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 * KSEGRP related storage.
56 static uma_zone_t ksegrp_zone;
57 static uma_zone_t thread_zone;
60 SYSCTL_NODE(_kern, OID_AUTO, threads, CTLFLAG_RW, 0, "thread allocation");
61 static int thread_debug = 0;
62 SYSCTL_INT(_kern_threads, OID_AUTO, debug, CTLFLAG_RW,
63 &thread_debug, 0, "thread debug");
65 int max_threads_per_proc = 1500;
66 SYSCTL_INT(_kern_threads, OID_AUTO, max_threads_per_proc, CTLFLAG_RW,
67 &max_threads_per_proc, 0, "Limit on threads per proc");
69 int max_groups_per_proc = 1500;
70 SYSCTL_INT(_kern_threads, OID_AUTO, max_groups_per_proc, CTLFLAG_RW,
71 &max_groups_per_proc, 0, "Limit on thread groups per proc");
74 SYSCTL_INT(_kern_threads, OID_AUTO, max_threads_hits, CTLFLAG_RD,
75 &max_threads_hits, 0, "");
79 TAILQ_HEAD(, thread) zombie_threads = TAILQ_HEAD_INITIALIZER(zombie_threads);
80 TAILQ_HEAD(, ksegrp) zombie_ksegrps = TAILQ_HEAD_INITIALIZER(zombie_ksegrps);
81 struct mtx kse_zombie_lock;
82 MTX_SYSINIT(kse_zombie_lock, &kse_zombie_lock, "kse zombie lock", MTX_SPIN);
85 sysctl_kse_virtual_cpu(SYSCTL_HANDLER_ARGS)
94 new_val = virtual_cpu;
95 error = sysctl_handle_int(oidp, &new_val, 0, req);
96 if (error != 0 || req->newptr == NULL)
100 virtual_cpu = new_val;
105 SYSCTL_PROC(_kern_threads, OID_AUTO, virtual_cpu, CTLTYPE_INT|CTLFLAG_RW,
106 0, sizeof(virtual_cpu), sysctl_kse_virtual_cpu, "I",
107 "debug virtual cpus");
110 static struct unrhdr *tid_unrhdr;
113 * Prepare a thread for use.
116 thread_ctor(void *mem, int size, void *arg, int flags)
120 td = (struct thread *)mem;
121 td->td_state = TDS_INACTIVE;
122 td->td_oncpu = NOCPU;
124 td->td_tid = alloc_unr(tid_unrhdr);
127 * Note that td_critnest begins life as 1 because the thread is not
128 * running and is thereby implicitly waiting to be on the receiving
129 * end of a context switch. A context switch must occur inside a
130 * critical section, and in fact, includes hand-off of the sched_lock.
131 * After a context switch to a newly created thread, it will release
132 * sched_lock for the first time, and its td_critnest will hit 0 for
133 * the first time. This happens on the far end of a context switch,
134 * and when it context switches away from itself, it will in fact go
135 * back into a critical section, and hand off the sched lock to the
141 audit_thread_alloc(td);
147 * Reclaim a thread after use.
150 thread_dtor(void *mem, int size, void *arg)
154 td = (struct thread *)mem;
157 /* Verify that this thread is in a safe state to free. */
158 switch (td->td_state) {
164 * We must never unlink a thread that is in one of
165 * these states, because it is currently active.
167 panic("bad state for thread unlinking");
172 panic("bad thread state");
177 audit_thread_free(td);
179 free_unr(tid_unrhdr, td->td_tid);
184 * Initialize type-stable parts of a thread (when newly created).
187 thread_init(void *mem, int size, int flags)
191 td = (struct thread *)mem;
193 vm_thread_new(td, 0);
194 cpu_thread_setup(td);
195 td->td_sleepqueue = sleepq_alloc();
196 td->td_turnstile = turnstile_alloc();
197 td->td_umtxq = umtxq_alloc();
198 td->td_sched = (struct td_sched *)&td[1];
204 * Tear down type-stable parts of a thread (just before being discarded).
