2 * Copyright (c) 2016-2019 Cisco and/or its affiliates.
3 * Copyright (c) 2019 Arm Limited
4 * Copyright (c) 2010-2017 Intel Corporation and/or its affiliates.
5 * Copyright (c) 2007-2009 Kip Macy kmacy@freebsd.org
6 * Inspired from DPDK rte_ring.h (SPSC only) (derived from freebsd bufring.h).
7 * Licensed under the Apache License, Version 2.0 (the "License");
8 * you may not use this file except in compliance with the License.
9 * You may obtain a copy of the License at:
11 * http://www.apache.org/licenses/LICENSE-2.0
13 * Unless required by applicable law or agreed to in writing, software
14 * distributed under the License is distributed on an "AS IS" BASIS,
15 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16 * See the License for the specific language governing permissions and
17 * limitations under the License.
20 #include <svm/svm_fifo.h>
21 #include <vppinfra/cpu.h>
23 CLIB_MARCH_FN (svm_fifo_copy_to_chunk, void, svm_fifo_t * f,
24 svm_fifo_chunk_t * c, u32 tail_idx, const u8 * src, u32 len,
25 svm_fifo_chunk_t ** last)
29 ASSERT (tail_idx >= c->start_byte && tail_idx < c->start_byte + c->length);
31 tail_idx -= c->start_byte;
32 n_chunk = c->length - tail_idx;
36 clib_memcpy_fast (&c->data[tail_idx], src, n_chunk);
38 while ((to_copy -= n_chunk))
40 n_chunk = clib_min (c->length, to_copy);
41 clib_memcpy_fast (&c->data[0], src + (len - to_copy), n_chunk);
42 c = c->length <= to_copy ? c->next : c;
49 clib_memcpy_fast (&c->data[tail_idx], src, len);
53 CLIB_MARCH_FN (svm_fifo_copy_from_chunk, void, svm_fifo_t * f,
54 svm_fifo_chunk_t * c, u32 head_idx, u8 * dst, u32 len,
55 svm_fifo_chunk_t ** last)
59 ASSERT (head_idx >= c->start_byte && head_idx < c->start_byte + c->length);
61 head_idx -= c->start_byte;
62 n_chunk = c->length - head_idx;
66 clib_memcpy_fast (dst, &c->data[head_idx], n_chunk);
68 while ((to_copy -= n_chunk))
70 n_chunk = clib_min (c->length, to_copy);
71 clib_memcpy_fast (dst + (len - to_copy), &c->data[0], n_chunk);
72 c = c->length <= to_copy ? c->next : c;
79 clib_memcpy_fast (dst, &c->data[head_idx], len);
83 #ifndef CLIB_MARCH_VARIANT
86 svm_fifo_copy_to_chunk (svm_fifo_t * f, svm_fifo_chunk_t * c, u32 tail_idx,
87 const u8 * src, u32 len, svm_fifo_chunk_t ** last)
89 CLIB_MARCH_FN_SELECT (svm_fifo_copy_to_chunk) (f, c, tail_idx, src, len,
94 svm_fifo_copy_from_chunk (svm_fifo_t * f, svm_fifo_chunk_t * c, u32 head_idx,
95 u8 * dst, u32 len, svm_fifo_chunk_t ** last)
97 CLIB_MARCH_FN_SELECT (svm_fifo_copy_from_chunk) (f, c, head_idx, dst, len,
102 position_lt (svm_fifo_t * f, u32 a, u32 b, u32 tail)
104 return (f_distance_to (f, a, tail) < f_distance_to (f, b, tail));
108 position_leq (svm_fifo_t * f, u32 a, u32 b, u32 tail)
110 return (f_distance_to (f, a, tail) <= f_distance_to (f, b, tail));
114 position_gt (svm_fifo_t * f, u32 a, u32 b, u32 tail)
116 return (f_distance_to (f, a, tail) > f_distance_to (f, b, tail));
120 position_diff (svm_fifo_t * f, u32 a, u32 b, u32 tail)
122 return f_distance_to (f, a, tail) - f_distance_to (f, b, tail);
126 ooo_segment_end_pos (svm_fifo_t * f, ooo_segment_t * s)
128 return (s->start + s->length) % f->size;
132 svm_fifo_free_ooo_data (svm_fifo_t * f)
134 pool_free (f->ooo_segments);
137 static inline ooo_segment_t *
138 ooo_segment_prev (svm_fifo_t * f, ooo_segment_t * s)
140 if (s->prev == OOO_SEGMENT_INVALID_INDEX)
142 return pool_elt_at_index (f->ooo_segments, s->prev);
145 static inline ooo_segment_t *
146 ooo_segment_next (svm_fifo_t * f, ooo_segment_t * s)
148 if (s->next == OOO_SEGMENT_INVALID_INDEX)
150 return pool_elt_at_index (f->ooo_segments, s->next);
153 static inline ooo_segment_t *
154 ooo_segment_alloc (svm_fifo_t * f, u32 start, u32 length)
158 pool_get (f->ooo_segments, s);
162 s->prev = s->next = OOO_SEGMENT_INVALID_INDEX;
168 ooo_segment_free (svm_fifo_t * f, u32 index)
170 ooo_segment_t *cur, *prev = 0, *next = 0;
171 cur = pool_elt_at_index (f->ooo_segments, index);
173 if (cur->next != OOO_SEGMENT_INVALID_INDEX)
175 next = pool_elt_at_index (f->ooo_segments, cur->next);
176 next->prev = cur->prev;
179 if (cur->prev != OOO_SEGMENT_INVALID_INDEX)
181 prev = pool_elt_at_index (f->ooo_segments, cur->prev);
182 prev->next = cur->next;
186 f->ooos_list_head = cur->next;
189 pool_put (f->ooo_segments, cur);
193 * Add segment to fifo's out-of-order segment list. Takes care of merging
194 * adjacent segments and removing overlapping ones.
