source: mainline/uspace/lib/c/generic/fibril.c@ 7db5cfd

lfn serial ticket/834-toolchain-update topic/msim-upgrade topic/simplify-dev-export
Last change on this file since 7db5cfd was 2654afb, checked in by Jakub Jermar <jakub@…>, 10 years ago

Remove support for the abandoned concept of fibril serialization.
Streamline fibril_switch() a little bit.
  • Property mode set to 100644
File size: 8.5 KB
Line 
1/*
2 * Copyright (c) 2006 Ondrej Palkovsky
3 * Copyright (c) 2007 Jakub Jermar
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 *
10 * - Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * - Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * - The name of the author may not be used to endorse or promote products
16 * derived from this software without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
19 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
20 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
21 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
23 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
27 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 */
29
30/** @addtogroup libc
31 * @{
32 */
33/** @file
34 */
35
36#include <adt/list.h>
37#include <fibril.h>
38#include <thread.h>
39#include <stack.h>
40#include <tls.h>
41#include <malloc.h>
42#include <abi/mm/as.h>
43#include <as.h>
44#include <unistd.h>
45#include <stdio.h>
46#include <libarch/barrier.h>
47#include <libarch/faddr.h>
48#include <futex.h>
49#include <assert.h>
50#include <async.h>
51#include <futex.h>
52
53#ifdef FUTEX_UPGRADABLE
54#include <rcu.h>
55#endif
56
57/**
58 * This futex serializes access to ready_list,
59 * manager_list and fibril_list.
60 */
61static futex_t fibril_futex = FUTEX_INITIALIZER;
62
63static LIST_INITIALIZE(ready_list);
64static LIST_INITIALIZE(manager_list);
65static LIST_INITIALIZE(fibril_list);
66
67/** Function that spans the whole life-cycle of a fibril.
68 *
69 * Each fibril begins execution in this function. Then the function implementing
70 * the fibril logic is called. After its return, the return value is saved.
71 * The fibril then switches to another fibril, which cleans up after it.
72 *
73 */
74static void fibril_main(void)
75{
76 fibril_t *fibril = __tcb_get()->fibril_data;
77
78#ifdef FUTEX_UPGRADABLE
79 rcu_register_fibril();
80#endif
81
82 /* Call the implementing function. */
83 fibril->retval = fibril->func(fibril->arg);
84
85 futex_down(&async_futex);
86 fibril_switch(FIBRIL_FROM_DEAD);
87 /* Not reached */
88}
89
90/** Setup fibril information into TCB structure
91 *
92 */
93fibril_t *fibril_setup(void)
94{
95 tcb_t *tcb = tls_make();
96 if (!tcb)
97 return NULL;
98
99 fibril_t *fibril = malloc(sizeof(fibril_t));
100 if (!fibril) {
101 tls_free(tcb);
102 return NULL;
103 }
104
105 tcb->fibril_data = fibril;
106 fibril->tcb = tcb;
107
108 fibril->func = NULL;
109 fibril->arg = NULL;
110 fibril->stack = NULL;
111 fibril->clean_after_me = NULL;
112 fibril->retval = 0;
113 fibril->flags = 0;
114
115 fibril->waits_for = NULL;
116
117 futex_lock(&fibril_futex);
118 list_append(&fibril->all_link, &fibril_list);
119 futex_unlock(&fibril_futex);
120
121 return fibril;
122}
123
124void fibril_teardown(fibril_t *fibril, bool locked)
125{
126 if (!locked)
127 futex_lock(&fibril_futex);
128 list_remove(&fibril->all_link);
129 if (!locked)
130 futex_unlock(&fibril_futex);
131 tls_free(fibril->tcb);
132 free(fibril);
133}
134
135/** Switch from the current fibril.
136 *
137 * If stype is FIBRIL_TO_MANAGER or FIBRIL_FROM_DEAD, the async_futex must
138 * be held.
139 *
140 * @param stype Switch type. One of FIBRIL_PREEMPT, FIBRIL_TO_MANAGER,
141 * FIBRIL_FROM_MANAGER, FIBRIL_FROM_DEAD. The parameter
142 * describes the circumstances of the switch.
143 *
144 * @return 0 if there is no ready fibril,
145 * @return 1 otherwise.
146 *
147 */
148int fibril_switch(fibril_switch_type_t stype)
149{
150 futex_lock(&fibril_futex);
151
152 switch (stype) {
153 case FIBRIL_PREEMPT:
154 case FIBRIL_FROM_MANAGER:
155 if (list_empty(&ready_list)) {
156 futex_unlock(&fibril_futex);
157 return 0;
158 }
159 break;
160 case FIBRIL_TO_MANAGER:
161 case FIBRIL_FROM_DEAD:
162 /* Make sure the async_futex is held. */
163 assert((atomic_signed_t) async_futex.val.count <= 0);
164
165 /* If we are going to manager and none exists, create it */
166 while (list_empty(&manager_list)) {
167 futex_unlock(&fibril_futex);
168 async_create_manager();
169 futex_lock(&fibril_futex);
170 }
171 break;
172 }
173
174 fibril_t *srcf = __tcb_get()->fibril_data;
175 if (stype != FIBRIL_FROM_DEAD) {
176
177 /* Save current state */
178 if (!context_save(&srcf->ctx)) {
179 if (srcf->clean_after_me) {
180 /*
181 * Cleanup after the dead fibril from which we
182 * restored context here.
