228 turnstile_free(td->td_turnstile);
229 sleepq_free(td->td_sleepqueue);
230 umtx_thread_fini(td);
231 seltdfini(td);
232}
233
234/*
235 * For a newly created process,
236 * link up all the structures and its initial threads etc.
237 * called from:
238 * {arch}/{arch}/machdep.c ia64_init(), init386() etc.
239 * proc_dtor() (should go away)
240 * proc_init()
241 */
242void
243proc_linkup0(struct proc *p, struct thread *td)
244{
245 TAILQ_INIT(&p->p_threads); /* all threads in proc */
246 proc_linkup(p, td);
247}
248
249void
250proc_linkup(struct proc *p, struct thread *td)
251{
252
253 sigqueue_init(&p->p_sigqueue, p);
254 p->p_ksi = ksiginfo_alloc(1);
255 if (p->p_ksi != NULL) {
256 /* XXX p_ksi may be null if ksiginfo zone is not ready */
257 p->p_ksi->ksi_flags = KSI_EXT | KSI_INS;
258 }
259 LIST_INIT(&p->p_mqnotifier);
260 p->p_numthreads = 0;
261 thread_link(td, p);
262}
263
264/*
265 * Initialize global thread allocation resources.
266 */
267void
268threadinit(void)
269{
270
271 mtx_init(&tid_lock, "TID lock", NULL, MTX_DEF);
272 /* leave one number for thread0 */
273 tid_unrhdr = new_unrhdr(PID_MAX + 2, INT_MAX, &tid_lock);
274
275 thread_zone = uma_zcreate("THREAD", sched_sizeof_thread(),
276 thread_ctor, thread_dtor, thread_init, thread_fini,
277 16 - 1, 0);
278 tidhashtbl = hashinit(maxproc / 2, M_TIDHASH, &tidhash);
279 rw_init(&tidhash_lock, "tidhash");
280}
281
282/*
283 * Place an unused thread on the zombie list.
284 * Use the slpq as that must be unused by now.
285 */
286void
287thread_zombie(struct thread *td)
288{
289 mtx_lock_spin(&zombie_lock);
290 TAILQ_INSERT_HEAD(&zombie_threads, td, td_slpq);
291 mtx_unlock_spin(&zombie_lock);
292}
293
294/*
295 * Release a thread that has exited after cpu_throw().
296 */
297void
298thread_stash(struct thread *td)
299{
300 atomic_subtract_rel_int(&td->td_proc->p_exitthreads, 1);
301 thread_zombie(td);
302}
303
304/*
305 * Reap zombie resources.
306 */
307void
308thread_reap(void)
309{
310 struct thread *td_first, *td_next;
311
312 /*
313 * Don't even bother to lock if none at this instant,
314 * we really don't care about the next instant..
315 */
316 if (!TAILQ_EMPTY(&zombie_threads)) {
317 mtx_lock_spin(&zombie_lock);
318 td_first = TAILQ_FIRST(&zombie_threads);
319 if (td_first)
320 TAILQ_INIT(&zombie_threads);
321 mtx_unlock_spin(&zombie_lock);
322 while (td_first) {
323 td_next = TAILQ_NEXT(td_first, td_slpq);
324 if (td_first->td_ucred)
325 crfree(td_first->td_ucred);
326 thread_free(td_first);
327 td_first = td_next;
328 }
329 }
330}
331
332/*
333 * Allocate a thread.
334 */
335struct thread *
336thread_alloc(int pages)
337{
338 struct thread *td;
339
340 thread_reap(); /* check if any zombies to get */
341
342 td = (struct thread *)uma_zalloc(thread_zone, M_WAITOK);
343 KASSERT(td->td_kstack == 0, ("thread_alloc got thread with kstack"));
344 if (!vm_thread_new(td, pages)) {
345 uma_zfree(thread_zone, td);
346 return (NULL);
347 }
348 cpu_thread_alloc(td);
349 return (td);
350}
351
352int
353thread_alloc_stack(struct thread *td, int pages)
354{
355
356 KASSERT(td->td_kstack == 0,
357 ("thread_alloc_stack called on a thread with kstack"));
358 if (!vm_thread_new(td, pages))
359 return (0);
360 cpu_thread_alloc(td);
361 return (1);
362}
363
364/*
365 * Deallocate a thread.
