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.
19 #ifndef __included_ssvm_fifo_h__
20 #define __included_ssvm_fifo_h__
22 #include <vppinfra/clib.h>
23 #include <vppinfra/vec.h>
24 #include <vppinfra/mheap.h>
25 #include <vppinfra/heap.h>
26 #include <vppinfra/pool.h>
27 #include <vppinfra/format.h>
30 /** Out-of-order segment */
33 u32 next; /**< Next linked-list element pool index */
34 u32 prev; /**< Previous linked-list element pool index */
36 u32 start; /**< Start of segment, normalized*/
37 u32 length; /**< Length of segment */
40 format_function_t format_ooo_segment;
41 format_function_t format_ooo_list;
43 #define SVM_FIFO_TRACE (0)
44 #define OOO_SEGMENT_INVALID_INDEX ((u32)~0)
45 #define SVM_FIFO_INVALID_SESSION_INDEX ((u32)~0)
46 #define SVM_FIFO_INVALID_INDEX ((u32)~0)
47 #define SVM_FIFO_MAX_EVT_SUBSCRIBERS 8
51 SVM_FIFO_NO_TX_NOTIF = 0,
52 SVM_FIFO_WANT_TX_NOTIF = 1,
53 SVM_FIFO_WANT_TX_NOTIF_IF_FULL = 2,
61 } svm_fifo_trace_elem_t;
63 typedef struct svm_fifo_chunk_
67 struct svm_fifo_chunk_ *next;
71 typedef enum svm_fifo_flag_
73 SVM_FIFO_F_SIZE_UPDATE = 1 << 0,
76 typedef struct _svm_fifo
78 CLIB_CACHE_LINE_ALIGN_MARK (shared_first);
79 u32 size; /**< size of the fifo */
80 u32 nitems; /**< usable size(size-1) */
81 u8 flags; /**< fifo flags */
82 svm_fifo_chunk_t *start_chunk;/**< first chunk in fifo chunk list */
83 svm_fifo_chunk_t *end_chunk; /**< end chunk in fifo chunk list */
84 svm_fifo_chunk_t *new_chunks; /**< chunks yet to be added to list */
86 CLIB_CACHE_LINE_ALIGN_MARK (shared_second);
87 volatile u32 has_event; /**< non-zero if deq event exists */
89 u32 master_session_index;
90 u32 client_session_index;
91 u8 master_thread_index;
92 u8 client_thread_index;
95 u32 ct_session_index; /**< Local session index for vpp */
96 u32 freelist_index; /**< aka log2(allocated_size) - const. */
97 i8 refcnt; /**< reference count */
98 struct _svm_fifo *next; /**< next in freelist/active chain */
99 struct _svm_fifo *prev; /**< prev in active chain */
101 CLIB_CACHE_LINE_ALIGN_MARK (consumer);
103 svm_fifo_chunk_t *head_chunk; /**< tracks chunk where head lands */
104 volatile u32 want_tx_ntf; /**< producer wants nudge */
105 volatile u32 has_tx_ntf;
107 CLIB_CACHE_LINE_ALIGN_MARK (producer);
109 svm_fifo_chunk_t *tail_chunk; /**< tracks chunk where tail lands */
111 ooo_segment_t *ooo_segments; /**< Pool of ooo segments */
112 u32 ooos_list_head; /**< Head of out-of-order linked-list */
113 u32 ooos_newest; /**< Last segment to have been updated */
114 volatile u8 n_subscribers;
115 u8 subscribers[SVM_FIFO_MAX_EVT_SUBSCRIBERS];
118 svm_fifo_trace_elem_t *trace;
121 svm_fifo_chunk_t default_chunk;
129 typedef struct svm_fifo_segment_
133 } svm_fifo_segment_t;
136 #define svm_fifo_trace_add(_f, _s, _l, _t) \
138 svm_fifo_trace_elem_t *trace_elt; \
139 vec_add2(_f->trace, trace_elt, 1); \
140 trace_elt->offset = _s; \
141 trace_elt->len = _l; \
142 trace_elt->action = _t; \
145 #define svm_fifo_trace_add(_f, _s, _l, _t)
148 u8 *svm_fifo_dump_trace (u8 * s, svm_fifo_t * f);
149 u8 *svm_fifo_replay (u8 * s, svm_fifo_t * f, u8 no_read, u8 verbose);
151 /* internal function */
153 f_load_head_tail_cons (svm_fifo_t * f, u32 * head, u32 * tail)
