2 * Copyright (C) 2001 Julian Elischer <julian@freebsd.org>.
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(s), this list of conditions and the following disclaimer as
10 * the first lines of this file unmodified other than the possible
11 * addition of one or more copyright notices.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice(s), this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY
17 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
18 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
19 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE LIABLE FOR ANY
20 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
21 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
22 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
23 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
32 #include <sys/param.h>
33 #include <sys/systm.h>
34 #include <sys/kernel.h>
36 #include <sys/mutex.h>
38 #include <sys/resourcevar.h>
40 #include <sys/sysctl.h>
41 #include <sys/sched.h>
42 #include <sys/sleepqueue.h>
43 #include <sys/turnstile.h>
47 #include <security/audit/audit.h>
50 #include <vm/vm_extern.h>
54 * thread related storage.
56 static uma_zone_t thread_zone;
58 SYSCTL_NODE(_kern, OID_AUTO, threads, CTLFLAG_RW, 0, "thread allocation");
60 int max_threads_per_proc = 1500;
61 SYSCTL_INT(_kern_threads, OID_AUTO, max_threads_per_proc, CTLFLAG_RW,
62 &max_threads_per_proc, 0, "Limit on threads per proc");
65 SYSCTL_INT(_kern_threads, OID_AUTO, max_threads_hits, CTLFLAG_RD,
66 &max_threads_hits, 0, "");
72 TAILQ_HEAD(, thread) zombie_threads = TAILQ_HEAD_INITIALIZER(zombie_threads);
73 struct mtx kse_zombie_lock;
74 MTX_SYSINIT(kse_zombie_lock, &kse_zombie_lock, "kse zombie lock", MTX_SPIN);
78 sysctl_kse_virtual_cpu(SYSCTL_HANDLER_ARGS)
87 new_val = virtual_cpu;
88 error = sysctl_handle_int(oidp, &new_val, 0, req);
89 if (error != 0 || req->newptr == NULL)
93 virtual_cpu = new_val;
98 SYSCTL_PROC(_kern_threads, OID_AUTO, virtual_cpu, CTLTYPE_INT|CTLFLAG_RW,
99 0, sizeof(virtual_cpu), sysctl_kse_virtual_cpu, "I",
100 "debug virtual cpus");
104 static struct unrhdr *tid_unrhdr;
107 * Prepare a thread for use.
110 thread_ctor(void *mem, int size, void *arg, int flags)
114 td = (struct thread *)mem;
115 td->td_state = TDS_INACTIVE;
116 td->td_oncpu = NOCPU;
118 td->td_tid = alloc_unr(tid_unrhdr);
121 * Note that td_critnest begins life as 1 because the thread is not
122 * running and is thereby implicitly waiting to be on the receiving
123 * end of a context switch. A context switch must occur inside a
124 * critical section, and in fact, includes hand-off of the sched_lock.
125 * After a context switch to a newly created thread, it will release
126 * sched_lock for the first time, and its td_critnest will hit 0 for
127 * the first time. This happens on the far end of a context switch,
128 * and when it context switches away from itself, it will in fact go
129 * back into a critical section, and hand off the sched lock to the
135 audit_thread_alloc(td);
137 umtx_thread_alloc(td);
142 * Reclaim a thread after use.
145 thread_dtor(void *mem, int size, void *arg)
149 td = (struct thread *)mem;
152 /* Verify that this thread is in a safe state to free. */
153 switch (td->td_state) {
159 * We must never unlink a thread that is in one of
160 * these states, because it is currently active.
162 panic("bad state for thread unlinking");
167 panic("bad thread state");
172 audit_thread_free(td);
174 free_unr(tid_unrhdr, td->td_tid);
179 * Initialize type-stable parts of a thread (when newly created).
182 thread_init(void *mem, int size, int flags)
186 td = (struct thread *)mem;
188 vm_thread_new(td, 0);
189 cpu_thread_setup(td);
190 td->td_sleepqueue = sleepq_alloc();
191 td->td_turnstile = turnstile_alloc();
192 td->td_sched = (struct td_sched *)&td[1];
194 umtx_thread_init(td);
199 * Tear down type-stable parts of a thread (just before being discarded).
