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)
20 #define offset_gt(_a, _b) ((i32)((_a)-(_b)) > 0)
21 #define offset_geq(_a, _b) ((i32)((_a)-(_b)) >= 0)
24 format_ooo_segment (u8 * s, va_list * args)
26 ooo_segment_t *seg = va_arg (*args, ooo_segment_t *);
28 s = format (s, "pos %u, len %u, next %d, prev %d",
29 seg->start, seg->length, seg->next, seg->prev);
34 format_ooo_list (u8 * s, va_list * args)
36 svm_fifo_t *f = va_arg (*args, svm_fifo_t *);
37 u32 ooo_segment_index = f->ooos_list_head;
40 while (ooo_segment_index != OOO_SEGMENT_INVALID_INDEX)
42 seg = pool_elt_at_index (f->ooo_segments, ooo_segment_index);
43 s = format (s, " %U\n", format_ooo_segment, seg);
44 ooo_segment_index = seg->next;
50 format_svm_fifo (u8 * s, va_list * args)
52 svm_fifo_t *f = va_arg (*args, svm_fifo_t *);
53 int verbose = va_arg (*args, int);
55 s = format (s, "cursize %u nitems %u has_event %d\n",
56 f->cursize, f->nitems, f->has_event);
57 s = format (s, " head %d tail %d\n", f->head, f->tail);
61 (s, " server session %d thread %d client session %d thread %d\n",
62 f->master_session_index, f->master_thread_index,
63 f->client_session_index, f->client_thread_index);
67 s = format (s, " ooo pool %d active elts\n",
68 pool_elts (f->ooo_segments));
69 if (svm_fifo_has_ooo_data (f))
70 s = format (s, " %U", format_ooo_list, f);
75 /** create an svm fifo, in the current heap. Fails vs blow up the process */
77 svm_fifo_create (u32 data_size_in_bytes)
81 f = clib_mem_alloc_aligned_or_null (sizeof (*f) + data_size_in_bytes,
82 CLIB_CACHE_LINE_BYTES);
86 memset (f, 0, sizeof (*f) + data_size_in_bytes);
87 f->nitems = data_size_in_bytes;
88 f->ooos_list_head = OOO_SEGMENT_INVALID_INDEX;
94 svm_fifo_free (svm_fifo_t * f)
96 pool_free (f->ooo_segments);
100 always_inline ooo_segment_t *
101 ooo_segment_new (svm_fifo_t * f, u32 start, u32 length)
105 pool_get (f->ooo_segments, s);
110 s->prev = s->next = OOO_SEGMENT_INVALID_INDEX;
116 ooo_segment_del (svm_fifo_t * f, u32 index)
118 ooo_segment_t *cur, *prev = 0, *next = 0;
119 cur = pool_elt_at_index (f->ooo_segments, index);
121 if (cur->next != OOO_SEGMENT_INVALID_INDEX)
123 next = pool_elt_at_index (f->ooo_segments, cur->next);
124 next->prev = cur->prev;
127 if (cur->prev != OOO_SEGMENT_INVALID_INDEX)
129 prev = pool_elt_at_index (f->ooo_segments, cur->prev);
130 prev->next = cur->next;
134 f->ooos_list_head = cur->next;
137 pool_put (f->ooo_segments, cur);
141 * Add segment to fifo's out-of-order segment list. Takes care of merging
142 * adjacent segments and removing overlapping ones.
