2 * Copyright (c) 1995-1998 John Birrell <jb@cimlogic.com.au>
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 * must display the following acknowledgement:
15 * This product includes software developed by John Birrell.
16 * 4. Neither the name of the author nor the names of any co-contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
20 * THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * $FreeBSD: src/lib/libc_r/uthread/uthread_kern.c,v 1.28.2.13 2002/10/22 14:44:03 fjoe Exp $
33 * $DragonFly: src/lib/libc_r/uthread/uthread_kern.c,v 1.6 2007/01/08 21:41:53 dillon Exp $
43 #include <sys/param.h>
44 #include <sys/types.h>
45 #include <sys/signalvar.h>
48 #include <sys/socket.h>
50 #include <sys/syscall.h>
53 #include "pthread_private.h"
55 /* #define DEBUG_THREAD_KERN */
56 #ifdef DEBUG_THREAD_KERN
57 #define DBG_MSG stdout_debug
62 /* Static function prototype definitions: */
64 thread_kern_poll(int wait_reqd);
67 dequeue_signals(void);
70 thread_run_switch_hook(pthread_t thread_out, pthread_t thread_in);
72 /* Static variables: */
73 static int last_tick = 0;
74 static int called_from_handler = 0;
77 * This is called when a signal handler finishes and wants to
78 * return to a previous frame.
81 _thread_kern_sched_frame(struct pthread_signal_frame *psf)
83 struct pthread *curthread = _get_curthread();
86 * Flag the pthread kernel as executing scheduler code
87 * to avoid a signal from interrupting this execution and
88 * corrupting the (soon-to-be) current frame.
90 _thread_kern_in_sched = 1;
92 /* Restore the signal frame: */
93 _thread_sigframe_restore(curthread, psf);
95 /* The signal mask was restored; check for any pending signals: */
96 curthread->check_pending = 1;
98 /* Switch to the thread scheduler: */
99 ___longjmp(_thread_kern_sched_jb, 1);
104 _thread_kern_sched(ucontext_t *ucp)
106 struct pthread *curthread = _get_curthread();
109 * Flag the pthread kernel as executing scheduler code
110 * to avoid a scheduler signal from interrupting this
111 * execution and calling the scheduler again.
113 _thread_kern_in_sched = 1;
115 /* Check if this function was called from the signal handler: */
117 /* XXX - Save FP registers? */
119 called_from_handler = 1;
120 DBG_MSG("Entering scheduler due to signal\n");
123 /* Save the state of the current thread: */
124 if (_setjmp(curthread->ctx.jb) != 0) {
125 DBG_MSG("Returned from ___longjmp, thread %p\n",
128 * This point is reached when a longjmp() is called
129 * to restore the state of a thread.
131 * This is the normal way out of the scheduler.
133 _thread_kern_in_sched = 0;
135 if (curthread->sig_defer_count == 0) {
136 if (((curthread->cancelflags &
137 PTHREAD_AT_CANCEL_POINT) == 0) &&
138 ((curthread->cancelflags &
139 PTHREAD_CANCEL_ASYNCHRONOUS) != 0))
141 * Cancellations override signals.
143 * Stick a cancellation point at the
144 * start of each async-cancellable
145 * thread's resumption.
147 * We allow threads woken at cancel
148 * points to do their own checks.
150 pthread_testcancel();
153 if (_sched_switch_hook != NULL) {
154 /* Run the installed switch hook: */
155 thread_run_switch_hook(_last_user_thread, curthread);
160 /* XXX - Restore FP registers? */
164 * Set the process signal mask in the context; it
165 * could have changed by the handler.