155 /* load-relaxed: consumer owned index */
157 /* load-acq: consumer foreign index (paired with store-rel in producer) */
158 *tail = clib_atomic_load_acq_n (&f->tail);
161 /* internal function */
163 f_load_head_tail_prod (svm_fifo_t * f, u32 * head, u32 * tail)
165 /* load relaxed: producer owned index */
167 /* load-acq: producer foreign index (paired with store-rel in consumer) */
168 *head = clib_atomic_load_acq_n (&f->head);
171 /* producer consumer role independent */
172 /* internal function */
174 f_load_head_tail_all_acq (svm_fifo_t * f, u32 * head, u32 * tail)
176 /* load-acq : consumer foreign index (paired with store-rel) */
177 *tail = clib_atomic_load_acq_n (&f->tail);
178 /* load-acq : producer foriegn index (paired with store-rel) */
179 *head = clib_atomic_load_acq_n (&f->head);
182 /* internal function */
184 f_free_count (svm_fifo_t * f, u32 head, u32 tail)
186 return (f->nitems + head - tail);
189 /* internal function */
191 f_cursize (svm_fifo_t * f, u32 head, u32 tail)
193 return (f->nitems - f_free_count (f, head, tail));
196 /* used by consumer */
198 svm_fifo_max_dequeue_cons (svm_fifo_t * f)
201 f_load_head_tail_cons (f, &head, &tail);
202 return f_cursize (f, head, tail);
205 /* used by producer*/
207 svm_fifo_max_dequeue_prod (svm_fifo_t * f)
210 f_load_head_tail_prod (f, &head, &tail);
211 return f_cursize (f, head, tail);
214 /* use producer or consumer specific functions for perfomance.
215 * svm_fifo_max_dequeue_cons (svm_fifo_t *f)
216 * svm_fifo_max_dequeue_prod (svm_fifo_t *f)
219 svm_fifo_max_dequeue (svm_fifo_t * f)
222 f_load_head_tail_all_acq (f, &head, &tail);
223 return f_cursize (f, head, tail);
226 /* used by producer */
228 svm_fifo_is_full_prod (svm_fifo_t * f)
230 return (svm_fifo_max_dequeue_prod (f) == f->nitems);
233 /* use producer or consumer specific functions for perfomance.
234 * svm_fifo_is_full_prod (svm_fifo_t * f)
235 * add cons version if needed
238 svm_fifo_is_full (svm_fifo_t * f)
240 return (svm_fifo_max_dequeue (f) == f->nitems);
243 /* used by consumer */
245 svm_fifo_is_empty_cons (svm_fifo_t * f)
247 return (svm_fifo_max_dequeue_cons (f) == 0);
250 /* used by producer */
252 svm_fifo_is_empty_prod (svm_fifo_t * f)
254 return (svm_fifo_max_dequeue_prod (f) == 0);
257 /* use producer or consumer specific functions for perfomance.
258 * svm_fifo_is_empty_cons (svm_fifo_t * f)
259 * svm_fifo_is_empty_prod (svm_fifo_t * f)
262 svm_fifo_is_empty (svm_fifo_t * f)
264 return (svm_fifo_max_dequeue (f) == 0);
267 /* used by producer*/
269 svm_fifo_max_enqueue_prod (svm_fifo_t * f)
272 f_load_head_tail_prod (f, &head, &tail);
273 return f_free_count (f, head, tail);
276 /* use producer or consumer specfic functions for perfomance.
277 * svm_fifo_max_enqueue_prod (svm_fifo_t *f)
278 * add consumer specific version if needed.
281 svm_fifo_max_enqueue (svm_fifo_t * f)
284 f_load_head_tail_all_acq (f, &head, &tail);
285 return f_free_count (f, head, tail);
289 svm_fifo_has_event (svm_fifo_t * f)
295 svm_fifo_has_ooo_data (svm_fifo_t * f)
297 return f->ooos_list_head != OOO_SEGMENT_INVALID_INDEX;
301 * Sets fifo event flag.
303 * Also acts as a release ordering.
305 * @return 1 if flag was not set.
