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
65 CLIB_CACHE_LINE_ALIGN_MARK (shared_first);
66 u32 size; /**< size of the fifo(must be power of 2) */
67 u32 nitems; /**< usable size(size-1) */
69 CLIB_CACHE_LINE_ALIGN_MARK (shared_second);
70 volatile u32 has_event; /**< non-zero if deq event exists */
72 u32 master_session_index;
73 u32 client_session_index;
74 u8 master_thread_index;
75 u8 client_thread_index;
78 u32 ct_session_index; /**< Local session index for vpp */
79 u32 freelist_index; /**< aka log2(allocated_size) - const. */
80 i8 refcnt; /**< reference count */
82 CLIB_CACHE_LINE_ALIGN_MARK (consumer);
84 volatile u32 want_tx_ntf; /**< producer wants nudge */
85 volatile u32 has_tx_ntf;
87 CLIB_CACHE_LINE_ALIGN_MARK (producer);
90 ooo_segment_t *ooo_segments; /**< Pool of ooo segments */
91 u32 ooos_list_head; /**< Head of out-of-order linked-list */
92 u32 ooos_newest; /**< Last segment to have been updated */
93 struct _svm_fifo *next; /**< next in freelist/active chain */
94 struct _svm_fifo *prev; /**< prev in active chain */
95 volatile u8 n_subscribers;
96 u8 subscribers[SVM_FIFO_MAX_EVT_SUBSCRIBERS];
99 svm_fifo_trace_elem_t *trace;
102 CLIB_CACHE_LINE_ALIGN_MARK (data);
110 typedef struct svm_fifo_segment_
114 } svm_fifo_segment_t;
117 #define svm_fifo_trace_add(_f, _s, _l, _t) \
119 svm_fifo_trace_elem_t *trace_elt; \
120 vec_add2(_f->trace, trace_elt, 1); \
121 trace_elt->offset = _s; \
122 trace_elt->len = _l; \
123 trace_elt->action = _t; \
126 #define svm_fifo_trace_add(_f, _s, _l, _t)
129 u8 *svm_fifo_dump_trace (u8 * s, svm_fifo_t * f);
130 u8 *svm_fifo_replay (u8 * s, svm_fifo_t * f, u8 no_read, u8 verbose);
132 /* internal function */
134 f_load_head_tail_cons (svm_fifo_t * f, u32 * head, u32 * tail)
136 /* load-relaxed: consumer owned index */
138 /* load-acq: consumer foreign index (paired with store-rel in producer) */
139 *tail = clib_atomic_load_acq_n (&f->tail);
142 /* internal function */
144 f_load_head_tail_prod (svm_fifo_t * f, u32 * head, u32 * tail)
146 /* load relaxed: producer owned index */
148 /* load-acq: producer foreign index (paired with store-rel in consumer) */
149 *head = clib_atomic_load_acq_n (&f->head);
152 /* producer consumer role independent */
153 /* internal function */
155 f_load_head_tail_all_acq (svm_fifo_t * f, u32 * head, u32 * tail)
157 /* load-acq : consumer foreign index (paired with store-rel) */
158 *tail = clib_atomic_load_acq_n (&f->tail);
159 /* load-acq : producer foriegn index (paired with store-rel) */
160 *head = clib_atomic_load_acq_n (&f->head);
163 /* internal function */
165 f_free_count (svm_fifo_t * f, u32 head, u32 tail)
167 return (f->nitems + head - tail);
170 /* internal function */
172 f_cursize (svm_fifo_t * f, u32 head, u32 tail)
174 return (f->nitems - f_free_count (f, head, tail));
177 /* used by consumer */
179 svm_fifo_max_dequeue_cons (svm_fifo_t * f)
182 f_load_head_tail_cons (f, &head, &tail);
183 return f_cursize (f, head, tail);
186 /* used by producer*/
188 svm_fifo_max_dequeue_prod (svm_fifo_t * f)
191 f_load_head_tail_prod (f, &head, &tail);
192 return f_cursize (f, head, tail);
195 /* use producer or consumer specific functions for perfomance.
196 * svm_fifo_max_dequeue_cons (svm_fifo_t *f)
197 * svm_fifo_max_dequeue_prod (svm_fifo_t *f)
200 svm_fifo_max_dequeue (svm_fifo_t * f)
203 f_load_head_tail_all_acq (f, &head, &tail);
204 return f_cursize (f, head, tail);
207 /* used by producer */
209 svm_fifo_is_full_prod (svm_fifo_t * f)
211 return (svm_fifo_max_dequeue_prod (f) == f->nitems);
214 /* use producer or consumer specific functions for perfomance.
