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>
24 position_lt (svm_fifo_t * f, u32 a, u32 b, u32 tail)
26 return (ooo_segment_distance_from_tail (f, a, tail)
27 < ooo_segment_distance_from_tail (f, b, tail));
31 position_leq (svm_fifo_t * f, u32 a, u32 b, u32 tail)
33 return (ooo_segment_distance_from_tail (f, a, tail)
34 <= ooo_segment_distance_from_tail (f, b, tail));
38 position_gt (svm_fifo_t * f, u32 a, u32 b, u32 tail)
40 return (ooo_segment_distance_from_tail (f, a, tail)
41 > ooo_segment_distance_from_tail (f, b, tail));
45 position_diff (svm_fifo_t * f, u32 posa, u32 posb, u32 tail)
47 return ooo_segment_distance_from_tail (f, posa, tail)
48 - ooo_segment_distance_from_tail (f, posb, tail);
52 ooo_segment_end_pos (svm_fifo_t * f, ooo_segment_t * s)
54 return s->start + s->length;
57 #ifndef CLIB_MARCH_VARIANT
60 format_ooo_segment (u8 * s, va_list * args)
62 svm_fifo_t *f = va_arg (*args, svm_fifo_t *);
63 ooo_segment_t *seg = va_arg (*args, ooo_segment_t *);
64 u32 normalized_start = (seg->start + f->nitems - f->tail) % f->size;
65 s = format (s, "[%u, %u], len %u, next %d, prev %d", normalized_start,
66 (normalized_start + seg->length) % f->size, seg->length,
67 seg->next, seg->prev);
72 svm_fifo_dump_trace (u8 * s, svm_fifo_t * f)
75 svm_fifo_trace_elem_t *seg = 0;
80 vec_foreach (seg, f->trace)
82 s = format (s, "{%u, %u, %u}, ", seg->offset, seg->len, seg->action);
96 svm_fifo_replay (u8 * s, svm_fifo_t * f, u8 no_read, u8 verbose)
100 svm_fifo_trace_elem_t *trace;
102 svm_fifo_t *dummy_fifo;
109 trace_len = vec_len (trace);
115 dummy_fifo = svm_fifo_create (f->size);
116 clib_memset (f->head_chunk->data, 0xFF, f->nitems);
117 vec_validate (data, f->nitems);
118 for (i = 0; i < vec_len (data); i++)
121 for (i = 0; i < trace_len; i++)
123 offset = trace[i].offset;
124 if (trace[i].action == 1)
127 s = format (s, "adding [%u, %u]:", trace[i].offset,
128 (trace[i].offset + trace[i].len) % dummy_fifo->size);
129 svm_fifo_enqueue_with_offset (dummy_fifo, trace[i].offset,
130 trace[i].len, &data[offset]);
132 else if (trace[i].action == 2)
135 s = format (s, "adding [%u, %u]:", 0, trace[i].len);
136 svm_fifo_enqueue_nowait (dummy_fifo, trace[i].len, &data[offset]);
141 s = format (s, "read: %u", trace[i].len);
142 svm_fifo_dequeue_drop (dummy_fifo, trace[i].len);
145 s = format (s, "%U", format_svm_fifo, dummy_fifo, 1);
148 s = format (s, "result: %U", format_svm_fifo, dummy_fifo, 1);
154 format_ooo_list (u8 * s, va_list * args)
156 svm_fifo_t *f = va_arg (*args, svm_fifo_t *);
157 u32 indent = va_arg (*args, u32);
158 u32 ooo_segment_index = f->ooos_list_head;
161 while (ooo_segment_index != OOO_SEGMENT_INVALID_INDEX)
163 seg = pool_elt_at_index (f->ooo_segments, ooo_segment_index);
164 s = format (s, "%U%U\n", format_white_space, indent, format_ooo_segment,
166 ooo_segment_index = seg->next;
173 format_svm_fifo (u8 * s, va_list * args)
175 svm_fifo_t *f = va_arg (*args, svm_fifo_t *);
176 int verbose = va_arg (*args, int);
182 indent = format_get_indent (s);
183 s = format (s, "cursize %u nitems %u has_event %d\n",
184 svm_fifo_max_dequeue (f), f->nitems, f->has_event);
185 s = format (s, "%Uhead %u tail %u segment manager %u\n", format_white_space,
186 indent, (f->head % f->size), (f->tail % f->size),
190 s = format (s, "%Uvpp session %d thread %d app session %d thread %d\n",
191 format_white_space, indent, f->master_session_index,
192 f->master_thread_index, f->client_session_index,
193 f->client_thread_index);
197 s = format (s, "%Uooo pool %d active elts newest %u\n",
198 format_white_space, indent, pool_elts (f->ooo_segments),
200 if (svm_fifo_has_ooo_data (f))
201 s = format (s, " %U", format_ooo_list, f, indent, verbose);
207 svm_fifo_init (svm_fifo_t * f, u32 size)
211 * usable size of the fifo set to rounded_data_size - 1
212 * to differentiate between free fifo and empty fifo.
