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>
39 #include <sys/sysctl.h>
40 #include <sys/sched.h>
41 #include <sys/sleepqueue.h>
42 #include <sys/turnstile.h>
47 #include <vm/vm_extern.h>
51 * KSEGRP related storage.
53 static uma_zone_t ksegrp_zone;
54 static uma_zone_t thread_zone;
57 SYSCTL_NODE(_kern, OID_AUTO, threads, CTLFLAG_RW, 0, "thread allocation");
58 static int thread_debug = 0;
59 SYSCTL_INT(_kern_threads, OID_AUTO, debug, CTLFLAG_RW,
60 &thread_debug, 0, "thread debug");
62 int max_threads_per_proc = 1500;
63 SYSCTL_INT(_kern_threads, OID_AUTO, max_threads_per_proc, CTLFLAG_RW,
64 &max_threads_per_proc, 0, "Limit on threads per proc");
66 int max_groups_per_proc = 1500;
67 SYSCTL_INT(_kern_threads, OID_AUTO, max_groups_per_proc, CTLFLAG_RW,
68 &max_groups_per_proc, 0, "Limit on thread groups per proc");
71 SYSCTL_INT(_kern_threads, OID_AUTO, max_threads_hits, CTLFLAG_RD,
72 &max_threads_hits, 0, "");
76 TAILQ_HEAD(, thread) zombie_threads = TAILQ_HEAD_INITIALIZER(zombie_threads);
77 TAILQ_HEAD(, ksegrp) zombie_ksegrps = TAILQ_HEAD_INITIALIZER(zombie_ksegrps);
78 struct mtx kse_zombie_lock;
79 MTX_SYSINIT(kse_zombie_lock, &kse_zombie_lock, "kse zombie lock", MTX_SPIN);
82 sysctl_kse_virtual_cpu(SYSCTL_HANDLER_ARGS)
91 new_val = virtual_cpu;
92 error = sysctl_handle_int(oidp, &new_val, 0, req);
93 if (error != 0 || req->newptr == NULL)
97 virtual_cpu = new_val;
102 SYSCTL_PROC(_kern_threads, OID_AUTO, virtual_cpu, CTLTYPE_INT|CTLFLAG_RW,
103 0, sizeof(virtual_cpu), sysctl_kse_virtual_cpu, "I",
104 "debug virtual cpus");
107 static struct unrhdr *tid_unrhdr;
110 * Prepare a thread for use.
113 thread_ctor(void *mem, int size, void *arg, int flags)
117 td = (struct thread *)mem;
118 td->td_state = TDS_INACTIVE;
119 td->td_oncpu = NOCPU;
121 td->td_tid = alloc_unr(tid_unrhdr);
124 * Note that td_critnest begins life as 1 because the thread is not
125 * running and is thereby implicitly waiting to be on the receiving
126 * end of a context switch. A context switch must occur inside a
127 * critical section, and in fact, includes hand-off of the sched_lock.
128 * After a context switch to a newly created thread, it will release
129 * sched_lock for the first time, and its td_critnest will hit 0 for
130 * the first time. This happens on the far end of a context switch,
131 * and when it context switches away from itself, it will in fact go
132 * back into a critical section, and hand off the sched lock to the
140 * Reclaim a thread after use.
143 thread_dtor(void *mem, int size, void *arg)
147 td = (struct thread *)mem;
150 /* Verify that this thread is in a safe state to free. */
151 switch (td->td_state) {
157 * We must never unlink a thread that is in one of
158 * these states, because it is currently active.
160 panic("bad state for thread unlinking");
165 panic("bad thread state");
170 free_unr(tid_unrhdr, td->td_tid);
175 * Initialize type-stable parts of a thread (when newly created).
178 thread_init(void *mem, int size, int flags)
182 td = (struct thread *)mem;
184 vm_thread_new(td, 0);
185 cpu_thread_setup(td);
186 td->td_sleepqueue = sleepq_alloc();
187 td->td_turnstile = turnstile_alloc();
188 td->td_umtxq = umtxq_alloc();
189 td->td_sched = (struct td_sched *)&td[1];
195 * Tear down type-stable parts of a thread (just before being discarded).