207 thread_fini(void *mem, int size)
211 td = (struct thread *)mem;
212 turnstile_free(td->td_turnstile);
213 sleepq_free(td->td_sleepqueue);
214 umtxq_free(td->td_umtxq);
215 vm_thread_dispose(td);
219 * Initialize type-stable parts of a ksegrp (when newly created).
222 ksegrp_ctor(void *mem, int size, void *arg, int flags)
226 kg = (struct ksegrp *)mem;
228 kg->kg_sched = (struct kg_sched *)&kg[1];
233 ksegrp_link(struct ksegrp *kg, struct proc *p)
236 TAILQ_INIT(&kg->kg_threads);
237 TAILQ_INIT(&kg->kg_runq); /* links with td_runq */
238 TAILQ_INIT(&kg->kg_upcalls); /* all upcall structure in ksegrp */
241 * the following counters are in the -zero- section
242 * and may not need clearing
244 kg->kg_numthreads = 0;
245 kg->kg_numupcalls = 0;
246 /* link it in now that it's consistent */
248 TAILQ_INSERT_HEAD(&p->p_ksegrps, kg, kg_ksegrp);
256 ksegrp_unlink(struct ksegrp *kg)
260 mtx_assert(&sched_lock, MA_OWNED);
261 KASSERT((kg->kg_numthreads == 0), ("ksegrp_unlink: residual threads"));
262 KASSERT((kg->kg_numupcalls == 0), ("ksegrp_unlink: residual upcalls"));
265 TAILQ_REMOVE(&p->p_ksegrps, kg, kg_ksegrp);
268 * Aggregate stats from the KSE
270 if (p->p_procscopegrp == kg)
271 p->p_procscopegrp = NULL;
275 * For a newly created process,
276 * link up all the structures and its initial threads etc.
278 * {arch}/{arch}/machdep.c ia64_init(), init386() etc.
279 * proc_dtor() (should go away)
283 proc_linkup(struct proc *p, struct ksegrp *kg, struct thread *td)
286 TAILQ_INIT(&p->p_ksegrps); /* all ksegrps in proc */
287 TAILQ_INIT(&p->p_threads); /* all threads in proc */
288 TAILQ_INIT(&p->p_suspended); /* Threads suspended */
289 sigqueue_init(&p->p_sigqueue, p);
290 p->p_ksi = ksiginfo_alloc(1);
291 if (p->p_ksi != NULL) {
292 /* XXX p_ksi may be null if ksiginfo zone is not ready */
293 p->p_ksi->ksi_flags = KSI_EXT | KSI_INS;
295 LIST_INIT(&p->p_mqnotifier);
304 * Initialize global thread allocation resources.
310 mtx_init(&tid_lock, "TID lock", NULL, MTX_DEF);
311 tid_unrhdr = new_unrhdr(PID_MAX + 1, INT_MAX, &tid_lock);
313 thread_zone = uma_zcreate("THREAD", sched_sizeof_thread(),
314 thread_ctor, thread_dtor, thread_init, thread_fini,
316 ksegrp_zone = uma_zcreate("KSEGRP", sched_sizeof_ksegrp(),
317 ksegrp_ctor, NULL, NULL, NULL,
319 kseinit(); /* set up kse specific stuff e.g. upcall zone*/
323 * Stash an embarasingly extra thread into the zombie thread queue.
326 thread_stash(struct thread *td)
328 mtx_lock_spin(&kse_zombie_lock);
329 TAILQ_INSERT_HEAD(&zombie_threads, td, td_runq);
330 mtx_unlock_spin(&kse_zombie_lock);
334 * Stash an embarasingly extra ksegrp into the zombie ksegrp queue.
337 ksegrp_stash(struct ksegrp *kg)
339 mtx_lock_spin(&kse_zombie_lock);
340 TAILQ_INSERT_HEAD(&zombie_ksegrps, kg, kg_ksegrp);
341 mtx_unlock_spin(&kse_zombie_lock);
345 * Reap zombie kse resource.
350 struct thread *td_first, *td_next;
351 struct ksegrp *kg_first, * kg_next;
354 * Don't even bother to lock if none at this instant,
355 * we really don't care about the next instant..