214 f->nitems = f->size - 1;
215 f->ooos_list_head = OOO_SEGMENT_INVALID_INDEX;
216 f->ct_session_index = SVM_FIFO_INVALID_SESSION_INDEX;
217 f->segment_index = SVM_FIFO_INVALID_INDEX;
219 f->head_chunk = &f->default_chunk;
220 f->tail_chunk = &f->default_chunk;
221 f->default_chunk.next = &f->default_chunk;
222 f->default_chunk.start_byte = 0;
223 f->default_chunk.length = f->size;
226 /** create an svm fifo, in the current heap. Fails vs blow up the process */
228 svm_fifo_create (u32 data_size_in_bytes)
231 u32 rounded_data_size;
233 /* always round fifo data size to the next highest power-of-two */
234 rounded_data_size = (1 << (max_log2 (data_size_in_bytes)));
235 f = clib_mem_alloc_aligned_or_null (sizeof (*f) + rounded_data_size,
236 CLIB_CACHE_LINE_BYTES);
240 clib_memset (f, 0, sizeof (*f));
241 svm_fifo_init (f, data_size_in_bytes);
246 svm_fifo_free (svm_fifo_t * f)
248 ASSERT (f->refcnt > 0);
250 if (--f->refcnt == 0)
252 pool_free (f->ooo_segments);
258 always_inline ooo_segment_t *
259 ooo_segment_new (svm_fifo_t * f, u32 start, u32 length)
263 pool_get (f->ooo_segments, s);
268 s->prev = s->next = OOO_SEGMENT_INVALID_INDEX;
274 ooo_segment_del (svm_fifo_t * f, u32 index)
276 ooo_segment_t *cur, *prev = 0, *next = 0;
277 cur = pool_elt_at_index (f->ooo_segments, index);
279 if (cur->next != OOO_SEGMENT_INVALID_INDEX)
281 next = pool_elt_at_index (f->ooo_segments, cur->next);
282 next->prev = cur->prev;
285 if (cur->prev != OOO_SEGMENT_INVALID_INDEX)
287 prev = pool_elt_at_index (f->ooo_segments, cur->prev);
288 prev->next = cur->next;
292 f->ooos_list_head = cur->next;
295 pool_put (f->ooo_segments, cur);
299 * Add segment to fifo's out-of-order segment list. Takes care of merging
300 * adjacent segments and removing overlapping ones.