198 thread_fini(void *mem, int size)
202 td = (struct thread *)mem;
203 turnstile_free(td->td_turnstile);
204 sleepq_free(td->td_sleepqueue);
205 umtxq_free(td->td_umtxq);
206 vm_thread_dispose(td);
210 * Initialize type-stable parts of a ksegrp (when newly created).
213 ksegrp_ctor(void *mem, int size, void *arg, int flags)
217 kg = (struct ksegrp *)mem;
219 kg->kg_sched = (struct kg_sched *)&kg[1];
224 ksegrp_link(struct ksegrp *kg, struct proc *p)
227 TAILQ_INIT(&kg->kg_threads);
228 TAILQ_INIT(&kg->kg_runq); /* links with td_runq */
229 TAILQ_INIT(&kg->kg_upcalls); /* all upcall structure in ksegrp */
232 * the following counters are in the -zero- section
233 * and may not need clearing
235 kg->kg_numthreads = 0;
236 kg->kg_numupcalls = 0;
237 /* link it in now that it's consistent */
239 TAILQ_INSERT_HEAD(&p->p_ksegrps, kg, kg_ksegrp);
247 ksegrp_unlink(struct ksegrp *kg)
251 mtx_assert(&sched_lock, MA_OWNED);
252 KASSERT((kg->kg_numthreads == 0), ("ksegrp_unlink: residual threads"));
253 KASSERT((kg->kg_numupcalls == 0), ("ksegrp_unlink: residual upcalls"));
256 TAILQ_REMOVE(&p->p_ksegrps, kg, kg_ksegrp);
259 * Aggregate stats from the KSE
261 if (p->p_procscopegrp == kg)
262 p->p_procscopegrp = NULL;
266 * For a newly created process,
267 * link up all the structures and its initial threads etc.
269 * {arch}/{arch}/machdep.c ia64_init(), init386() etc.
270 * proc_dtor() (should go away)
274 proc_linkup(struct proc *p, struct ksegrp *kg, struct thread *td)
277 TAILQ_INIT(&p->p_ksegrps); /* all ksegrps in proc */
278 TAILQ_INIT(&p->p_threads); /* all threads in proc */
279 TAILQ_INIT(&p->p_suspended); /* Threads suspended */
280 sigqueue_init(&p->p_sigqueue, p);
289 * Initialize global thread allocation resources.
295 mtx_init(&tid_lock, "TID lock", NULL, MTX_DEF);
296 tid_unrhdr = new_unrhdr(PID_MAX + 1, INT_MAX, &tid_lock);
298 thread_zone = uma_zcreate("THREAD", sched_sizeof_thread(),
299 thread_ctor, thread_dtor, thread_init, thread_fini,
301 ksegrp_zone = uma_zcreate("KSEGRP", sched_sizeof_ksegrp(),
302 ksegrp_ctor, NULL, NULL, NULL,
304 kseinit(); /* set up kse specific stuff e.g. upcall zone*/
308 * Stash an embarasingly extra thread into the zombie thread queue.
311 thread_stash(struct thread *td)
313 mtx_lock_spin(&kse_zombie_lock);
314 TAILQ_INSERT_HEAD(&zombie_threads, td, td_runq);
315 mtx_unlock_spin(&kse_zombie_lock);
319 * Stash an embarasingly extra ksegrp into the zombie ksegrp queue.
322 ksegrp_stash(struct ksegrp *kg)
324 mtx_lock_spin(&kse_zombie_lock);
325 TAILQ_INSERT_HEAD(&zombie_ksegrps, kg, kg_ksegrp);
326 mtx_unlock_spin(&kse_zombie_lock);
330 * Reap zombie kse resource.
335 struct thread *td_first, *td_next;
336 struct ksegrp *kg_first, * kg_next;
339 * Don't even bother to lock if none at this instant,
340 * we really don't care about the next instant..
