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 "opt_witness.h"
30 #include "opt_kdtrace.h"
31 #include "opt_hwpmc_hooks.h"
33 #include <sys/cdefs.h>
34 __FBSDID("$FreeBSD$");
36 #include <sys/param.h>
37 #include <sys/systm.h>
38 #include <sys/kernel.h>
40 #include <sys/mutex.h>
42 #include <sys/resourcevar.h>
45 #include <sys/sched.h>
46 #include <sys/sleepqueue.h>
47 #include <sys/selinfo.h>
48 #include <sys/turnstile.h>
50 #include <sys/rwlock.h>
52 #include <sys/cpuset.h>
54 #include <sys/pmckern.h>
57 #include <security/audit/audit.h>
60 #include <vm/vm_extern.h>
62 #include <sys/eventhandler.h>
64 SDT_PROVIDER_DECLARE(proc);
65 SDT_PROBE_DEFINE(proc, , , lwp_exit, lwp-exit);
69 * thread related storage.
71 static uma_zone_t thread_zone;
73 TAILQ_HEAD(, thread) zombie_threads = TAILQ_HEAD_INITIALIZER(zombie_threads);
74 static struct mtx zombie_lock;
75 MTX_SYSINIT(zombie_lock, &zombie_lock, "zombie lock", MTX_SPIN);
77 static void thread_zombie(struct thread *);
79 #define TID_BUFFER_SIZE 1024
82 static struct unrhdr *tid_unrhdr;
83 static lwpid_t tid_buffer[TID_BUFFER_SIZE];
84 static int tid_head, tid_tail;
85 static MALLOC_DEFINE(M_TIDHASH, "tidhash", "thread hash");
87 struct tidhashhead *tidhashtbl;
89 struct rwlock tidhash_lock;
96 tid = alloc_unr(tid_unrhdr);
100 if (tid_head == tid_tail) {
101 mtx_unlock(&tid_lock);
104 tid = tid_buffer[tid_head++];
105 tid_head %= TID_BUFFER_SIZE;
106 mtx_unlock(&tid_lock);
111 tid_free(lwpid_t tid)
113 lwpid_t tmp_tid = -1;
116 if ((tid_tail + 1) % TID_BUFFER_SIZE == tid_head) {
117 tmp_tid = tid_buffer[tid_head++];
118 tid_head = (tid_head + 1) % TID_BUFFER_SIZE;
120 tid_buffer[tid_tail++] = tid;
121 tid_tail %= TID_BUFFER_SIZE;
122 mtx_unlock(&tid_lock);
124 free_unr(tid_unrhdr, tmp_tid);
128 * Prepare a thread for use.
131 thread_ctor(void *mem, int size, void *arg, int flags)
135 td = (struct thread *)mem;
136 td->td_state = TDS_INACTIVE;
137 td->td_oncpu = NOCPU;
139 td->td_tid = tid_alloc();
142 * Note that td_critnest begins life as 1 because the thread is not
143 * running and is thereby implicitly waiting to be on the receiving
144 * end of a context switch.
147 td->td_lend_user_pri = PRI_MAX;
148 EVENTHANDLER_INVOKE(thread_ctor, td);
150 audit_thread_alloc(td);
152 umtx_thread_alloc(td);
157 * Reclaim a thread after use.
160 thread_dtor(void *mem, int size, void *arg)
164 td = (struct thread *)mem;
167 /* Verify that this thread is in a safe state to free. */
168 switch (td->td_state) {
174 * We must never unlink a thread that is in one of
175 * these states, because it is currently active.
177 panic("bad state for thread unlinking");
182 panic("bad thread state");
187 audit_thread_free(td);
189 /* Free all OSD associated to this thread. */
192 EVENTHANDLER_INVOKE(thread_dtor, td);
193 tid_free(td->td_tid);
197 * Initialize type-stable parts of a thread (when newly created).
200 thread_init(void *mem, int size, int flags)
204 td = (struct thread *)mem;
206 td->td_sleepqueue = sleepq_alloc();
207 td->td_turnstile = turnstile_alloc();
208 EVENTHANDLER_INVOKE(thread_init, td);
209 td->td_sched = (struct td_sched *)&td[1];
210 umtx_thread_init(td);
216 * Tear down type-stable parts of a thread (just before being discarded).
