summaryrefslogtreecommitdiffstats
path: root/src/svm/svm_fifo.h
blob: 39556173e4d1937181c55d2aa12801c91a52d6e8 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
/*
 * Copyright (c) 2016 Cisco and/or its affiliates.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at:
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
#ifndef __included_ssvm_fifo_h__
#define __included_ssvm_fifo_h__

#include <vppinfra/clib.h>
#include <vppinfra/vec.h>
#include <vppinfra/mheap.h>
#include <vppinfra/heap.h>
#include <vppinfra/pool.h>
#include <vppinfra/format.h>
#include <pthread.h>

typedef enum
{
  SVM_FIFO_TAG_NOT_HELD = 0,
  SVM_FIFO_TAG_DEQUEUE,
  SVM_FIFO_TAG_ENQUEUE,
} svm_lock_tag_t;

/** Out-of-order segment */
typedef struct
{
  u32 next;	/**< Next linked-list element pool index */
  u32 prev;	/**< Previous linked-list element pool index */

  u32 fifo_position;	/**< Start of segment, normalized*/
  u32 length;		/**< Length of segment */
} ooo_segment_t;

#define OOO_SEGMENT_INVALID_INDEX ((u32)~0)

typedef struct
{
  pthread_mutex_t mutex;	/* 8 bytes */
  pthread_cond_t condvar;	/* 8 bytes */
  svm_lock_tag_t tag;

  volatile u32 cursize;		/**< current fifo size */
  volatile u8 has_event;	/**< non-zero if deq event exists */
  u32 owner_pid;
  u32 nitems;

  /* Backpointers */
  u32 server_session_index;
  u32 client_session_index;
  u8 server_thread_index;
  u8 client_thread_index;
    CLIB_CACHE_LINE_ALIGN_MARK (end_shared);
  u32 head;
    CLIB_CACHE_LINE_ALIGN_MARK (end_consumer);

  /* producer */
  u32 tail;

  ooo_segment_t *ooo_segments;	/**< Pool of ooo segments */
  u32 ooos_list_head;		/**< Head of out-of-order linked-list */
  u32 ooos_newest;		/**< Last segment to have been updated */

    CLIB_CACHE_LINE_ALIGN_MARK (data);
} svm_fifo_t;

static inline int
svm_fifo_lock (svm_fifo_t * f, u32 pid, u32 tag, int nowait)
{
  if (PREDICT_TRUE (nowait == 0))
    pthread_mutex_lock (&f->mutex);
  else
    {
      if (pthread_mutex_trylock (&f->mutex))
	return -1;
    }
  f->owner_pid = pid;
  f->tag = tag;
  return 0;
}

static inline void
svm_fifo_unlock (svm_fifo_t * f)
{
  f->owner_pid = 0;
  f->tag = 0;
  CLIB_MEMORY_BARRIER ();
  pthread_mutex_unlock (&f->mutex);
}

static inline u32
svm_fifo_max_dequeue (svm_fifo_t * f)
{
  return f->cursize;
}

static inline u32
svm_fifo_max_enqueue (svm_fifo_t * f)
{
  return f->nitems - f->cursize;
}

static inline u8
svm_fifo_has_ooo_data (svm_fifo_t * f)
{
  return f->ooos_list_head != OOO_SEGMENT_INVALID_INDEX;
}

/**
 * Sets fifo event flag.
 *
 * @return 1 if flag was not set.
 */
always_inline u8
svm_fifo_set_event (svm_fifo_t * f)
{
  /* Probably doesn't need to be atomic. Still, better avoid surprises */
  return __sync_lock_test_and_set (&f->has_event, 1) == 0;
}

/**
 * Unsets fifo event flag.
 */
always_inline void
svm_fifo_unset_event (svm_fifo_t * f)
{
  /* Probably doesn't need to be atomic. Still, better avoid surprises */
  __sync_lock_test_and_set (&f->has_event, 0);
}

svm_fifo_t *svm_fifo_create (u32 data_size_in_bytes);

int svm_fifo_enqueue_nowait (svm_fifo_t * f, int pid, u32 max_bytes,
			     u8 * copy_from_here);

int svm_fifo_enqueue_with_offset (svm_fifo_t * f, int pid,
				  u32 offset, u32 required_bytes,
				  u8 * copy_from_here);

int svm_fifo_dequeue_nowait (svm_fifo_t * f, int pid, u32 max_bytes,
			     u8 * copy_here);

int svm_fifo_peek (svm_fifo_t * f, int pid, u32 offset, u32 max_bytes,
		   u8 * copy_here);
int svm_fifo_dequeue_drop (svm_fifo_t * f, int pid, u32 max_bytes);

always_inline ooo_segment_t *
svm_fifo_newest_ooo_segment (svm_fifo_t * f)
{
  return f->ooo_segments + f->ooos_newest;
}

always_inline u32
ooo_segment_offset (svm_fifo_t * f, ooo_segment_t * s)
{
  return ((f->nitems + s->fifo_position - f->tail) % f->nitems);
}

always_inline u32
ooo_segment_end_offset (svm_fifo_t * f, ooo_segment_t * s)
{
  return ((f->nitems + s->fifo_position + s->length - f->tail) % f->nitems);
}

#endif /* __included_ssvm_fifo_h__ */

/*
 * fd.io coding-style-patch-verification: ON
 *
 * Local Variables:
 * eval: (c-set-style "gnu")
 * End:
 */