366 */
367void
368thread_free(struct thread *td)
369{
370
371 lock_profile_thread_exit(td);
372 if (td->td_cpuset)
373 cpuset_rel(td->td_cpuset);
374 td->td_cpuset = NULL;
375 cpu_thread_free(td);
376 if (td->td_kstack != 0)
377 vm_thread_dispose(td);
378 uma_zfree(thread_zone, td);
379}
380
381/*
382 * Discard the current thread and exit from its context.
383 * Always called with scheduler locked.
384 *
385 * Because we can't free a thread while we're operating under its context,
386 * push the current thread into our CPU's deadthread holder. This means
387 * we needn't worry about someone else grabbing our context before we
388 * do a cpu_throw().
389 */
390void
391thread_exit(void)
392{
393 uint64_t runtime, new_switchtime;
394 struct thread *td;
395 struct thread *td2;
396 struct proc *p;
397 int wakeup_swapper;
398
399 td = curthread;
400 p = td->td_proc;
401
402 PROC_SLOCK_ASSERT(p, MA_OWNED);
403 mtx_assert(&Giant, MA_NOTOWNED);
404
405 PROC_LOCK_ASSERT(p, MA_OWNED);
406 KASSERT(p != NULL, ("thread exiting without a process"));
407 CTR3(KTR_PROC, "thread_exit: thread %p (pid %ld, %s)", td,
408 (long)p->p_pid, td->td_name);
409 KASSERT(TAILQ_EMPTY(&td->td_sigqueue.sq_list), ("signal pending"));
410
411#ifdef AUDIT
412 AUDIT_SYSCALL_EXIT(0, td);
413#endif
414 umtx_thread_exit(td);
415 /*
416 * drop FPU & debug register state storage, or any other
417 * architecture specific resources that
418 * would not be on a new untouched process.
419 */
420 cpu_thread_exit(td); /* XXXSMP */
421
422 /*
423 * The last thread is left attached to the process
424 * So that the whole bundle gets recycled. Skip
425 * all this stuff if we never had threads.
426 * EXIT clears all sign of other threads when
427 * it goes to single threading, so the last thread always
428 * takes the short path.
429 */
430 if (p->p_flag & P_HADTHREADS) {
431 if (p->p_numthreads > 1) {
432 thread_unlink(td);
433 td2 = FIRST_THREAD_IN_PROC(p);
434 sched_exit_thread(td2, td);
435
436 /*
437 * The test below is NOT true if we are the
438 * sole exiting thread. P_STOPPED_SINGLE is unset
439 * in exit1() after it is the only survivor.
440 */
441 if (P_SHOULDSTOP(p) == P_STOPPED_SINGLE) {
442 if (p->p_numthreads == p->p_suspcount) {
443 thread_lock(p->p_singlethread);
444 wakeup_swapper = thread_unsuspend_one(
445 p->p_singlethread);
446 thread_unlock(p->p_singlethread);
447 if (wakeup_swapper)
448 kick_proc0();
449 }
450 }
451
452 atomic_add_int(&td->td_proc->p_exitthreads, 1);
453 PCPU_SET(deadthread, td);
454 } else {
455 /*
456 * The last thread is exiting.. but not through exit()
457 */
458 panic ("thread_exit: Last thread exiting on its own");
459 }
460 }
461#ifdef HWPMC_HOOKS
462 /*
463 * If this thread is part of a process that is being tracked by hwpmc(4),
464 * inform the module of the thread's impending exit.