219 thread_fini(void *mem, int size)
223 td = (struct thread *)mem;
224 EVENTHANDLER_INVOKE(thread_fini, td);
225 turnstile_free(td->td_turnstile);
226 sleepq_free(td->td_sleepqueue);
227 umtx_thread_fini(td);
232 * For a newly created process,
233 * link up all the structures and its initial threads etc.
235 * {arch}/{arch}/machdep.c ia64_init(), init386() etc.
236 * proc_dtor() (should go away)
240 proc_linkup0(struct proc *p, struct thread *td)
242 TAILQ_INIT(&p->p_threads); /* all threads in proc */
247 proc_linkup(struct proc *p, struct thread *td)
250 sigqueue_init(&p->p_sigqueue, p);
251 p->p_ksi = ksiginfo_alloc(1);
252 if (p->p_ksi != NULL) {
253 /* XXX p_ksi may be null if ksiginfo zone is not ready */
254 p->p_ksi->ksi_flags = KSI_EXT | KSI_INS;
256 LIST_INIT(&p->p_mqnotifier);
262 * Initialize global thread allocation resources.
268 mtx_init(&tid_lock, "TID lock", NULL, MTX_DEF);
269 /* leave one number for thread0 */
270 tid_unrhdr = new_unrhdr(PID_MAX + 2, INT_MAX, &tid_lock);
272 thread_zone = uma_zcreate("THREAD", sched_sizeof_thread(),
273 thread_ctor, thread_dtor, thread_init, thread_fini,
275 tidhashtbl = hashinit(maxproc / 2, M_TIDHASH, &tidhash);
276 rw_init(&tidhash_lock, "tidhash");
280 * Place an unused thread on the zombie list.
281 * Use the slpq as that must be unused by now.
284 thread_zombie(struct thread *td)
286 mtx_lock_spin(&zombie_lock);
287 TAILQ_INSERT_HEAD(&zombie_threads, td, td_slpq);
288 mtx_unlock_spin(&zombie_lock);
292 * Release a thread that has exited after cpu_throw().
295 thread_stash(struct thread *td)
297 atomic_subtract_rel_int(&td->td_proc->p_exitthreads, 1);
302 * Reap zombie resources.
307 struct thread *td_first, *td_next;
310 * Don't even bother to lock if none at this instant,
311 * we really don't care about the next instant..
313 if (!TAILQ_EMPTY(&zombie_threads)) {
314 mtx_lock_spin(&zombie_lock);
315 td_first = TAILQ_FIRST(&zombie_threads);
317 TAILQ_INIT(&zombie_threads);
318 mtx_unlock_spin(&zombie_lock);
320 td_next = TAILQ_NEXT(td_first, td_slpq);
321 if (td_first->td_ucred)
322 crfree(td_first->td_ucred);
323 thread_free(td_first);
333 thread_alloc(int pages)
337 thread_reap(); /* check if any zombies to get */
339 td = (struct thread *)uma_zalloc(thread_zone, M_WAITOK);
340 KASSERT(td->td_kstack == 0, ("thread_alloc got thread with kstack"));
341 if (!vm_thread_new(td, pages)) {
342 uma_zfree(thread_zone, td);
345 cpu_thread_alloc(td);
350 thread_alloc_stack(struct thread *td, int pages)
353 KASSERT(td->td_kstack == 0,
354 ("thread_alloc_stack called on a thread with kstack"));
355 if (!vm_thread_new(td, pages))
357 cpu_thread_alloc(td);
362 * Deallocate a thread.
365 thread_free(struct thread *td)
368 lock_profile_thread_exit(td);
370 cpuset_rel(td->td_cpuset);
371 td->td_cpuset = NULL;
373 if (td->td_kstack != 0)
374 vm_thread_dispose(td);
375 uma_zfree(thread_zone, td);
379 * Discard the current thread and exit from its context.
380 * Always called with scheduler locked.