167 ucp->uc_sigmask = _process_sigmask;
169 /* Resume the interrupted thread: */
173 /* Switch to the thread scheduler: */
174 ___longjmp(_thread_kern_sched_jb, 1);
178 _thread_kern_sched_sig(void)
180 struct pthread *curthread = _get_curthread();
182 curthread->check_pending = 1;
183 _thread_kern_sched(NULL);
188 _thread_kern_scheduler(void)
192 struct pthread *curthread = _get_curthread();
193 pthread_t pthread, pthread_h;
194 unsigned int current_tick;
197 /* If the currently running thread is a user thread, save it: */
198 if ((curthread->flags & PTHREAD_FLAGS_PRIVATE) == 0)
199 _last_user_thread = curthread;
201 if (called_from_handler != 0) {
202 called_from_handler = 0;
205 * We were called from a signal handler; restore the process
208 if (__sys_sigprocmask(SIG_SETMASK,
209 &_process_sigmask, NULL) != 0)
210 PANIC("Unable to restore process mask after signal");
214 * Enter a scheduling loop that finds the next thread that is
215 * ready to run. This loop completes when there are no more threads
216 * in the global list or when a thread has its state restored by
217 * either a sigreturn (if the state was saved as a sigcontext) or a
218 * longjmp (if the state was saved by a setjmp).
220 while (!(TAILQ_EMPTY(&_thread_list))) {
221 /* Get the current time of day: */
223 TIMEVAL_TO_TIMESPEC(&tv, &ts);
224 current_tick = _sched_ticks;
227 * Protect the scheduling queues from access by the signal
233 if (curthread != &_thread_kern_thread) {
235 * This thread no longer needs to yield the CPU.
237 curthread->yield_on_sig_undefer = 0;
239 if (curthread->state != PS_RUNNING) {
241 * Save the current time as the time that the
242 * thread became inactive:
244 curthread->last_inactive = (long)current_tick;
245 if (curthread->last_inactive <
246 curthread->last_active) {
247 /* Account for a rollover: */
248 curthread->last_inactive =+
254 * Place the currently running thread into the
255 * appropriate queue(s).
257 switch (curthread->state) {
259 case PS_STATE_MAX: /* to silence -Wall */
262 * Dead and suspended threads are not placed
269 * Runnable threads can't be placed in the
270 * priority queue until after waiting threads
271 * are polled (to preserve round-robin
278 * States which do not depend on file descriptor I/O
279 * operations or timeouts:
290 /* No timeouts for these states: */
291 curthread->wakeup_time.tv_sec = -1;
292 curthread->wakeup_time.tv_nsec = -1;
294 /* Restart the time slice: */
295 curthread->slice_usec = -1;
297 /* Insert into the waiting queue: */
298 PTHREAD_WAITQ_INSERT(curthread);
301 /* States which can timeout: */
304 /* Restart the time slice: */
305 curthread->slice_usec = -1;
307 /* Insert into the waiting queue: */
308 PTHREAD_WAITQ_INSERT(curthread);
311 /* States that require periodic work: */
313 /* No timeouts for this state: */
314 curthread->wakeup_time.tv_sec = -1;
315 curthread->wakeup_time.tv_nsec = -1;
317 /* Increment spinblock count: */
325 /* Restart the time slice: */
326 curthread->slice_usec = -1;
328 /* Insert into the waiting queue: */
329 PTHREAD_WAITQ_INSERT(curthread);
331 /* Insert into the work queue: */
332 PTHREAD_WORKQ_INSERT(curthread);
337 * Are there pending signals for this thread?
339 * This check has to be performed after the thread
340 * has been placed in the queue(s) appropriate for
341 * its state. The process of adding pending signals
342 * can change a threads state, which in turn will
343 * attempt to add or remove the thread from any
344 * scheduling queue to which it belongs.
346 if (curthread->check_pending != 0) {
347 curthread->check_pending = 0;
348 _thread_sig_check_pending(curthread);
353 * Avoid polling file descriptors if there are none
356 if (TAILQ_EMPTY(&_workq) != 0) {
359 * Poll file descriptors only if a new scheduling signal
360 * has occurred or if we have no more runnable threads.
362 else if (((current_tick = _sched_ticks) != last_tick) ||
363 ((curthread->state != PS_RUNNING) &&
364 (PTHREAD_PRIOQ_FIRST() == NULL))) {
365 /* Unprotect the scheduling queues: */
369 * Poll file descriptors to update the state of threads
370 * waiting on file I/O where data may be available:
374 /* Protect the scheduling queues: */
377 last_tick = current_tick;
380 * Wake up threads that have timedout. This has to be
381 * done after polling in case a thread does a poll or
382 * select with zero time.