202 thread_fini(void *mem, int size)
206 td = (struct thread *)mem;
207 turnstile_free(td->td_turnstile);
208 sleepq_free(td->td_sleepqueue);
209 umtx_thread_fini(td);
210 vm_thread_dispose(td);
214 * For a newly created process,
215 * link up all the structures and its initial threads etc.
217 * {arch}/{arch}/machdep.c ia64_init(), init386() etc.
218 * proc_dtor() (should go away)
222 proc_linkup(struct proc *p, struct thread *td)
224 TAILQ_INIT(&p->p_threads); /* all threads in proc */
225 TAILQ_INIT(&p->p_upcalls); /* upcall list */
226 sigqueue_init(&p->p_sigqueue, p);
227 p->p_ksi = ksiginfo_alloc(1);
228 if (p->p_ksi != NULL) {
229 /* XXX p_ksi may be null if ksiginfo zone is not ready */
230 p->p_ksi->ksi_flags = KSI_EXT | KSI_INS;
232 LIST_INIT(&p->p_mqnotifier);
238 * Initialize global thread allocation resources.
244 mtx_init(&tid_lock, "TID lock", NULL, MTX_DEF);
245 tid_unrhdr = new_unrhdr(PID_MAX + 1, INT_MAX, &tid_lock);
247 thread_zone = uma_zcreate("THREAD", sched_sizeof_thread(),
248 thread_ctor, thread_dtor, thread_init, thread_fini,
251 kseinit(); /* set up kse specific stuff e.g. upcall zone*/
256 * Stash an embarasingly extra thread into the zombie thread queue.
257 * Use the slpq as that must be unused by now.
260 thread_stash(struct thread *td)
262 mtx_lock_spin(&kse_zombie_lock);
263 TAILQ_INSERT_HEAD(&zombie_threads, td, td_slpq);
264 mtx_unlock_spin(&kse_zombie_lock);
268 * Reap zombie kse resource.
273 struct thread *td_first, *td_next;
276 * Don't even bother to lock if none at this instant,
277 * we really don't care about the next instant..
279 if (!TAILQ_EMPTY(&zombie_threads)) {
280 mtx_lock_spin(&kse_zombie_lock);
281 td_first = TAILQ_FIRST(&zombie_threads);
283 TAILQ_INIT(&zombie_threads);
284 mtx_unlock_spin(&kse_zombie_lock);
286 td_next = TAILQ_NEXT(td_first, td_slpq);
287 if (td_first->td_ucred)
288 crfree(td_first->td_ucred);
289 thread_free(td_first);
302 thread_reap(); /* check if any zombies to get */
303 return (uma_zalloc(thread_zone, M_WAITOK));
308 * Deallocate a thread.
311 thread_free(struct thread *td)
314 cpu_thread_clean(td);
315 uma_zfree(thread_zone, td);
319 * Discard the current thread and exit from its context.
320 * Always called with scheduler locked.
322 * Because we can't free a thread while we're operating under its context,
323 * push the current thread into our CPU's deadthread holder. This means
324 * we needn't worry about someone else grabbing our context before we
325 * do a cpu_throw(). This may not be needed now as we are under schedlock.
326 * Maybe we can just do a thread_stash() as thr_exit1 does.
329 * libthr expects its thread exit to return for the last
330 * thread, meaning that the program is back to non-threaded
331 * mode I guess. Because we do this (cpu_throw) unconditionally
332 * here, they have their own version of it. (thr_exit1())
333 * that doesn't do it all if this was the last thread.
334 * It is also called from thread_suspend_check().
335 * Of course in the end, they end up coming here through exit1
336 * anyhow.. After fixing 'thr' to play by the rules we should be able
337 * to merge these two functions together.
344 * thread_user_enter()
347 * thread_suspend_check()
352 uint64_t new_switchtime;
359 mtx_assert(&sched_lock, MA_OWNED);
360 mtx_assert(&Giant, MA_NOTOWNED);
361 PROC_LOCK_ASSERT(p, MA_OWNED);
362 KASSERT(p != NULL, ("thread exiting without a process"));
363 CTR3(KTR_PROC, "thread_exit: thread %p (pid %ld, %s)", td,
364 (long)p->p_pid, p->p_comm);
365 KASSERT(TAILQ_EMPTY(&td->td_sigqueue.sq_list), ("signal pending"));
368 AUDIT_SYSCALL_EXIT(0, td);
372 if (td->td_standin != NULL) {
374 * Note that we don't need to free the cred here as it
375 * is done in thread_reap().
