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->default_chunk.start_byte = 0;
220 f->default_chunk.length = f->size;
221 f->default_chunk.next = f->start_chunk = &f->default_chunk;
222 f->end_chunk = f->head_chunk = f->tail_chunk = f->start_chunk;
225 /** create an svm fifo, in the current heap. Fails vs blow up the process */
227 svm_fifo_create (u32 data_size_in_bytes)
230 u32 rounded_data_size;
232 /* always round fifo data size to the next highest power-of-two */
233 rounded_data_size = (1 << (max_log2 (data_size_in_bytes)));
234 f = clib_mem_alloc_aligned_or_null (sizeof (*f) + rounded_data_size,
235 CLIB_CACHE_LINE_BYTES);
239 clib_memset (f, 0, sizeof (*f));
240 svm_fifo_init (f, data_size_in_bytes);
245 svm_fifo_free (svm_fifo_t * f)
247 ASSERT (f->refcnt > 0);
249 if (--f->refcnt == 0)
251 pool_free (f->ooo_segments);
257 always_inline ooo_segment_t *
258 ooo_segment_new (svm_fifo_t * f, u32 start, u32 length)
262 pool_get (f->ooo_segments, s);
267 s->prev = s->next = OOO_SEGMENT_INVALID_INDEX;
273 ooo_segment_del (svm_fifo_t * f, u32 index)
275 ooo_segment_t *cur, *prev = 0, *next = 0;
276 cur = pool_elt_at_index (f->ooo_segments, index);
278 if (cur->next != OOO_SEGMENT_INVALID_INDEX)
280 next = pool_elt_at_index (f->ooo_segments, cur->next);
281 next->prev = cur->prev;
284 if (cur->prev != OOO_SEGMENT_INVALID_INDEX)
286 prev = pool_elt_at_index (f->ooo_segments, cur->prev);
287 prev->next = cur->next;
291 f->ooos_list_head = cur->next;
294 pool_put (f->ooo_segments, cur);
298 * Add segment to fifo's out-of-order segment list. Takes care of merging
299 * adjacent segments and removing overlapping ones.
302 ooo_segment_add (svm_fifo_t * f, u32 offset, u32 head, u32 tail, u32 length)
304 ooo_segment_t *s, *new_s, *prev, *next, *it;
305 u32 new_index, s_end_pos, s_index;
306 u32 offset_pos, offset_end_pos;
308 ASSERT (offset + length <= ooo_segment_distance_from_tail (f, head, tail)
311 offset_pos = tail + offset;
312 offset_end_pos = tail + offset + length;
314 f->ooos_newest = OOO_SEGMENT_INVALID_INDEX;
316 if (f->ooos_list_head == OOO_SEGMENT_INVALID_INDEX)
318 s = ooo_segment_new (f, offset_pos, length);
319 f->ooos_list_head = s - f->ooo_segments;
320 f->ooos_newest = f->ooos_list_head;
324 /* Find first segment that starts after new segment */
325 s = pool_elt_at_index (f->ooo_segments, f->ooos_list_head);
326 while (s->next != OOO_SEGMENT_INVALID_INDEX
327 && position_lt (f, s->start, offset_pos, tail))
328 s = pool_elt_at_index (f->ooo_segments, s->next);
330 /* If we have a previous and we overlap it, use it as starting point */
331 prev = ooo_segment_get_prev (f, s);
333 && position_leq (f, offset_pos, ooo_segment_end_pos (f, prev), tail))
336 s_end_pos = ooo_segment_end_pos (f, s);
338 /* Since we have previous, offset start position cannot be smaller
339 * than prev->start. Check tail */
340 ASSERT (position_lt (f, s->start, offset_pos, tail));
344 s_index = s - f->ooo_segments;
345 s_end_pos = ooo_segment_end_pos (f, s);
347 /* No overlap, add before current segment */
348 if (position_lt (f, offset_end_pos, s->start, tail))
350 new_s = ooo_segment_new (f, offset_pos, length);
351 new_index = new_s - f->ooo_segments;
353 /* Pool might've moved, get segment again */
354 s = pool_elt_at_index (f->ooo_segments, s_index);
355 if (s->prev != OOO_SEGMENT_INVALID_INDEX)
357 new_s->prev = s->prev;
358 prev = pool_elt_at_index (f->ooo_segments, new_s->prev);
359 prev->next = new_index;
364 f->ooos_list_head = new_index;
367 new_s->next = s_index;
369 f->ooos_newest = new_index;
372 /* No overlap, add after current segment */
373 else if (position_gt (f, offset_pos, s_end_pos, tail))
375 new_s = ooo_segment_new (f, offset_pos, length);
