = f->tail % nitems;
368 total_copy_bytes = max_bytes;
371 /* Any out-of-order segments to collect? */
372 if (PREDICT_FALSE (f->ooos_list_head != OOO_SEGMENT_INVALID_INDEX))
373 total_copy_bytes += ooo_segment_try_collect (f, total_copy_bytes);
375 /* Atomically increase the queue length */
376 __sync_fetch_and_add (&f->cursize, total_copy_bytes);
378 return (total_copy_bytes);
382 svm_fifo_enqueue_nowait (svm_fifo_t * f,
383 int pid, u32 max_bytes, u8 * copy_from_here)
385 return svm_fifo_enqueue_internal (f, pid, max_bytes, copy_from_here);
389 * Enqueue a future segment.
391 * Two choices: either copies the entire segment, or copies nothing
392 * Returns 0 of the entire segment was copied
393 * Returns -1 if none of the segment was copied due to lack of space
396 svm_fifo_enqueue_with_offset_internal (svm_fifo_t * f,
402 u32 total_copy_bytes, first_copy_bytes, second_copy_bytes;
404 u32 normalized_offset;
407 /* Safety: don't wrap more than nitems/2 */
408 ASSERT ((f->nitems + offset - f->tail) % f->nitems < f->nitems / 2);
410 /* Users would do do well to avoid this */
411 if (PREDICT_FALSE (f->tail == (offset % f->nitems)))
413 rv = svm_fifo_enqueue_internal (f, pid, required_bytes, copy_from_here);
419 /* read cursize, which can only increase while we're working */
420 cursize = svm_fifo_max_dequeue (f);
423 /* Will this request fit? */
424 if ((required_bytes + offset) > (nitems - cursize))
427 ooo_segment_add (f, offset, required_bytes);
429 /* Number of bytes we're going to copy */
430 total_copy_bytes = required_bytes;
431 normalized_offset = offset % nitems;
433 /* Number of bytes in first copy segment */
434 first_copy_bytes = ((nitems - normalized_offset) < total_copy_bytes)
435 ? (nitems - normalized_offset) : total_copy_bytes;
437 clib_memcpy (&f->data[normalized_offset], copy_from_here, first_copy_bytes);
439 /* Number of bytes in second copy segment, if any */
440 second_copy_bytes = total_copy_bytes - first_copy_bytes;
441 if (second_copy_bytes)
443 normalized_offset += first_copy_bytes;
444 normalized_offset %= nitems;
446 ASSERT (normalized_offset == 0);
448 clib_memcpy (&f->data[normalized_offset],
449 copy_from_here + first_copy_bytes, second_copy_bytes);
457 svm_fifo_enqueue_with_offset (svm_fifo_t * f,
460 u32 required_bytes, u8 * copy_from_here)
462 return svm_fifo_enqueue_with_offset_internal
463 (f, pid, offset, required_bytes, copy_from_here);
468 svm_fifo_dequeue_internal (svm_fifo_t * f,
469 int pid, u32 max_bytes, u8 * copy_here)
471 u32 total_copy_bytes, first_copy_bytes, second_copy_bytes;
474 /* read cursize, which can only increase while we're working */
475 cursize = svm_fifo_max_dequeue (f);
476 if (PREDICT_FALSE (cursize == 0))
477 return -2; /* nothing in the fifo */
481 /* Number of bytes we're going to copy */
482 total_copy_bytes = (cursize < max_bytes) ? cursize : max_bytes;
484 if (PREDICT_TRUE (copy_here != 0))
486 /* Number of bytes in first copy segment */
487 first_copy_bytes = ((nitems - f->head) < total_copy_bytes)
488 ? (nitems - f->head) : total_copy_bytes;
489 clib_memcpy (copy_here, &f->data[f->head], first_copy_bytes);
490 f->head += first_copy_bytes;
491 f->head = (f->head == nitems) ? 0 : f->head;
493 /* Number of bytes in second copy segment, if any */
494 second_copy_bytes = total_copy_bytes - first_copy_bytes;
495 if (second_copy_bytes)
497 clib_memcpy (copy_here + first_copy_bytes,
498 &f->data[f->head], second_copy_bytes);
499 f->head += second_copy_bytes;
500 f->head = (f->head == nitems) ? 0 : f->head;