377 thread_stash(td->td_standin);
378 td->td_standin = NULL;
382 umtx_thread_exit(td);
385 * drop FPU & debug register state storage, or any other
386 * architecture specific resources that
387 * would not be on a new untouched process.
389 cpu_thread_exit(td); /* XXXSMP */
393 * The thread is exiting. scheduler can release its stuff
394 * and collect stats etc.
395 * XXX this is not very right, since PROC_UNLOCK may still
396 * need scheduler stuff.
398 sched_thread_exit(td);
401 /* Do the same timestamp bookkeeping that mi_switch() would do. */
402 new_switchtime = cpu_ticks();
403 p->p_rux.rux_runtime += (new_switchtime - PCPU_GET(switchtime));
404 p->p_rux.rux_uticks += td->td_uticks;
405 p->p_rux.rux_sticks += td->td_sticks;
406 p->p_rux.rux_iticks += td->td_iticks;
407 PCPU_SET(switchtime, new_switchtime);
408 PCPU_SET(switchticks, ticks);
411 /* Add our usage into the usage of all our children. */
412 if (p->p_numthreads == 1)
413 ruadd(p->p_ru, &p->p_rux, &p->p_stats->p_cru, &p->p_crux);
416 * The last thread is left attached to the process
417 * So that the whole bundle gets recycled. Skip
418 * all this stuff if we never had threads.
419 * EXIT clears all sign of other threads when
420 * it goes to single threading, so the last thread always
421 * takes the short path.
423 if (p->p_flag & P_HADTHREADS) {
424 if (p->p_numthreads > 1) {
427 sched_exit_thread(FIRST_THREAD_IN_PROC(p), td);
430 * The test below is NOT true if we are the
431 * sole exiting thread. P_STOPPED_SNGL is unset
432 * in exit1() after it is the only survivor.
434 if (P_SHOULDSTOP(p) == P_STOPPED_SINGLE) {
435 if (p->p_numthreads == p->p_suspcount) {
436 thread_unsuspend_one(p->p_singlethread);
442 * Because each upcall structure has an owner thread,
443 * owner thread exits only when process is in exiting
444 * state, so upcall to userland is no longer needed,
445 * deleting upcall structure is safe here.
446 * So when all threads in a group is exited, all upcalls
447 * in the group should be automatically freed.
448 * XXXKSE This is a KSE thing and should be exported
455 PCPU_SET(deadthread, td);
458 * The last thread is exiting.. but not through exit()
460 * Theoretically this can't happen
461 * exit1() - clears threading flags before coming here
462 * kse_exit() - treats last thread specially
463 * thr_exit() - treats last thread specially
465 * thread_user_enter() - only if more exist
466 * thread_userret() - only if more exist
468 * thread_suspend_check() - only if more exist
470 panic ("thread_exit: Last thread exiting on its own");
474 * non threaded process comes here.
475 * This includes an EX threaded process that is coming
476 * here via exit1(). (exit1 dethreads the proc first).
480 td->td_state = TDS_INACTIVE;
481 CTR1(KTR_PROC, "thread_exit: cpu_throw() thread %p", td);
482 cpu_throw(td, choosethread());
483 panic("I'm a teapot!");
488 * Do any thread specific cleanups that may be needed in wait()
489 * called with Giant, proc and schedlock not held.
492 thread_wait(struct proc *p)
496 mtx_assert(&Giant, MA_NOTOWNED);
497 KASSERT((p->p_numthreads == 1), ("Multiple threads in wait1()"));
498 FOREACH_THREAD_IN_PROC(p, td) {
500 if (td->td_standin != NULL) {
501 if (td->td_standin->td_ucred != NULL) {
502 crfree(td->td_standin->td_ucred);
503 td->td_standin->td_ucred = NULL;
505 thread_free(td->td_standin);
506 td->td_standin = NULL;
509 cpu_thread_clean(td);
510 crfree(td->td_ucred);
512 thread_reap(); /* check for zombie threads etc. */
516 * Link a thread to a process.