376 new_index = new_s - f->ooo_segments;
378 /* Pool might've moved, get segment again */
379 s = pool_elt_at_index (f->ooo_segments, s_index);
381 /* Needs to be last */
382 ASSERT (s->next == OOO_SEGMENT_INVALID_INDEX);
384 new_s->prev = s_index;
386 f->ooos_newest = new_index;
396 if (position_lt (f, offset_pos, s->start, tail))
398 s->start = offset_pos;
399 s->length = position_diff (f, s_end_pos, s->start, tail);
400 f->ooos_newest = s - f->ooo_segments;
405 /* Overlapping tail */
406 if (position_gt (f, offset_end_pos, s_end_pos, tail))
408 s->length = position_diff (f, offset_end_pos, s->start, tail);
410 /* Remove the completely overlapped segments in the tail */
411 it = ooo_segment_next (f, s);
412 while (it && position_leq (f, ooo_segment_end_pos (f, it),
413 offset_end_pos, tail))
415 next = ooo_segment_next (f, it);
416 ooo_segment_del (f, it - f->ooo_segments);
420 /* If partial overlap with last, merge */
421 if (it && position_leq (f, it->start, offset_end_pos, tail))
423 s->length = position_diff (f, ooo_segment_end_pos (f, it),
425 ooo_segment_del (f, it - f->ooo_segments);
427 f->ooos_newest = s - f->ooo_segments;
432 * Removes segments that can now be enqueued because the fifo's tail has
433 * advanced. Returns the number of bytes added to tail.
436 ooo_segment_try_collect (svm_fifo_t * f, u32 n_bytes_enqueued, u32 * tail)
439 u32 index, bytes = 0;
442 s = pool_elt_at_index (f->ooo_segments, f->ooos_list_head);
443 diff = ooo_segment_distance_to_tail (f, s->start, *tail);
445 ASSERT (diff != n_bytes_enqueued);
447 if (diff > n_bytes_enqueued)
450 /* If last tail update overlaps one/multiple ooo segments, remove them */
451 while (0 <= diff && diff < n_bytes_enqueued)
453 index = s - f->ooo_segments;
455 /* Segment end is beyond the tail. Advance tail and remove segment */
456 if (s->length > diff)
458 bytes = s->length - diff;
459 *tail = *tail + bytes;
460 ooo_segment_del (f, index);
464 /* If we have next go on */
465 if (s->next != OOO_SEGMENT_INVALID_INDEX)
467 s = pool_elt_at_index (f->ooo_segments, s->next);
468 diff = ooo_segment_distance_to_tail (f, s->start, *tail);
469 ooo_segment_del (f, index);
474 ooo_segment_del (f, index);
479 ASSERT (bytes <= f->nitems);
483 CLIB_MARCH_FN (svm_fifo_enqueue_nowait, int, svm_fifo_t * f, u32 len,
486 u32 n_chunk, to_copy, tail, head, free_count, tail_idx;
489 f_load_head_tail_prod (f, &head, &tail);
491 /* free space in fifo can only increase during enqueue: SPSC */
492 free_count = f_free_count (f, head, tail);
494 f->ooos_newest = OOO_SEGMENT_INVALID_INDEX;
496 if (PREDICT_FALSE (free_count == 0))
497 return SVM_FIFO_FULL;
499 /* number of bytes we're going to copy */
500 to_copy = len = clib_min (free_count, len);
503 tail_idx = tail % f->size;
504 ASSERT (tail_idx >= c->start_byte);
505 tail_idx -= c->start_byte;
506 n_chunk = c->length - tail_idx;
508 if (n_chunk < to_copy)
510 clib_memcpy_fast (&c->data[tail_idx], src, n_chunk);
511 while ((to_copy -= n_chunk))
514 n_chunk = clib_min (c->length, to_copy);
515 clib_memcpy_fast (&c->data[0], src + (len - to_copy), n_chunk);
521 clib_memcpy_fast (&c->data[tail_idx], src, to_copy);
525 svm_fifo_trace_add (f, head, n_total, 2);
527 /* collect out-of-order segments */
528 if (PREDICT_FALSE (f->ooos_list_head != OOO_SEGMENT_INVALID_INDEX))
529 len += ooo_segment_try_collect (f, len, &tail);
531 ASSERT (len <= free_count);
533 /* store-rel: producer owned index (paired with load-acq in consumer) */
534 clib_atomic_store_rel_n (&f->tail, tail);
539 #ifndef CLIB_MARCH_VARIANT
541 svm_fifo_enqueue_nowait (svm_fifo_t * f, u32 max_bytes,
542 const u8 * copy_from_here)
544 return CLIB_MARCH_FN_SELECT (svm_fifo_enqueue_nowait) (f, max_bytes,
550 * Enqueue a future segment.