183 */
184 void *stack = srcf->clean_after_me->stack;
185 if (stack) {
186 /*
187 * This check is necessary because a
188 * thread could have exited like a
189 * normal fibril using the
190 * FIBRIL_FROM_DEAD switch type. In that
191 * case, its fibril will not have the
192 * stack member filled.
193 */
194 as_area_destroy(stack);
195 }
196 fibril_teardown(srcf->clean_after_me, true);
197 srcf->clean_after_me = NULL;
198 }
199
200 return 1; /* futex_unlock already done here */
201 }
202
203 /* Put the current fibril into the correct run list */
204 switch (stype) {
205 case FIBRIL_PREEMPT:
206 list_append(&srcf->link, &ready_list);
207 break;
208 case FIBRIL_FROM_MANAGER:
209 list_append(&srcf->link, &manager_list);
210 break;
211 default:
212 assert(stype == FIBRIL_TO_MANAGER);
213
214 /*
215 * Don't put the current fibril into any list, it should
216 * already be somewhere, or it will be lost.
217 */
218 break;
219 }
220 }
221
222 fibril_t *dstf;
223
224 /* Choose a new fibril to run */
225 switch (stype) {
226 case FIBRIL_TO_MANAGER:
227 case FIBRIL_FROM_DEAD:
228 dstf = list_get_instance(list_first(&manager_list), fibril_t,
229 link);
230
231 if (stype == FIBRIL_FROM_DEAD)
232 dstf->clean_after_me = srcf;
233 break;
234 default:
235 dstf = list_get_instance(list_first(&ready_list), fibril_t,
236 link);
237 break;
238 }
239
240 list_remove(&dstf->link);
241
242 futex_unlock(&fibril_futex);
243
244#ifdef FUTEX_UPGRADABLE
245 if (stype == FIBRIL_FROM_DEAD) {
246 rcu_deregister_fibril();
247 }
248#endif
249
250 context_restore(&dstf->ctx);
251 /* not reached */
252}
253
254/** Create a new fibril.
255 *
256 * @param func Implementing function of the new fibril.
257 * @param arg Argument to pass to func.
258 * @param stksz Stack size in bytes.
259 *
260 * @return 0 on failure or TLS of the new fibril.
261 *
262 */
263fid_t fibril_create_generic(int (*func)(void *), void *arg, size_t stksz)
264{
265 fibril_t *fibril;
266
267 fibril = fibril_setup();
268 if (fibril == NULL)
269 return 0;
270
271 size_t stack_size = (stksz == FIBRIL_DFLT_STK_SIZE) ?
272 stack_size_get() : stksz;
273 fibril->stack = as_area_create((void *) -1, stack_size,
274 AS_AREA_READ | AS_AREA_WRITE | AS_AREA_CACHEABLE | AS_AREA_GUARD |
275 AS_AREA_LATE_RESERVE);
276 if (fibril->stack == (void *) -1) {
277 fibril_teardown(fibril, false);
278 return 0;
279 }
280
281 fibril->func = func;
282 fibril->arg = arg;
283
284 context_save(&fibril->ctx);
285 context_set(&fibril->ctx, FADDR(fibril_main), fibril->stack,
286 stack_size, fibril->tcb);
287
288 return (fid_t) fibril;
289}
290
291/** Delete a fibril that has never run.
292 *
293 * Free resources of a fibril that has been created with fibril_create()
294 * but never readied using fibril_add_ready().
295 *
296 * @param fid Pointer to the fibril structure of the fibril to be
297 * added.
298 */
299void fibril_destroy(fid_t fid)
300{
301 fibril_t *fibril = (fibril_t *) fid;
302
303 as_area_destroy(fibril->stack);
304 fibril_teardown(fibril, false);
305}
306
307/** Add a fibril to the ready list.
308 *
309 * @param fid Pointer to the fibril structure of the fibril to be
310 * added.
311 *
312 */
313void fibril_add_ready(fid_t fid)
314{
315 fibril_t *fibril = (fibril_t *) fid;
316
317 futex_lock(&fibril_futex);
318 list_append(&fibril->link, &ready_list);
319 futex_unlock(&fibril_futex);
320}
321
322/** Add a fibril to the manager list.
323 *
324 * @param fid Pointer to the fibril structure of the fibril to be
325 * added.
326 *
327 */
328void fibril_add_manager(fid_t fid)
329{
330 fibril_t *fibril = (fibril_t *) fid;
331
332 futex_lock(&fibril_futex);
333 list_append(&fibril->link, &manager_list);
334 futex_unlock(&fibril_futex);
335}
336
337/** Remove one manager from the manager list. */
338void fibril_remove_manager(void)
339{
340 futex_lock(&fibril_futex);
341 if (!list_empty(&manager_list))
342 list_remove(list_first(&manager_list));
343 futex_unlock(&fibril_futex);
344}
345
346/** Return fibril id of the currently running fibril.
347 *
348 * @return fibril ID of the currently running fibril.
349 *
350 */
351fid_t fibril_get_id(void)
352{
353 return (fid_t) __tcb_get()->fibril_data;
354}
355
356/** @}
357 */
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