357 if ((!TAILQ_EMPTY(&zombie_threads))
358 || (!TAILQ_EMPTY(&zombie_ksegrps))) {
359 mtx_lock_spin(&kse_zombie_lock);
360 td_first = TAILQ_FIRST(&zombie_threads);
361 kg_first = TAILQ_FIRST(&zombie_ksegrps);
363 TAILQ_INIT(&zombie_threads);
365 TAILQ_INIT(&zombie_ksegrps);
366 mtx_unlock_spin(&kse_zombie_lock);
368 td_next = TAILQ_NEXT(td_first, td_runq);
369 if (td_first->td_ucred)
370 crfree(td_first->td_ucred);
371 thread_free(td_first);
375 kg_next = TAILQ_NEXT(kg_first, kg_ksegrp);
376 ksegrp_free(kg_first);
380 * there will always be a thread on the list if one of these
393 return (uma_zalloc(ksegrp_zone, M_WAITOK));
402 thread_reap(); /* check if any zombies to get */
403 return (uma_zalloc(thread_zone, M_WAITOK));
407 * Deallocate a ksegrp.
410 ksegrp_free(struct ksegrp *td)
412 uma_zfree(ksegrp_zone, td);
416 * Deallocate a thread.
419 thread_free(struct thread *td)
422 cpu_thread_clean(td);
423 uma_zfree(thread_zone, td);
427 * Discard the current thread and exit from its context.
428 * Always called with scheduler locked.
430 * Because we can't free a thread while we're operating under its context,
431 * push the current thread into our CPU's deadthread holder. This means
432 * we needn't worry about someone else grabbing our context before we
433 * do a cpu_throw(). This may not be needed now as we are under schedlock.
434 * Maybe we can just do a thread_stash() as thr_exit1 does.
437 * libthr expects its thread exit to return for the last
438 * thread, meaning that the program is back to non-threaded
439 * mode I guess. Because we do this (cpu_throw) unconditionally
440 * here, they have their own version of it. (thr_exit1())
441 * that doesn't do it all if this was the last thread.
442 * It is also called from thread_suspend_check().
443 * Of course in the end, they end up coming here through exit1
444 * anyhow.. After fixing 'thr' to play by the rules we should be able
445 * to merge these two functions together.
451 * thread_user_enter()
453 * thread_suspend_check()
458 uint64_t new_switchtime;
467 mtx_assert(&sched_lock, MA_OWNED);
468 mtx_assert(&Giant, MA_NOTOWNED);
469 PROC_LOCK_ASSERT(p, MA_OWNED);
470 KASSERT(p != NULL, ("thread exiting without a process"));
471 KASSERT(kg != NULL, ("thread exiting without a kse group"));
472 CTR3(KTR_PROC, "thread_exit: thread %p (pid %ld, %s)", td,
473 (long)p->p_pid, p->p_comm);
474 KASSERT(TAILQ_EMPTY(&td->td_sigqueue.sq_list), ("signal pending"));
477 AUDIT_SYSCALL_EXIT(0, td);
480 if (td->td_standin != NULL) {
482 * Note that we don't need to free the cred here as it
483 * is done in thread_reap().
485 thread_stash(td->td_standin);
486 td->td_standin = NULL;
490 * drop FPU & debug register state storage, or any other
491 * architecture specific resources that
492 * would not be on a new untouched process.
494 cpu_thread_exit(td); /* XXXSMP */
497 * The thread is exiting. scheduler can release its stuff
498 * and collect stats etc.
499 * XXX this is not very right, since PROC_UNLOCK may still
500 * need scheduler stuff.
502 sched_thread_exit(td);
504 /* Do the same timestamp bookkeeping that mi_switch() would do. */
505 new_switchtime = cpu_ticks();
506 p->p_rux.rux_runtime += (new_switchtime - PCPU_GET(switchtime));
507 p->p_rux.rux_uticks += td->td_uticks;
508 p->p_rux.rux_sticks += td->td_sticks;
509 p->p_rux.rux_iticks += td->td_iticks;
510 PCPU_SET(switchtime, new_switchtime);
511 PCPU_SET(switchticks, ticks);
514 /* Add our usage into the usage of all our children. */
515 if (p->p_numthreads == 1)
516 ruadd(p->p_ru, &p->p_rux, &p->p_stats->p_cru, &p->p_crux);
519 * The last thread is left attached to the process
520 * So that the whole bundle gets recycled. Skip
521 * all this stuff if we never had threads.