342 if ((!TAILQ_EMPTY(&zombie_threads))
343 || (!TAILQ_EMPTY(&zombie_ksegrps))) {
344 mtx_lock_spin(&kse_zombie_lock);
345 td_first = TAILQ_FIRST(&zombie_threads);
346 kg_first = TAILQ_FIRST(&zombie_ksegrps);
348 TAILQ_INIT(&zombie_threads);
350 TAILQ_INIT(&zombie_ksegrps);
351 mtx_unlock_spin(&kse_zombie_lock);
353 td_next = TAILQ_NEXT(td_first, td_runq);
354 if (td_first->td_ucred)
355 crfree(td_first->td_ucred);
356 thread_free(td_first);
360 kg_next = TAILQ_NEXT(kg_first, kg_ksegrp);
361 ksegrp_free(kg_first);
365 * there will always be a thread on the list if one of these
378 return (uma_zalloc(ksegrp_zone, M_WAITOK));
387 thread_reap(); /* check if any zombies to get */
388 return (uma_zalloc(thread_zone, M_WAITOK));
392 * Deallocate a ksegrp.
395 ksegrp_free(struct ksegrp *td)
397 uma_zfree(ksegrp_zone, td);
401 * Deallocate a thread.
404 thread_free(struct thread *td)
407 cpu_thread_clean(td);
408 uma_zfree(thread_zone, td);
412 * Discard the current thread and exit from its context.
413 * Always called with scheduler locked.
415 * Because we can't free a thread while we're operating under its context,
416 * push the current thread into our CPU's deadthread holder. This means
417 * we needn't worry about someone else grabbing our context before we
418 * do a cpu_throw(). This may not be needed now as we are under schedlock.
419 * Maybe we can just do a thread_stash() as thr_exit1 does.
422 * libthr expects its thread exit to return for the last
423 * thread, meaning that the program is back to non-threaded
424 * mode I guess. Because we do this (cpu_throw) unconditionally
425 * here, they have their own version of it. (thr_exit1())
426 * that doesn't do it all if this was the last thread.
427 * It is also called from thread_suspend_check().
428 * Of course in the end, they end up coming here through exit1
429 * anyhow.. After fixing 'thr' to play by the rules we should be able
430 * to merge these two functions together.
436 * thread_user_enter()
438 * thread_suspend_check()
451 mtx_assert(&sched_lock, MA_OWNED);
452 mtx_assert(&Giant, MA_NOTOWNED);
453 PROC_LOCK_ASSERT(p, MA_OWNED);
454 KASSERT(p != NULL, ("thread exiting without a process"));
455 KASSERT(kg != NULL, ("thread exiting without a kse group"));
456 CTR3(KTR_PROC, "thread_exit: thread %p (pid %ld, %s)", td,
457 (long)p->p_pid, p->p_comm);
458 KASSERT(TAILQ_EMPTY(&td->td_sigqueue.sq_list), ("signal pending"));
460 if (td->td_standin != NULL) {
462 * Note that we don't need to free the cred here as it
463 * is done in thread_reap().
465 thread_stash(td->td_standin);
466 td->td_standin = NULL;
470 * drop FPU & debug register state storage, or any other
471 * architecture specific resources that
472 * would not be on a new untouched process.
474 cpu_thread_exit(td); /* XXXSMP */
477 * The thread is exiting. scheduler can release its stuff
478 * and collect stats etc.
480 sched_thread_exit(td);
483 * The last thread is left attached to the process
484 * So that the whole bundle gets recycled. Skip
485 * all this stuff if we never had threads.
486 * EXIT clears all sign of other threads when
487 * it goes to single threading, so the last thread always
488 * takes the short path.
490 if (p->p_flag & P_HADTHREADS) {
491 if (p->p_numthreads > 1) {
494 /* XXX first arg not used in 4BSD or ULE */
495 sched_exit_thread(FIRST_THREAD_IN_PROC(p), td);
498 * The test below is NOT true if we are the
499 * sole exiting thread. P_STOPPED_SNGL is unset
500 * in exit1() after it is the only survivor.
