2 * Copyright (c) 2016 Cisco and/or its affiliates.
3 * Licensed under the Apache License, Version 2.0 (the "License");
4 * you may not use this file except in compliance with the License.
5 * You may obtain a copy of the License at:
7 * http://www.apache.org/licenses/LICENSE-2.0
9 * Unless required by applicable law or agreed to in writing, software
10 * distributed under the License is distributed on an "AS IS" BASIS,
11 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 * See the License for the specific language governing permissions and
13 * limitations under the License.
15 #ifndef __included_ssvm_fifo_h__
16 #define __included_ssvm_fifo_h__
18 #include <vppinfra/clib.h>
19 #include <vppinfra/vec.h>
20 #include <vppinfra/mheap.h>
21 #include <vppinfra/heap.h>
22 #include <vppinfra/pool.h>
23 #include <vppinfra/format.h>
26 /** Out-of-order segment */
29 u32 next; /**< Next linked-list element pool index */
30 u32 prev; /**< Previous linked-list element pool index */
32 u32 start; /**< Start of segment, normalized*/
33 u32 length; /**< Length of segment */
36 format_function_t format_ooo_segment;
37 format_function_t format_ooo_list;
39 #define SVM_FIFO_TRACE (0)
40 #define OOO_SEGMENT_INVALID_INDEX ((u32)~0)
41 #define SVM_FIFO_INVALID_SESSION_INDEX ((u32)~0)
42 #define SVM_FIFO_INVALID_INDEX ((u32)~0)
43 #define SVM_FIFO_MAX_EVT_SUBSCRIBERS 8
47 SVM_FIFO_NO_TX_NOTIF = 0,
48 SVM_FIFO_WANT_TX_NOTIF = 1,
49 SVM_FIFO_WANT_TX_NOTIF_IF_FULL = 2,
57 } svm_fifo_trace_elem_t;
59 typedef struct _svm_fifo
61 CLIB_CACHE_LINE_ALIGN_MARK (shared_first);
62 volatile u32 cursize; /**< current fifo size */
65 CLIB_CACHE_LINE_ALIGN_MARK (shared_second);
66 volatile u32 has_event; /**< non-zero if deq event exists */
68 u32 master_session_index;
69 u32 client_session_index;
70 u8 master_thread_index;
71 u8 client_thread_index;
74 u32 ct_session_index; /**< Local session index for vpp */
75 u32 freelist_index; /**< aka log2(allocated_size) - const. */
76 i8 refcnt; /**< reference count */
78 CLIB_CACHE_LINE_ALIGN_MARK (consumer);
80 volatile u32 want_tx_ntf; /**< producer wants nudge */
81 volatile u32 has_tx_ntf;
83 CLIB_CACHE_LINE_ALIGN_MARK (producer);
86 ooo_segment_t *ooo_segments; /**< Pool of ooo segments */
87 u32 ooos_list_head; /**< Head of out-of-order linked-list */
88 u32 ooos_newest; /**< Last segment to have been updated */
89 struct _svm_fifo *next; /**< next in freelist/active chain */
90 struct _svm_fifo *prev; /**< prev in active chain */
91 volatile u8 n_subscribers;
92 u8 subscribers[SVM_FIFO_MAX_EVT_SUBSCRIBERS];
95 svm_fifo_trace_elem_t *trace;
98 CLIB_CACHE_LINE_ALIGN_MARK (data);
106 typedef struct svm_fifo_segment_
110 } svm_fifo_segment_t;
113 #define svm_fifo_trace_add(_f, _s, _l, _t) \
115 svm_fifo_trace_elem_t *trace_elt; \
116 vec_add2(_f->trace, trace_elt, 1); \
117 trace_elt->offset = _s; \
118 trace_elt->len = _l; \
119 trace_elt->action = _t; \
122 #define svm_fifo_trace_add(_f, _s, _l, _t)
125 u8 *svm_fifo_dump_trace (u8 * s, svm_fifo_t * f);
126 u8 *svm_fifo_replay (u8 * s, svm_fifo_t * f, u8 no_read, u8 verbose);
129 svm_fifo_max_dequeue (svm_fifo_t * f)
131 return clib_atomic_load_acq_n (&f->cursize);
135 svm_fifo_is_full (svm_fifo_t * f)
137 return (clib_atomic_load_acq_n (&f->cursize) == f->nitems);
141 svm_fifo_is_empty (svm_fifo_t * f)
143 return (clib_atomic_load_acq_n (&f->cursize) == 0);
147 svm_fifo_max_enqueue (svm_fifo_t * f)
149 return f->nitems - svm_fifo_max_dequeue (f);
153 svm_fifo_has_event (svm_fifo_t * f)
159 svm_fifo_has_ooo_data (svm_fifo_t * f)
161 return f->ooos_list_head != OOO_SEGMENT_INVALID_INDEX;
165 * Sets fifo event flag.