522 * EXIT clears all sign of other threads when
523 * it goes to single threading, so the last thread always
524 * takes the short path.
526 if (p->p_flag & P_HADTHREADS) {
527 if (p->p_numthreads > 1) {
530 /* XXX first arg not used in 4BSD or ULE */
531 sched_exit_thread(FIRST_THREAD_IN_PROC(p), td);
534 * The test below is NOT true if we are the
535 * sole exiting thread. P_STOPPED_SNGL is unset
536 * in exit1() after it is the only survivor.
538 if (P_SHOULDSTOP(p) == P_STOPPED_SINGLE) {
539 if (p->p_numthreads == p->p_suspcount) {
540 thread_unsuspend_one(p->p_singlethread);
545 * Because each upcall structure has an owner thread,
546 * owner thread exits only when process is in exiting
547 * state, so upcall to userland is no longer needed,
548 * deleting upcall structure is safe here.
549 * So when all threads in a group is exited, all upcalls
550 * in the group should be automatically freed.
551 * XXXKSE This is a KSE thing and should be exported
557 * If the thread we unlinked above was the last one,
558 * then this ksegrp should go away too.
560 if (kg->kg_numthreads == 0) {
562 * let the scheduler know about this in case
563 * it needs to recover stats or resources.
564 * Theoretically we could let
565 * sched_exit_ksegrp() do the equivalent of
566 * setting the concurrency to 0
567 * but don't do it yet to avoid changing
568 * the existing scheduler code until we
570 * We supply a random other ksegrp
571 * as the recipient of any built up
572 * cpu usage etc. (If the scheduler wants it).
574 * This is probably not fair so think of
577 sched_exit_ksegrp(FIRST_KSEGRP_IN_PROC(p), td);
578 sched_set_concurrency(kg, 0); /* XXX TEMP */
583 td->td_ksegrp = NULL;
584 PCPU_SET(deadthread, td);
587 * The last thread is exiting.. but not through exit()
589 * Theoretically this can't happen
590 * exit1() - clears threading flags before coming here
591 * kse_exit() - treats last thread specially
592 * thr_exit() - treats last thread specially
593 * thread_user_enter() - only if more exist
594 * thread_userret() - only if more exist
595 * thread_suspend_check() - only if more exist
597 panic ("thread_exit: Last thread exiting on its own");
601 * non threaded process comes here.
602 * This includes an EX threaded process that is coming
603 * here via exit1(). (exit1 dethreads the proc first).
607 td->td_state = TDS_INACTIVE;
608 CTR1(KTR_PROC, "thread_exit: cpu_throw() thread %p", td);
609 cpu_throw(td, choosethread());
610 panic("I'm a teapot!");
615 * Do any thread specific cleanups that may be needed in wait()
616 * called with Giant, proc and schedlock not held.
619 thread_wait(struct proc *p)
623 mtx_assert(&Giant, MA_NOTOWNED);
624 KASSERT((p->p_numthreads == 1), ("Multiple threads in wait1()"));
625 KASSERT((p->p_numksegrps == 1), ("Multiple ksegrps in wait1()"));
626 FOREACH_THREAD_IN_PROC(p, td) {
627 if (td->td_standin != NULL) {
628 if (td->td_standin->td_ucred != NULL) {
629 crfree(td->td_standin->td_ucred);
630 td->td_standin->td_ucred = NULL;
632 thread_free(td->td_standin);
633 td->td_standin = NULL;
635 cpu_thread_clean(td);
636 crfree(td->td_ucred);
638 thread_reap(); /* check for zombie threads etc. */
642 * Link a thread to a process.
643 * set up anything that needs to be initialized for it to
644 * be used by the process.
646 * Note that we do not link to the proc's ucred here.
647 * The thread is linked as if running but no KSE assigned.