384 PTHREAD_WAITQ_SETACTIVE();
385 while (((pthread = TAILQ_FIRST(&_waitingq)) != NULL) &&
386 (pthread->wakeup_time.tv_sec != -1) &&
387 (((pthread->wakeup_time.tv_sec == 0) &&
388 (pthread->wakeup_time.tv_nsec == 0)) ||
389 (pthread->wakeup_time.tv_sec < ts.tv_sec) ||
390 ((pthread->wakeup_time.tv_sec == ts.tv_sec) &&
391 (pthread->wakeup_time.tv_nsec <= ts.tv_nsec)))) {
392 switch (pthread->state) {
395 /* Return zero file descriptors ready: */
396 pthread->data.poll_data->nfds = 0;
400 * Remove this thread from the waiting queue
401 * (and work queue if necessary) and place it
402 * in the ready queue.
404 PTHREAD_WAITQ_CLEARACTIVE();
405 if (pthread->flags & PTHREAD_FLAGS_IN_WORKQ)
406 PTHREAD_WORKQ_REMOVE(pthread);
407 PTHREAD_NEW_STATE(pthread, PS_RUNNING);
408 PTHREAD_WAITQ_SETACTIVE();
412 * Flag the timeout in the thread structure:
414 pthread->timeout = 1;
416 PTHREAD_WAITQ_CLEARACTIVE();
419 * Check to see if the current thread needs to be added
420 * to the priority queue:
422 if (add_to_prioq != 0) {
424 * Save the current time as the time that the
425 * thread became inactive:
427 current_tick = _sched_ticks;
428 curthread->last_inactive = (long)current_tick;
429 if (curthread->last_inactive <
430 curthread->last_active) {
431 /* Account for a rollover: */
432 curthread->last_inactive =+ UINT_MAX + 1;
435 if ((curthread->slice_usec != -1) &&
436 (curthread->attr.sched_policy != SCHED_FIFO)) {
438 * Accumulate the number of microseconds for
439 * which the current thread has run:
441 curthread->slice_usec +=
442 (curthread->last_inactive -
443 curthread->last_active) *
444 (long)_clock_res_usec;
445 /* Check for time quantum exceeded: */
446 if (curthread->slice_usec > TIMESLICE_USEC)
447 curthread->slice_usec = -1;
450 if (curthread->slice_usec == -1) {
452 * The thread exceeded its time
453 * quantum or it yielded the CPU;
454 * place it at the tail of the
455 * queue for its priority.
457 PTHREAD_PRIOQ_INSERT_TAIL(curthread);
460 * The thread hasn't exceeded its
461 * interval. Place it at the head
462 * of the queue for its priority.
464 PTHREAD_PRIOQ_INSERT_HEAD(curthread);
469 * Get the highest priority thread in the ready queue.
471 pthread_h = PTHREAD_PRIOQ_FIRST();
473 /* Check if there are no threads ready to run: */
474 if (pthread_h == NULL) {
476 * Lock the pthread kernel by changing the pointer to
477 * the running thread to point to the global kernel
480 _set_curthread(&_thread_kern_thread);
481 curthread = &_thread_kern_thread;
483 DBG_MSG("No runnable threads, using kernel thread %p\n",
486 /* Unprotect the scheduling queues: */
490 * There are no threads ready to run, so wait until
491 * something happens that changes this condition:
496 * This process' usage will likely be very small
497 * while waiting in a poll. Since the scheduling
498 * clock is based on the profiling timer, it is
499 * unlikely that the profiling timer will fire
500 * and update the time of day. To account for this,
501 * get the time of day after polling with a timeout.