517 * set up anything that needs to be initialized for it to
518 * be used by the process.
520 * Note that we do not link to the proc's ucred here.
521 * The thread is linked as if running but no KSE assigned.
524 * thread_schedule_upcall()
528 thread_link(struct thread *td, struct proc *p)
531 td->td_state = TDS_INACTIVE;
535 LIST_INIT(&td->td_contested);
536 sigqueue_init(&td->td_sigqueue, p);
537 callout_init(&td->td_slpcallout, CALLOUT_MPSAFE);
538 TAILQ_INSERT_HEAD(&p->p_threads, td, td_plist);
543 * Convert a process with one thread to an unthreaded process.
545 * thread_single(exit) (called from execve and exit)
546 * kse_exit() XXX may need cleaning up wrt KSE stuff
549 thread_unthread(struct thread *td)
551 struct proc *p = td->td_proc;
553 KASSERT((p->p_numthreads == 1), ("Unthreading with >1 threads"));
556 p->p_flag &= ~(P_SA|P_HADTHREADS);
557 td->td_mailbox = NULL;
558 td->td_pflags &= ~(TDP_SA | TDP_CAN_UNBIND);
559 if (td->td_standin != NULL) {
560 thread_stash(td->td_standin);
561 td->td_standin = NULL;
563 sched_set_concurrency(p, 1);
565 p->p_flag &= ~P_HADTHREADS;
574 thread_unlink(struct thread *td)
576 struct proc *p = td->td_proc;
578 mtx_assert(&sched_lock, MA_OWNED);
579 TAILQ_REMOVE(&p->p_threads, td, td_plist);
581 /* could clear a few other things here */
582 /* Must NOT clear links to proc! */
586 * Enforce single-threading.
588 * Returns 1 if the caller must abort (another thread is waiting to
589 * exit the process or similar). Process is locked!
590 * Returns 0 when you are successfully the only thread running.
591 * A process has successfully single threaded in the suspend mode when
592 * There are no threads in user mode. Threads in the kernel must be
593 * allowed to continue until they get to the user boundary. They may even
594 * copy out their return values and data before suspending. They may however be
595 * accelerated in reaching the user boundary as we will wake up
596 * any sleeping threads that are interruptable. (PCATCH).
599 thread_single(int mode)
608 mtx_assert(&Giant, MA_NOTOWNED);
609 PROC_LOCK_ASSERT(p, MA_OWNED);
610 KASSERT((td != NULL), ("curthread is NULL"));
612 if ((p->p_flag & P_HADTHREADS) == 0)
615 /* Is someone already single threading? */
616 if (p->p_singlethread != NULL && p->p_singlethread != td)
619 if (mode == SINGLE_EXIT) {
620 p->p_flag |= P_SINGLE_EXIT;
621 p->p_flag &= ~P_SINGLE_BOUNDARY;
623 p->p_flag &= ~P_SINGLE_EXIT;
624 if (mode == SINGLE_BOUNDARY)
625 p->p_flag |= P_SINGLE_BOUNDARY;
627 p->p_flag &= ~P_SINGLE_BOUNDARY;
629 p->p_flag |= P_STOPPED_SINGLE;
630 mtx_lock_spin(&sched_lock);
631 p->p_singlethread = td;
632 if (mode == SINGLE_EXIT)
633 remaining = p->p_numthreads;
634 else if (mode == SINGLE_BOUNDARY)
635 remaining = p->p_numthreads - p->p_boundary_count;
637 remaining = p->p_numthreads - p->p_suspcount;
638 while (remaining != 1) {
639 if (P_SHOULDSTOP(p) != P_STOPPED_SINGLE)
641 FOREACH_THREAD_IN_PROC(p, td2) {
644 td2->td_flags |= TDF_ASTPENDING;
645 if (TD_IS_INHIBITED(td2)) {
648 if (td->td_flags & TDF_DBSUSPEND)
649 td->td_flags &= ~TDF_DBSUSPEND;
650 if (TD_IS_SUSPENDED(td2))
651 thread_unsuspend_one(td2);
652 if (TD_ON_SLEEPQ(td2) &&
653 (td2->td_flags & TDF_SINTR))
654 sleepq_abort(td2, EINTR);
656 case SINGLE_BOUNDARY:
657 if (TD_IS_SUSPENDED(td2) &&
658 !(td2->td_flags & TDF_BOUNDARY))
659 thread_unsuspend_one(td2);
660 if (TD_ON_SLEEPQ(td2) &&
661 (td2->td_flags & TDF_SINTR))
662 sleepq_abort(td2, ERESTART);
665 if (TD_IS_SUSPENDED(td2))
668 * maybe other inhibited states too?