382 * Because we can't free a thread while we're operating under its context,
383 * push the current thread into our CPU's deadthread holder. This means
384 * we needn't worry about someone else grabbing our context before we
390 uint64_t runtime, new_switchtime;
399 PROC_SLOCK_ASSERT(p, MA_OWNED);
400 mtx_assert(&Giant, MA_NOTOWNED);
402 PROC_LOCK_ASSERT(p, MA_OWNED);
403 KASSERT(p != NULL, ("thread exiting without a process"));
404 CTR3(KTR_PROC, "thread_exit: thread %p (pid %ld, %s)", td,
405 (long)p->p_pid, td->td_name);
406 KASSERT(TAILQ_EMPTY(&td->td_sigqueue.sq_list), ("signal pending"));
409 AUDIT_SYSCALL_EXIT(0, td);
411 umtx_thread_exit(td);
413 * drop FPU & debug register state storage, or any other
414 * architecture specific resources that
415 * would not be on a new untouched process.
417 cpu_thread_exit(td); /* XXXSMP */
420 * The last thread is left attached to the process
421 * So that the whole bundle gets recycled. Skip
422 * all this stuff if we never had threads.
423 * EXIT clears all sign of other threads when
424 * it goes to single threading, so the last thread always
425 * takes the short path.
427 if (p->p_flag & P_HADTHREADS) {
428 if (p->p_numthreads > 1) {
430 td2 = FIRST_THREAD_IN_PROC(p);
431 sched_exit_thread(td2, td);
434 * The test below is NOT true if we are the
435 * sole exiting thread. P_STOPPED_SINGLE is unset
436 * in exit1() after it is the only survivor.
438 if (P_SHOULDSTOP(p) == P_STOPPED_SINGLE) {
439 if (p->p_numthreads == p->p_suspcount) {
440 thread_lock(p->p_singlethread);
441 wakeup_swapper = thread_unsuspend_one(
443 thread_unlock(p->p_singlethread);
449 atomic_add_int(&td->td_proc->p_exitthreads, 1);
450 PCPU_SET(deadthread, td);
453 * The last thread is exiting.. but not through exit()
455 panic ("thread_exit: Last thread exiting on its own");
460 * If this thread is part of a process that is being tracked by hwpmc(4),
461 * inform the module of the thread's impending exit.
463 if (PMC_PROC_IS_USING_PMCS(td->td_proc))
464 PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_OUT);
468 /* Do the same timestamp bookkeeping that mi_switch() would do. */
469 new_switchtime = cpu_ticks();
470 runtime = new_switchtime - PCPU_GET(switchtime);
471 td->td_runtime += runtime;
472 td->td_incruntime += runtime;
473 PCPU_SET(switchtime, new_switchtime);
474 PCPU_SET(switchticks, ticks);
475 PCPU_INC(cnt.v_swtch);
477 /* Save our resource usage in our process. */
478 td->td_ru.ru_nvcsw++;
480 rucollect(&p->p_ru, &td->td_ru);
484 td->td_state = TDS_INACTIVE;
486 witness_thread_exit(td);
488 CTR1(KTR_PROC, "thread_exit: cpu_throw() thread %p", td);
490 panic("I'm a teapot!");
495 * Do any thread specific cleanups that may be needed in wait()
496 * called with Giant, proc and schedlock not held.
499 thread_wait(struct proc *p)
503 mtx_assert(&Giant, MA_NOTOWNED);
504 KASSERT((p->p_numthreads == 1), ("Multiple threads in wait1()"));
505 td = FIRST_THREAD_IN_PROC(p);
506 /* Lock the last thread so we spin until it exits cpu_throw(). */
509 /* Wait for any remaining threads to exit cpu_throw(). */
510 while (p->p_exitthreads)
511 sched_relinquish(curthread);
512 lock_profile_thread_exit(td);
513 cpuset_rel(td->td_cpuset);
514 td->td_cpuset = NULL;
515 cpu_thread_clean(td);
516 crfree(td->td_ucred);
517 thread_reap(); /* check for zombie threads etc. */
521 * Link a thread to a process.
522 * set up anything that needs to be initialized for it to
523 * be used by the process.
526 thread_link(struct thread *td, struct proc *p)
530 * XXX This can't be enabled because it's called for proc0 before
531 * its lock has been created.
532 * PROC_LOCK_ASSERT(p, MA_OWNED);
534 td->td_state = TDS_INACTIVE;
536 td->td_flags = TDF_INMEM;
538 LIST_INIT(&td->td_contested);
539 LIST_INIT(&td->td_lprof[0]);
540 LIST_INIT(&td->td_lprof[1]);
541 sigqueue_init(&td->td_sigqueue, p);
542 callout_init(&td->td_slpcallout, CALLOUT_MPSAFE);
543 TAILQ_INSERT_HEAD(&p->p_threads, td, td_plist);
548 * Convert a process with one thread to an unthreaded process.