552 * Two choices: either copies the entire segment, or copies nothing
553 * Returns 0 of the entire segment was copied
554 * Returns -1 if none of the segment was copied due to lack of space
556 CLIB_MARCH_FN (svm_fifo_enqueue_with_offset, int, svm_fifo_t * f,
557 u32 offset, u32 len, u8 * src)
559 u32 to_copy, n_chunk, tail, head, free_count, tail_offset_idx;
562 f_load_head_tail_prod (f, &head, &tail);
564 /* free space in fifo can only increase during enqueue: SPSC */
565 free_count = f_free_count (f, head, tail);
567 /* will this request fit? */
568 if ((len + offset) > free_count)
571 f->ooos_newest = OOO_SEGMENT_INVALID_INDEX;
573 ASSERT (len < f->nitems);
574 svm_fifo_trace_add (f, offset, len, 1);
576 ooo_segment_add (f, offset, head, tail, len);
579 tail_offset_idx = (tail + offset) % f->size;
580 tail_offset_idx -= c->start_byte;
581 n_chunk = c->length - tail_offset_idx;
584 if (n_chunk < to_copy)
586 clib_memcpy_fast (&c->data[tail_offset_idx], src, n_chunk);
587 while ((to_copy -= n_chunk))
590 n_chunk = clib_min (c->length, to_copy);
591 clib_memcpy_fast (&c->data[0], src + (len - to_copy), n_chunk);
596 clib_memcpy_fast (&c->data[tail_offset_idx], src, len);
602 #ifndef CLIB_MARCH_VARIANT
605 svm_fifo_enqueue_with_offset (svm_fifo_t * f, u32 offset, u32 required_bytes,
608 return CLIB_MARCH_FN_SELECT (svm_fifo_enqueue_with_offset) (f, offset,
614 svm_fifo_overwrite_head (svm_fifo_t * f, u8 * data, u32 len)
617 u32 head, tail, head_idx;
620 ASSERT (len <= f->nitems);
622 f_load_head_tail_cons (f, &head, &tail);
624 head_idx = head % f->size;
625 head_idx -= c->start_byte;
626 n_chunk = c->length - head_idx;
628 clib_memcpy_fast (&c->data[head_idx], data, len);
631 clib_memcpy_fast (&c->data[head_idx], data, n_chunk);
632 clib_memcpy_fast (&c->next->data[0], data + n_chunk, len - n_chunk);
637 CLIB_MARCH_FN (svm_fifo_dequeue_nowait, int, svm_fifo_t * f, u32 len,
640 u32 to_copy, n_chunk, tail, head, cursize, head_idx;
643 f_load_head_tail_cons (f, &head, &tail);
645 /* current size of fifo can only increase during dequeue: SPSC */
646 cursize = f_cursize (f, head, tail);
648 if (PREDICT_FALSE (cursize == 0))
649 return -2; /* nothing in the fifo */
651 to_copy = len = clib_min (cursize, len);
652 ASSERT (cursize >= to_copy);
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 if (PREDICT_FALSE (f->flags & SVM_FIFO_F_SIZE_UPDATE))
677 svm_fifo_try_size_update (f, head);
679 /* store-rel: consumer owned index (paired with load-acq in producer) */
680 clib_atomic_store_rel_n (&f->head, head);
685 #ifndef CLIB_MARCH_VARIANT
688 svm_fifo_dequeue_nowait (svm_fifo_t * f, u32 max_bytes, u8 * copy_here)
690 return CLIB_MARCH_FN_SELECT (svm_fifo_dequeue_nowait) (f, max_bytes,
695 CLIB_MARCH_FN (svm_fifo_peek, int, svm_fifo_t * f, u32 relative_offset,
698 u32 to_copy, n_chunk, tail, head, cursize, head_idx;
701 f_load_head_tail_cons (f, &head, &tail);
703 /* current size of fifo can only increase during peek: SPSC */
704 cursize = f_cursize (f, head, tail);
706 if (PREDICT_FALSE (cursize < relative_offset))
707 return -2; /* nothing in the fifo */
709 to_copy = len = clib_min (cursize - relative_offset, len);
712 head_idx = (head + relative_offset) % f->size;
713 head_idx -= c->start_byte;
714 n_chunk = c->length - head_idx;
716 if (n_chunk < to_copy)
718 clib_memcpy_fast (dst, &c->data[head_idx], n_chunk);
719 while ((to_copy -= n_chunk))
722 n_chunk = clib_min (c->length, to_copy);