303 ooo_segment_add (svm_fifo_t * f, u32 offset, u32 head, u32 tail, u32 length)
305 ooo_segment_t *s, *new_s, *prev, *next, *it;
306 u32 new_index, s_end_pos, s_index;
307 u32 offset_pos, offset_end_pos;
309 ASSERT (offset + length <= ooo_segment_distance_from_tail (f, head, tail)
312 offset_pos = tail + offset;
313 offset_end_pos = tail + offset + length;
315 f->ooos_newest = OOO_SEGMENT_INVALID_INDEX;
317 if (f->ooos_list_head == OOO_SEGMENT_INVALID_INDEX)
319 s = ooo_segment_new (f, offset_pos, length);
320 f->ooos_list_head = s - f->ooo_segments;
321 f->ooos_newest = f->ooos_list_head;
325 /* Find first segment that starts after new segment */
326 s = pool_elt_at_index (f->ooo_segments, f->ooos_list_head);
327 while (s->next != OOO_SEGMENT_INVALID_INDEX
328 && position_lt (f, s->start, offset_pos, tail))
329 s = pool_elt_at_index (f->ooo_segments, s->next);
331 /* If we have a previous and we overlap it, use it as starting point */
332 prev = ooo_segment_get_prev (f, s);
334 && position_leq (f, offset_pos, ooo_segment_end_pos (f, prev), tail))
337 s_end_pos = ooo_segment_end_pos (f, s);
339 /* Since we have previous, offset start position cannot be smaller
340 * than prev->start. Check tail */
341 ASSERT (position_lt (f, s->start, offset_pos, tail));
345 s_index = s - f->ooo_segments;
346 s_end_pos = ooo_segment_end_pos (f, s);
348 /* No overlap, add before current segment */
349 if (position_lt (f, offset_end_pos, s->start, tail))
351 new_s = ooo_segment_new (f, offset_pos, length);
352 new_index = new_s - f->ooo_segments;
354 /* Pool might've moved, get segment again */
355 s = pool_elt_at_index (f->ooo_segments, s_index);
356 if (s->prev != OOO_SEGMENT_INVALID_INDEX)
358 new_s->prev = s->prev;
359 prev = pool_elt_at_index (f->ooo_segments, new_s->prev);
360 prev->next = new_index;
365 f->ooos_list_head = new_index;
368 new_s->next = s_index;
370 f->ooos_newest = new_index;
373 /* No overlap, add after current segment */
374 else if (position_gt (f, offset_pos, s_end_pos, tail))
376 new_s = ooo_segment_new (f, offset_pos, length);
377 new_index = new_s - f->ooo_segments;
379 /* Pool might've moved, get segment again */
380 s = pool_elt_at_index (f->ooo_segments, s_index);
382 /* Needs to be last */
383 ASSERT (s->next == OOO_SEGMENT_INVALID_INDEX);
385 new_s->prev = s_index;
387 f->ooos_newest = new_index;
397 if (position_lt (f, offset_pos, s->start, tail))
399 s->start = offset_pos;
400 s->length = position_diff (f, s_end_pos, s->start, tail);
401 f->ooos_newest = s - f->ooo_segments;
406 /* Overlapping tail */
407 if (position_gt (f, offset_end_pos, s_end_pos, tail))
409 s->length = position_diff (f, offset_end_pos, s->start, tail);
411 /* Remove the completely overlapped segments in the tail */
412 it = ooo_segment_next (f, s);
413 while (it && position_leq (f, ooo_segment_end_pos (f, it),
414 offset_end_pos, tail))
416 next = ooo_segment_next (f, it);
417 ooo_segment_del (f, it - f->ooo_segments);
421 /* If partial overlap with last, merge */
422 if (it && position_leq (f, it->start, offset_end_pos, tail))
424 s->length = position_diff (f, ooo_segment_end_pos (f, it),
426 ooo_segment_del (f, it - f->ooo_segments);
428 f->ooos_newest = s - f->ooo_segments;
433 * Removes segments that can now be enqueued because the fifo's tail has
434 * advanced. Returns the number of bytes added to tail.