502 if (P_SHOULDSTOP(p) == P_STOPPED_SINGLE) {
503 if (p->p_numthreads == p->p_suspcount) {
504 thread_unsuspend_one(p->p_singlethread);
509 * Because each upcall structure has an owner thread,
510 * owner thread exits only when process is in exiting
511 * state, so upcall to userland is no longer needed,
512 * deleting upcall structure is safe here.
513 * So when all threads in a group is exited, all upcalls
514 * in the group should be automatically freed.
515 * XXXKSE This is a KSE thing and should be exported
521 * If the thread we unlinked above was the last one,
522 * then this ksegrp should go away too.
524 if (kg->kg_numthreads == 0) {
526 * let the scheduler know about this in case
527 * it needs to recover stats or resources.
528 * Theoretically we could let
529 * sched_exit_ksegrp() do the equivalent of
530 * setting the concurrency to 0
531 * but don't do it yet to avoid changing
532 * the existing scheduler code until we
534 * We supply a random other ksegrp
535 * as the recipient of any built up
536 * cpu usage etc. (If the scheduler wants it).
538 * This is probably not fair so think of
541 sched_exit_ksegrp(FIRST_KSEGRP_IN_PROC(p), td);
542 sched_set_concurrency(kg, 0); /* XXX TEMP */
547 td->td_ksegrp = NULL;
548 PCPU_SET(deadthread, td);
551 * The last thread is exiting.. but not through exit()
553 * Theoretically this can't happen
554 * exit1() - clears threading flags before coming here
555 * kse_exit() - treats last thread specially
556 * thr_exit() - treats last thread specially
557 * thread_user_enter() - only if more exist
558 * thread_userret() - only if more exist
559 * thread_suspend_check() - only if more exist
561 panic ("thread_exit: Last thread exiting on its own");
565 * non threaded process comes here.
566 * This includes an EX threaded process that is coming
567 * here via exit1(). (exit1 dethreads the proc first).
571 td->td_state = TDS_INACTIVE;
572 CTR1(KTR_PROC, "thread_exit: cpu_throw() thread %p", td);
573 cpu_throw(td, choosethread());
574 panic("I'm a teapot!");
579 * Do any thread specific cleanups that may be needed in wait()
580 * called with Giant, proc and schedlock not held.
583 thread_wait(struct proc *p)
587 mtx_assert(&Giant, MA_NOTOWNED);
588 KASSERT((p->p_numthreads == 1), ("Multiple threads in wait1()"));
589 KASSERT((p->p_numksegrps == 1), ("Multiple ksegrps in wait1()"));
590 FOREACH_THREAD_IN_PROC(p, td) {
591 if (td->td_standin != NULL) {
592 if (td->td_standin->td_ucred != NULL) {
593 crfree(td->td_standin->td_ucred);
594 td->td_standin->td_ucred = NULL;
596 thread_free(td->td_standin);
597 td->td_standin = NULL;
599 cpu_thread_clean(td);
600 crfree(td->td_ucred);
602 thread_reap(); /* check for zombie threads etc. */
606 * Link a thread to a process.
607 * set up anything that needs to be initialized for it to
608 * be used by the process.
610 * Note that we do not link to the proc's ucred here.
611 * The thread is linked as if running but no KSE assigned.
614 * thread_schedule_upcall()
618 thread_link(struct thread *td, struct ksegrp *kg)
623 td->td_state = TDS_INACTIVE;
629 LIST_INIT(&td->td_contested);
630 sigqueue_init(&td->td_sigqueue, p);
631 callout_init(&td->td_slpcallout, CALLOUT_MPSAFE);
632 TAILQ_INSERT_HEAD(&p->p_threads, td, td_plist);
633 TAILQ_INSERT_HEAD(&kg->kg_threads, td, td_kglist);
639 * Convert a process with one thread to an unthreaded process.