723 clib_memcpy_fast (dst + (len - to_copy), &c->data[0], n_chunk);
729 clib_memcpy_fast (dst, &c->data[head_idx], to_copy);
734 #ifndef CLIB_MARCH_VARIANT
737 svm_fifo_peek (svm_fifo_t * f, u32 relative_offset, u32 max_bytes,
740 return CLIB_MARCH_FN_SELECT (svm_fifo_peek) (f, relative_offset, max_bytes,
745 svm_fifo_dequeue_drop (svm_fifo_t * f, u32 max_bytes)
747 u32 total_drop_bytes;
748 u32 tail, head, cursize;
750 f_load_head_tail_cons (f, &head, &tail);
752 /* number of bytes we're going to drop */
753 cursize = f_cursize (f, head, tail);
755 if (PREDICT_FALSE (cursize == 0))
756 return -2; /* nothing in the fifo */
758 svm_fifo_trace_add (f, tail, total_drop_bytes, 3);
760 /* number of bytes we're going to drop */
761 total_drop_bytes = (cursize < max_bytes) ? cursize : max_bytes;
764 head += total_drop_bytes;
766 ASSERT (cursize >= total_drop_bytes);
767 /* store-rel: consumer owned index (paired with load-acq in producer) */
768 clib_atomic_store_rel_n (&f->head, head);
770 return total_drop_bytes;
774 svm_fifo_dequeue_drop_all (svm_fifo_t * f)
776 /* consumer foreign index */
777 u32 tail = clib_atomic_load_acq_n (&f->tail);
778 /* store-rel: consumer owned index (paired with load-acq in producer) */
779 clib_atomic_store_rel_n (&f->head, tail);
783 svm_fifo_segments (svm_fifo_t * f, svm_fifo_segment_t * fs)
785 u32 cursize, head, tail, head_idx;
787 f_load_head_tail_cons (f, &head, &tail);
789 /* consumer function, cursize can only increase while we're working */
790 cursize = f_cursize (f, head, tail);
792 if (PREDICT_FALSE (cursize == 0))
793 return -2; /* nothing in the fifo */
795 head_idx = head % f->size;
799 fs[0].len = f->size - head_idx;
800 fs[0].data = f->head_chunk->data + head_idx;
801 fs[1].len = cursize - fs[0].len;
802 fs[1].data = f->head_chunk->data;
807 fs[0].data = f->head_chunk->data + head_idx;
815 svm_fifo_segments_free (svm_fifo_t * f, svm_fifo_segment_t * fs)
819 /* consumer owned index */
821 head_idx = head % f->size;
823 ASSERT (fs[0].data == f->head_chunk->data + head_idx);
824 head += fs[0].len + fs[1].len;
825 /* store-rel: consumer owned index (paired with load-acq in producer) */
826 clib_atomic_store_rel_n (&f->head, head);
829 /* Assumption: no prod and cons are accessing either dest or src fifo */
831 svm_fifo_clone (svm_fifo_t * df, svm_fifo_t * sf)
834 clib_memcpy_fast (df->head_chunk->data, sf->head_chunk->data, sf->size);
836 f_load_head_tail_all_acq (sf, &head, &tail);
837 clib_atomic_store_rel_n (&df->head, head);
838 clib_atomic_store_rel_n (&df->tail, tail);
842 svm_fifo_number_ooo_segments (svm_fifo_t * f)
844 return pool_elts (f->ooo_segments);
848 svm_fifo_first_ooo_segment (svm_fifo_t * f)
850 return pool_elt_at_index (f->ooo_segments, f->ooos_list_head);
854 * Set fifo pointers to requested offset
857 svm_fifo_init_pointers (svm_fifo_t * f, u32 pointer)
859 clib_atomic_store_rel_n (&f->head, pointer);
860 clib_atomic_store_rel_n (&f->tail, pointer);
864 svm_fifo_add_subscriber (svm_fifo_t * f, u8 subscriber)
866 if (f->n_subscribers >= SVM_FIFO_MAX_EVT_SUBSCRIBERS)
868 f->subscribers[f->n_subscribers++] = subscriber;
872 svm_fifo_del_subscriber (svm_fifo_t * f, u8 subscriber)
876 for (i = 0; i < f->n_subscribers; i++)
878 if (f->subscribers[i] != subscriber)
880 f->subscribers[i] = f->subscribers[f->n_subscribers - 1];
888 * fd.io coding-style-patch-verification: ON
891 * eval: (c-set-style "gnu")