465 */
466 if (PMC_PROC_IS_USING_PMCS(td->td_proc))
467 PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_OUT);
468#endif
469 PROC_UNLOCK(p);
470
471 /* Do the same timestamp bookkeeping that mi_switch() would do. */
472 new_switchtime = cpu_ticks();
473 runtime = new_switchtime - PCPU_GET(switchtime);
474 td->td_runtime += runtime;
475 td->td_incruntime += runtime;
476 PCPU_SET(switchtime, new_switchtime);
477 PCPU_SET(switchticks, ticks);
478 PCPU_INC(cnt.v_swtch);
479
480 /* Save our resource usage in our process. */
481 td->td_ru.ru_nvcsw++;
482 ruxagg(p, td);
483 rucollect(&p->p_ru, &td->td_ru);
484
485 thread_lock(td);
486 PROC_SUNLOCK(p);
487 td->td_state = TDS_INACTIVE;
488#ifdef WITNESS
489 witness_thread_exit(td);
490#endif
491 CTR1(KTR_PROC, "thread_exit: cpu_throw() thread %p", td);
492 sched_throw(td);
493 panic("I'm a teapot!");
494 /* NOTREACHED */
495}
496
497/*
498 * Do any thread specific cleanups that may be needed in wait()
499 * called with Giant, proc and schedlock not held.
500 */
501void
502thread_wait(struct proc *p)
503{
504 struct thread *td;
505
506 mtx_assert(&Giant, MA_NOTOWNED);
507 KASSERT((p->p_numthreads == 1), ("Multiple threads in wait1()"));
508 td = FIRST_THREAD_IN_PROC(p);
509 /* Lock the last thread so we spin until it exits cpu_throw(). */
510 thread_lock(td);
511 thread_unlock(td);
512 /* Wait for any remaining threads to exit cpu_throw(). */
513 while (p->p_exitthreads)
514 sched_relinquish(curthread);
515 lock_profile_thread_exit(td);
516 cpuset_rel(td->td_cpuset);
517 td->td_cpuset = NULL;
518 cpu_thread_clean(td);
519 crfree(td->td_ucred);
520 thread_reap(); /* check for zombie threads etc. */
521}
522
523/*
524 * Link a thread to a process.
525 * set up anything that needs to be initialized for it to
526 * be used by the process.
527 */
528void
529thread_link(struct thread *td, struct proc *p)
530{
531
532 /*
533 * XXX This can't be enabled because it's called for proc0 before
534 * its lock has been created.
535 * PROC_LOCK_ASSERT(p, MA_OWNED);
536 */
537 td->td_state = TDS_INACTIVE;
538 td->td_proc = p;
539 td->td_flags = TDF_INMEM;
540
541 LIST_INIT(&td->td_contested);
542 LIST_INIT(&td->td_lprof[0]);
543 LIST_INIT(&td->td_lprof[1]);
544 sigqueue_init(&td->td_sigqueue, p);
545 callout_init(&td->td_slpcallout, CALLOUT_MPSAFE);
546 TAILQ_INSERT_HEAD(&p->p_threads, td, td_plist);
547 p->p_numthreads++;
548}
549
550/*
551 * Convert a process with one thread to an unthreaded process.
552 */
553void
554thread_unthread(struct thread *td)
555{
556 struct proc *p = td->td_proc;
557
558 KASSERT((p->p_numthreads == 1), ("Unthreading with >1 threads"));
559 p->p_flag &= ~P_HADTHREADS;
560}
561
562/*
563 * Called from:
564 * thread_exit()
565 */
566void
567thread_unlink(struct thread *td)
568{
569 struct proc *p = td->td_proc;
570
571 PROC_LOCK_ASSERT(p, MA_OWNED);
572 TAILQ_REMOVE(&p->p_threads, td, td_plist);
573 p->p_numthreads--;
574 /* could clear a few other things here */
575 /* Must NOT clear links to proc! */
576}
577
578static int
579calc_remaining(struct proc *p, int mode)
580{
581 int remaining;
582
583 PROC_LOCK_ASSERT(p, MA_OWNED);
584 PROC_SLOCK_ASSERT(p, MA_OWNED);
585 if (mode == SINGLE_EXIT)
586 remaining = p->p_numthreads;
587 else if (mode == SINGLE_BOUNDARY)
588 remaining = p->p_numthreads - p->p_boundary_count;
589 else if (mode == SINGLE_NO_EXIT)
590 remaining = p->p_numthreads - p->p_suspcount;
591 else
592 panic("calc_remaining: wrong mode %d", mode);
593 return (remaining);
594}
595
596/*
597 * Enforce single-threading.