197 ooo_segment_add (svm_fifo_t * f, u32 offset, u32 head, u32 tail, u32 length)
199 ooo_segment_t *s, *new_s, *prev, *next, *it;
200 u32 new_index, s_end_pos, s_index;
201 u32 offset_pos, offset_end_pos;
203 ASSERT (offset + length <= f_distance_to (f, head, tail) || head == tail);
205 offset_pos = (tail + offset) % f->size;
206 offset_end_pos = (tail + offset + length) % f->size;
208 f->ooos_newest = OOO_SEGMENT_INVALID_INDEX;
210 if (f->ooos_list_head == OOO_SEGMENT_INVALID_INDEX)
212 s = ooo_segment_alloc (f, offset_pos, length);
213 f->ooos_list_head = s - f->ooo_segments;
214 f->ooos_newest = f->ooos_list_head;
218 /* Find first segment that starts after new segment */
219 s = pool_elt_at_index (f->ooo_segments, f->ooos_list_head);
220 while (s->next != OOO_SEGMENT_INVALID_INDEX
221 && position_lt (f, s->start, offset_pos, tail))
222 s = pool_elt_at_index (f->ooo_segments, s->next);
224 /* If we have a previous and we overlap it, use it as starting point */
225 prev = ooo_segment_prev (f, s);
227 && position_leq (f, offset_pos, ooo_segment_end_pos (f, prev), tail))
230 s_end_pos = ooo_segment_end_pos (f, s);
232 /* Since we have previous, offset start position cannot be smaller
233 * than prev->start. Check tail */
234 ASSERT (position_lt (f, s->start, offset_pos, tail));
238 s_index = s - f->ooo_segments;
239 s_end_pos = ooo_segment_end_pos (f, s);
241 /* No overlap, add before current segment */
242 if (position_lt (f, offset_end_pos, s->start, tail))
244 new_s = ooo_segment_alloc (f, offset_pos, length);
245 new_index = new_s - f->ooo_segments;
247 /* Pool might've moved, get segment again */
248 s = pool_elt_at_index (f->ooo_segments, s_index);
249 if (s->prev != OOO_SEGMENT_INVALID_INDEX)
251 new_s->prev = s->prev;
252 prev = pool_elt_at_index (f->ooo_segments, new_s->prev);
253 prev->next = new_index;
258 f->ooos_list_head = new_index;
261 new_s->next = s_index;
263 f->ooos_newest = new_index;
266 /* No overlap, add after current segment */
267 else if (position_gt (f, offset_pos, s_end_pos, tail))
269 new_s = ooo_segment_alloc (f, offset_pos, length);
270 new_index = new_s - f->ooo_segments;
272 /* Pool might've moved, get segment again */
273 s = pool_elt_at_index (f->ooo_segments, s_index);
275 /* Needs to be last */
276 ASSERT (s->next == OOO_SEGMENT_INVALID_INDEX);
278 new_s->prev = s_index;
280 f->ooos_newest = new_index;
290 if (position_lt (f, offset_pos, s->start, tail))
292 s->start = offset_pos;
293 s->length = position_diff (f, s_end_pos, s->start, tail);
294 f->ooos_newest = s - f->ooo_segments;
299 /* Overlapping tail */
300 if (position_gt (f, offset_end_pos, s_end_pos, tail))
302 s->length = position_diff (f, offset_end_pos, s->start, tail);
304 /* Remove the completely overlapped segments in the tail */
305 it = ooo_segment_next (f, s);
306 while (it && position_leq (f, ooo_segment_end_pos (f, it),
307 offset_end_pos, tail))
309 next = ooo_segment_next (f, it);
310 ooo_segment_free (f, it - f->ooo_segments);
314 /* If partial overlap with last, merge */
315 if (it && position_leq (f, it->start, offset_end_pos, tail))
317 s->length = position_diff (f, ooo_segment_end_pos (f, it),
319 ooo_segment_free (f, it - f->ooo_segments);
321 f->ooos_newest = s - f->ooo_segments;
326 * Removes segments that can now be enqueued because the fifo's tail has
327 * advanced. Returns the number of bytes added to tail.