215 * svm_fifo_is_full_prod (svm_fifo_t * f)
216 * add cons version if needed
219 svm_fifo_is_full (svm_fifo_t * f)
221 return (svm_fifo_max_dequeue (f) == f->nitems);
224 /* used by consumer */
226 svm_fifo_is_empty_cons (svm_fifo_t * f)
228 return (svm_fifo_max_dequeue_cons (f) == 0);
231 /* used by producer */
233 svm_fifo_is_empty_prod (svm_fifo_t * f)
235 return (svm_fifo_max_dequeue_prod (f) == 0);
238 /* use producer or consumer specific functions for perfomance.
239 * svm_fifo_is_empty_cons (svm_fifo_t * f)
240 * svm_fifo_is_empty_prod (svm_fifo_t * f)
243 svm_fifo_is_empty (svm_fifo_t * f)
245 return (svm_fifo_max_dequeue (f) == 0);
248 /* used by producer*/
250 svm_fifo_max_enqueue_prod (svm_fifo_t * f)
253 f_load_head_tail_prod (f, &head, &tail);
254 return f_free_count (f, head, tail);
257 /* use producer or consumer specfic functions for perfomance.
258 * svm_fifo_max_enqueue_prod (svm_fifo_t *f)
259 * add consumer specific version if needed.
262 svm_fifo_max_enqueue (svm_fifo_t * f)
265 f_load_head_tail_all_acq (f, &head, &tail);
266 return f_free_count (f, head, tail);
270 svm_fifo_has_event (svm_fifo_t * f)
276 svm_fifo_has_ooo_data (svm_fifo_t * f)
278 return f->ooos_list_head != OOO_SEGMENT_INVALID_INDEX;
282 * Sets fifo event flag.
284 * Also acts as a release ordering.
286 * @return 1 if flag was not set.
289 svm_fifo_set_event (svm_fifo_t * f)
291 /* return __sync_lock_test_and_set (&f->has_event, 1) == 0;
292 return __sync_bool_compare_and_swap (&f->has_event, 0, 1); */
293 return !clib_atomic_swap_rel_n (&f->has_event, 1);
297 * Unsets fifo event flag.
299 * Also acts as an acquire barrier.
302 svm_fifo_unset_event (svm_fifo_t * f)
304 clib_atomic_swap_acq_n (&f->has_event, 0);
307 svm_fifo_t *svm_fifo_create (u32 data_size_in_bytes);
308 void svm_fifo_free (svm_fifo_t * f);
310 int svm_fifo_enqueue_nowait (svm_fifo_t * f, u32 max_bytes,
311 const u8 * copy_from_here);
312 int svm_fifo_enqueue_with_offset (svm_fifo_t * f, u32 offset,
313 u32 required_bytes, u8 * copy_from_here);
314 int svm_fifo_dequeue_nowait (svm_fifo_t * f, u32 max_bytes, u8 * copy_here);
316 int svm_fifo_peek (svm_fifo_t * f, u32 offset, u32 max_bytes, u8 * copy_here);
317 int svm_fifo_dequeue_drop (svm_fifo_t * f, u32 max_bytes);
318 void svm_fifo_dequeue_drop_all (svm_fifo_t * f);
319 int svm_fifo_segments (svm_fifo_t * f, svm_fifo_segment_t * fs);
320 void svm_fifo_segments_free (svm_fifo_t * f, svm_fifo_segment_t * fs);
321 void svm_fifo_init_pointers (svm_fifo_t * f, u32 pointer);
322 void svm_fifo_clone (svm_fifo_t * df, svm_fifo_t * sf);
323 void svm_fifo_overwrite_head (svm_fifo_t * f, u8 * data, u32 len);
324 void svm_fifo_add_subscriber (svm_fifo_t * f, u8 subscriber);
325 void svm_fifo_del_subscriber (svm_fifo_t * f, u8 subscriber);
326 format_function_t format_svm_fifo;
329 * Max contiguous chunk of data that can be read
332 svm_fifo_max_read_chunk (svm_fifo_t * f)
335 u32 head_idx, tail_idx;
336 f_load_head_tail_cons (f, &head, &tail);
337 head_idx = head % f->size;
338 tail_idx = tail % f->size;
339 return tail_idx > head_idx ? (tail_idx - head_idx) : (f->size - head_idx);
343 * Max contiguous chunk of data that can be written
346 svm_fifo_max_write_chunk (svm_fifo_t * f)
349 u32 head_idx, tail_idx;
350 f_load_head_tail_prod (f, &head, &tail);
351 head_idx = head % f->size;
352 tail_idx = tail % f->size;
353 return tail_idx >= head_idx ? (f->size - tail_idx) : (head_idx - tail_idx);
357 * Advance tail pointer
359 * Useful for moving tail pointer after external enqueue.