670 if ((td2->td_flags & TDF_SINTR) &&
671 (td2->td_inhibitors &
672 (TDI_SLEEPING | TDI_SWAPPED)))
673 thread_suspend_one(td2);
678 else if (TD_IS_RUNNING(td2) && td != td2) {
683 if (mode == SINGLE_EXIT)
684 remaining = p->p_numthreads;
685 else if (mode == SINGLE_BOUNDARY)
686 remaining = p->p_numthreads - p->p_boundary_count;
688 remaining = p->p_numthreads - p->p_suspcount;
691 * Maybe we suspended some threads.. was it enough?
698 * Wake us up when everyone else has suspended.
699 * In the mean time we suspend as well.
702 thread_suspend_one(td);
704 mi_switch(SW_VOL, NULL);
705 mtx_unlock_spin(&sched_lock);
707 mtx_lock_spin(&sched_lock);
708 if (mode == SINGLE_EXIT)
709 remaining = p->p_numthreads;
710 else if (mode == SINGLE_BOUNDARY)
711 remaining = p->p_numthreads - p->p_boundary_count;
713 remaining = p->p_numthreads - p->p_suspcount;
715 if (mode == SINGLE_EXIT) {
717 * We have gotten rid of all the other threads and we
718 * are about to either exit or exec. In either case,
719 * we try our utmost to revert to being a non-threaded
722 p->p_singlethread = NULL;
723 p->p_flag &= ~(P_STOPPED_SINGLE | P_SINGLE_EXIT);
726 mtx_unlock_spin(&sched_lock);
731 * Called in from locations that can safely check to see
732 * whether we have to suspend or at least throttle for a
733 * single-thread event (e.g. fork).
735 * Such locations include userret().
736 * If the "return_instead" argument is non zero, the thread must be able to
737 * accept 0 (caller may continue), or 1 (caller must abort) as a result.
739 * The 'return_instead' argument tells the function if it may do a
740 * thread_exit() or suspend, or whether the caller must abort and back
743 * If the thread that set the single_threading request has set the
744 * P_SINGLE_EXIT bit in the process flags then this call will never return
745 * if 'return_instead' is false, but will exit.
747 * P_SINGLE_EXIT | return_instead == 0| return_instead != 0
748 *---------------+--------------------+---------------------
749 * 0 | returns 0 | returns 0 or 1
750 * | when ST ends | immediatly
751 *---------------+--------------------+---------------------
752 * 1 | thread exits | returns 1
754 * 0 = thread_exit() or suspension ok,
755 * other = return error instead of stopping the thread.
757 * While a full suspension is under effect, even a single threading
758 * thread would be suspended if it made this call (but it shouldn't).
759 * This call should only be made from places where
760 * thread_exit() would be safe as that may be the outcome unless
761 * return_instead is set.
764 thread_suspend_check(int return_instead)
771 mtx_assert(&Giant, MA_NOTOWNED);
772 PROC_LOCK_ASSERT(p, MA_OWNED);
773 while (P_SHOULDSTOP(p) ||
774 ((p->p_flag & P_TRACED) && (td->td_flags & TDF_DBSUSPEND))) {
775 if (P_SHOULDSTOP(p) == P_STOPPED_SINGLE) {
776 KASSERT(p->p_singlethread != NULL,
777 ("singlethread not set"));
779 * The only suspension in action is a
780 * single-threading. Single threader need not stop.
781 * XXX Should be safe to access unlocked
782 * as it can only be set to be true by us.