167 * Also acts as a release barrier.
169 * @return 1 if flag was not set.
172 svm_fifo_set_event (svm_fifo_t * f)
174 /* return __sync_lock_test_and_set (&f->has_event, 1) == 0;
175 return __sync_bool_compare_and_swap (&f->has_event, 0, 1); */
176 return !__atomic_exchange_n (&f->has_event, 1, __ATOMIC_RELEASE);
180 * Unsets fifo event flag.
182 * Also acts as a release barrier.
185 svm_fifo_unset_event (svm_fifo_t * f)
187 clib_atomic_release (&f->has_event);
190 svm_fifo_t *svm_fifo_create (u32 data_size_in_bytes);
191 void svm_fifo_free (svm_fifo_t * f);
193 int svm_fifo_enqueue_nowait (svm_fifo_t * f, u32 max_bytes,
194 const u8 * copy_from_here);
195 int svm_fifo_enqueue_with_offset (svm_fifo_t * f, u32 offset,
196 u32 required_bytes, u8 * copy_from_here);
197 int svm_fifo_dequeue_nowait (svm_fifo_t * f, u32 max_bytes, u8 * copy_here);
199 int svm_fifo_peek (svm_fifo_t * f, u32 offset, u32 max_bytes, u8 * copy_here);
200 int svm_fifo_dequeue_drop (svm_fifo_t * f, u32 max_bytes);
201 void svm_fifo_dequeue_drop_all (svm_fifo_t * f);
202 int svm_fifo_segments (svm_fifo_t * f, svm_fifo_segment_t * fs);
203 void svm_fifo_segments_free (svm_fifo_t * f, svm_fifo_segment_t * fs);
204 void svm_fifo_init_pointers (svm_fifo_t * f, u32 pointer);
205 void svm_fifo_overwrite_head (svm_fifo_t * f, u8 * data, u32 len);
206 void svm_fifo_add_subscriber (svm_fifo_t * f, u8 subscriber);
207 void svm_fifo_del_subscriber (svm_fifo_t * f, u8 subscriber);
208 format_function_t format_svm_fifo;
211 * Max contiguous chunk of data that can be read
214 svm_fifo_max_read_chunk (svm_fifo_t * f)
216 return ((f->tail > f->head) ? (f->tail - f->head) : (f->nitems - f->head));
220 * Max contiguous chunk of data that can be written
223 svm_fifo_max_write_chunk (svm_fifo_t * f)
225 return ((f->tail >= f->head) ? (f->nitems - f->tail) : (f->head - f->tail));
229 * Advance tail pointer
231 * Useful for moving tail pointer after external enqueue.