437 ooo_segment_try_collect (svm_fifo_t * f, u32 n_bytes_enqueued, u32 * tail)
440 u32 index, bytes = 0;
443 s = pool_elt_at_index (f->ooo_segments, f->ooos_list_head);
444 diff = ooo_segment_distance_to_tail (f, s->start, *tail);
446 ASSERT (diff != n_bytes_enqueued);
448 if (diff > n_bytes_enqueued)
451 /* If last tail update overlaps one/multiple ooo segments, remove them */
452 while (0 <= diff && diff < n_bytes_enqueued)
454 index = s - f->ooo_segments;
456 /* Segment end is beyond the tail. Advance tail and remove segment */
457 if (s->length > diff)
459 bytes = s->length - diff;
460 *tail = *tail + bytes;
461 ooo_segment_del (f, index);
465 /* If we have next go on */
466 if (s->next != OOO_SEGMENT_INVALID_INDEX)
468 s = pool_elt_at_index (f->ooo_segments, s->next);
469 diff = ooo_segment_distance_to_tail (f, s->start, *tail);
470 ooo_segment_del (f, index);
475 ooo_segment_del (f, index);
480 ASSERT (bytes <= f->nitems);
484 CLIB_MARCH_FN (svm_fifo_enqueue_nowait, int, svm_fifo_t * f, u32 len,
487 u32 n_chunk, to_copy, tail, head, free_count, tail_idx;
490 f_load_head_tail_prod (f, &head, &tail);
492 /* free space in fifo can only increase during enqueue: SPSC */
493 free_count = f_free_count (f, head, tail);
495 f->ooos_newest = OOO_SEGMENT_INVALID_INDEX;
497 if (PREDICT_FALSE (free_count == 0))
498 return SVM_FIFO_FULL;
500 /* number of bytes we're going to copy */
501 to_copy = len = clib_min (free_count, len);
504 tail_idx = tail % f->size;
505 ASSERT (tail_idx >= c->start_byte);
506 tail_idx -= c->start_byte;
507 n_chunk = c->length - tail_idx;
509 if (n_chunk < to_copy)
511 clib_memcpy_fast (&c->data[tail_idx], src, n_chunk);
512 while ((to_copy -= n_chunk))
515 n_chunk = clib_min (c->length, to_copy);
516 clib_memcpy_fast (&c->data[0], src + (len - to_copy), n_chunk);
522 clib_memcpy_fast (&c->data[tail_idx], src, to_copy);
526 svm_fifo_trace_add (f, head, n_total, 2);
528 /* collect out-of-order segments */
529 if (PREDICT_FALSE (f->ooos_list_head != OOO_SEGMENT_INVALID_INDEX))
530 len += ooo_segment_try_collect (f, len, &tail);
532 ASSERT (len <= free_count);
534 /* store-rel: producer owned index (paired with load-acq in consumer) */
535 clib_atomic_store_rel_n (&f->tail, tail);
540 #ifndef CLIB_MARCH_VARIANT
542 svm_fifo_enqueue_nowait (svm_fifo_t * f, u32 max_bytes,
543 const u8 * copy_from_here)
545 return CLIB_MARCH_FN_SELECT (svm_fifo_enqueue_nowait) (f, max_bytes,
551 * Enqueue a future segment.
553 * Two choices: either copies the entire segment, or copies nothing
554 * Returns 0 of the entire segment was copied
555 * Returns -1 if none of the segment was copied due to lack of space
557 CLIB_MARCH_FN (svm_fifo_enqueue_with_offset, int, svm_fifo_t * f,
558 u32 offset, u32 len, u8 * src)
560 u32 to_copy, n_chunk, tail, head, free_count, tail_offset_idx;
563 f_load_head_tail_prod (f, &head, &tail);
565 /* free space in fifo can only increase during enqueue: SPSC */
566 free_count = f_free_count (f, head, tail);
568 /* will this request fit? */
569 if ((len + offset) > free_count)
572 f->ooos_newest = OOO_SEGMENT_INVALID_INDEX;
574 ASSERT (len < f->nitems);
575 svm_fifo_trace_add (f, offset, len, 1);