145 ooo_segment_add (svm_fifo_t * f, u32 offset, u32 length)
147 ooo_segment_t *s, *new_s, *prev, *next, *it;
148 u32 new_index, end_offset, s_sof, s_eof, s_index;
150 end_offset = offset + length;
152 if (f->ooos_list_head == OOO_SEGMENT_INVALID_INDEX)
154 s = ooo_segment_new (f, offset, length);
155 f->ooos_list_head = s - f->ooo_segments;
156 f->ooos_newest = f->ooos_list_head;
160 /* Find first segment that starts after new segment */
161 s = pool_elt_at_index (f->ooo_segments, f->ooos_list_head);
162 while (s->next != OOO_SEGMENT_INVALID_INDEX
163 && offset_leq (ooo_segment_offset (f, s), offset))
164 s = pool_elt_at_index (f->ooo_segments, s->next);
166 /* If we have a previous and we overlap it, use it as starting point */
167 prev = ooo_segment_get_prev (f, s);
168 if (prev && offset_leq (offset, ooo_segment_end_offset (f, prev)))
171 prev = ooo_segment_get_prev (f, s);
172 s_sof = ooo_segment_offset (f, s);
173 s_eof = ooo_segment_end_offset (f, s);
177 s_index = s - f->ooo_segments;
178 s_sof = ooo_segment_offset (f, s);
179 s_eof = ooo_segment_end_offset (f, s);
181 /* No overlap, add before current segment */
182 if (offset_lt (end_offset, s_sof))
184 new_s = ooo_segment_new (f, offset, length);
185 new_index = new_s - f->ooo_segments;
187 /* Pool might've moved, get segment again */
188 s = pool_elt_at_index (f->ooo_segments, s_index);
189 if (s->prev != OOO_SEGMENT_INVALID_INDEX)
191 new_s->prev = s->prev;
192 prev = pool_elt_at_index (f->ooo_segments, new_s->prev);
193 prev->next = new_index;
198 f->ooos_list_head = new_index;
201 new_s->next = s - f->ooo_segments;
203 f->ooos_newest = new_index;
206 /* No overlap, add after current segment */
207 else if (offset_gt (offset, s_eof))
209 new_s = ooo_segment_new (f, offset, length);
210 new_index = new_s - f->ooo_segments;
212 /* Pool might've moved, get segment again */
213 s = pool_elt_at_index (f->ooo_segments, s_index);
215 if (s->next != OOO_SEGMENT_INVALID_INDEX)
217 new_s->next = s->next;
218 next = pool_elt_at_index (f->ooo_segments, new_s->next);
219 next->prev = new_index;
222 new_s->prev = s - f->ooo_segments;
224 f->ooos_newest = new_index;
236 if (offset_lt (offset, s_sof))
239 s->length = s_eof - ooo_segment_offset (f, s);
241 /* Last but overlapping previous */
242 else if (offset_gt (end_offset, s_eof))
244 s->length = end_offset - ooo_segment_offset (f, s);
246 /* New segment completely covered by current one */
253 /* The new segment's tail may cover multiple smaller ones */
254 if (offset_geq (end_offset, s_eof))
256 /* Remove the completely overlapped segments */
257 it = (s->next != OOO_SEGMENT_INVALID_INDEX) ?
258 pool_elt_at_index (f->ooo_segments, s->next) : 0;
259 while (it && offset_leq (ooo_segment_end_offset (f, it), end_offset))
261 next = (it->next != OOO_SEGMENT_INVALID_INDEX) ?
262 pool_elt_at_index (f->ooo_segments, it->next) : 0;
263 ooo_segment_del (f, it - f->ooo_segments);
267 /* If partial overlap with last, merge */
268 if (it && offset_leq (ooo_segment_offset (f, it), end_offset))
270 s->length = ooo_segment_end_offset (f, it) -
271 ooo_segment_offset (f, s);
272 ooo_segment_del (f, it - f->ooo_segments);
277 /* Most recently updated segment */
278 f->ooos_newest = s - f->ooo_segments;
282 * Removes segments that can now be enqueued because the fifo's tail has
283 * advanced. Returns the number of bytes added to tail.
286 ooo_segment_try_collect (svm_fifo_t * f, u32 n_bytes_enqueued)
289 u32 index, bytes = 0, diff;
290 u32 cursize, norm_start, nitems;
292 /* current size has not yet been updated */
293 cursize = svm_fifo_max_dequeue (f) + n_bytes_enqueued;
296 s = pool_elt_at_index (f->ooo_segments, f->ooos_list_head);
298 norm_start = s->start % nitems;
299 diff = (f->nitems + (i32) (f->tail - norm_start)) % nitems;
304 /* If last tail update overlaps one/multiple ooo segments, remove them */
305 while (0 < diff && diff < cursize)
307 index = s - f->ooo_segments;
309 /* Segment end is beyond the tail. Advance tail and remove segment */
310 if (diff < s->length)
312 f->tail += s->length - diff;
313 f->tail %= f->nitems;
314 bytes = s->length - diff;
315 ooo_segment_del (f, index);
319 /* If we have next go on */
320 if (s->next != OOO_SEGMENT_INVALID_INDEX)
322 s = pool_elt_at_index (f->ooo_segments, s->next);
323 norm_start = s->start % nitems;
324 diff = (f->nitems + (i32) (f->tail - norm_start)) % nitems;
325 ooo_segment_del (f, index);
330 ooo_segment_del (f, index);
335 /* If tail is adjacent to an ooo segment, 'consume' it */
338 bytes = ((nitems - cursize) >= s->length) ? s->length :
344 ooo_segment_del (f, s - f->ooo_segments);
351 svm_fifo_enqueue_internal (svm_fifo_t * f, u32 max_bytes, u8 * copy_from_here)
353 u32 total_copy_bytes, first_copy_bytes, second_copy_bytes;
356 /* read cursize, which can only increase while we're working */
357 cursize = svm_fifo_max_dequeue (f);
359 if (PREDICT_FALSE (cursize == f->nitems))
360 return -2; /* fifo stuffed */
364 /* Number of bytes we're going to copy */
365 total_copy_bytes = (nitems - cursize) < max_bytes ?