330 ooo_segment_try_collect (svm_fifo_t * f, u32 n_bytes_enqueued, u32 * tail)
332 u32 s_index, bytes = 0;
336 s = pool_elt_at_index (f->ooo_segments, f->ooos_list_head);
337 diff = f_distance_from (f, s->start, *tail);
339 ASSERT (diff != n_bytes_enqueued);
341 if (diff > n_bytes_enqueued)
344 /* If last tail update overlaps one/multiple ooo segments, remove them */
345 while (0 <= diff && diff < n_bytes_enqueued)
347 s_index = s - f->ooo_segments;
349 /* Segment end is beyond the tail. Advance tail and remove segment */
350 if (s->length > diff)
352 bytes = s->length - diff;
353 *tail = (*tail + bytes) % f->size;
354 ooo_segment_free (f, s_index);
358 /* If we have next go on */
359 if (s->next != OOO_SEGMENT_INVALID_INDEX)
361 s = pool_elt_at_index (f->ooo_segments, s->next);
362 diff = f_distance_from (f, s->start, *tail);
363 ooo_segment_free (f, s_index);
368 ooo_segment_free (f, s_index);
373 ASSERT (bytes <= f->nitems);
377 static ooo_segment_t *
378 ooo_segment_last (svm_fifo_t * f)
382 if (f->ooos_list_head == OOO_SEGMENT_INVALID_INDEX)
385 s = svm_fifo_first_ooo_segment (f);
386 while (s->next != OOO_SEGMENT_INVALID_INDEX)
387 s = pool_elt_at_index (f->ooo_segments, s->next);
392 svm_fifo_init (svm_fifo_t * f, u32 size)
396 * usable size of the fifo set to rounded_data_size - 1
397 * to differentiate between free fifo and empty fifo.
399 f->nitems = f->size - 1;
400 f->ooos_list_head = OOO_SEGMENT_INVALID_INDEX;
401 f->segment_index = SVM_FIFO_INVALID_INDEX;
403 f->head = f->tail = f->flags = 0;
404 f->head_chunk = f->tail_chunk = f->ooo_enq = f->ooo_deq = f->start_chunk;
408 svm_fifo_init_chunks (svm_fifo_t * f)
410 svm_fifo_chunk_t *c, *prev;
412 if (f->start_chunk->next == f->start_chunk)
415 f->flags |= SVM_FIFO_F_MULTI_CHUNK;
416 rb_tree_init (&f->chunk_lookup);
417 rb_tree_add2 (&f->chunk_lookup, 0, pointer_to_uword (f->start_chunk));
419 f->start_chunk->start_byte = 0;
420 prev = f->start_chunk;
423 while (c != f->start_chunk)
425 c->start_byte = prev->start_byte + prev->length;
426 rb_tree_add2 (&f->chunk_lookup, c->start_byte, pointer_to_uword (c));
433 * Creates a fifo in the current heap. Fails vs blow up the process
436 svm_fifo_create (u32 data_size_in_bytes)
438 u32 rounded_data_size;
442 f = clib_mem_alloc_aligned_or_null (sizeof (*f), CLIB_CACHE_LINE_BYTES);
446 clib_memset (f, 0, sizeof (*f));
448 /* always round fifo data size to the next highest power-of-two */
449 rounded_data_size = (1 << (max_log2 (data_size_in_bytes)));
450 c = clib_mem_alloc_aligned_or_null (sizeof (*c) + rounded_data_size,
451 CLIB_CACHE_LINE_BYTES);
460 c->length = data_size_in_bytes;
461 f->start_chunk = f->end_chunk = c;
463 svm_fifo_init (f, data_size_in_bytes);
468 * Creates a fifo chunk in the current heap
471 svm_fifo_chunk_alloc (u32 size)
476 /* round chunk size to the next highest power-of-two */
477 rounded_size = (1 << (max_log2 (size)));
478 c = clib_mem_alloc_aligned_or_null (sizeof (*c) + rounded_size,
479 CLIB_CACHE_LINE_BYTES);
483 clib_memset (c, 0, sizeof (*c));
484 c->length = rounded_size;
489 svm_fifo_chunk_includes_pos (svm_fifo_chunk_t * c, u32 pos)
491 return (pos >= c->start_byte && pos < c->start_byte + c->length);
495 * Find chunk for given byte position
498 * @param pos normalized position in fifo
500 * @return chunk that includes given position or 0
502 static svm_fifo_chunk_t *
503 svm_fifo_find_chunk (svm_fifo_t * f, u32 pos)