650 * thread_schedule_upcall()
654 thread_link(struct thread *td, struct ksegrp *kg)
659 td->td_state = TDS_INACTIVE;
665 LIST_INIT(&td->td_contested);
666 sigqueue_init(&td->td_sigqueue, p);
667 callout_init(&td->td_slpcallout, CALLOUT_MPSAFE);
668 TAILQ_INSERT_HEAD(&p->p_threads, td, td_plist);
669 TAILQ_INSERT_HEAD(&kg->kg_threads, td, td_kglist);
675 * Convert a process with one thread to an unthreaded process.
677 * thread_single(exit) (called from execve and exit)
678 * kse_exit() XXX may need cleaning up wrt KSE stuff
681 thread_unthread(struct thread *td)
683 struct proc *p = td->td_proc;
685 KASSERT((p->p_numthreads == 1), ("Unthreading with >1 threads"));
687 p->p_flag &= ~(P_SA|P_HADTHREADS);
688 td->td_mailbox = NULL;
689 td->td_pflags &= ~(TDP_SA | TDP_CAN_UNBIND);
690 if (td->td_standin != NULL) {
691 thread_stash(td->td_standin);
692 td->td_standin = NULL;
694 sched_set_concurrency(td->td_ksegrp, 1);
702 thread_unlink(struct thread *td)
704 struct proc *p = td->td_proc;
705 struct ksegrp *kg = td->td_ksegrp;
707 mtx_assert(&sched_lock, MA_OWNED);
708 TAILQ_REMOVE(&p->p_threads, td, td_plist);
710 TAILQ_REMOVE(&kg->kg_threads, td, td_kglist);
712 /* could clear a few other things here */
713 /* Must NOT clear links to proc and ksegrp! */
717 * Enforce single-threading.
719 * Returns 1 if the caller must abort (another thread is waiting to
720 * exit the process or similar). Process is locked!
721 * Returns 0 when you are successfully the only thread running.
722 * A process has successfully single threaded in the suspend mode when
723 * There are no threads in user mode. Threads in the kernel must be
724 * allowed to continue until they get to the user boundary. They may even
725 * copy out their return values and data before suspending. They may however be
726 * accelerated in reaching the user boundary as we will wake up
727 * any sleeping threads that are interruptable. (PCATCH).
730 thread_single(int mode)
739 mtx_assert(&Giant, MA_NOTOWNED);
740 PROC_LOCK_ASSERT(p, MA_OWNED);
741 KASSERT((td != NULL), ("curthread is NULL"));
743 if ((p->p_flag & P_HADTHREADS) == 0)
746 /* Is someone already single threading? */
747 if (p->p_singlethread != NULL && p->p_singlethread != td)
750 if (mode == SINGLE_EXIT) {
751 p->p_flag |= P_SINGLE_EXIT;
752 p->p_flag &= ~P_SINGLE_BOUNDARY;
754 p->p_flag &= ~P_SINGLE_EXIT;
755 if (mode == SINGLE_BOUNDARY)
756 p->p_flag |= P_SINGLE_BOUNDARY;
758 p->p_flag &= ~P_SINGLE_BOUNDARY;
760 p->p_flag |= P_STOPPED_SINGLE;
761 mtx_lock_spin(&sched_lock);
762 p->p_singlethread = td;
763 if (mode == SINGLE_EXIT)
764 remaining = p->p_numthreads;
765 else if (mode == SINGLE_BOUNDARY)
766 remaining = p->p_numthreads - p->p_boundary_count;
768 remaining = p->p_numthreads - p->p_suspcount;
769 while (remaining != 1) {
770 if (P_SHOULDSTOP(p) != P_STOPPED_SINGLE)
772 FOREACH_THREAD_IN_PROC(p, td2) {
775 td2->td_flags |= TDF_ASTPENDING;
776 if (TD_IS_INHIBITED(td2)) {
779 if (td->td_flags & TDF_DBSUSPEND)
780 td->td_flags &= ~TDF_DBSUSPEND;
781 if (TD_IS_SUSPENDED(td2))
782 thread_unsuspend_one(td2);
783 if (TD_ON_SLEEPQ(td2) &&
784 (td2->td_flags & TDF_SINTR))
785 sleepq_abort(td2, EINTR);
787 case SINGLE_BOUNDARY:
788 if (TD_IS_SUSPENDED(td2) &&
789 !(td2->td_flags & TDF_BOUNDARY))
790 thread_unsuspend_one(td2);
791 if (TD_ON_SLEEPQ(td2) &&
792 (td2->td_flags & TDF_SINTR))
793 sleepq_abort(td2, ERESTART);
796 if (TD_IS_SUSPENDED(td2))
799 * maybe other inhibitted states too?