503 gettimeofday((struct timeval *) &_sched_tod, NULL);
505 /* Check once more for a runnable thread: */
507 pthread_h = PTHREAD_PRIOQ_FIRST();
511 if (pthread_h != NULL) {
512 /* Remove the thread from the ready queue: */
513 PTHREAD_PRIOQ_REMOVE(pthread_h);
515 /* Unprotect the scheduling queues: */
519 * Check for signals queued while the scheduling
520 * queues were protected:
522 while (_sigq_check_reqd != 0) {
523 /* Clear before handling queued signals: */
524 _sigq_check_reqd = 0;
526 /* Protect the scheduling queues again: */
532 * Check for a higher priority thread that
533 * became runnable due to signal handling.
535 if (((pthread = PTHREAD_PRIOQ_FIRST()) != NULL) &&
536 (pthread->active_priority > pthread_h->active_priority)) {
537 /* Remove the thread from the ready queue: */
538 PTHREAD_PRIOQ_REMOVE(pthread);
541 * Insert the lower priority thread
542 * at the head of its priority list:
544 PTHREAD_PRIOQ_INSERT_HEAD(pthread_h);
546 /* There's a new thread in town: */
550 /* Unprotect the scheduling queues: */
554 /* Make the selected thread the current thread: */
555 _set_curthread(pthread_h);
556 curthread = pthread_h;
559 * Save the current time as the time that the thread
562 current_tick = _sched_ticks;
563 curthread->last_active = (long) current_tick;
566 * Check if this thread is running for the first time
567 * or running again after using its full time slice
570 if (curthread->slice_usec == -1) {
571 /* Reset the accumulated time slice period: */
572 curthread->slice_usec = 0;
576 * If we had a context switch, run any
577 * installed switch hooks.
579 if ((_sched_switch_hook != NULL) &&
580 (_last_user_thread != curthread)) {
581 thread_run_switch_hook(_last_user_thread,
585 * Continue the thread at its current frame:
588 _setcontext(&curthread->ctx.uc);
590 ___longjmp(curthread->ctx.jb, 1);
592 /* This point should not be reached. */
593 PANIC("Thread has returned from sigreturn or longjmp");
597 /* There are no more threads, so exit this process: */
602 _thread_kern_sched_state(enum pthread_state state, char *fname, int lineno)
604 struct pthread *curthread = _get_curthread();
607 * Flag the pthread kernel as executing scheduler code
608 * to avoid a scheduler signal from interrupting this
609 * execution and calling the scheduler again.
611 _thread_kern_in_sched = 1;
614 * Prevent the signal handler from fiddling with this thread
615 * before its state is set and is placed into the proper queue.
619 /* Change the state of the current thread: */
620 curthread->state = state;
621 curthread->fname = fname;
622 curthread->lineno = lineno;
624 /* Schedule the next thread that is ready: */
625 _thread_kern_sched(NULL);
629 _thread_kern_sched_state_unlock(enum pthread_state state,
630 spinlock_t *lock, char *fname, int lineno)
632 struct pthread *curthread = _get_curthread();
635 * Flag the pthread kernel as executing scheduler code
636 * to avoid a scheduler signal from interrupting this
637 * execution and calling the scheduler again.
639 _thread_kern_in_sched = 1;
642 * Prevent the signal handler from fiddling with this thread
643 * before its state is set and it is placed into the proper
648 /* Change the state of the current thread: */
649 curthread->state = state;
650 curthread->fname = fname;
651 curthread->lineno = lineno;
655 /* Schedule the next thread that is ready: */
656 _thread_kern_sched(NULL);
660 thread_kern_poll(int wait_reqd)
664 int kern_pipe_added = 0;
667 struct pthread *pthread;
671 /* Check if the caller wants to wait: */
672 if (wait_reqd == 0) {
676 /* Get the current time of day: */
678 TIMEVAL_TO_TIMESPEC(&tv, &ts);
681 pthread = TAILQ_FIRST(&_waitingq);
684 if ((pthread == NULL) || (pthread->wakeup_time.tv_sec == -1)) {
686 * Either there are no threads in the waiting queue,
687 * or there are no threads that can timeout.