505 rb_tree_t *rt = &f->chunk_lookup;
506 rb_node_t *cur, *prev;
509 cur = rb_node (rt, rt->root);
510 while (pos != cur->key)
514 cur = rb_node_left (rt, cur);
516 cur = rb_node_right (rt, cur);
518 if (rb_node_is_tnil (rt, cur))
520 /* Hit tnil as a left child. Find predecessor */
523 cur = rb_tree_predecessor (rt, prev);
524 if (rb_node_is_tnil (rt, cur))
526 c = uword_to_pointer (cur->opaque, svm_fifo_chunk_t *);
527 if (svm_fifo_chunk_includes_pos (c, pos))
531 /* Hit tnil as a right child. Check if this is the one */
532 c = uword_to_pointer (prev->opaque, svm_fifo_chunk_t *);
533 if (svm_fifo_chunk_includes_pos (c, pos))
540 if (!rb_node_is_tnil (rt, cur))
541 return uword_to_pointer (cur->opaque, svm_fifo_chunk_t *);
546 svm_fifo_grow (svm_fifo_t * f, svm_fifo_chunk_t * c)
548 svm_fifo_chunk_t *prev;
554 f->end_chunk->next = c;
557 add_bytes += c->length;
562 prev->next = f->start_chunk;
563 f->size += add_bytes;
564 f->nitems = f->size - 1;
569 svm_fifo_try_grow (svm_fifo_t * f, u32 new_head)
571 if (new_head > f->tail)
574 svm_fifo_grow (f, f->new_chunks);
575 f->flags &= ~SVM_FIFO_F_GROW;
579 svm_fifo_add_chunk (svm_fifo_t * f, svm_fifo_chunk_t * c)
581 svm_fifo_chunk_t *cur, *prev;
583 /* Initialize rbtree if needed and add default chunk to it. Expectation is
584 * that this is called with the heap where the rbtree's pool is pushed. */
585 if (!(f->flags & SVM_FIFO_F_MULTI_CHUNK))
587 ASSERT (f->start_chunk->next == f->start_chunk);
588 rb_tree_init (&f->chunk_lookup);
589 rb_tree_add2 (&f->chunk_lookup, 0, pointer_to_uword (f->start_chunk));
590 f->flags |= SVM_FIFO_F_MULTI_CHUNK;
593 /* Initialize chunks and add to lookup rbtree */
597 prev = f->new_chunks;
607 cur->start_byte = prev->start_byte + prev->length;
608 rb_tree_add2 (&f->chunk_lookup, cur->start_byte,
609 pointer_to_uword (cur));
614 /* If fifo is not wrapped, update the size now */
615 if (!svm_fifo_is_wrapped (f))
617 ASSERT (!f->new_chunks);
618 svm_fifo_grow (f, c);
622 /* Postpone size update */
626 f->flags |= SVM_FIFO_F_GROW;
631 * Removes chunks that are after fifo end byte
634 svm_fifo_collect_chunks (svm_fifo_t * f)
636 svm_fifo_chunk_t *list, *cur;
638 f->flags &= ~SVM_FIFO_F_COLLECT_CHUNKS;
640 list = f->new_chunks;
645 rb_tree_del (&f->chunk_lookup, cur->start_byte);
653 svm_fifo_try_shrink (svm_fifo_t * f, u32 head, u32 tail)
655 u32 len_to_shrink = 0, tail_pos, len, last_pos;
656 svm_fifo_chunk_t *cur, *prev, *next, *start;
659 if (f->ooos_list_head != OOO_SEGMENT_INVALID_INDEX)
661 ooo_segment_t *last = ooo_segment_last (f);
662 tail_pos = ooo_segment_end_pos (f, last);
665 if (f->size_decrement)
667 /* Figure out available free space considering that there may be
669 len = clib_min (f->size_decrement, f_free_count (f, head, tail_pos));
671 f->size_decrement -= len;
674 /* Remove tail chunks if the following hold:
676 * - last used byte less than start of last chunk
678 if (tail_pos >= head && tail_pos < f->end_chunk->start_byte)
680 /* Lookup the last position not to be removed. Since size still needs
681 * to be nitems + 1, nitems must fall within the usable space. Also,
682 * first segment is not removable, so tail_pos can be 0. */
683 last_pos = tail_pos > 0 ? tail_pos - 1 : tail_pos;
684 prev = svm_fifo_find_chunk (f, clib_max (f->nitems, last_pos));
686 /* If tail_pos is first position in next, skip the chunk, otherwise,
687 * we must update the tail and, if fifo size is 0, even the head.