577 ooo_segment_add (f, offset, head, tail, len);
580 tail_offset_idx = (tail + offset) % f->size;
581 tail_offset_idx -= c->start_byte;
582 n_chunk = c->length - tail_offset_idx;
585 if (n_chunk < to_copy)
587 clib_memcpy_fast (&c->data[tail_offset_idx], src, n_chunk);
588 while ((to_copy -= n_chunk))
591 n_chunk = clib_min (c->length, to_copy);
592 clib_memcpy_fast (&c->data[0], src + (len - to_copy), n_chunk);
597 clib_memcpy_fast (&c->data[tail_offset_idx], src, len);
603 #ifndef CLIB_MARCH_VARIANT
606 svm_fifo_enqueue_with_offset (svm_fifo_t * f, u32 offset, u32 required_bytes,
609 return CLIB_MARCH_FN_SELECT (svm_fifo_enqueue_with_offset) (f, offset,
615 svm_fifo_overwrite_head (svm_fifo_t * f, u8 * data, u32 len)
618 u32 head, tail, head_idx;
621 ASSERT (len <= f->nitems);
623 f_load_head_tail_cons (f, &head, &tail);
625 head_idx = head % f->size;
626 head_idx -= c->start_byte;
627 n_chunk = c->length - head_idx;
629 clib_memcpy_fast (&c->data[head_idx], data, len);
632 clib_memcpy_fast (&c->data[head_idx], data, n_chunk);
633 clib_memcpy_fast (&c->next->data[0], data + n_chunk, len - n_chunk);
638 CLIB_MARCH_FN (svm_fifo_dequeue_nowait, int, svm_fifo_t * f, u32 len,
641 u32 to_copy, n_chunk, tail, head, cursize, head_idx;
644 f_load_head_tail_cons (f, &head, &tail);
646 /* current size of fifo can only increase during dequeue: SPSC */
647 cursize = f_cursize (f, head, tail);
649 if (PREDICT_FALSE (cursize == 0))
650 return -2; /* nothing in the fifo */
652 to_copy = len = clib_min (cursize, len);
655 head_idx = head % f->size;
656 head_idx -= c->start_byte;
657 n_chunk = c->length - head_idx;
659 if (n_chunk < to_copy)
661 clib_memcpy_fast (dst, &c->data[head_idx], n_chunk);
662 while ((to_copy -= n_chunk))
665 n_chunk = clib_min (c->length, to_copy);
666 clib_memcpy_fast (dst + (len - to_copy), &c->data[0], n_chunk);
672 clib_memcpy_fast (dst, &c->data[head_idx], to_copy);
676 ASSERT (cursize >= to_copy);
677 /* store-rel: consumer owned index (paired with load-acq in producer) */
678 clib_atomic_store_rel_n (&f->head, head);
683 #ifndef CLIB_MARCH_VARIANT
686 svm_fifo_dequeue_nowait (svm_fifo_t * f, u32 max_bytes, u8 * copy_here)
688 return CLIB_MARCH_FN_SELECT (svm_fifo_dequeue_nowait) (f, max_bytes,
693 CLIB_MARCH_FN (svm_fifo_peek, int, svm_fifo_t * f, u32 relative_offset,
696 u32 to_copy, n_chunk, tail, head, cursize, head_idx;
699 f_load_head_tail_cons (f, &head, &tail);
701 /* current size of fifo can only increase during peek: SPSC */
702 cursize = f_cursize (f, head, tail);
704 if (PREDICT_FALSE (cursize < relative_offset))
705 return -2; /* nothing in the fifo */
707 to_copy = len = clib_min (cursize - relative_offset, len);
710 head_idx = (head + relative_offset) % f->size;
711 head_idx -= c->start_byte;
712 n_chunk = c->length - head_idx;
714 if (n_chunk < to_copy)
716 clib_memcpy_fast (dst, &c->data[head_idx], n_chunk);
717 while ((to_copy -= n_chunk))
720 n_chunk = clib_min (c->length, to_copy);
721 clib_memcpy_fast (dst + (len - to_copy), &c->data[0], n_chunk);
727 clib_memcpy_fast (dst, &c->data[head_idx], to_copy);
732 #ifndef CLIB_MARCH_VARIANT
735 svm_fifo_peek (svm_fifo_t * f, u32 relative_offset, u32 max_bytes,