366 (nitems - cursize) : max_bytes;
368 if (PREDICT_TRUE (copy_from_here != 0))
370 /* Number of bytes in first copy segment */
371 first_copy_bytes = ((nitems - f->tail) < total_copy_bytes)
372 ? (nitems - f->tail) : total_copy_bytes;
374 clib_memcpy (&f->data[f->tail], copy_from_here, first_copy_bytes);
375 f->tail += first_copy_bytes;
376 f->tail = (f->tail == nitems) ? 0 : f->tail;
378 /* Number of bytes in second copy segment, if any */
379 second_copy_bytes = total_copy_bytes - first_copy_bytes;
380 if (second_copy_bytes)
382 clib_memcpy (&f->data[f->tail], copy_from_here + first_copy_bytes,
384 f->tail += second_copy_bytes;
385 f->tail = (f->tail == nitems) ? 0 : f->tail;
390 /* Account for a zero-copy enqueue done elsewhere */
391 ASSERT (max_bytes <= (nitems - cursize));
392 f->tail += max_bytes;
393 f->tail = f->tail % nitems;
394 total_copy_bytes = max_bytes;
397 /* Any out-of-order segments to collect? */
398 if (PREDICT_FALSE (f->ooos_list_head != OOO_SEGMENT_INVALID_INDEX))
399 total_copy_bytes += ooo_segment_try_collect (f, total_copy_bytes);
401 /* Atomically increase the queue length */
402 __sync_fetch_and_add (&f->cursize, total_copy_bytes);
404 return (total_copy_bytes);
408 svm_fifo_enqueue_nowait (svm_fifo_t * f, u32 max_bytes, u8 * copy_from_here)
410 return svm_fifo_enqueue_internal (f, max_bytes, copy_from_here);
414 * Enqueue a future segment.
416 * Two choices: either copies the entire segment, or copies nothing
417 * Returns 0 of the entire segment was copied
418 * Returns -1 if none of the segment was copied due to lack of space
421 svm_fifo_enqueue_with_offset_internal (svm_fifo_t * f,
426 u32 total_copy_bytes, first_copy_bytes, second_copy_bytes;
428 u32 normalized_offset, offset_from_tail;
430 /* read cursize, which can only increase while we're working */
431 cursize = svm_fifo_max_dequeue (f);
433 normalized_offset = offset % nitems;
435 /* Will this request fit? */
436 offset_from_tail = (nitems + normalized_offset - f->tail) % nitems;
437 if ((required_bytes + offset_from_tail) > (nitems - cursize))
440 ooo_segment_add (f, offset, required_bytes);
442 /* Number of bytes we're going to copy */
443 total_copy_bytes = required_bytes;
445 /* Number of bytes in first copy segment */
446 first_copy_bytes = ((nitems - normalized_offset) < total_copy_bytes)
447 ? (nitems - normalized_offset) : total_copy_bytes;
449 clib_memcpy (&f->data[normalized_offset], copy_from_here, first_copy_bytes);
451 /* Number of bytes in second copy segment, if any */
452 second_copy_bytes = total_copy_bytes - first_copy_bytes;
453 if (second_copy_bytes)
455 normalized_offset += first_copy_bytes;
456 normalized_offset %= nitems;
458 ASSERT (normalized_offset == 0);
460 clib_memcpy (&f->data[normalized_offset],
461 copy_from_here + first_copy_bytes, second_copy_bytes);
469 svm_fifo_enqueue_with_offset (svm_fifo_t * f,
471 u32 required_bytes, u8 * copy_from_here)
473 return svm_fifo_enqueue_with_offset_internal (f, offset, required_bytes,
479 svm_fifo_dequeue_internal (svm_fifo_t * f, u32 max_bytes, u8 * copy_here)
481 u32 total_copy_bytes, first_copy_bytes, second_copy_bytes;
484 /* read cursize, which can only increase while we're working */
485 cursize = svm_fifo_max_dequeue (f);
486 if (PREDICT_FALSE (cursize == 0))
487 return -2; /* nothing in the fifo */
491 /* Number of bytes we're going to copy */
492 total_copy_bytes = (cursize < max_bytes) ? cursize : max_bytes;
494 if (PREDICT_TRUE (copy_here != 0))
496 /* Number of bytes in first copy segment */
