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 s = format (s, "%U", format_ooo_list, f);
74 /** create an svm fifo, in the current heap. Fails vs blow up the process */
76 svm_fifo_create (u32 data_size_in_bytes)
80 f = clib_mem_alloc_aligned_or_null (sizeof (*f) + data_size_in_bytes,
81 CLIB_CACHE_LINE_BYTES);
85 memset (f, 0, sizeof (*f) + data_size_in_bytes);
86 f->nitems = data_size_in_bytes;
87 f->ooos_list_head = OOO_SEGMENT_INVALID_INDEX;
93 svm_fifo_free (svm_fifo_t * f)
95 pool_free (f->ooo_segments);
99 always_inline ooo_segment_t *
100 ooo_segment_new (svm_fifo_t * f, u32 start, u32 length)
104 pool_get (f->ooo_segments, s);
109 s->prev = s->next = OOO_SEGMENT_INVALID_INDEX;
115 ooo_segment_del (svm_fifo_t * f, u32 index)
117 ooo_segment_t *cur, *prev = 0, *next = 0;
118 cur = pool_elt_at_index (f->ooo_segments, index);
120 if (cur->next != OOO_SEGMENT_INVALID_INDEX)
122 next = pool_elt_at_index (f->ooo_segments, cur->next);
123 next->prev = cur->prev;
126 if (cur->prev != OOO_SEGMENT_INVALID_INDEX)
128 prev = pool_elt_at_index (f->ooo_segments, cur->prev);
129 prev->next = cur->next;
133 f->ooos_list_head = cur->next;
136 pool_put (f->ooo_segments, cur);
140 * Add segment to fifo's out-of-order segment list. Takes care of merging
141 * adjacent segments and removing overlapping ones.
144 ooo_segment_add (svm_fifo_t * f, u32 offset, u32 length)
146 ooo_segment_t *s, *new_s, *prev, *next, *it;
147 u32 new_index, end_offset, s_sof, s_eof, s_index;
149 end_offset = offset + length;
151 if (f->ooos_list_head == OOO_SEGMENT_INVALID_INDEX)
153 s = ooo_segment_new (f, offset, length);
154 f->ooos_list_head = s - f->ooo_segments;
155 f->ooos_newest = f->ooos_list_head;
159 /* Find first segment that starts after new segment */
160 s = pool_elt_at_index (f->ooo_segments, f->ooos_list_head);
161 while (s->next != OOO_SEGMENT_INVALID_INDEX
162 && offset_leq (ooo_segment_offset (f, s), offset))
163 s = pool_elt_at_index (f->ooo_segments, s->next);
165 /* If we have a previous and we overlap it, use it as starting point */
166 prev = ooo_segment_get_prev (f, s);
167 if (prev && offset_leq (offset, ooo_segment_end_offset (f, prev)))
170 prev = ooo_segment_get_prev (f, s);
171 s_sof = ooo_segment_offset (f, s);
172 s_eof = ooo_segment_end_offset (f, s);
176 s_index = s - f->ooo_segments;
177 s_sof = ooo_segment_offset (f, s);
178 s_eof = ooo_segment_end_offset (f, s);
180 /* No overlap, add before current segment */
181 if (offset_lt (end_offset, s_sof))
183 new_s = ooo_segment_new (f, offset, length);
184 new_index = new_s - f->ooo_segments;
186 /* Pool might've moved, get segment again */
187 s = pool_elt_at_index (f->ooo_segments, s_index);
188 if (s->prev != OOO_SEGMENT_INVALID_INDEX)
190 new_s->prev = s->prev;
191 prev = pool_elt_at_index (f->ooo_segments, new_s->prev);
192 prev->next = new_index;
197 f->ooos_list_head = new_index;
200 new_s->next = s - f->ooo_segments;
202 f->ooos_newest = new_index;
205 /* No overlap, add after current segment */
206 else if (offset_gt (offset, s_eof))
208 new_s = ooo_segment_new (f, offset, length);
209 new_index = new_s - f->ooo_segments;
211 /* Pool might've moved, get segment again */
212 s = pool_elt_at_index (f->ooo_segments, s_index);
214 if (s->next != OOO_SEGMENT_INVALID_INDEX)
216 new_s->next = s->next;
217 next = pool_elt_at_index (f->ooo_segments, new_s->next);
218 next->prev = new_index;
221 new_s->prev = s - f->ooo_segments;
223 f->ooos_newest = new_index;
235 if (offset_lt (offset, s_sof))
238 s->length = s_eof - ooo_segment_offset (f, s);
240 /* Last but overlapping previous */
241 else if (offset_gt (end_offset, s_eof))
243 s->length = end_offset - ooo_segment_offset (f, s);
245 /* New segment completely covered by current one */
252 /* The new segment's tail may cover multiple smaller ones */
253 if (offset_geq (end_offset, s_eof))
255 /* Remove the completely overlapped segments */
256 it = (s->next != OOO_SEGMENT_INVALID_INDEX) ?