598 *
599 * Returns 1 if the caller must abort (another thread is waiting to
600 * exit the process or similar). Process is locked!
601 * Returns 0 when you are successfully the only thread running.
602 * A process has successfully single threaded in the suspend mode when
603 * There are no threads in user mode. Threads in the kernel must be
604 * allowed to continue until they get to the user boundary. They may even
605 * copy out their return values and data before suspending. They may however be
606 * accelerated in reaching the user boundary as we will wake up
607 * any sleeping threads that are interruptable. (PCATCH).
608 */
609int
610thread_single(int mode)
611{
612 struct thread *td;
613 struct thread *td2;
614 struct proc *p;
615 int remaining, wakeup_swapper;
616
617 td = curthread;
618 p = td->td_proc;
619 mtx_assert(&Giant, MA_NOTOWNED);
620 PROC_LOCK_ASSERT(p, MA_OWNED);
621 KASSERT((td != NULL), ("curthread is NULL"));
622
623 if ((p->p_flag & P_HADTHREADS) == 0)
624 return (0);
625
626 /* Is someone already single threading? */
627 if (p->p_singlethread != NULL && p->p_singlethread != td)
628 return (1);
629
630 if (mode == SINGLE_EXIT) {
631 p->p_flag |= P_SINGLE_EXIT;
632 p->p_flag &= ~P_SINGLE_BOUNDARY;
633 } else {
634 p->p_flag &= ~P_SINGLE_EXIT;
635 if (mode == SINGLE_BOUNDARY)
636 p->p_flag |= P_SINGLE_BOUNDARY;
637 else
638 p->p_flag &= ~P_SINGLE_BOUNDARY;
639 }
640 p->p_flag |= P_STOPPED_SINGLE;
641 PROC_SLOCK(p);
642 p->p_singlethread = td;
643 remaining = calc_remaining(p, mode);
644 while (remaining != 1) {
645 if (P_SHOULDSTOP(p) != P_STOPPED_SINGLE)
646 goto stopme;
647 wakeup_swapper = 0;
648 FOREACH_THREAD_IN_PROC(p, td2) {
649 if (td2 == td)
650 continue;
651 thread_lock(td2);
652 td2->td_flags |= TDF_ASTPENDING | TDF_NEEDSUSPCHK;
653 if (TD_IS_INHIBITED(td2)) {
654 switch (mode) {
655 case SINGLE_EXIT:
656 if (TD_IS_SUSPENDED(td2))
657 wakeup_swapper |=
658 thread_unsuspend_one(td2);
659 if (TD_ON_SLEEPQ(td2) &&
660 (td2->td_flags & TDF_SINTR))
661 wakeup_swapper |=
662 sleepq_abort(td2, EINTR);
663 break;
664 case SINGLE_BOUNDARY:
665 if (TD_IS_SUSPENDED(td2) &&
666 !(td2->td_flags & TDF_BOUNDARY))
667 wakeup_swapper |=
668 thread_unsuspend_one(td2);
669 if (TD_ON_SLEEPQ(td2) &&
670 (td2->td_flags & TDF_SINTR))
671 wakeup_swapper |=
672 sleepq_abort(td2, ERESTART);
673 break;
674 case SINGLE_NO_EXIT:
675 if (TD_IS_SUSPENDED(td2) &&
676 !(td2->td_flags & TDF_BOUNDARY))
677 wakeup_swapper |=
678 thread_unsuspend_one(td2);
679 if (TD_ON_SLEEPQ(td2) &&
680 (td2->td_flags & TDF_SINTR))
681 wakeup_swapper |=
682 sleepq_abort(td2, ERESTART);
683 break;
684 default:
685 break;
686 }
687 }
688#ifdef SMP
689 else if (TD_IS_RUNNING(td2) && td != td2) {
690 forward_signal(td2);
691 }
692#endif
693 thread_unlock(td2);
694 }
695 if (wakeup_swapper)
696 kick_proc0();
697 remaining = calc_remaining(p, mode);
698
699 /*
700 * Maybe we suspended some threads.. was it enough?