308 svm_fifo_set_event (svm_fifo_t * f)
310 /* return __sync_lock_test_and_set (&f->has_event, 1) == 0;
311 return __sync_bool_compare_and_swap (&f->has_event, 0, 1); */
312 return !clib_atomic_swap_rel_n (&f->has_event, 1);
316 * Unsets fifo event flag.
318 * Also acts as an acquire barrier.
321 svm_fifo_unset_event (svm_fifo_t * f)
323 clib_atomic_swap_acq_n (&f->has_event, 0);
326 svm_fifo_t *svm_fifo_create (u32 data_size_in_bytes);
327 void svm_fifo_init (svm_fifo_t * f, u32 size);
328 void svm_fifo_free (svm_fifo_t * f);
330 int svm_fifo_enqueue_nowait (svm_fifo_t * f, u32 max_bytes,
331 const u8 * copy_from_here);
332 int svm_fifo_enqueue_with_offset (svm_fifo_t * f, u32 offset,
333 u32 required_bytes, u8 * copy_from_here);
334 int svm_fifo_dequeue_nowait (svm_fifo_t * f, u32 max_bytes, u8 * copy_here);
336 int svm_fifo_peek (svm_fifo_t * f, u32 offset, u32 max_bytes, u8 * copy_here);
337 int svm_fifo_dequeue_drop (svm_fifo_t * f, u32 max_bytes);
338 void svm_fifo_dequeue_drop_all (svm_fifo_t * f);
339 int svm_fifo_segments (svm_fifo_t * f, svm_fifo_segment_t * fs);
340 void svm_fifo_segments_free (svm_fifo_t * f, svm_fifo_segment_t * fs);
341 void svm_fifo_init_pointers (svm_fifo_t * f, u32 pointer);
342 void svm_fifo_clone (svm_fifo_t * df, svm_fifo_t * sf);
343 void svm_fifo_overwrite_head (svm_fifo_t * f, u8 * data, u32 len);
344 void svm_fifo_add_subscriber (svm_fifo_t * f, u8 subscriber);
345 void svm_fifo_del_subscriber (svm_fifo_t * f, u8 subscriber);
346 format_function_t format_svm_fifo;
349 * Max contiguous chunk of data that can be read
352 svm_fifo_max_read_chunk (svm_fifo_t * f)
355 u32 head_idx, tail_idx;
356 f_load_head_tail_cons (f, &head, &tail);
357 head_idx = head % f->size;
358 tail_idx = tail % f->size;
359 return tail_idx > head_idx ? (tail_idx - head_idx) : (f->size - head_idx);
363 * Max contiguous chunk of data that can be written
366 svm_fifo_max_write_chunk (svm_fifo_t * f)
369 u32 head_idx, tail_idx;
370 f_load_head_tail_prod (f, &head, &tail);
371 head_idx = head % f->size;
372 tail_idx = tail % f->size;
373 return tail_idx >= head_idx ? (f->size - tail_idx) : (head_idx - tail_idx);
377 * Advance tail pointer
379 * Useful for moving tail pointer after external enqueue.