784 if (p->p_singlethread == td)
785 return (0); /* Exempt from stopping. */
787 if ((p->p_flag & P_SINGLE_EXIT) && return_instead)
790 /* Should we goto user boundary if we didn't come from there? */
791 if (P_SHOULDSTOP(p) == P_STOPPED_SINGLE &&
792 (p->p_flag & P_SINGLE_BOUNDARY) && return_instead)
795 /* If thread will exit, flush its pending signals */
796 if ((p->p_flag & P_SINGLE_EXIT) && (p->p_singlethread != td))
797 sigqueue_flush(&td->td_sigqueue);
799 mtx_lock_spin(&sched_lock);
802 * If the process is waiting for us to exit,
803 * this thread should just suicide.
804 * Assumes that P_SINGLE_EXIT implies P_STOPPED_SINGLE.
806 if ((p->p_flag & P_SINGLE_EXIT) && (p->p_singlethread != td))
810 * When a thread suspends, it just
811 * gets taken off all queues.
813 thread_suspend_one(td);
814 if (return_instead == 0) {
815 p->p_boundary_count++;
816 td->td_flags |= TDF_BOUNDARY;
818 if (P_SHOULDSTOP(p) == P_STOPPED_SINGLE) {
819 if (p->p_numthreads == p->p_suspcount)
820 thread_unsuspend_one(p->p_singlethread);
823 mi_switch(SW_INVOL, NULL);
824 if (return_instead == 0) {
825 p->p_boundary_count--;
826 td->td_flags &= ~TDF_BOUNDARY;
828 mtx_unlock_spin(&sched_lock);
835 thread_suspend_one(struct thread *td)
837 struct proc *p = td->td_proc;
839 mtx_assert(&sched_lock, MA_OWNED);
840 PROC_LOCK_ASSERT(p, MA_OWNED);
841 KASSERT(!TD_IS_SUSPENDED(td), ("already suspended"));
843 TD_SET_SUSPENDED(td);
847 thread_unsuspend_one(struct thread *td)
849 struct proc *p = td->td_proc;
851 mtx_assert(&sched_lock, MA_OWNED);
852 PROC_LOCK_ASSERT(p, MA_OWNED);
853 KASSERT(TD_IS_SUSPENDED(td), ("Thread not suspended"));
854 TD_CLR_SUSPENDED(td);
860 * Allow all threads blocked by single threading to continue running.
863 thread_unsuspend(struct proc *p)
867 mtx_assert(&sched_lock, MA_OWNED);
868 PROC_LOCK_ASSERT(p, MA_OWNED);
869 if (!P_SHOULDSTOP(p)) {
870 FOREACH_THREAD_IN_PROC(p, td) {
871 if (TD_IS_SUSPENDED(td)) {
872 thread_unsuspend_one(td);
875 } else if ((P_SHOULDSTOP(p) == P_STOPPED_SINGLE) &&
876 (p->p_numthreads == p->p_suspcount)) {
878 * Stopping everything also did the job for the single
879 * threading request. Now we've downgraded to single-threaded,
882 thread_unsuspend_one(p->p_singlethread);
887 * End the single threading mode..
890 thread_single_end(void)
897 PROC_LOCK_ASSERT(p, MA_OWNED);
898 p->p_flag &= ~(P_STOPPED_SINGLE | P_SINGLE_EXIT | P_SINGLE_BOUNDARY);
899 mtx_lock_spin(&sched_lock);
900 p->p_singlethread = NULL;
902 * If there are other threads they mey now run,
903 * unless of course there is a blanket 'stop order'
904 * on the process. The single threader must be allowed
905 * to continue however as this is a bad place to stop.
907 if ((p->p_numthreads != 1) && (!P_SHOULDSTOP(p))) {
908 FOREACH_THREAD_IN_PROC(p, td) {
909 if (TD_IS_SUSPENDED(td)) {
910 thread_unsuspend_one(td);
914 mtx_unlock_spin(&sched_lock);
918 thread_find(struct proc *p, lwpid_t tid)
922 PROC_LOCK_ASSERT(p, MA_OWNED);
923 mtx_lock_spin(&sched_lock);
924 FOREACH_THREAD_IN_PROC(p, td) {
925 if (td->td_tid == tid)
928 mtx_unlock_spin(&sched_lock);