691 else if (pthread->wakeup_time.tv_sec - ts.tv_sec > 60000)
692 /* Limit maximum timeout to prevent rollover. */
696 * Calculate the time left for the next thread to
699 timeout_ms = ((pthread->wakeup_time.tv_sec - ts.tv_sec) *
700 1000) + ((pthread->wakeup_time.tv_nsec - ts.tv_nsec) /
703 * Don't allow negative timeouts:
710 /* Protect the scheduling queues: */
714 * Check to see if the signal queue needs to be walked to look
715 * for threads awoken by a signal while in the scheduler.
717 if (_sigq_check_reqd != 0) {
718 /* Reset flag before handling queued signals: */
719 _sigq_check_reqd = 0;
725 * Check for a thread that became runnable due to a signal:
727 if (PTHREAD_PRIOQ_FIRST() != NULL) {
729 * Since there is at least one runnable thread,
736 * Form the poll table:
739 if (timeout_ms != 0) {
740 /* Add the kernel pipe to the poll table: */
741 _thread_pfd_table[nfds].fd = _thread_kern_pipe[0];
742 _thread_pfd_table[nfds].events = POLLRDNORM;
743 _thread_pfd_table[nfds].revents = 0;
748 PTHREAD_WAITQ_SETACTIVE();
749 TAILQ_FOREACH(pthread, &_workq, qe) {
750 switch (pthread->state) {
753 * If the lock is available, let the thread run.
755 if (pthread->data.spinlock->access_lock == 0) {
756 PTHREAD_WAITQ_CLEARACTIVE();
757 PTHREAD_WORKQ_REMOVE(pthread);
758 PTHREAD_NEW_STATE(pthread,PS_RUNNING);
759 PTHREAD_WAITQ_SETACTIVE();
760 /* One less thread in a spinblock state: */
763 * Since there is at least one runnable
764 * thread, disable the wait.
770 /* File descriptor read wait: */
772 /* Limit number of polled files to table size: */
773 if (nfds < _thread_dtablesize) {
774 _thread_pfd_table[nfds].events = POLLRDNORM;
775 _thread_pfd_table[nfds].fd = pthread->data.fd.fd;
780 /* File descriptor write wait: */
782 /* Limit number of polled files to table size: */
783 if (nfds < _thread_dtablesize) {
784 _thread_pfd_table[nfds].events = POLLWRNORM;
785 _thread_pfd_table[nfds].fd = pthread->data.fd.fd;
790 /* File descriptor poll or select wait: */
793 /* Limit number of polled files to table size: */
794 if (pthread->data.poll_data->nfds + nfds <
795 _thread_dtablesize) {
796 for (i = 0; i < pthread->data.poll_data->nfds; i++) {
797 _thread_pfd_table[nfds + i].fd =
798 pthread->data.poll_data->fds[i].fd;
799 _thread_pfd_table[nfds + i].events =
800 pthread->data.poll_data->fds[i].events;
802 nfds += pthread->data.poll_data->nfds;
806 /* Other states do not depend on file I/O. */
811 PTHREAD_WAITQ_CLEARACTIVE();
814 * Wait for a file descriptor to be ready for read, write, or
815 * an exception, or a timeout to occur:
817 count = __sys_poll(_thread_pfd_table, nfds, timeout_ms);
819 if (kern_pipe_added != 0)
821 * Remove the pthread kernel pipe file descriptor
822 * from the pollfd table:
829 * Check if it is possible that there are bytes in the kernel
830 * read pipe waiting to be read:
832 if (count < 0 || ((kern_pipe_added != 0) &&
833 (_thread_pfd_table[0].revents & POLLRDNORM))) {
835 * If the kernel read pipe was included in the
839 /* Decrement the count of file descriptors: */
843 if (_sigq_check_reqd != 0) {
844 /* Reset flag before handling signals: */
845 _sigq_check_reqd = 0;
852 * Check if any file descriptors are ready:
856 * Enter a loop to look for threads waiting on file
857 * descriptors that are flagged as available by the
860 PTHREAD_WAITQ_SETACTIVE();
861 TAILQ_FOREACH(pthread, &_workq, qe) {
862 switch (pthread->state) {
865 * If the lock is available, let the thread run.