688 * We should not invalidate the tail for the caller and must not change
689 * consumer owned variables from code that's typically called by the
691 if (next->start_byte == tail_pos)
696 while (next != f->start_chunk)
700 len_to_shrink += cur->length;
704 f->size -= len_to_shrink;
706 prev->next = f->start_chunk;
708 cur->next = f->new_chunks;
709 f->new_chunks = start;
713 if (!f->size_decrement && f->size == f->nitems + 1)
715 f->flags &= ~SVM_FIFO_F_SHRINK;
716 f->flags |= SVM_FIFO_F_COLLECT_CHUNKS;
717 if (f->start_chunk == f->start_chunk->next)
718 f->flags &= ~SVM_FIFO_F_MULTI_CHUNK;
723 * Request to reduce fifo size by amount of bytes
726 svm_fifo_reduce_size (svm_fifo_t * f, u32 len, u8 try_shrink)
728 svm_fifo_chunk_t *cur;
731 /* Abort if trying to reduce by more than fifo size or if
732 * fifo is undergoing resizing already */
733 if (len >= f->size || f->size > f->nitems + 1
734 || (f->flags & SVM_FIFO_F_SHRINK) || (f->flags & SVM_FIFO_F_GROW))
737 /* last chunk that will not be removed */
738 cur = svm_fifo_find_chunk (f, f->nitems - len);
740 /* sum length of chunks that will be removed */
742 while (cur != f->start_chunk)
744 actual_len += cur->length;
748 ASSERT (actual_len <= len);
752 f->size_decrement = actual_len;
753 f->flags |= SVM_FIFO_F_SHRINK;
758 f_load_head_tail_prod (f, &head, &tail);
759 svm_fifo_try_shrink (f, head, tail);
766 svm_fifo_free_chunk_lookup (svm_fifo_t * f)
768 rb_tree_free_nodes (&f->chunk_lookup);
772 svm_fifo_free (svm_fifo_t * f)
774 ASSERT (f->refcnt > 0);
776 if (--f->refcnt == 0)
778 /* ooo data is not allocated on segment heap */
779 svm_fifo_free_chunk_lookup (f);
785 svm_fifo_overwrite_head (svm_fifo_t * f, u8 * src, u32 len)
788 u32 head, tail, head_idx;
791 ASSERT (len <= f->nitems);
793 f_load_head_tail_cons (f, &head, &tail);
795 head_idx = head - c->start_byte;
796 n_chunk = c->length - head_idx;
798 clib_memcpy_fast (&c->data[head_idx], src, len);
801 clib_memcpy_fast (&c->data[head_idx], src, n_chunk);
802 clib_memcpy_fast (&c->next->data[0], src + n_chunk, len - n_chunk);
807 svm_fifo_enqueue (svm_fifo_t * f, u32 len, const u8 * src)
809 u32 tail, head, free_count;
811 f_load_head_tail_prod (f, &head, &tail);
813 /* free space in fifo can only increase during enqueue: SPSC */
814 free_count = f_free_count (f, head, tail);
816 f->ooos_newest = OOO_SEGMENT_INVALID_INDEX;
818 if (PREDICT_FALSE (free_count == 0))
819 return SVM_FIFO_EFULL;
821 /* number of bytes we're going to copy */
822 len = clib_min (free_count, len);
823 svm_fifo_copy_to_chunk (f, f->tail_chunk, tail, src, len, &f->tail_chunk);
824 tail = (tail + len) % f->size;
826 svm_fifo_trace_add (f, head, len, 2);
828 /* collect out-of-order segments */
829 if (PREDICT_FALSE (f->ooos_list_head != OOO_SEGMENT_INVALID_INDEX))
831 len += ooo_segment_try_collect (f, len, &tail);
832 if (!svm_fifo_chunk_includes_pos (f->tail_chunk, tail))
833 f->tail_chunk = svm_fifo_find_chunk (f, tail);
836 /* store-rel: producer owned index (paired with load-acq in consumer) */
837 clib_atomic_store_rel_n (&f->tail, tail);
843 * Enqueue a future segment.