701 */
702 if (remaining == 1)
703 break;
704
705stopme:
706 /*
707 * Wake us up when everyone else has suspended.
708 * In the mean time we suspend as well.
709 */
710 thread_suspend_switch(td);
711 remaining = calc_remaining(p, mode);
712 }
713 if (mode == SINGLE_EXIT) {
714 /*
715 * We have gotten rid of all the other threads and we
716 * are about to either exit or exec. In either case,
717 * we try our utmost to revert to being a non-threaded
718 * process.
719 */
720 p->p_singlethread = NULL;
721 p->p_flag &= ~(P_STOPPED_SINGLE | P_SINGLE_EXIT);
722 thread_unthread(td);
723 }
724 PROC_SUNLOCK(p);
725 return (0);
726}
727
728/*
729 * Called in from locations that can safely check to see
730 * whether we have to suspend or at least throttle for a
731 * single-thread event (e.g. fork).
732 *
733 * Such locations include userret().
734 * If the "return_instead" argument is non zero, the thread must be able to
735 * accept 0 (caller may continue), or 1 (caller must abort) as a result.
736 *
737 * The 'return_instead' argument tells the function if it may do a
738 * thread_exit() or suspend, or whether the caller must abort and back
739 * out instead.
740 *
741 * If the thread that set the single_threading request has set the
742 * P_SINGLE_EXIT bit in the process flags then this call will never return
743 * if 'return_instead' is false, but will exit.
744 *
745 * P_SINGLE_EXIT | return_instead == 0| return_instead != 0
746 *---------------+--------------------+---------------------
747 * 0 | returns 0 | returns 0 or 1
748 * | when ST ends | immediatly
749 *---------------+--------------------+---------------------
750 * 1 | thread exits | returns 1
751 * | | immediatly
752 * 0 = thread_exit() or suspension ok,
753 * other = return error instead of stopping the thread.
754 *
755 * While a full suspension is under effect, even a single threading
756 * thread would be suspended if it made this call (but it shouldn't).
757 * This call should only be made from places where
758 * thread_exit() would be safe as that may be the outcome unless
759 * return_instead is set.
760 */
761int
762thread_suspend_check(int return_instead)
763{
764 struct thread *td;
765 struct proc *p;
766 int wakeup_swapper;
767
768 td = curthread;
769 p = td->td_proc;
770 mtx_assert(&Giant, MA_NOTOWNED);
771 PROC_LOCK_ASSERT(p, MA_OWNED);
772 while (P_SHOULDSTOP(p) ||
773 ((p->p_flag & P_TRACED) && (td->td_dbgflags & TDB_SUSPEND))) {
774 if (P_SHOULDSTOP(p) == P_STOPPED_SINGLE) {
775 KASSERT(p->p_singlethread != NULL,
776 ("singlethread not set"));
777 /*
778 * The only suspension in action is a
779 * single-threading. Single threader need not stop.
780 * XXX Should be safe to access unlocked
781 * as it can only be set to be true by us.
782 */
783 if (p->p_singlethread == td)
784 return (0); /* Exempt from stopping. */
785 }
786 if ((p->p_flag & P_SINGLE_EXIT) && return_instead)
787 return (EINTR);
788
789 /* Should we goto user boundary if we didn't come from there? */
790 if (P_SHOULDSTOP(p) == P_STOPPED_SINGLE &&
791 (p->p_flag & P_SINGLE_BOUNDARY) && return_instead)
792 return (ERESTART);
793
794 /*
795 * If the process is waiting for us to exit,
796 * this thread should just suicide.
797 * Assumes that P_SINGLE_EXIT implies P_STOPPED_SINGLE.