382 svm_fifo_enqueue_nocopy (svm_fifo_t * f, u32 bytes)
384 ASSERT (bytes <= svm_fifo_max_enqueue_prod (f));
385 /* load-relaxed: producer owned index */
388 /* store-rel: producer owned index (paired with load-acq in consumer) */
389 clib_atomic_store_rel_n (&f->tail, tail);
393 svm_fifo_head (svm_fifo_t * f)
395 /* load-relaxed: consumer owned index */
396 return (f->head_chunk->data
397 + ((f->head % f->size) - f->head_chunk->start_byte));
401 svm_fifo_tail (svm_fifo_t * f)
403 /* load-relaxed: producer owned index */
404 return (f->tail_chunk->data
405 + ((f->tail % f->size) - f->tail_chunk->start_byte));
409 svm_fifo_add_want_tx_ntf (svm_fifo_t * f, u8 ntf_type)
411 f->want_tx_ntf |= ntf_type;
415 svm_fifo_del_want_tx_ntf (svm_fifo_t * f, u8 ntf_type)
417 f->want_tx_ntf &= ~ntf_type;
421 svm_fifo_clear_tx_ntf (svm_fifo_t * f)
423 /* Set the flag if want_tx_notif_if_full was the only ntf requested */
424 f->has_tx_ntf = f->want_tx_ntf == SVM_FIFO_WANT_TX_NOTIF_IF_FULL;
425 svm_fifo_del_want_tx_ntf (f, SVM_FIFO_WANT_TX_NOTIF);
429 svm_fifo_reset_tx_ntf (svm_fifo_t * f)
435 svm_fifo_needs_tx_ntf (svm_fifo_t * f, u32 n_last_deq)
437 u8 want_ntf = f->want_tx_ntf;
439 if (PREDICT_TRUE (want_ntf == SVM_FIFO_NO_TX_NOTIF))
441 else if (want_ntf & SVM_FIFO_WANT_TX_NOTIF)
443 else if (want_ntf & SVM_FIFO_WANT_TX_NOTIF_IF_FULL)
445 u32 max_deq = svm_fifo_max_dequeue_cons (f);
446 u32 nitems = f->nitems;
447 if (!f->has_tx_ntf && max_deq < nitems
448 && max_deq + n_last_deq >= nitems)
457 svm_fifo_n_subscribers (svm_fifo_t * f)
459 return f->n_subscribers;
462 u32 svm_fifo_number_ooo_segments (svm_fifo_t * f);
463 ooo_segment_t *svm_fifo_first_ooo_segment (svm_fifo_t * f);
465 always_inline ooo_segment_t *
466 svm_fifo_newest_ooo_segment (svm_fifo_t * f)
468 if (f->ooos_newest == OOO_SEGMENT_INVALID_INDEX)
470 return pool_elt_at_index (f->ooo_segments, f->ooos_newest);
474 svm_fifo_newest_ooo_segment_reset (svm_fifo_t * f)
476 f->ooos_newest = OOO_SEGMENT_INVALID_INDEX;
480 ooo_segment_distance_from_tail (svm_fifo_t * f, u32 pos, u32 tail)
482 return ((pos - tail) % f->size);
486 ooo_segment_distance_to_tail (svm_fifo_t * f, u32 pos, u32 tail)
488 return ((tail - pos) % f->size);
492 ooo_segment_offset_prod (svm_fifo_t * f, ooo_segment_t * s)
495 /* load-relaxed: producer owned index */
498 return ooo_segment_distance_from_tail (f, s->start, tail);
502 ooo_segment_length (svm_fifo_t * f, ooo_segment_t * s)
507 always_inline ooo_segment_t *
508 ooo_segment_get_prev (svm_fifo_t * f, ooo_segment_t * s)
510 if (s->prev == OOO_SEGMENT_INVALID_INDEX)
512 return pool_elt_at_index (f->ooo_segments, s->prev);
515 always_inline ooo_segment_t *
516 ooo_segment_next (svm_fifo_t * f, ooo_segment_t * s)
518 if (s->next == OOO_SEGMENT_INVALID_INDEX)
520 return pool_elt_at_index (f->ooo_segments, s->next);
524 svm_fifo_is_wrapped (svm_fifo_t * f)
527 f_load_head_tail_all_acq (f, &head, &tail);
528 return head % f->size > tail % f->size;
532 svm_fifo_size_update (svm_fifo_t * f, svm_fifo_chunk_t * c)
534 svm_fifo_chunk_t *prev;
540 c->start_byte = prev->start_byte + prev->length;
541 add_bytes += c->length;
547 prev->next = f->start_chunk;
548 f->size += add_bytes;
549 f->nitems = f->size - 1;
554 svm_fifo_add_chunk (svm_fifo_t * f, svm_fifo_chunk_t * c)
556 if (svm_fifo_is_wrapped (f))
560 svm_fifo_chunk_t *prev;
562 prev = f->new_chunks;
571 f->flags |= SVM_FIFO_F_SIZE_UPDATE;
575 svm_fifo_size_update (f, c);
579 svm_fifo_try_size_update (svm_fifo_t * f, u32 new_head)
581 if (new_head % f->size > f->tail % f->size)
584 svm_fifo_size_update (f, f->new_chunks);
585 f->flags &= ~SVM_FIFO_F_SIZE_UPDATE;
587 #endif /* __included_ssvm_fifo_h__ */
590 * fd.io coding-style-patch-verification: ON
593 * eval: (c-set-style "gnu")