801 if ((td2->td_flags & TDF_SINTR) &&
802 (td2->td_inhibitors &
803 (TDI_SLEEPING | TDI_SWAPPED)))
804 thread_suspend_one(td2);
809 else if (TD_IS_RUNNING(td2) && td != td2) {
814 if (mode == SINGLE_EXIT)
815 remaining = p->p_numthreads;
816 else if (mode == SINGLE_BOUNDARY)
817 remaining = p->p_numthreads - p->p_boundary_count;
819 remaining = p->p_numthreads - p->p_suspcount;
822 * Maybe we suspended some threads.. was it enough?
829 * Wake us up when everyone else has suspended.
830 * In the mean time we suspend as well.
833 thread_suspend_one(td);
835 mi_switch(SW_VOL, NULL);
836 mtx_unlock_spin(&sched_lock);
838 mtx_lock_spin(&sched_lock);
839 if (mode == SINGLE_EXIT)
840 remaining = p->p_numthreads;
841 else if (mode == SINGLE_BOUNDARY)
842 remaining = p->p_numthreads - p->p_boundary_count;
844 remaining = p->p_numthreads - p->p_suspcount;
846 if (mode == SINGLE_EXIT) {
848 * We have gotten rid of all the other threads and we
849 * are about to either exit or exec. In either case,
850 * we try our utmost to revert to being a non-threaded
853 p->p_singlethread = NULL;
854 p->p_flag &= ~(P_STOPPED_SINGLE | P_SINGLE_EXIT);
857 mtx_unlock_spin(&sched_lock);
862 * Called in from locations that can safely check to see
863 * whether we have to suspend or at least throttle for a
864 * single-thread event (e.g. fork).
866 * Such locations include userret().
867 * If the "return_instead" argument is non zero, the thread must be able to
868 * accept 0 (caller may continue), or 1 (caller must abort) as a result.
870 * The 'return_instead' argument tells the function if it may do a
871 * thread_exit() or suspend, or whether the caller must abort and back
874 * If the thread that set the single_threading request has set the
875 * P_SINGLE_EXIT bit in the process flags then this call will never return
876 * if 'return_instead' is false, but will exit.
878 * P_SINGLE_EXIT | return_instead == 0| return_instead != 0
879 *---------------+--------------------+---------------------
880 * 0 | returns 0 | returns 0 or 1
881 * | when ST ends | immediatly
882 *---------------+--------------------+---------------------
883 * 1 | thread exits | returns 1
885 * 0 = thread_exit() or suspension ok,
886 * other = return error instead of stopping the thread.
888 * While a full suspension is under effect, even a single threading
889 * thread would be suspended if it made this call (but it shouldn't).
890 * This call should only be made from places where
891 * thread_exit() would be safe as that may be the outcome unless
892 * return_instead is set.
895 thread_suspend_check(int return_instead)
902 mtx_assert(&Giant, MA_NOTOWNED);
903 PROC_LOCK_ASSERT(p, MA_OWNED);
904 while (P_SHOULDSTOP(p) ||
905 ((p->p_flag & P_TRACED) && (td->td_flags & TDF_DBSUSPEND))) {
906 if (P_SHOULDSTOP(p) == P_STOPPED_SINGLE) {
907 KASSERT(p->p_singlethread != NULL,
908 ("singlethread not set"));
910 * The only suspension in action is a
911 * single-threading. Single threader need not stop.
912 * XXX Should be safe to access unlocked
913 * as it can only be set to be true by us.