798 */
799 if ((p->p_flag & P_SINGLE_EXIT) && (p->p_singlethread != td)) {
800 PROC_UNLOCK(p);
801 tidhash_remove(td);
802 PROC_LOCK(p);
803 tdsigcleanup(td);
804 PROC_SLOCK(p);
805 thread_stopped(p);
806 thread_exit();
807 }
808
809 PROC_SLOCK(p);
810 thread_stopped(p);
811 if (P_SHOULDSTOP(p) == P_STOPPED_SINGLE) {
812 if (p->p_numthreads == p->p_suspcount + 1) {
813 thread_lock(p->p_singlethread);
814 wakeup_swapper =
815 thread_unsuspend_one(p->p_singlethread);
816 thread_unlock(p->p_singlethread);
817 if (wakeup_swapper)
818 kick_proc0();
819 }
820 }
821 PROC_UNLOCK(p);
822 thread_lock(td);
823 /*
824 * When a thread suspends, it just
825 * gets taken off all queues.
826 */
827 thread_suspend_one(td);
828 if (return_instead == 0) {
829 p->p_boundary_count++;
830 td->td_flags |= TDF_BOUNDARY;
831 }
832 PROC_SUNLOCK(p);
833 mi_switch(SW_INVOL | SWT_SUSPEND, NULL);
834 if (return_instead == 0)
835 td->td_flags &= ~TDF_BOUNDARY;
836 thread_unlock(td);
837 PROC_LOCK(p);
838 if (return_instead == 0) {
839 PROC_SLOCK(p);
840 p->p_boundary_count--;
841 PROC_SUNLOCK(p);
842 }
843 }
844 return (0);
845}
846
847void
848thread_suspend_switch(struct thread *td)
849{
850 struct proc *p;
851
852 p = td->td_proc;
853 KASSERT(!TD_IS_SUSPENDED(td), ("already suspended"));
854 PROC_LOCK_ASSERT(p, MA_OWNED);
855 PROC_SLOCK_ASSERT(p, MA_OWNED);
856 /*
857 * We implement thread_suspend_one in stages here to avoid
858 * dropping the proc lock while the thread lock is owned.
859 */
860 thread_stopped(p);
861 p->p_suspcount++;
862 PROC_UNLOCK(p);
863 thread_lock(td);
864 td->td_flags &= ~TDF_NEEDSUSPCHK;
865 TD_SET_SUSPENDED(td);
866 sched_sleep(td, 0);
867 PROC_SUNLOCK(p);
868 DROP_GIANT();
869 mi_switch(SW_VOL | SWT_SUSPEND, NULL);
870 thread_unlock(td);
871 PICKUP_GIANT();
872 PROC_LOCK(p);
873 PROC_SLOCK(p);
874}
875
876void
877thread_suspend_one(struct thread *td)
878{
879 struct proc *p = td->td_proc;
880
881 PROC_SLOCK_ASSERT(p, MA_OWNED);
882 THREAD_LOCK_ASSERT(td, MA_OWNED);
883 KASSERT(!TD_IS_SUSPENDED(td), ("already suspended"));
884 p->p_suspcount++;
885 td->td_flags &= ~TDF_NEEDSUSPCHK;
886 TD_SET_SUSPENDED(td);
887 sched_sleep(td, 0);
888}
889
890int
891thread_unsuspend_one(struct thread *td)
892{
893 struct proc *p = td->td_proc;
894
895 PROC_SLOCK_ASSERT(p, MA_OWNED);
896 THREAD_LOCK_ASSERT(td, MA_OWNED);
897 KASSERT(TD_IS_SUSPENDED(td), ("Thread not suspended"));
898 TD_CLR_SUSPENDED(td);
899 p->p_suspcount--;
900 return (setrunnable(td));
901}
902
903/*
904 * Allow all threads blocked by single threading to continue running.
905 */
906void
907thread_unsuspend(struct proc *p)
908{
909 struct thread *td;
910 int wakeup_swapper;
911
912 PROC_LOCK_ASSERT(p, MA_OWNED);
913 PROC_SLOCK_ASSERT(p, MA_OWNED);
914 wakeup_swapper = 0;
915 if (!P_SHOULDSTOP(p)) {
916 FOREACH_THREAD_IN_PROC(p, td) {
917 thread_lock(td);
918 if (TD_IS_SUSPENDED(td)) {
919 wakeup_swapper |= thread_unsuspend_one(td);
920 }
921 thread_unlock(td);
922 }
923 } else if ((P_SHOULDSTOP(p) == P_STOPPED_SINGLE) &&
924 (p->p_numthreads == p->p_suspcount)) {
925 /*
926 * Stopping everything also did the job for the single
927 * threading request. Now we've downgraded to single-threaded,
928 * let it continue.