641 * thread_single(exit) (called from execve and exit)
642 * kse_exit() XXX may need cleaning up wrt KSE stuff
645 thread_unthread(struct thread *td)
647 struct proc *p = td->td_proc;
649 KASSERT((p->p_numthreads == 1), ("Unthreading with >1 threads"));
651 p->p_flag &= ~(P_SA|P_HADTHREADS);
652 td->td_mailbox = NULL;
653 td->td_pflags &= ~(TDP_SA | TDP_CAN_UNBIND);
654 if (td->td_standin != NULL) {
655 thread_stash(td->td_standin);
656 td->td_standin = NULL;
658 sched_set_concurrency(td->td_ksegrp, 1);
666 thread_unlink(struct thread *td)
668 struct proc *p = td->td_proc;
669 struct ksegrp *kg = td->td_ksegrp;
671 mtx_assert(&sched_lock, MA_OWNED);
672 TAILQ_REMOVE(&p->p_threads, td, td_plist);
674 TAILQ_REMOVE(&kg->kg_threads, td, td_kglist);
676 /* could clear a few other things here */
677 /* Must NOT clear links to proc and ksegrp! */
681 * Enforce single-threading.
683 * Returns 1 if the caller must abort (another thread is waiting to
684 * exit the process or similar). Process is locked!
685 * Returns 0 when you are successfully the only thread running.
686 * A process has successfully single threaded in the suspend mode when
687 * There are no threads in user mode. Threads in the kernel must be
688 * allowed to continue until they get to the user boundary. They may even
689 * copy out their return values and data before suspending. They may however be
690 * accellerated in reaching the user boundary as we will wake up
691 * any sleeping threads that are interruptable. (PCATCH).
694 thread_single(int mode)
703 mtx_assert(&Giant, MA_NOTOWNED);
704 PROC_LOCK_ASSERT(p, MA_OWNED);
705 KASSERT((td != NULL), ("curthread is NULL"));
707 if ((p->p_flag & P_HADTHREADS) == 0)
710 /* Is someone already single threading? */
711 if (p->p_singlethread != NULL && p->p_singlethread != td)
714 if (mode == SINGLE_EXIT) {
715 p->p_flag |= P_SINGLE_EXIT;
716 p->p_flag &= ~P_SINGLE_BOUNDARY;
718 p->p_flag &= ~P_SINGLE_EXIT;
719 if (mode == SINGLE_BOUNDARY)
720 p->p_flag |= P_SINGLE_BOUNDARY;
722 p->p_flag &= ~P_SINGLE_BOUNDARY;
724 p->p_flag |= P_STOPPED_SINGLE;
725 mtx_lock_spin(&sched_lock);
726 p->p_singlethread = td;
727 if (mode == SINGLE_EXIT)
728 remaining = p->p_numthreads;
729 else if (mode == SINGLE_BOUNDARY)
730 remaining = p->p_numthreads - p->p_boundary_count;
732 remaining = p->p_numthreads - p->p_suspcount;
733 while (remaining != 1) {
734 FOREACH_THREAD_IN_PROC(p, td2) {
737 td2->td_flags |= TDF_ASTPENDING;
738 if (TD_IS_INHIBITED(td2)) {
741 if (td->td_flags & TDF_DBSUSPEND)
742 td->td_flags &= ~TDF_DBSUSPEND;
743 if (TD_IS_SUSPENDED(td2))
744 thread_unsuspend_one(td2);
745 if (TD_ON_SLEEPQ(td2) &&
746 (td2->td_flags & TDF_SINTR))
749 case SINGLE_BOUNDARY:
750 if (TD_IS_SUSPENDED(td2) &&
751 !(td2->td_flags & TDF_BOUNDARY))
752 thread_unsuspend_one(td2);
753 if (TD_ON_SLEEPQ(td2) &&
754 (td2->td_flags & TDF_SINTR))
758 if (TD_IS_SUSPENDED(td2))
761 * maybe other inhibitted states too?