867 if (pthread->data.spinlock->access_lock == 0) {
868 PTHREAD_WAITQ_CLEARACTIVE();
869 PTHREAD_WORKQ_REMOVE(pthread);
870 PTHREAD_NEW_STATE(pthread,PS_RUNNING);
871 PTHREAD_WAITQ_SETACTIVE();
874 * One less thread in a spinblock state:
880 /* File descriptor read wait: */
882 if ((nfds < _thread_dtablesize) &&
883 ((_thread_pfd_table[nfds].revents
884 & (POLLRDNORM | POLLHUP
885 | POLLERR | POLLNVAL)) != 0)) {
886 PTHREAD_WAITQ_CLEARACTIVE();
887 PTHREAD_WORKQ_REMOVE(pthread);
888 PTHREAD_NEW_STATE(pthread,PS_RUNNING);
889 PTHREAD_WAITQ_SETACTIVE();
894 /* File descriptor write wait: */
896 if ((nfds < _thread_dtablesize) &&
897 ((_thread_pfd_table[nfds].revents
898 & (POLLWRNORM | POLLHUP
899 | POLLERR | POLLNVAL)) != 0)) {
900 PTHREAD_WAITQ_CLEARACTIVE();
901 PTHREAD_WORKQ_REMOVE(pthread);
902 PTHREAD_NEW_STATE(pthread,PS_RUNNING);
903 PTHREAD_WAITQ_SETACTIVE();
908 /* File descriptor poll or select wait: */
911 if (pthread->data.poll_data->nfds + nfds <
912 _thread_dtablesize) {
914 * Enter a loop looking for I/O
918 for (i = 0; i < pthread->data.poll_data->nfds; i++) {
919 if (_thread_pfd_table[nfds + i].revents != 0) {
920 pthread->data.poll_data->fds[i].revents =
921 _thread_pfd_table[nfds + i].revents;
926 /* Increment before destroying: */
927 nfds += pthread->data.poll_data->nfds;
930 pthread->data.poll_data->nfds = found;
931 PTHREAD_WAITQ_CLEARACTIVE();
932 PTHREAD_WORKQ_REMOVE(pthread);
933 PTHREAD_NEW_STATE(pthread,PS_RUNNING);
934 PTHREAD_WAITQ_SETACTIVE();
938 nfds += pthread->data.poll_data->nfds;
941 /* Other states do not depend on file I/O. */
946 PTHREAD_WAITQ_CLEARACTIVE();
948 else if (_spinblock_count != 0) {
950 * Enter a loop to look for threads waiting on a spinlock
951 * that is now available.
953 PTHREAD_WAITQ_SETACTIVE();
954 TAILQ_FOREACH(pthread, &_workq, qe) {
955 if (pthread->state == PS_SPINBLOCK) {
957 * If the lock is available, let the thread run.
959 if (pthread->data.spinlock->access_lock == 0) {
960 PTHREAD_WAITQ_CLEARACTIVE();
961 PTHREAD_WORKQ_REMOVE(pthread);
962 PTHREAD_NEW_STATE(pthread,PS_RUNNING);
963 PTHREAD_WAITQ_SETACTIVE();
966 * One less thread in a spinblock state:
972 PTHREAD_WAITQ_CLEARACTIVE();
975 /* Unprotect the scheduling queues: */
978 while (_sigq_check_reqd != 0) {
979 /* Handle queued signals: */
980 _sigq_check_reqd = 0;
982 /* Protect the scheduling queues: */
987 /* Unprotect the scheduling queues: */
993 _thread_kern_set_timeout(const struct timespec * timeout)
995 struct pthread *curthread = _get_curthread();
996 struct timespec current_time;
999 /* Reset the timeout flag for the running thread: */
1000 curthread->timeout = 0;
1002 /* Check if the thread is to wait forever: */
1003 if (timeout == NULL) {
1005 * Set the wakeup time to something that can be recognised as
1006 * different to an actual time of day:
1008 curthread->wakeup_time.tv_sec = -1;
1009 curthread->wakeup_time.tv_nsec = -1;
1011 /* Check if no waiting is required: */
1012 else if (timeout->tv_sec == 0 && timeout->tv_nsec == 0) {