845 * Two choices: either copies the entire segment, or copies nothing
846 * Returns 0 of the entire segment was copied
847 * Returns -1 if none of the segment was copied due to lack of space
850 svm_fifo_enqueue_with_offset (svm_fifo_t * f, u32 offset, u32 len, u8 * src)
852 u32 tail, head, free_count, tail_idx;
854 f_load_head_tail_prod (f, &head, &tail);
856 if (PREDICT_FALSE (f->flags & SVM_FIFO_F_SHRINK))
857 svm_fifo_try_shrink (f, head, tail);
859 /* free space in fifo can only increase during enqueue: SPSC */
860 free_count = f_free_count (f, head, tail);
862 /* will this request fit? */
863 if ((len + offset) > free_count)
864 return SVM_FIFO_EFULL;
866 f->ooos_newest = OOO_SEGMENT_INVALID_INDEX;
867 svm_fifo_trace_add (f, offset, len, 1);
868 ooo_segment_add (f, offset, head, tail, len);
869 tail_idx = (tail + offset) % f->size;
871 if (!svm_fifo_chunk_includes_pos (f->ooo_enq, tail_idx))
872 f->ooo_enq = svm_fifo_find_chunk (f, tail_idx);
874 svm_fifo_copy_to_chunk (f, f->ooo_enq, tail_idx, src, len, &f->ooo_enq);
883 svm_fifo_enqueue_nocopy (svm_fifo_t * f, u32 len)
887 ASSERT (len <= svm_fifo_max_enqueue_prod (f));
888 /* load-relaxed: producer owned index */
890 tail = (tail + len) % f->size;
892 if (!svm_fifo_chunk_includes_pos (f->tail_chunk, tail))
893 f->tail_chunk = svm_fifo_find_chunk (f, tail);
895 /* store-rel: producer owned index (paired with load-acq in consumer) */
896 clib_atomic_store_rel_n (&f->tail, tail);
900 svm_fifo_dequeue (svm_fifo_t * f, u32 len, u8 * dst)
902 u32 tail, head, cursize;
904 f_load_head_tail_cons (f, &head, &tail);
906 /* current size of fifo can only increase during dequeue: SPSC */
907 cursize = f_cursize (f, head, tail);
909 if (PREDICT_FALSE (cursize == 0))
910 return SVM_FIFO_EEMPTY;
912 len = clib_min (cursize, len);
913 svm_fifo_copy_from_chunk (f, f->head_chunk, head, dst, len, &f->head_chunk);
914 head = (head + len) % f->size;
916 if (PREDICT_FALSE (f->flags & SVM_FIFO_F_GROW))
917 svm_fifo_try_grow (f, head);
919 /* store-rel: consumer owned index (paired with load-acq in producer) */
920 clib_atomic_store_rel_n (&f->head, head);
926 svm_fifo_peek (svm_fifo_t * f, u32 offset, u32 len, u8 * dst)
928 u32 tail, head, cursize, head_idx;
930 f_load_head_tail_cons (f, &head, &tail);
932 /* current size of fifo can only increase during peek: SPSC */
933 cursize = f_cursize (f, head, tail);
935 if (PREDICT_FALSE (cursize < offset))
936 return SVM_FIFO_EEMPTY;
938 len = clib_min (cursize - offset, len);
939 head_idx = (head + offset) % f->size;
940 if (!svm_fifo_chunk_includes_pos (f->ooo_deq, head_idx))
941 f->ooo_deq = svm_fifo_find_chunk (f, head_idx);
943 svm_fifo_copy_from_chunk (f, f->ooo_deq, head_idx, dst, len, &f->ooo_deq);
948 svm_fifo_dequeue_drop (svm_fifo_t * f, u32 len)
950 u32 total_drop_bytes, tail, head, cursize;
952 f_load_head_tail_cons (f, &head, &tail);
954 /* number of bytes available */
955 cursize = f_cursize (f, head, tail);
956 if (PREDICT_FALSE (cursize == 0))
957 return SVM_FIFO_EEMPTY;
959 /* number of bytes we're going to drop */
960 total_drop_bytes = clib_min (cursize, len);
962 svm_fifo_trace_add (f, tail, total_drop_bytes, 3);
965 head = (head + total_drop_bytes) % f->size;
967 if (!svm_fifo_chunk_includes_pos (f->head_chunk, head))
968 f->head_chunk = svm_fifo_find_chunk (f, head);