497 first_copy_bytes = ((nitems - f->head) < total_copy_bytes)
498 ? (nitems - f->head) : total_copy_bytes;
499 clib_memcpy (copy_here, &f->data[f->head], first_copy_bytes);
500 f->head += first_copy_bytes;
501 f->head = (f->head == nitems) ? 0 : f->head;
503 /* Number of bytes in second copy segment, if any */
504 second_copy_bytes = total_copy_bytes - first_copy_bytes;
505 if (second_copy_bytes)
507 clib_memcpy (copy_here + first_copy_bytes,
508 &f->data[f->head], second_copy_bytes);
509 f->head += second_copy_bytes;
510 f->head = (f->head == nitems) ? 0 : f->head;
515 /* Account for a zero-copy dequeue done elsewhere */
516 ASSERT (max_bytes <= cursize);
517 f->head += max_bytes;
518 f->head = f->head % nitems;
519 cursize -= max_bytes;
520 total_copy_bytes = max_bytes;
523 __sync_fetch_and_sub (&f->cursize, total_copy_bytes);
525 return (total_copy_bytes);
529 svm_fifo_dequeue_nowait (svm_fifo_t * f, u32 max_bytes, u8 * copy_here)
531 return svm_fifo_dequeue_internal (f, max_bytes, copy_here);
535 svm_fifo_peek (svm_fifo_t * f, u32 relative_offset, u32 max_bytes,
538 u32 total_copy_bytes, first_copy_bytes, second_copy_bytes;
539 u32 cursize, nitems, real_head;
541 /* read cursize, which can only increase while we're working */
542 cursize = svm_fifo_max_dequeue (f);
543 if (PREDICT_FALSE (cursize < relative_offset))
544 return -2; /* nothing in the fifo */
547 real_head = f->head + relative_offset;
548 real_head = real_head >= nitems ? real_head - nitems : real_head;
550 /* Number of bytes we're going to copy */
551 total_copy_bytes = (cursize - relative_offset < max_bytes) ?
552 cursize - relative_offset : max_bytes;
554 if (PREDICT_TRUE (copy_here != 0))
556 /* Number of bytes in first copy segment */
558 ((nitems - real_head) < total_copy_bytes) ?
559 (nitems - real_head) : total_copy_bytes;
560 clib_memcpy (copy_here, &f->data[real_head], first_copy_bytes);
562 /* Number of bytes in second copy segment, if any */
563 second_copy_bytes = total_copy_bytes - first_copy_bytes;
564 if (second_copy_bytes)
566 clib_memcpy (copy_here + first_copy_bytes, &f->data[0],
570 return total_copy_bytes;
574 svm_fifo_dequeue_drop (svm_fifo_t * f, u32 max_bytes)
576 u32 total_drop_bytes, first_drop_bytes, second_drop_bytes;
579 /* read cursize, which can only increase while we're working */
580 cursize = svm_fifo_max_dequeue (f);
581 if (PREDICT_FALSE (cursize == 0))
582 return -2; /* nothing in the fifo */
586 /* Number of bytes we're going to drop */
587 total_drop_bytes = (cursize < max_bytes) ? cursize : max_bytes;
589 /* Number of bytes in first copy segment */
591 ((nitems - f->head) < total_drop_bytes) ?
592 (nitems - f->head) : total_drop_bytes;
593 f->head += first_drop_bytes;
594 f->head = (f->head == nitems) ? 0 : f->head;
596 /* Number of bytes in second drop segment, if any */
597 second_drop_bytes = total_drop_bytes - first_drop_bytes;
598 if (second_drop_bytes)
600 f->head += second_drop_bytes;
601 f->head = (f->head == nitems) ? 0 : f->head;
604 __sync_fetch_and_sub (&f->cursize, total_drop_bytes);
606 return total_drop_bytes;
610 svm_fifo_number_ooo_segments (svm_fifo_t * f)
612 return pool_elts (f->ooo_segments);
616 svm_fifo_first_ooo_segment (svm_fifo_t * f)
618 return pool_elt_at_index (f->ooo_segments, f->ooos_list_head);
622 * Set fifo pointers to requested offset
625 svm_fifo_init_pointers (svm_fifo_t * f, u32 pointer)
627 f->head = f->tail = pointer % f->nitems;
631 * fd.io coding-style-patch-verification: ON
634 * eval: (c-set-style "gnu")