1013 /* Set the wake up time to 'immediately': */
1014 curthread->wakeup_time.tv_sec = 0;
1015 curthread->wakeup_time.tv_nsec = 0;
1017 /* Get the current time: */
1018 GET_CURRENT_TOD(tv);
1019 TIMEVAL_TO_TIMESPEC(&tv, ¤t_time);
1021 /* Calculate the time for the current thread to wake up: */
1022 curthread->wakeup_time.tv_sec = current_time.tv_sec + timeout->tv_sec;
1023 curthread->wakeup_time.tv_nsec = current_time.tv_nsec + timeout->tv_nsec;
1025 /* Check if the nanosecond field needs to wrap: */
1026 if (curthread->wakeup_time.tv_nsec >= 1000000000) {
1027 /* Wrap the nanosecond field: */
1028 curthread->wakeup_time.tv_sec += 1;
1029 curthread->wakeup_time.tv_nsec -= 1000000000;
1035 _thread_kern_sig_defer(void)
1037 struct pthread *curthread = _get_curthread();
1039 /* Allow signal deferral to be recursive. */
1040 curthread->sig_defer_count++;
1044 _thread_kern_sig_undefer(void)
1046 struct pthread *curthread = _get_curthread();
1049 * Perform checks to yield only if we are about to undefer
1052 if (curthread->sig_defer_count > 1) {
1053 /* Decrement the signal deferral count. */
1054 curthread->sig_defer_count--;
1056 else if (curthread->sig_defer_count == 1) {
1057 /* Reenable signals: */
1058 curthread->sig_defer_count = 0;
1061 * Check if there are queued signals:
1063 if (_sigq_check_reqd != 0)
1064 _thread_kern_sched(NULL);
1067 * Check for asynchronous cancellation before delivering any
1070 if (((curthread->cancelflags & PTHREAD_AT_CANCEL_POINT) == 0) &&
1071 ((curthread->cancelflags & PTHREAD_CANCEL_ASYNCHRONOUS) != 0))
1072 pthread_testcancel();
1075 * If there are pending signals or this thread has
1076 * to yield the CPU, call the kernel scheduler:
1078 * XXX - Come back and revisit the pending signal problem
1080 if ((curthread->yield_on_sig_undefer != 0) ||
1081 SIGNOTEMPTY(curthread->sigpend)) {
1082 curthread->yield_on_sig_undefer = 0;
1083 _thread_kern_sched(NULL);
1089 dequeue_signals(void)
1095 * Enter a loop to clear the pthread kernel pipe:
1097 while (((num = __sys_extpread(_thread_kern_pipe[0], bufr,
1098 sizeof(bufr), O_FNONBLOCKING, -1)) > 0) ||
1099 (num == -1 && errno == EINTR)) {
1102 if ((num < 0) && (errno != EAGAIN)) {
1104 * The only error we should expect is if there is
1107 PANIC("Unable to read from thread kernel pipe");
1109 /* Handle any pending signals: */
1110 _thread_sig_handle_pending();
1114 thread_run_switch_hook(pthread_t thread_out, pthread_t thread_in)
1116 pthread_t tid_out = thread_out;
1117 pthread_t tid_in = thread_in;
1119 if ((tid_out != NULL) &&
1120 (tid_out->flags & PTHREAD_FLAGS_PRIVATE) != 0)
1122 if ((tid_in != NULL) &&
1123 (tid_in->flags & PTHREAD_FLAGS_PRIVATE) != 0)
1126 if ((_sched_switch_hook != NULL) && (tid_out != tid_in)) {
1127 /* Run the scheduler switch hook: */
1128 _sched_switch_hook(tid_out, tid_in);
1133 _get_curthread(void)
1135 if (_thread_initial == NULL)
1138 return (_thread_run);
1142 _set_curthread(struct pthread *newthread)
1144 _thread_run = newthread;
1145 tls_set_tcb(newthread->tcb);