551 thread_unthread(struct thread *td)
553 struct proc *p = td->td_proc;
555 KASSERT((p->p_numthreads == 1), ("Unthreading with >1 threads"));
556 p->p_flag &= ~P_HADTHREADS;
564 thread_unlink(struct thread *td)
566 struct proc *p = td->td_proc;
568 PROC_LOCK_ASSERT(p, MA_OWNED);
569 TAILQ_REMOVE(&p->p_threads, td, td_plist);
571 /* could clear a few other things here */
572 /* Must NOT clear links to proc! */
576 calc_remaining(struct proc *p, int mode)
580 PROC_LOCK_ASSERT(p, MA_OWNED);
581 PROC_SLOCK_ASSERT(p, MA_OWNED);
582 if (mode == SINGLE_EXIT)
583 remaining = p->p_numthreads;
584 else if (mode == SINGLE_BOUNDARY)
585 remaining = p->p_numthreads - p->p_boundary_count;
586 else if (mode == SINGLE_NO_EXIT)
587 remaining = p->p_numthreads - p->p_suspcount;
589 panic("calc_remaining: wrong mode %d", mode);
594 * Enforce single-threading.
596 * Returns 1 if the caller must abort (another thread is waiting to
597 * exit the process or similar). Process is locked!
598 * Returns 0 when you are successfully the only thread running.
599 * A process has successfully single threaded in the suspend mode when
600 * There are no threads in user mode. Threads in the kernel must be
601 * allowed to continue until they get to the user boundary. They may even
602 * copy out their return values and data before suspending. They may however be
603 * accelerated in reaching the user boundary as we will wake up
604 * any sleeping threads that are interruptable. (PCATCH).
607 thread_single(int mode)
612 int remaining, wakeup_swapper;
616 mtx_assert(&Giant, MA_NOTOWNED);
617 PROC_LOCK_ASSERT(p, MA_OWNED);
618 KASSERT((td != NULL), ("curthread is NULL"));
620 if ((p->p_flag & P_HADTHREADS) == 0)
623 /* Is someone already single threading? */
624 if (p->p_singlethread != NULL && p->p_singlethread != td)
627 if (mode == SINGLE_EXIT) {
628 p->p_flag |= P_SINGLE_EXIT;
629 p->p_flag &= ~P_SINGLE_BOUNDARY;
631 p->p_flag &= ~P_SINGLE_EXIT;
632 if (mode == SINGLE_BOUNDARY)
633 p->p_flag |= P_SINGLE_BOUNDARY;
635 p->p_flag &= ~P_SINGLE_BOUNDARY;
637 p->p_flag |= P_STOPPED_SINGLE;
639 p->p_singlethread = td;
640 remaining = calc_remaining(p, mode);
641 while (remaining != 1) {
642 if (P_SHOULDSTOP(p) != P_STOPPED_SINGLE)
645 FOREACH_THREAD_IN_PROC(p, td2) {
649 td2->td_flags |= TDF_ASTPENDING | TDF_NEEDSUSPCHK;
650 if (TD_IS_INHIBITED(td2)) {
653 if (TD_IS_SUSPENDED(td2))
655 thread_unsuspend_one(td2);
656 if (TD_ON_SLEEPQ(td2) &&
657 (td2->td_flags & TDF_SINTR))
659 sleepq_abort(td2, EINTR);
661 case SINGLE_BOUNDARY:
662 if (TD_IS_SUSPENDED(td2) &&
663 !(td2->td_flags & TDF_BOUNDARY))
665 thread_unsuspend_one(td2);
666 if (TD_ON_SLEEPQ(td2) &&
667 (td2->td_flags & TDF_SINTR))
669 sleepq_abort(td2, ERESTART);
672 if (TD_IS_SUSPENDED(td2) &&
673 !(td2->td_flags & TDF_BOUNDARY))
675 thread_unsuspend_one(td2);
676 if (TD_ON_SLEEPQ(td2) &&
677 (td2->td_flags & TDF_SINTR))
679 sleepq_abort(td2, ERESTART);
686 else if (TD_IS_RUNNING(td2) && td != td2) {
694 remaining = calc_remaining(p, mode);
697 * Maybe we suspended some threads.. was it enough?