505 /* Account for a zero-copy dequeue done elsewhere */
506 ASSERT (max_bytes <= cursize);
507 f->head += max_bytes;
508 f->head = f->head % nitems;
509 cursize -= max_bytes;
510 total_copy_bytes = max_bytes;
513 __sync_fetch_and_sub (&f->cursize, total_copy_bytes);
515 return (total_copy_bytes);
519 svm_fifo_dequeue_nowait (svm_fifo_t * f,
520 int pid, u32 max_bytes, u8 * copy_here)
522 return svm_fifo_dequeue_internal (f, pid, max_bytes, copy_here);
526 svm_fifo_peek (svm_fifo_t * f, int pid, u32 offset, u32 max_bytes,
529 u32 total_copy_bytes, first_copy_bytes, second_copy_bytes;
530 u32 cursize, nitems, real_head;
532 /* read cursize, which can only increase while we're working */
533 cursize = svm_fifo_max_dequeue (f);
534 if (PREDICT_FALSE (cursize == 0))
535 return -2; /* nothing in the fifo */
538 real_head = f->head + offset;
539 real_head = real_head >= nitems ? real_head - nitems : real_head;
541 /* Number of bytes we're going to copy */
542 total_copy_bytes = (cursize < max_bytes) ? cursize : max_bytes;
544 if (PREDICT_TRUE (copy_here != 0))
546 /* Number of bytes in first copy segment */
548 ((nitems - real_head) < total_copy_bytes) ?
549 (nitems - real_head) : total_copy_bytes;
550 clib_memcpy (copy_here, &f->data[real_head], first_copy_bytes);
552 /* Number of bytes in second copy segment, if any */
553 second_copy_bytes = total_copy_bytes - first_copy_bytes;
554 if (second_copy_bytes)
556 clib_memcpy (copy_here + first_copy_bytes, &f->data[0],
560 return total_copy_bytes;
564 svm_fifo_dequeue_drop (svm_fifo_t * f, int pid, u32 max_bytes)
566 u32 total_drop_bytes, first_drop_bytes, second_drop_bytes;
569 /* read cursize, which can only increase while we're working */
570 cursize = svm_fifo_max_dequeue (f);
571 if (PREDICT_FALSE (cursize == 0))
572 return -2; /* nothing in the fifo */
576 /* Number of bytes we're going to drop */
577 total_drop_bytes = (cursize < max_bytes) ? cursize : max_bytes;
579 /* Number of bytes in first copy segment */
581 ((nitems - f->head) < total_drop_bytes) ?
582 (nitems - f->head) : total_drop_bytes;
583 f->head += first_drop_bytes;
584 f->head = (f->head == nitems) ? 0 : f->head;
586 /* Number of bytes in second drop segment, if any */
587 second_drop_bytes = total_drop_bytes - first_drop_bytes;
588 if (second_drop_bytes)
590 f->head += second_drop_bytes;
591 f->head = (f->head == nitems) ? 0 : f->head;
594 __sync_fetch_and_sub (&f->cursize, total_drop_bytes);
596 return total_drop_bytes;
600 format_svm_fifo (u8 * s, va_list * args)
602 svm_fifo_t *f = va_arg (*args, svm_fifo_t *);
603 int verbose = va_arg (*args, int);
605 s = format (s, "cursize %u nitems %u has_event %d\n",
606 f->cursize, f->nitems, f->has_event);
607 s = format (s, "head %d tail %d\n", f->head, f->tail);
611 (s, "server session %d thread %d client session %d thread %d\n",
612 f->server_session_index, f->server_thread_index,
613 f->client_session_index, f->client_thread_index);
620 s = format (s, "ooo pool %d active elts\n",
621 pool_elts (f->ooo_segments));
623 seg_index = f->ooos_list_head;
625 while (seg_index != OOO_SEGMENT_INVALID_INDEX)
627 seg = pool_elt_at_index (f->ooo_segments, seg_index);
628 s = format (s, " pos %u, len %u next %d\n",
629 seg->start, seg->length, seg->next);
630 seg_index = seg->next;
637 svm_fifo_number_ooo_segments (svm_fifo_t * f)
639 return pool_elts (f->ooo_segments);
643 svm_fifo_first_ooo_segment (svm_fifo_t * f)
645 return pool_elt_at_index (f->ooo_segments, f->ooos_list_head);
649 * fd.io coding-style-patch-verification: ON
652 * eval: (c-set-style "gnu")