738 return CLIB_MARCH_FN_SELECT (svm_fifo_peek) (f, relative_offset, max_bytes,
743 svm_fifo_dequeue_drop (svm_fifo_t * f, u32 max_bytes)
745 u32 total_drop_bytes;
746 u32 tail, head, cursize;
748 f_load_head_tail_cons (f, &head, &tail);
750 /* number of bytes we're going to drop */
751 cursize = f_cursize (f, head, tail);
753 if (PREDICT_FALSE (cursize == 0))
754 return -2; /* nothing in the fifo */
756 svm_fifo_trace_add (f, tail, total_drop_bytes, 3);
758 /* number of bytes we're going to drop */
759 total_drop_bytes = (cursize < max_bytes) ? cursize : max_bytes;
762 head += total_drop_bytes;
764 ASSERT (cursize >= total_drop_bytes);
765 /* store-rel: consumer owned index (paired with load-acq in producer) */
766 clib_atomic_store_rel_n (&f->head, head);
768 return total_drop_bytes;
772 svm_fifo_dequeue_drop_all (svm_fifo_t * f)
774 /* consumer foreign index */
775 u32 tail = clib_atomic_load_acq_n (&f->tail);
776 /* store-rel: consumer owned index (paired with load-acq in producer) */
777 clib_atomic_store_rel_n (&f->head, tail);
781 svm_fifo_segments (svm_fifo_t * f, svm_fifo_segment_t * fs)
783 u32 cursize, head, tail, head_idx;
785 f_load_head_tail_cons (f, &head, &tail);
787 /* consumer function, cursize can only increase while we're working */
788 cursize = f_cursize (f, head, tail);
790 if (PREDICT_FALSE (cursize == 0))
791 return -2; /* nothing in the fifo */
793 head_idx = head % f->size;
797 fs[0].len = f->size - head_idx;
798 fs[0].data = f->head_chunk->data + head_idx;
799 fs[1].len = cursize - fs[0].len;
800 fs[1].data = f->head_chunk->data;
805 fs[0].data = f->head_chunk->data + head_idx;
813 svm_fifo_segments_free (svm_fifo_t * f, svm_fifo_segment_t * fs)
817 /* consumer owned index */
819 head_idx = head % f->size;
821 ASSERT (fs[0].data == f->head_chunk->data + head_idx);
822 head += fs[0].len + fs[1].len;
823 /* store-rel: consumer owned index (paired with load-acq in producer) */
824 clib_atomic_store_rel_n (&f->head, head);
827 /* Assumption: no prod and cons are accessing either dest or src fifo */
829 svm_fifo_clone (svm_fifo_t * df, svm_fifo_t * sf)
832 clib_memcpy_fast (df->head_chunk->data, sf->head_chunk->data, sf->size);
834 f_load_head_tail_all_acq (sf, &head, &tail);
835 clib_atomic_store_rel_n (&df->head, head);
836 clib_atomic_store_rel_n (&df->tail, tail);
840 svm_fifo_number_ooo_segments (svm_fifo_t * f)
842 return pool_elts (f->ooo_segments);
846 svm_fifo_first_ooo_segment (svm_fifo_t * f)
848 return pool_elt_at_index (f->ooo_segments, f->ooos_list_head);
852 * Set fifo pointers to requested offset
855 svm_fifo_init_pointers (svm_fifo_t * f, u32 pointer)
857 clib_atomic_store_rel_n (&f->head, pointer);
858 clib_atomic_store_rel_n (&f->tail, pointer);
862 svm_fifo_add_subscriber (svm_fifo_t * f, u8 subscriber)
864 if (f->n_subscribers >= SVM_FIFO_MAX_EVT_SUBSCRIBERS)
866 f->subscribers[f->n_subscribers++] = subscriber;
870 svm_fifo_del_subscriber (svm_fifo_t * f, u8 subscriber)
874 for (i = 0; i < f->n_subscribers; i++)
876 if (f->subscribers[i] != subscriber)
878 f->subscribers[i] = f->subscribers[f->n_subscribers - 1];
886 * fd.io coding-style-patch-verification: ON
889 * eval: (c-set-style "gnu")