704 * Wake us up when everyone else has suspended.
705 * In the mean time we suspend as well.
707 thread_suspend_switch(td);
708 remaining = calc_remaining(p, mode);
710 if (mode == SINGLE_EXIT) {
712 * We have gotten rid of all the other threads and we
713 * are about to either exit or exec. In either case,
714 * we try our utmost to revert to being a non-threaded
717 p->p_singlethread = NULL;
718 p->p_flag &= ~(P_STOPPED_SINGLE | P_SINGLE_EXIT);
726 * Called in from locations that can safely check to see
727 * whether we have to suspend or at least throttle for a
728 * single-thread event (e.g. fork).
730 * Such locations include userret().
731 * If the "return_instead" argument is non zero, the thread must be able to
732 * accept 0 (caller may continue), or 1 (caller must abort) as a result.
734 * The 'return_instead' argument tells the function if it may do a
735 * thread_exit() or suspend, or whether the caller must abort and back
738 * If the thread that set the single_threading request has set the
739 * P_SINGLE_EXIT bit in the process flags then this call will never return
740 * if 'return_instead' is false, but will exit.
742 * P_SINGLE_EXIT | return_instead == 0| return_instead != 0
743 *---------------+--------------------+---------------------
744 * 0 | returns 0 | returns 0 or 1
745 * | when ST ends | immediatly
746 *---------------+--------------------+---------------------
747 * 1 | thread exits | returns 1
749 * 0 = thread_exit() or suspension ok,
750 * other = return error instead of stopping the thread.
752 * While a full suspension is under effect, even a single threading
753 * thread would be suspended if it made this call (but it shouldn't).
754 * This call should only be made from places where
755 * thread_exit() would be safe as that may be the outcome unless
756 * return_instead is set.
759 thread_suspend_check(int return_instead)
767 mtx_assert(&Giant, MA_NOTOWNED);
768 PROC_LOCK_ASSERT(p, MA_OWNED);
769 while (P_SHOULDSTOP(p) ||
770 ((p->p_flag & P_TRACED) && (td->td_dbgflags & TDB_SUSPEND))) {
771 if (P_SHOULDSTOP(p) == P_STOPPED_SINGLE) {
772 KASSERT(p->p_singlethread != NULL,
773 ("singlethread not set"));
775 * The only suspension in action is a
776 * single-threading. Single threader need not stop.
777 * XXX Should be safe to access unlocked
778 * as it can only be set to be true by us.
780 if (p->p_singlethread == td)
781 return (0); /* Exempt from stopping. */
783 if ((p->p_flag & P_SINGLE_EXIT) && return_instead)
786 /* Should we goto user boundary if we didn't come from there? */
787 if (P_SHOULDSTOP(p) == P_STOPPED_SINGLE &&
788 (p->p_flag & P_SINGLE_BOUNDARY) && return_instead)
792 * If the process is waiting for us to exit,
793 * this thread should just suicide.
794 * Assumes that P_SINGLE_EXIT implies P_STOPPED_SINGLE.
796 if ((p->p_flag & P_SINGLE_EXIT) && (p->p_singlethread != td)) {
808 if (P_SHOULDSTOP(p) == P_STOPPED_SINGLE) {
809 if (p->p_numthreads == p->p_suspcount + 1) {
810 thread_lock(p->p_singlethread);
812 thread_unsuspend_one(p->p_singlethread);
813 thread_unlock(p->p_singlethread);
821 * When a thread suspends, it just
822 * gets taken off all queues.
824 thread_suspend_one(td);
825 if (return_instead == 0) {
826 p->p_boundary_count++;
827 td->td_flags |= TDF_BOUNDARY;
830 mi_switch(SW_INVOL | SWT_SUSPEND, NULL);
831 if (return_instead == 0)
832 td->td_flags &= ~TDF_BOUNDARY;
835 if (return_instead == 0) {
837 p->p_boundary_count--;
845 thread_suspend_switch(struct thread *td)
850 KASSERT(!TD_IS_SUSPENDED(td), ("already suspended"));
851 PROC_LOCK_ASSERT(p, MA_OWNED);
852 PROC_SLOCK_ASSERT(p, MA_OWNED);
854 * We implement thread_suspend_one in stages here to avoid
855 * dropping the proc lock while the thread lock is owned.