257 pool_elt_at_index (f->ooo_segments, s->next) : 0;
258 while (it && offset_leq (ooo_segment_end_offset (f, it), end_offset))
260 next = (it->next != OOO_SEGMENT_INVALID_INDEX) ?
261 pool_elt_at_index (f->ooo_segments, it->next) : 0;
262 ooo_segment_del (f, it - f->ooo_segments);
266 /* If partial overlap with last, merge */
267 if (it && offset_leq (ooo_segment_offset (f, it), end_offset))
269 s->length = ooo_segment_end_offset (f, it) -
270 ooo_segment_offset (f, s);
271 ooo_segment_del (f, it - f->ooo_segments);
276 /* Most recently updated segment */
277 f->ooos_newest = s - f->ooo_segments;
281 * Removes segments that can now be enqueued because the fifo's tail has
282 * advanced. Returns the number of bytes added to tail.
285 ooo_segment_try_collect (svm_fifo_t * f, u32 n_bytes_enqueued)
288 u32 index, bytes = 0, diff;
289 u32 cursize, norm_start, nitems;
291 /* current size has not yet been updated */
292 cursize = svm_fifo_max_dequeue (f) + n_bytes_enqueued;
295 s = pool_elt_at_index (f->ooo_segments, f->ooos_list_head);
297 norm_start = s->start % nitems;
298 diff = (f->nitems + (i32) (f->tail - norm_start)) % nitems;
303 /* If last tail update overlaps one/multiple ooo segments, remove them */
304 while (0 < diff && diff < cursize)
306 index = s - f->ooo_segments;
308 /* Segment end is beyond the tail. Advance tail and remove segment */
309 if (diff < s->length)
311 f->tail += s->length - diff;
312 f->tail %= f->nitems;
313 bytes = s->length - diff;
314 ooo_segment_del (f, index);
318 /* If we have next go on */
319 if (s->next != OOO_SEGMENT_INVALID_INDEX)
321 s = pool_elt_at_index (f->ooo_segments, s->next);
322 norm_start = s->start % nitems;
323 diff = (f->nitems + (i32) (f->tail - norm_start)) % nitems;
324 ooo_segment_del (f, index);
329 ooo_segment_del (f, index);
334 /* If tail is adjacent to an ooo segment, 'consume' it */
337 bytes = ((nitems - cursize) >= s->length) ? s->length :
343 ooo_segment_del (f, s - f->ooo_segments);
350 svm_fifo_enqueue_internal (svm_fifo_t * f, u32 max_bytes, u8 * copy_from_here)
352 u32 total_copy_bytes, first_copy_bytes, second_copy_bytes;
355 /* read cursize, which can only increase while we're working */
356 cursize = svm_fifo_max_dequeue (f);
358 if (PREDICT_FALSE (cursize == f->nitems))
359 return -2; /* fifo stuffed */
363 /* Number of bytes we're going to copy */
364 total_copy_bytes = (nitems - cursize) < max_bytes ?