915 if (p->p_singlethread == td)
916 return (0); /* Exempt from stopping. */
918 if ((p->p_flag & P_SINGLE_EXIT) && return_instead)
921 /* Should we goto user boundary if we didn't come from there? */
922 if (P_SHOULDSTOP(p) == P_STOPPED_SINGLE &&
923 (p->p_flag & P_SINGLE_BOUNDARY) && return_instead)
926 /* If thread will exit, flush its pending signals */
927 if ((p->p_flag & P_SINGLE_EXIT) && (p->p_singlethread != td))
928 sigqueue_flush(&td->td_sigqueue);
930 mtx_lock_spin(&sched_lock);
933 * If the process is waiting for us to exit,
934 * this thread should just suicide.
935 * Assumes that P_SINGLE_EXIT implies P_STOPPED_SINGLE.
937 if ((p->p_flag & P_SINGLE_EXIT) && (p->p_singlethread != td))
941 * When a thread suspends, it just
942 * moves to the processes's suspend queue
945 thread_suspend_one(td);
946 if (return_instead == 0) {
947 p->p_boundary_count++;
948 td->td_flags |= TDF_BOUNDARY;
950 if (P_SHOULDSTOP(p) == P_STOPPED_SINGLE) {
951 if (p->p_numthreads == p->p_suspcount)
952 thread_unsuspend_one(p->p_singlethread);
955 mi_switch(SW_INVOL, NULL);
956 if (return_instead == 0) {
957 p->p_boundary_count--;
958 td->td_flags &= ~TDF_BOUNDARY;
960 mtx_unlock_spin(&sched_lock);
967 thread_suspend_one(struct thread *td)
969 struct proc *p = td->td_proc;
971 mtx_assert(&sched_lock, MA_OWNED);
972 PROC_LOCK_ASSERT(p, MA_OWNED);
973 KASSERT(!TD_IS_SUSPENDED(td), ("already suspended"));
975 TD_SET_SUSPENDED(td);
976 TAILQ_INSERT_TAIL(&p->p_suspended, td, td_runq);
980 thread_unsuspend_one(struct thread *td)
982 struct proc *p = td->td_proc;
984 mtx_assert(&sched_lock, MA_OWNED);
985 PROC_LOCK_ASSERT(p, MA_OWNED);
986 TAILQ_REMOVE(&p->p_suspended, td, td_runq);
987 TD_CLR_SUSPENDED(td);
993 * Allow all threads blocked by single threading to continue running.
996 thread_unsuspend(struct proc *p)
1000 mtx_assert(&sched_lock, MA_OWNED);
1001 PROC_LOCK_ASSERT(p, MA_OWNED);
1002 if (!P_SHOULDSTOP(p)) {
1003 while ((td = TAILQ_FIRST(&p->p_suspended))) {
1004 thread_unsuspend_one(td);
1006 } else if ((P_SHOULDSTOP(p) == P_STOPPED_SINGLE) &&
1007 (p->p_numthreads == p->p_suspcount)) {
1009 * Stopping everything also did the job for the single
1010 * threading request. Now we've downgraded to single-threaded,
1013 thread_unsuspend_one(p->p_singlethread);
1018 * End the single threading mode..
1021 thread_single_end(void)
1028 PROC_LOCK_ASSERT(p, MA_OWNED);
1029 p->p_flag &= ~(P_STOPPED_SINGLE | P_SINGLE_EXIT | P_SINGLE_BOUNDARY);
1030 mtx_lock_spin(&sched_lock);
1031 p->p_singlethread = NULL;
1032 p->p_procscopegrp = NULL;
1034 * If there are other threads they mey now run,
1035 * unless of course there is a blanket 'stop order'
1036 * on the process. The single threader must be allowed
1037 * to continue however as this is a bad place to stop.
1039 if ((p->p_numthreads != 1) && (!P_SHOULDSTOP(p))) {
1040 while ((td = TAILQ_FIRST(&p->p_suspended))) {
1041 thread_unsuspend_one(td);
1044 mtx_unlock_spin(&sched_lock);
1048 thread_find(struct proc *p, lwpid_t tid)
1052 PROC_LOCK_ASSERT(p, MA_OWNED);
1053 mtx_lock_spin(&sched_lock);
1054 FOREACH_THREAD_IN_PROC(p, td) {
1055 if (td->td_tid == tid)
1058 mtx_unlock_spin(&sched_lock);