929 */
930 thread_lock(p->p_singlethread);
931 wakeup_swapper = thread_unsuspend_one(p->p_singlethread);
932 thread_unlock(p->p_singlethread);
933 }
934 if (wakeup_swapper)
935 kick_proc0();
936}
937
938/*
939 * End the single threading mode..
940 */
941void
942thread_single_end(void)
943{
944 struct thread *td;
945 struct proc *p;
946 int wakeup_swapper;
947
948 td = curthread;
949 p = td->td_proc;
950 PROC_LOCK_ASSERT(p, MA_OWNED);
951 p->p_flag &= ~(P_STOPPED_SINGLE | P_SINGLE_EXIT | P_SINGLE_BOUNDARY);
952 PROC_SLOCK(p);
953 p->p_singlethread = NULL;
954 wakeup_swapper = 0;
955 /*
956 * If there are other threads they may now run,
957 * unless of course there is a blanket 'stop order'
958 * on the process. The single threader must be allowed
959 * to continue however as this is a bad place to stop.
960 */
961 if ((p->p_numthreads != 1) && (!P_SHOULDSTOP(p))) {
962 FOREACH_THREAD_IN_PROC(p, td) {
963 thread_lock(td);
964 if (TD_IS_SUSPENDED(td)) {
965 wakeup_swapper |= thread_unsuspend_one(td);
966 }
967 thread_unlock(td);
968 }
969 }
970 PROC_SUNLOCK(p);
971 if (wakeup_swapper)
972 kick_proc0();
973}
974
975struct thread *
976thread_find(struct proc *p, lwpid_t tid)
977{
978 struct thread *td;
979
980 PROC_LOCK_ASSERT(p, MA_OWNED);
981 FOREACH_THREAD_IN_PROC(p, td) {
982 if (td->td_tid == tid)
983 break;
984 }
985 return (td);
986}
987
988/* Locate a thread by number; return with proc lock held. */
989struct thread *
990tdfind(lwpid_t tid, pid_t pid)
991{
992#define RUN_THRESH 16
993 struct thread *td;
994 int run = 0;
995
996 rw_rlock(&tidhash_lock);
997 LIST_FOREACH(td, TIDHASH(tid), td_hash) {
998 if (td->td_tid == tid) {
999 if (pid != -1 && td->td_proc->p_pid != pid) {
1000 td = NULL;
1001 break;
1002 }
1003 PROC_LOCK(td->td_proc);
1004 if (td->td_proc->p_state == PRS_NEW) {
1005 PROC_UNLOCK(td->td_proc);
1006 td = NULL;
1007 break;
1008 }
1009 if (run > RUN_THRESH) {
1010 if (rw_try_upgrade(&tidhash_lock)) {
1011 LIST_REMOVE(td, td_hash);
1012 LIST_INSERT_HEAD(TIDHASH(td->td_tid),
1013 td, td_hash);
1014 rw_wunlock(&tidhash_lock);
1015 return (td);
1016 }
1017 }
1018 break;
1019 }
1020 run++;
1021 }
1022 rw_runlock(&tidhash_lock);
1023 return (td);
1024}
1025
1026void
1027tidhash_add(struct thread *td)
1028{
1029 rw_wlock(&tidhash_lock);
1030 LIST_INSERT_HEAD(TIDHASH(td->td_tid), td, td_hash);
1031 rw_wunlock(&tidhash_lock);
1032}
1033
1034void
1035tidhash_remove(struct thread *td)
1036{
1037 rw_wlock(&tidhash_lock);
1038 LIST_REMOVE(td, td_hash);
1039 rw_wunlock(&tidhash_lock);
1040}
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