861 td->td_flags &= ~TDF_NEEDSUSPCHK;
862 TD_SET_SUSPENDED(td);
866 mi_switch(SW_VOL | SWT_SUSPEND, NULL);
874 thread_suspend_one(struct thread *td)
876 struct proc *p = td->td_proc;
878 PROC_SLOCK_ASSERT(p, MA_OWNED);
879 THREAD_LOCK_ASSERT(td, MA_OWNED);
880 KASSERT(!TD_IS_SUSPENDED(td), ("already suspended"));
882 td->td_flags &= ~TDF_NEEDSUSPCHK;
883 TD_SET_SUSPENDED(td);
888 thread_unsuspend_one(struct thread *td)
890 struct proc *p = td->td_proc;
892 PROC_SLOCK_ASSERT(p, MA_OWNED);
893 THREAD_LOCK_ASSERT(td, MA_OWNED);
894 KASSERT(TD_IS_SUSPENDED(td), ("Thread not suspended"));
895 TD_CLR_SUSPENDED(td);
897 return (setrunnable(td));
901 * Allow all threads blocked by single threading to continue running.
904 thread_unsuspend(struct proc *p)
909 PROC_LOCK_ASSERT(p, MA_OWNED);
910 PROC_SLOCK_ASSERT(p, MA_OWNED);
912 if (!P_SHOULDSTOP(p)) {
913 FOREACH_THREAD_IN_PROC(p, td) {
915 if (TD_IS_SUSPENDED(td)) {
916 wakeup_swapper |= thread_unsuspend_one(td);
920 } else if ((P_SHOULDSTOP(p) == P_STOPPED_SINGLE) &&
921 (p->p_numthreads == p->p_suspcount)) {
923 * Stopping everything also did the job for the single
924 * threading request. Now we've downgraded to single-threaded,
927 thread_lock(p->p_singlethread);
928 wakeup_swapper = thread_unsuspend_one(p->p_singlethread);
929 thread_unlock(p->p_singlethread);
936 * End the single threading mode..
939 thread_single_end(void)
947 PROC_LOCK_ASSERT(p, MA_OWNED);
948 p->p_flag &= ~(P_STOPPED_SINGLE | P_SINGLE_EXIT | P_SINGLE_BOUNDARY);
950 p->p_singlethread = NULL;
953 * If there are other threads they may now run,
954 * unless of course there is a blanket 'stop order'
955 * on the process. The single threader must be allowed
956 * to continue however as this is a bad place to stop.
958 if ((p->p_numthreads != 1) && (!P_SHOULDSTOP(p))) {
959 FOREACH_THREAD_IN_PROC(p, td) {
961 if (TD_IS_SUSPENDED(td)) {
962 wakeup_swapper |= thread_unsuspend_one(td);
973 thread_find(struct proc *p, lwpid_t tid)
977 PROC_LOCK_ASSERT(p, MA_OWNED);
978 FOREACH_THREAD_IN_PROC(p, td) {
979 if (td->td_tid == tid)
985 /* Locate a thread by number; return with proc lock held. */
987 tdfind(lwpid_t tid, pid_t pid)
989 #define RUN_THRESH 16
993 rw_rlock(&tidhash_lock);
994 LIST_FOREACH(td, TIDHASH(tid), td_hash) {
995 if (td->td_tid == tid) {
996 if (pid != -1 && td->td_proc->p_pid != pid) {
1000 PROC_LOCK(td->td_proc);
1001 if (td->td_proc->p_state == PRS_NEW) {
1002 PROC_UNLOCK(td->td_proc);
1006 if (run > RUN_THRESH) {
1007 if (rw_try_upgrade(&tidhash_lock)) {
1008 LIST_REMOVE(td, td_hash);
1009 LIST_INSERT_HEAD(TIDHASH(td->td_tid),
1011 rw_wunlock(&tidhash_lock);
1019 rw_runlock(&tidhash_lock);
1024 tidhash_add(struct thread *td)
1026 rw_wlock(&tidhash_lock);
1027 LIST_INSERT_HEAD(TIDHASH(td->td_tid), td, td_hash);
1028 rw_wunlock(&tidhash_lock);
1032 tidhash_remove(struct thread *td)
1034 rw_wlock(&tidhash_lock);
1035 LIST_REMOVE(td, td_hash);
1036 rw_wunlock(&tidhash_lock);