362 svm_fifo_enqueue_nocopy (svm_fifo_t * f, u32 bytes)
364 ASSERT (bytes <= svm_fifo_max_enqueue_prod (f));
365 /* load-relaxed: producer owned index */
368 /* store-rel: producer owned index (paired with load-acq in consumer) */
369 clib_atomic_store_rel_n (&f->tail, tail);
373 svm_fifo_head (svm_fifo_t * f)
375 /* load-relaxed: consumer owned index */
376 return (f->data + (f->head % f->size));
380 svm_fifo_tail (svm_fifo_t * f)
382 /* load-relaxed: producer owned index */
383 return (f->data + (f->tail % f->size));
387 svm_fifo_add_want_tx_ntf (svm_fifo_t * f, u8 ntf_type)
389 f->want_tx_ntf |= ntf_type;
393 svm_fifo_del_want_tx_ntf (svm_fifo_t * f, u8 ntf_type)
395 f->want_tx_ntf &= ~ntf_type;
399 svm_fifo_clear_tx_ntf (svm_fifo_t * f)
401 /* Set the flag if want_tx_notif_if_full was the only ntf requested */
402 f->has_tx_ntf = f->want_tx_ntf == SVM_FIFO_WANT_TX_NOTIF_IF_FULL;
403 svm_fifo_del_want_tx_ntf (f, SVM_FIFO_WANT_TX_NOTIF);
407 svm_fifo_reset_tx_ntf (svm_fifo_t * f)
413 svm_fifo_needs_tx_ntf (svm_fifo_t * f, u32 n_last_deq)
415 u8 want_ntf = f->want_tx_ntf;
417 if (PREDICT_TRUE (want_ntf == SVM_FIFO_NO_TX_NOTIF))
419 else if (want_ntf & SVM_FIFO_WANT_TX_NOTIF)
421 else if (want_ntf & SVM_FIFO_WANT_TX_NOTIF_IF_FULL)
423 u32 max_deq = svm_fifo_max_dequeue_cons (f);
424 u32 nitems = f->nitems;
425 if (!f->has_tx_ntf && max_deq < nitems
426 && max_deq + n_last_deq >= nitems)
435 svm_fifo_n_subscribers (svm_fifo_t * f)
437 return f->n_subscribers;
440 u32 svm_fifo_number_ooo_segments (svm_fifo_t * f);
441 ooo_segment_t *svm_fifo_first_ooo_segment (svm_fifo_t * f);
443 always_inline ooo_segment_t *
444 svm_fifo_newest_ooo_segment (svm_fifo_t * f)
446 if (f->ooos_newest == OOO_SEGMENT_INVALID_INDEX)
448 return pool_elt_at_index (f->ooo_segments, f->ooos_newest);
452 svm_fifo_newest_ooo_segment_reset (svm_fifo_t * f)
454 f->ooos_newest = OOO_SEGMENT_INVALID_INDEX;
458 ooo_segment_distance_from_tail (svm_fifo_t * f, u32 pos, u32 tail)
460 return ((pos - tail) % f->size);
464 ooo_segment_distance_to_tail (svm_fifo_t * f, u32 pos, u32 tail)
466 return ((tail - pos) % f->size);
470 ooo_segment_offset_prod (svm_fifo_t * f, ooo_segment_t * s)
473 /* load-relaxed: producer owned index */
476 return ooo_segment_distance_from_tail (f, s->start, tail);
480 ooo_segment_length (svm_fifo_t * f, ooo_segment_t * s)
485 always_inline ooo_segment_t *
486 ooo_segment_get_prev (svm_fifo_t * f, ooo_segment_t * s)
488 if (s->prev == OOO_SEGMENT_INVALID_INDEX)
490 return pool_elt_at_index (f->ooo_segments, s->prev);
493 always_inline ooo_segment_t *
494 ooo_segment_next (svm_fifo_t * f, ooo_segment_t * s)
496 if (s->next == OOO_SEGMENT_INVALID_INDEX)
498 return pool_elt_at_index (f->ooo_segments, s->next);
501 #endif /* __included_ssvm_fifo_h__ */
504 * fd.io coding-style-patch-verification: ON
507 * eval: (c-set-style "gnu")