365 (nitems - cursize) : max_bytes;
367 if (PREDICT_TRUE (copy_from_here != 0))
369 /* Number of bytes in first copy segment */
370 first_copy_bytes = ((nitems - f->tail) < total_copy_bytes)
371 ? (nitems - f->tail) : total_copy_bytes;
373 clib_memcpy (&f->data[f->tail], copy_from_here, first_copy_bytes);
374 f->tail += first_copy_bytes;
375 f->tail = (f->tail == nitems) ? 0 : f->tail;
377 /* Number of bytes in second copy segment, if any */
378 second_copy_bytes = total_copy_bytes - first_copy_bytes;
379 if (second_copy_bytes)
381 clib_memcpy (&f->data[f->tail], copy_from_here + first_copy_bytes,
383 f->tail += second_copy_bytes;
384 f->tail = (f->tail == nitems) ? 0 : f->tail;
389 /* Account for a zero-copy enqueue done elsewhere */
390 ASSERT (max_bytes <= (nitems - cursize));
391 f->tail += max_bytes;
392 f->tail = f->tail % nitems;
393 total_copy_bytes = max_bytes;
396 /* Any out-of-order segments to collect? */
397 if (PREDICT_FALSE (f->ooos_list_head != OOO_SEGMENT_INVALID_INDEX))
398 total_copy_bytes += ooo_segment_try_collect (f, total_copy_bytes);
400 /* Atomically increase the queue length */
401 __sync_fetch_and_add (&f->cursize, total_copy_bytes);
403 return (total_copy_bytes);
407 svm_fifo_enqueue_nowait (svm_fifo_t * f, u32 max_bytes, u8 * copy_from_here)
409 return svm_fifo_enqueue_internal (f, max_bytes, copy_from_here);
413 * Enqueue a future segment.
415 * Two choices: either copies the entire segment, or copies nothing
416 * Returns 0 of the entire segment was copied
417 * Returns -1 if none of the segment was copied due to lack of space
420 svm_fifo_enqueue_with_offset_internal (svm_fifo_t * f,
425 u32 total_copy_bytes, first_copy_bytes, second_copy_bytes;
427 u32 normalized_offset, offset_from_tail;
429 /* read cursize, which can only increase while we're working */
430 cursize = svm_fifo_max_dequeue (f);
432 normalized_offset = offset % nitems;
434 /* Will this request fit? */
435 offset_from_tail = (nitems + normalized_offset - f->tail) % nitems;
436 if ((required_bytes + offset_from_tail) > (nitems - cursize))
439 ooo_segment_add (f, offset, required_bytes);
441 /* Number of bytes we're going to copy */
442 total_copy_bytes = required_bytes;
444 /* Number of bytes in first copy segment */
445 first_copy_bytes = ((nitems - normalized_offset) < total_copy_bytes)
446 ? (nitems - normalized_offset) : total_copy_bytes;
448 clib_memcpy (&f->data[normalized_offset], copy_from_here, first_copy_bytes);
450 /* Number of bytes in second copy segment, if any */
451 second_copy_bytes = total_copy_bytes - first_copy_bytes;
452 if (second_copy_bytes)
454 normalized_offset += first_copy_bytes;
455 normalized_offset %= nitems;
457 ASSERT (normalized_offset == 0);
459 clib_memcpy (&f->data[normalized_offset],
460 copy_from_here + first_copy_bytes, second_copy_bytes);
468 svm_fifo_enqueue_with_offset (svm_fifo_t * f,
470 u32 required_bytes, u8 * copy_from_here)
472 return svm_fifo_enqueue_with_offset_internal (f, offset, required_bytes,
478 svm_fifo_dequeue_internal (svm_fifo_t * f, u32 max_bytes, u8 * copy_here)
480 u32 total_copy_bytes, first_copy_bytes, second_copy_bytes;
483 /* read cursize, which can only increase while we're working */
484 cursize = svm_fifo_max_dequeue (f);
485 if (PREDICT_FALSE (cursize == 0))
486 return -2; /* nothing in the fifo */
490 /* Number of bytes we're going to copy */
491 total_copy_bytes = (cursize < max_bytes) ? cursize : max_bytes;
493 if (PREDICT_TRUE (copy_here != 0))