970 if (PREDICT_FALSE (f->flags & SVM_FIFO_F_GROW))
971 svm_fifo_try_grow (f, head);
973 /* store-rel: consumer owned index (paired with load-acq in producer) */
974 clib_atomic_store_rel_n (&f->head, head);
976 return total_drop_bytes;
980 svm_fifo_dequeue_drop_all (svm_fifo_t * f)
982 /* consumer foreign index */
983 u32 tail = clib_atomic_load_acq_n (&f->tail);
985 if (!svm_fifo_chunk_includes_pos (f->head_chunk, tail))
986 f->head_chunk = svm_fifo_find_chunk (f, tail);
988 if (PREDICT_FALSE (f->flags & SVM_FIFO_F_GROW))
989 svm_fifo_try_grow (f, tail);
991 /* store-rel: consumer owned index (paired with load-acq in producer) */
992 clib_atomic_store_rel_n (&f->head, tail);
996 svm_fifo_segments (svm_fifo_t * f, svm_fifo_seg_t * fs)
998 u32 cursize, head, tail, head_idx;
1000 f_load_head_tail_cons (f, &head, &tail);
1002 /* consumer function, cursize can only increase while we're working */
1003 cursize = f_cursize (f, head, tail);
1005 if (PREDICT_FALSE (cursize == 0))
1006 return SVM_FIFO_EEMPTY;
1012 fs[0].len = f->size - head_idx;
1013 fs[0].data = f->head_chunk->data + head_idx;
1014 fs[1].len = cursize - fs[0].len;
1015 fs[1].data = f->head_chunk->data;
1019 fs[0].len = cursize;
1020 fs[0].data = f->head_chunk->data + head_idx;
1028 svm_fifo_segments_free (svm_fifo_t * f, svm_fifo_seg_t * fs)
1032 /* consumer owned index */
1035 ASSERT (fs[0].data == f->head_chunk->data + head);
1036 head = (head + fs[0].len + fs[1].len) % f->size;
1037 /* store-rel: consumer owned index (paired with load-acq in producer) */
1038 clib_atomic_store_rel_n (&f->head, head);
1045 * - no prod and cons are accessing either dest or src fifo
1046 * - fifo is not multi chunk
1049 svm_fifo_clone (svm_fifo_t * df, svm_fifo_t * sf)
1052 clib_memcpy_fast (df->head_chunk->data, sf->head_chunk->data, sf->size);
1054 f_load_head_tail_all_acq (sf, &head, &tail);
1055 clib_atomic_store_rel_n (&df->head, head);
1056 clib_atomic_store_rel_n (&df->tail, tail);
1060 svm_fifo_n_ooo_segments (svm_fifo_t * f)
1062 return pool_elts (f->ooo_segments);
1066 svm_fifo_first_ooo_segment (svm_fifo_t * f)
1068 return pool_elt_at_index (f->ooo_segments, f->ooos_list_head);
1072 * Set fifo pointers to requested offset
1075 svm_fifo_init_pointers (svm_fifo_t * f, u32 head, u32 tail)
1077 head = head % f->size;
1078 tail = tail % f->size;
1079 clib_atomic_store_rel_n (&f->head, head);
1080 clib_atomic_store_rel_n (&f->tail, tail);
1081 if (f->flags & SVM_FIFO_F_MULTI_CHUNK)
1083 svm_fifo_chunk_t *c;
1084 c = svm_fifo_find_chunk (f, head);
1086 f->head_chunk = f->ooo_deq = c;
1087 c = svm_fifo_find_chunk (f, tail);
1089 f->tail_chunk = f->ooo_enq = c;
1094 svm_fifo_add_subscriber (svm_fifo_t * f, u8 subscriber)
1096 if (f->n_subscribers >= SVM_FIFO_MAX_EVT_SUBSCRIBERS)
1098 f->subscribers[f->n_subscribers++] = subscriber;
1102 svm_fifo_del_subscriber (svm_fifo_t * f, u8 subscriber)
1106 for (i = 0; i < f->n_subscribers; i++)
1108 if (f->subscribers[i] != subscriber)
1110 f->subscribers[i] = f->subscribers[f->n_subscribers - 1];
1117 svm_fifo_is_sane (svm_fifo_t * f)
1119 if (f->size - 1 != f->nitems && !(f->flags & SVM_FIFO_F_SHRINK))
1121 if (!svm_fifo_chunk_includes_pos (f->head_chunk, f->head))
1123 if (!svm_fifo_chunk_includes_pos (f->tail_chunk, f->tail))
1126 if (f->start_chunk->next != f->start_chunk)
1128 svm_fifo_chunk_t *c, *prev = 0, *tmp;