763 if ((td2->td_flags & TDF_SINTR) &&
764 (td2->td_inhibitors &
765 (TDI_SLEEPING | TDI_SWAPPED)))
766 thread_suspend_one(td2);
771 if (mode == SINGLE_EXIT)
772 remaining = p->p_numthreads;
773 else if (mode == SINGLE_BOUNDARY)
774 remaining = p->p_numthreads - p->p_boundary_count;
776 remaining = p->p_numthreads - p->p_suspcount;
779 * Maybe we suspended some threads.. was it enough?
785 * Wake us up when everyone else has suspended.
786 * In the mean time we suspend as well.
788 thread_suspend_one(td);
790 mi_switch(SW_VOL, NULL);
791 mtx_unlock_spin(&sched_lock);
793 mtx_lock_spin(&sched_lock);
794 if (mode == SINGLE_EXIT)
795 remaining = p->p_numthreads;
796 else if (mode == SINGLE_BOUNDARY)
797 remaining = p->p_numthreads - p->p_boundary_count;
799 remaining = p->p_numthreads - p->p_suspcount;
801 if (mode == SINGLE_EXIT) {
803 * We have gotten rid of all the other threads and we
804 * are about to either exit or exec. In either case,
805 * we try our utmost to revert to being a non-threaded
808 p->p_singlethread = NULL;
809 p->p_flag &= ~(P_STOPPED_SINGLE | P_SINGLE_EXIT);
812 mtx_unlock_spin(&sched_lock);
817 * Called in from locations that can safely check to see
818 * whether we have to suspend or at least throttle for a
819 * single-thread event (e.g. fork).
821 * Such locations include userret().
822 * If the "return_instead" argument is non zero, the thread must be able to
823 * accept 0 (caller may continue), or 1 (caller must abort) as a result.
825 * The 'return_instead' argument tells the function if it may do a
826 * thread_exit() or suspend, or whether the caller must abort and back
829 * If the thread that set the single_threading request has set the
830 * P_SINGLE_EXIT bit in the process flags then this call will never return
831 * if 'return_instead' is false, but will exit.
833 * P_SINGLE_EXIT | return_instead == 0| return_instead != 0
834 *---------------+--------------------+---------------------
835 * 0 | returns 0 | returns 0 or 1
836 * | when ST ends | immediatly
837 *---------------+--------------------+---------------------
838 * 1 | thread exits | returns 1
840 * 0 = thread_exit() or suspension ok,
841 * other = return error instead of stopping the thread.
843 * While a full suspension is under effect, even a single threading
844 * thread would be suspended if it made this call (but it shouldn't).
845 * This call should only be made from places where
846 * thread_exit() would be safe as that may be the outcome unless
847 * return_instead is set.
850 thread_suspend_check(int return_instead)
857 mtx_assert(&Giant, MA_NOTOWNED);
858 PROC_LOCK_ASSERT(p, MA_OWNED);
859 while (P_SHOULDSTOP(p) ||
860 ((p->p_flag & P_TRACED) && (td->td_flags & TDF_DBSUSPEND))) {
861 if (P_SHOULDSTOP(p) == P_STOPPED_SINGLE) {
862 KASSERT(p->p_singlethread != NULL,
863 ("singlethread not set"));
865 * The only suspension in action is a
866 * single-threading. Single threader need not stop.
867 * XXX Should be safe to access unlocked
868 * as it can only be set to be true by us.
870 if (p->p_singlethread == td)
871 return (0); /* Exempt from stopping. */
873 if ((p->p_flag & P_SINGLE_EXIT) && return_instead)
876 /* Should we goto user boundary if we didn't come from there? */
877 if (P_SHOULDSTOP(p) == P_STOPPED_SINGLE &&
878 (p->p_flag & P_SINGLE_BOUNDARY) && return_instead)
881 /* If thread will exit, flush its pending signals */
882 if ((p->p_flag & P_SINGLE_EXIT) && (p->p_singlethread != td))
883 sigqueue_flush(&td->td_sigqueue);
885 mtx_lock_spin(&sched_lock);
888 * If the process is waiting for us to exit,
889 * this thread should just suicide.
