summaryrefslogtreecommitdiff
path: root/lib/event.c
blob: 10f83c28921add680cd98bc5ee49289a0006c286 (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
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
/*
 *	BIRD Library -- Event Processing
 *
 *	(c) 1999 Martin Mares <mj@ucw.cz>
 *
 *	Can be freely distributed and used under the terms of the GNU GPL.
 */

/**
 * DOC: Events
 *
 * Events are there to keep track of deferred execution.
 * Since BIRD is single-threaded, it requires long lasting tasks to be split to smaller
 * parts, so that no module can monopolize the CPU. To split such a task, just create
 * an &event resource, point it to the function you want to have called and call ev_schedule()
 * to ask the core to run the event when nothing more important requires attention.
 *
 * You can also define your own event lists (the &event_list structure), enqueue your
 * events in them and explicitly ask to run them.
 */

#undef LOCAL_DEBUG

#include "nest/bird.h"
#include "lib/event.h"
#include "lib/locking.h"
#include "lib/io-loop.h"

extern _Thread_local struct coroutine *this_coro;

event_list global_event_list;
event_list global_work_list;

inline void
ev_postpone(event *e)
{
  event_list *el = e->list;
  if (!el)
    return;

  ASSERT_DIE(birdloop_inside(el->loop));

  LOCK_DOMAIN(event, el->lock);
  if (ev_active(e))
    rem_node(&e->n);
  UNLOCK_DOMAIN(event, el->lock);
}

static void
ev_dump(resource *r)
{
  event *e = (event *) r;

  debug("(code %p, data %p, %s)\n",
	e->hook,
	e->data,
	e->n.next ? "scheduled" : "inactive");
}

static struct resclass ev_class = {
  "Event",
  sizeof(event),
  (void (*)(resource *)) ev_postpone,
  ev_dump,
  NULL,
  NULL
};

/**
 * ev_new - create a new event
 * @p: resource pool
 *
 * This function creates a new event resource. To use it,
 * you need to fill the structure fields and call ev_schedule().
 */
event *
ev_new(pool *p)
{
  event *e = ralloc(p, &ev_class);
  return e;
}

/**
 * ev_run - run an event
 * @e: an event
 *
 * This function explicitly runs the event @e (calls its hook
 * function) and removes it from an event list if it's linked to any.
 *
 * From the hook function, you can call ev_enqueue() or ev_schedule()
 * to re-add the event.
 */
inline void
ev_run(event *e)
{
  ev_postpone(e);
  e->hook(e->data);
}

/**
 * ev_enqueue - enqueue an event
 * @l: an event list
 * @e: an event
 *
 * ev_enqueue() stores the event @e to the specified event
 * list @l which can be run by calling ev_run_list().
 */
inline void
ev_send(event_list *l, event *e)
{
  DBG("ev_send(%p, %p)\n", l, e);
  ASSERT_DIE(e->hook);
  ASSERT_DIE(!e->list || (e->list == l) || (e->list->loop == l->loop));

  e->list = l;

  struct event_cork *ec = e->cork;

  uint ping = 0;

  if (ec)
  {
    LOCK_DOMAIN(cork, ec->lock);
    LOCK_DOMAIN(event, l->lock);

    if (!enlisted(&e->n))
      if (ec->count)
	add_tail(&ec->events, &e->n);
      else
      {
	add_tail(&l->events, &e->n);
	ping = 1;
      }

    UNLOCK_DOMAIN(event, l->lock);
    UNLOCK_DOMAIN(cork, ec->lock);
  }
  else
  {
    LOCK_DOMAIN(event, l->lock);

    if (!enlisted(&e->n))
    {
      add_tail(&l->events, &e->n);
      ping = 1;
    }

    UNLOCK_DOMAIN(event, l->lock);
  }

  if (ping)
    birdloop_ping(l->loop);
}

void io_log_event(void *hook, void *data);

/**
 * ev_run_list - run an event list
 * @l: an event list
 *
 * This function calls ev_run() for all events enqueued in the list @l.
 */
int
ev_run_list(event_list *l)
{
  const _Bool legacy = LEGACY_EVENT_LIST(l);

  if (legacy)
    ASSERT_THE_BIRD_LOCKED;

  node *n;

  list tmp_list;
  init_list(&tmp_list);

  /* Move the event list contents to a local list to avoid executing repeatedly added events */
  LOCK_DOMAIN(event, l->lock);
  add_tail_list(&tmp_list, &l->events);
  init_list(&l->events);
  UNLOCK_DOMAIN(event, l->lock);

  WALK_LIST_FIRST(n, tmp_list)
    {
      event *e = SKIP_BACK(event, n, n);
      ASSERT_DIE(n->next->prev == n);

      if (legacy)
      {
	/* The legacy way of event execution */
	io_log_event(e->hook, e->data);
	ev_postpone(e);
	e->hook(e->data);
      }
      else
      {
	// io_log_event(e->hook, e->data); /* TODO: add support for event logging in other io loops */
	ASSERT_DIE(e->list == l);
	LOCK_DOMAIN(event, l->lock);
	rem_node(&e->n);
	UNLOCK_DOMAIN(event, l->lock);
	e->hook(e->data);
      }
    }

  LOCK_DOMAIN(event, l->lock);
  int repeat = ! EMPTY_LIST(l->events);
  UNLOCK_DOMAIN(event, l->lock);
  return repeat;
}

int
ev_run_list_limited(event_list *l, uint limit)
{
  ASSERT_DIE(LEGACY_EVENT_LIST(l));
  ASSERT_THE_BIRD_LOCKED;

  node *n;
  list tmp_list;

  LOCK_DOMAIN(event, l->lock);
  init_list(&tmp_list);
  add_tail_list(&tmp_list, &l->events);
  init_list(&l->events);
  UNLOCK_DOMAIN(event, l->lock);

  WALK_LIST_FIRST(n, tmp_list)
    {
      event *e = SKIP_BACK(event, n, n);

      if (!limit)
	break;

      io_log_event(e->hook, e->data);

      ev_run(e);
      limit--;
    }

  LOCK_DOMAIN(event, l->lock);
  if (!EMPTY_LIST(tmp_list))
  {
    /* Attach new items after the unprocessed old items */
    add_tail_list(&tmp_list, &l->events);
    init_list(&l->events);
    add_tail_list(&l->events, &tmp_list);
  }

  int repeat = ! EMPTY_LIST(l->events);
  UNLOCK_DOMAIN(event, l->lock);

  return repeat;
}

void ev_cork(struct event_cork *ec)
{
  LOCK_DOMAIN(cork, ec->lock);
  ec->count++;
  UNLOCK_DOMAIN(cork, ec->lock);
}

void ev_uncork(struct event_cork *ec)
{
  LOCK_DOMAIN(cork, ec->lock);

  if (--ec->count)
  {
    UNLOCK_DOMAIN(cork, ec->lock);
    return;
  }

  node *n;
  WALK_LIST_FIRST(n, ec->events)
    {
      event *e = SKIP_BACK(event, n, n);
      event_list *el = e->list;

      rem_node(&e->n);

      LOCK_DOMAIN(event, el->lock);
      add_tail(&el->events, &e->n);
      UNLOCK_DOMAIN(event, el->lock);

      birdloop_ping(el->loop);
    }

  struct birdsock *sk;
  WALK_LIST_FIRST2(sk, cork_node, ec->sockets)
    {
//      log(L_TRACE "Socket %p uncorked", sk);
      rem_node(&sk->cork_node);
      sk_ping(sk);
    }

  UNLOCK_DOMAIN(cork, ec->lock);
}