495 /* Number of bytes in first copy segment */
496 first_copy_bytes = ((nitems - f->head) < total_copy_bytes)
497 ? (nitems - f->head) : total_copy_bytes;
498 clib_memcpy (copy_here, &f->data[f->head], first_copy_bytes);
499 f->head += first_copy_bytes;
500 f->head = (f->head == nitems) ? 0 : f->head;
502 /* Number of bytes in second copy segment, if any */
503 second_copy_bytes = total_copy_bytes - first_copy_bytes;
504 if (second_copy_bytes)
506 clib_memcpy (copy_here + first_copy_bytes,
507 &f->data[f->head], second_copy_bytes);
508 f->head += second_copy_bytes;
509 f->head = (f->head == nitems) ? 0 : f->head;
514 /* Account for a zero-copy dequeue done elsewhere */
515 ASSERT (max_bytes <= cursize);
516 f->head += max_bytes;
517 f->head = f->head % nitems;
518 cursize -= max_bytes;
519 total_copy_bytes = max_bytes;
522 __sync_fetch_and_sub (&f->cursize, total_copy_bytes);
524 return (total_copy_bytes);
528 svm_fifo_dequeue_nowait (svm_fifo_t * f, u32 max_bytes, u8 * copy_here)
530 return svm_fifo_dequeue_internal (f, max_bytes, copy_here);
534 svm_fifo_peek (svm_fifo_t * f, u32 relative_offset, u32 max_bytes,
537 u32 total_copy_bytes, first_copy_bytes, second_copy_bytes;
538 u32 cursize, nitems, real_head;
540 /* read cursize, which can only increase while we're working */
541 cursize = svm_fifo_max_dequeue (f);
542 if (PREDICT_FALSE (cursize == 0))
543 return -2; /* nothing in the fifo */
546 real_head = f->head + relative_offset;
547 real_head = real_head >= nitems ? real_head - nitems : real_head;
549 /* Number of bytes we're going to copy */
550 total_copy_bytes = (cursize < max_bytes) ? cursize : max_bytes;
552 if (PREDICT_TRUE (copy_here != 0))
554 /* Number of bytes in first copy segment */
556 ((nitems - real_head) < total_copy_bytes) ?
557 (nitems - real_head) : total_copy_bytes;
558 clib_memcpy (copy_here, &f->data[real_head], first_copy_bytes);
560 /* Number of bytes in second copy segment, if any */
561 second_copy_bytes = total_copy_bytes - first_copy_bytes;
562 if (second_copy_bytes)
564 clib_memcpy (copy_here + first_copy_bytes, &f->data[0],
568 return total_copy_bytes;
572 svm_fifo_dequeue_drop (svm_fifo_t * f, u32 max_bytes)
574 u32 total_drop_bytes, first_drop_bytes, second_drop_bytes;
577 /* read cursize, which can only increase while we're working */
578 cursize = svm_fifo_max_dequeue (f);
579 if (PREDICT_FALSE (cursize == 0))
580 return -2; /* nothing in the fifo */
584 /* Number of bytes we're going to drop */
585 total_drop_bytes = (cursize < max_bytes) ? cursize : max_bytes;
587 /* Number of bytes in first copy segment */
589 ((nitems - f->head) < total_drop_bytes) ?
590 (nitems - f->head) : total_drop_bytes;
591 f->head += first_drop_bytes;
592 f->head = (f->head == nitems) ? 0 : f->head;
594 /* Number of bytes in second drop segment, if any */
595 second_drop_bytes = total_drop_bytes - first_drop_bytes;
596 if (second_drop_bytes)
598 f->head += second_drop_bytes;
599 f->head = (f->head == nitems) ? 0 : f->head;
602 __sync_fetch_and_sub (&f->cursize, total_drop_bytes);
604 return total_drop_bytes;
608 svm_fifo_number_ooo_segments (svm_fifo_t * f)
610 return pool_elts (f->ooo_segments);
614 svm_fifo_first_ooo_segment (svm_fifo_t * f)
616 return pool_elt_at_index (f->ooo_segments, f->ooos_list_head);
620 * Set fifo pointers to requested offset
623 svm_fifo_init_pointers (svm_fifo_t * f, u32 pointer)
625 f->head = f->tail = pointer % f->nitems;
629 * fd.io coding-style-patch-verification: ON
632 * eval: (c-set-style "gnu")