890 * Assumes that P_SINGLE_EXIT implies P_STOPPED_SINGLE.
892 if ((p->p_flag & P_SINGLE_EXIT) && (p->p_singlethread != td))
896 * When a thread suspends, it just
897 * moves to the processes's suspend queue
900 thread_suspend_one(td);
901 if (return_instead == 0) {
902 p->p_boundary_count++;
903 td->td_flags |= TDF_BOUNDARY;
905 if (P_SHOULDSTOP(p) == P_STOPPED_SINGLE) {
906 if (p->p_numthreads == p->p_suspcount)
907 thread_unsuspend_one(p->p_singlethread);
910 mi_switch(SW_INVOL, NULL);
911 if (return_instead == 0) {
912 p->p_boundary_count--;
913 td->td_flags &= ~TDF_BOUNDARY;
915 mtx_unlock_spin(&sched_lock);
922 thread_suspend_one(struct thread *td)
924 struct proc *p = td->td_proc;
926 mtx_assert(&sched_lock, MA_OWNED);
927 PROC_LOCK_ASSERT(p, MA_OWNED);
928 KASSERT(!TD_IS_SUSPENDED(td), ("already suspended"));
930 TD_SET_SUSPENDED(td);
931 TAILQ_INSERT_TAIL(&p->p_suspended, td, td_runq);
935 thread_unsuspend_one(struct thread *td)
937 struct proc *p = td->td_proc;
939 mtx_assert(&sched_lock, MA_OWNED);
940 PROC_LOCK_ASSERT(p, MA_OWNED);
941 TAILQ_REMOVE(&p->p_suspended, td, td_runq);
942 TD_CLR_SUSPENDED(td);
948 * Allow all threads blocked by single threading to continue running.
951 thread_unsuspend(struct proc *p)
955 mtx_assert(&sched_lock, MA_OWNED);
956 PROC_LOCK_ASSERT(p, MA_OWNED);
957 if (!P_SHOULDSTOP(p)) {
958 while ((td = TAILQ_FIRST(&p->p_suspended))) {
959 thread_unsuspend_one(td);
961 } else if ((P_SHOULDSTOP(p) == P_STOPPED_SINGLE) &&
962 (p->p_numthreads == p->p_suspcount)) {
964 * Stopping everything also did the job for the single
965 * threading request. Now we've downgraded to single-threaded,
968 thread_unsuspend_one(p->p_singlethread);
973 * End the single threading mode..
976 thread_single_end(void)
983 PROC_LOCK_ASSERT(p, MA_OWNED);
984 p->p_flag &= ~(P_STOPPED_SINGLE | P_SINGLE_EXIT | P_SINGLE_BOUNDARY);
985 mtx_lock_spin(&sched_lock);
986 p->p_singlethread = NULL;
987 p->p_procscopegrp = NULL;
989 * If there are other threads they mey now run,
990 * unless of course there is a blanket 'stop order'
991 * on the process. The single threader must be allowed
992 * to continue however as this is a bad place to stop.
994 if ((p->p_numthreads != 1) && (!P_SHOULDSTOP(p))) {
995 while ((td = TAILQ_FIRST(&p->p_suspended))) {
996 thread_unsuspend_one(td);
999 mtx_unlock_spin(&sched_lock);
1003 * Called before going into an interruptible sleep to see if we have been
1004 * interrupted or requested to exit.
1007 thread_sleep_check(struct thread *td)
1012 mtx_assert(&sched_lock, MA_OWNED);
1013 if (p->p_flag & P_HADTHREADS) {
1014 if (p->p_singlethread != td) {
1015 if (p->p_flag & P_SINGLE_EXIT)
1017 if (p->p_flag & P_SINGLE_BOUNDARY)
1020 if (td->td_flags & TDF_INTERRUPT)
1021 return (td->td_intrval);