1131 if (!(f->flags & SVM_FIFO_F_MULTI_CHUNK))
1137 tmp = svm_fifo_find_chunk (f, c->start_byte);
1140 if (prev && (prev->start_byte + prev->length != c->start_byte))
1146 while (c != f->start_chunk);
1148 if (size != f->size)
1156 format_ooo_segment (u8 * s, va_list * args)
1158 svm_fifo_t *f = va_arg (*args, svm_fifo_t *);
1159 ooo_segment_t *seg = va_arg (*args, ooo_segment_t *);
1160 u32 normalized_start = (seg->start + f->nitems - f->tail) % f->size;
1161 s = format (s, "[%u, %u], len %u, next %d, prev %d", normalized_start,
1162 (normalized_start + seg->length) % f->size, seg->length,
1163 seg->next, seg->prev);
1168 svm_fifo_dump_trace (u8 * s, svm_fifo_t * f)
1171 svm_fifo_trace_elem_t *seg = 0;
1176 vec_foreach (seg, f->trace)
1178 s = format (s, "{%u, %u, %u}, ", seg->offset, seg->len, seg->action);
1181 s = format (s, "\n");
1183 s = format (s, "\n");
1192 svm_fifo_replay (u8 * s, svm_fifo_t * f, u8 no_read, u8 verbose)
1196 svm_fifo_trace_elem_t *trace;
1198 svm_fifo_t *dummy_fifo;
1205 trace_len = vec_len (trace);
1211 dummy_fifo = svm_fifo_create (f->size);
1212 clib_memset (f->head_chunk->data, 0xFF, f->nitems);
1213 vec_validate (data, f->nitems);
1214 for (i = 0; i < vec_len (data); i++)
1217 for (i = 0; i < trace_len; i++)
1219 offset = trace[i].offset;
1220 if (trace[i].action == 1)
1223 s = format (s, "adding [%u, %u]:", trace[i].offset,
1224 (trace[i].offset + trace[i].len) % dummy_fifo->size);
1225 svm_fifo_enqueue_with_offset (dummy_fifo, trace[i].offset,
1226 trace[i].len, &data[offset]);
1228 else if (trace[i].action == 2)
1231 s = format (s, "adding [%u, %u]:", 0, trace[i].len);
1232 svm_fifo_enqueue (dummy_fifo, trace[i].len, &data[offset]);
1237 s = format (s, "read: %u", trace[i].len);
1238 svm_fifo_dequeue_drop (dummy_fifo, trace[i].len);
1241 s = format (s, "%U", format_svm_fifo, dummy_fifo, 1);
1244 s = format (s, "result: %U", format_svm_fifo, dummy_fifo, 1);
1250 format_ooo_list (u8 * s, va_list * args)
1252 svm_fifo_t *f = va_arg (*args, svm_fifo_t *);
1253 u32 indent = va_arg (*args, u32);
1254 u32 ooo_segment_index = f->ooos_list_head;
1257 while (ooo_segment_index != OOO_SEGMENT_INVALID_INDEX)
1259 seg = pool_elt_at_index (f->ooo_segments, ooo_segment_index);
1260 s = format (s, "%U%U\n", format_white_space, indent, format_ooo_segment,
1262 ooo_segment_index = seg->next;
1269 format_svm_fifo (u8 * s, va_list * args)
1271 svm_fifo_t *f = va_arg (*args, svm_fifo_t *);
1272 int verbose = va_arg (*args, int);
1278 indent = format_get_indent (s);
1279 s = format (s, "cursize %u nitems %u has_event %d\n",
1280 svm_fifo_max_dequeue (f), f->nitems, f->has_event);
1281 s = format (s, "%Uhead %u tail %u segment manager %u\n", format_white_space,
1282 indent, (f->head % f->size), (f->tail % f->size),
1283 f->segment_manager);
1286 s = format (s, "%Uvpp session %d thread %d app session %d thread %d\n",
1287 format_white_space, indent, f->master_session_index,
1288 f->master_thread_index, f->client_session_index,
1289 f->client_thread_index);
1293 s = format (s, "%Uooo pool %d active elts newest %u\n",
1294 format_white_space, indent, pool_elts (f->ooo_segments),
1296 if (svm_fifo_has_ooo_data (f))
1297 s = format (s, " %U", format_ooo_list, f, indent, verbose);
1304 * fd.io coding-style-patch-verification: ON
1307 * eval: (c-set-style "gnu")