234 svm_fifo_enqueue_nocopy (svm_fifo_t * f, u32 bytes)
236 ASSERT (bytes <= svm_fifo_max_enqueue (f));
237 f->tail = (f->tail + bytes) % f->nitems;
238 clib_atomic_fetch_add_rel (&f->cursize, bytes);
242 svm_fifo_head (svm_fifo_t * f)
244 return (f->data + f->head);
248 svm_fifo_tail (svm_fifo_t * f)
250 return (f->data + f->tail);
254 svm_fifo_nitems (svm_fifo_t * f)
260 svm_fifo_add_want_tx_ntf (svm_fifo_t * f, u8 ntf_type)
262 f->want_tx_ntf |= ntf_type;
266 svm_fifo_del_want_tx_ntf (svm_fifo_t * f, u8 ntf_type)
268 f->want_tx_ntf &= ~ntf_type;
272 svm_fifo_clear_tx_ntf (svm_fifo_t * f)
274 /* Set the flag if want_tx_notif_if_full was the only ntf requested */
275 f->has_tx_ntf = f->want_tx_ntf == SVM_FIFO_WANT_TX_NOTIF_IF_FULL;
276 svm_fifo_del_want_tx_ntf (f, SVM_FIFO_WANT_TX_NOTIF);
280 svm_fifo_reset_tx_ntf (svm_fifo_t * f)
286 svm_fifo_needs_tx_ntf (svm_fifo_t * f, u32 n_last_deq)
288 u8 want_ntf = f->want_tx_ntf;
290 if (PREDICT_TRUE (want_ntf == SVM_FIFO_NO_TX_NOTIF))
292 else if (want_ntf & SVM_FIFO_WANT_TX_NOTIF)
294 else if (want_ntf & SVM_FIFO_WANT_TX_NOTIF_IF_FULL)
296 u32 max_deq = svm_fifo_max_dequeue (f);
297 u32 nitems = svm_fifo_nitems (f);
298 if (!f->has_tx_ntf && max_deq < nitems
299 && max_deq + n_last_deq >= nitems)
308 svm_fifo_n_subscribers (svm_fifo_t * f)
310 return f->n_subscribers;
313 u32 svm_fifo_number_ooo_segments (svm_fifo_t * f);
314 ooo_segment_t *svm_fifo_first_ooo_segment (svm_fifo_t * f);
316 always_inline ooo_segment_t *
317 svm_fifo_newest_ooo_segment (svm_fifo_t * f)
319 if (f->ooos_newest == OOO_SEGMENT_INVALID_INDEX)
321 return pool_elt_at_index (f->ooo_segments, f->ooos_newest);
325 svm_fifo_newest_ooo_segment_reset (svm_fifo_t * f)
327 f->ooos_newest = OOO_SEGMENT_INVALID_INDEX;
331 ooo_segment_distance_from_tail (svm_fifo_t * f, u32 pos)
333 /* Ambiguous. Assumption is that ooo segments don't touch tail */
334 if (PREDICT_FALSE (pos == f->tail && f->tail == f->head))
337 return (((f->nitems + pos) - f->tail) % f->nitems);
341 ooo_segment_distance_to_tail (svm_fifo_t * f, u32 pos)
343 return (((f->nitems + f->tail) - pos) % f->nitems);
347 ooo_segment_offset (svm_fifo_t * f, ooo_segment_t * s)
349 return ooo_segment_distance_from_tail (f, s->start);
353 ooo_segment_end_offset (svm_fifo_t * f, ooo_segment_t * s)
355 return ooo_segment_distance_from_tail (f, s->start) + s->length;
359 ooo_segment_length (svm_fifo_t * f, ooo_segment_t * s)
364 always_inline ooo_segment_t *
365 ooo_segment_get_prev (svm_fifo_t * f, ooo_segment_t * s)
367 if (s->prev == OOO_SEGMENT_INVALID_INDEX)
369 return pool_elt_at_index (f->ooo_segments, s->prev);
372 always_inline ooo_segment_t *
373 ooo_segment_next (svm_fifo_t * f, ooo_segment_t * s)
375 if (s->next == OOO_SEGMENT_INVALID_INDEX)
377 return pool_elt_at_index (f->ooo_segments, s->next);
380 #endif /* __included_ssvm_fifo_h__ */
383 * fd.io coding-style-patch-verification: ON
386 * eval: (c-set-style "gnu")