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_hwpmc_hooks.h"
32 #include <sys/cdefs.h>
33 __FBSDID("$FreeBSD$");
35 #include <sys/param.h>
36 #include <sys/systm.h>
37 #include <sys/kernel.h>
39 #include <sys/mutex.h>
41 #include <sys/rangelock.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);
68 * thread related storage.
70 static uma_zone_t thread_zone;
72 TAILQ_HEAD(, thread) zombie_threads = TAILQ_HEAD_INITIALIZER(zombie_threads);
73 static struct mtx zombie_lock;
74 MTX_SYSINIT(zombie_lock, &zombie_lock, "zombie lock", MTX_SPIN);
76 static void thread_zombie(struct thread *);
78 #define TID_BUFFER_SIZE 1024
81 static struct unrhdr *tid_unrhdr;
82 static lwpid_t tid_buffer[TID_BUFFER_SIZE];
83 static int tid_head, tid_tail;
84 static MALLOC_DEFINE(M_TIDHASH, "tidhash", "thread hash");
86 struct tidhashhead *tidhashtbl;
88 struct rwlock tidhash_lock;
95 tid = alloc_unr(tid_unrhdr);
99 if (tid_head == tid_tail) {
100 mtx_unlock(&tid_lock);
103 tid = tid_buffer[tid_head];
104 tid_head = (tid_head + 1) % TID_BUFFER_SIZE;
105 mtx_unlock(&tid_lock);
110 tid_free(lwpid_t tid)
112 lwpid_t tmp_tid = -1;
115 if ((tid_tail + 1) % TID_BUFFER_SIZE == tid_head) {
116 tmp_tid = tid_buffer[tid_head];
117 tid_head = (tid_head + 1) % TID_BUFFER_SIZE;
119 tid_buffer[tid_tail] = tid;
120 tid_tail = (tid_tail + 1) % TID_BUFFER_SIZE;
121 mtx_unlock(&tid_lock);
123 free_unr(tid_unrhdr, tmp_tid);
127 * Prepare a thread for use.
130 thread_ctor(void *mem, int size, void *arg, int flags)
134 td = (struct thread *)mem;
135 td->td_state = TDS_INACTIVE;
136 td->td_oncpu = NOCPU;
138 td->td_tid = tid_alloc();
141 * Note that td_critnest begins life as 1 because the thread is not
142 * running and is thereby implicitly waiting to be on the receiving
143 * end of a context switch.
146 td->td_lend_user_pri = PRI_MAX;
147 EVENTHANDLER_INVOKE(thread_ctor, td);
149 audit_thread_alloc(td);
151 umtx_thread_alloc(td);
156 * Reclaim a thread after use.
159 thread_dtor(void *mem, int size, void *arg)
163 td = (struct thread *)mem;
166 /* Verify that this thread is in a safe state to free. */
167 switch (td->td_state) {
173 * We must never unlink a thread that is in one of
174 * these states, because it is currently active.
176 panic("bad state for thread unlinking");
181 panic("bad thread state");
186 audit_thread_free(td);
188 /* Free all OSD associated to this thread. */
191 EVENTHANDLER_INVOKE(thread_dtor, td);
192 tid_free(td->td_tid);
196 * Initialize type-stable parts of a thread (when newly created).
199 thread_init(void *mem, int size, int flags)
203 td = (struct thread *)mem;
205 td->td_sleepqueue = sleepq_alloc();
206 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 rlqentry_free(td->td_rlqe);
226 turnstile_free(td->td_turnstile);
227 sleepq_free(td->td_sleepqueue);
228 umtx_thread_fini(td);
233 * For a newly created process,
234 * link up all the structures and its initial threads etc.
236 * {arch}/{arch}/machdep.c {arch}_init(), init386() etc.
237 * proc_dtor() (should go away)
241 proc_linkup0(struct proc *p, struct thread *td)
243 TAILQ_INIT(&p->p_threads); /* all threads in proc */
248 proc_linkup(struct proc *p, struct thread *td)
251 sigqueue_init(&p->p_sigqueue, p);
252 p->p_ksi = ksiginfo_alloc(1);
253 if (p->p_ksi != NULL) {
254 /* XXX p_ksi may be null if ksiginfo zone is not ready */
255 p->p_ksi->ksi_flags = KSI_EXT | KSI_INS;
257 LIST_INIT(&p->p_mqnotifier);
263 * Initialize global thread allocation resources.
269 mtx_init(&tid_lock, "TID lock", NULL, MTX_DEF);
272 * pid_max cannot be greater than PID_MAX.
273 * leave one number for thread0.
275 tid_unrhdr = new_unrhdr(PID_MAX + 2, INT_MAX, &tid_lock);
277 thread_zone = uma_zcreate("THREAD", sched_sizeof_thread(),
278 thread_ctor, thread_dtor, thread_init, thread_fini,
280 tidhashtbl = hashinit(maxproc / 2, M_TIDHASH, &tidhash);
281 rw_init(&tidhash_lock, "tidhash");
285 * Place an unused thread on the zombie list.
286 * Use the slpq as that must be unused by now.
289 thread_zombie(struct thread *td)
291 mtx_lock_spin(&zombie_lock);
292 TAILQ_INSERT_HEAD(&zombie_threads, td, td_slpq);
293 mtx_unlock_spin(&zombie_lock);
297 * Release a thread that has exited after cpu_throw().
300 thread_stash(struct thread *td)
302 atomic_subtract_rel_int(&td->td_proc->p_exitthreads, 1);
307 * Reap zombie resources.
312 struct thread *td_first, *td_next;
315 * Don't even bother to lock if none at this instant,
316 * we really don't care about the next instant..
318 if (!TAILQ_EMPTY(&zombie_threads)) {
319 mtx_lock_spin(&zombie_lock);
320 td_first = TAILQ_FIRST(&zombie_threads);
322 TAILQ_INIT(&zombie_threads);
323 mtx_unlock_spin(&zombie_lock);
325 td_next = TAILQ_NEXT(td_first, td_slpq);
326 if (td_first->td_ucred)
327 crfree(td_first->td_ucred);
328 thread_free(td_first);
338 thread_alloc(int pages)
342 thread_reap(); /* check if any zombies to get */
344 td = (struct thread *)uma_zalloc(thread_zone, M_WAITOK);
345 KASSERT(td->td_kstack == 0, ("thread_alloc got thread with kstack"));
346 if (!vm_thread_new(td, pages)) {
347 uma_zfree(thread_zone, td);
350 cpu_thread_alloc(td);
355 thread_alloc_stack(struct thread *td, int pages)
358 KASSERT(td->td_kstack == 0,
359 ("thread_alloc_stack called on a thread with kstack"));
360 if (!vm_thread_new(td, pages))
362 cpu_thread_alloc(td);
367 * Deallocate a thread.
370 thread_free(struct thread *td)
373 lock_profile_thread_exit(td);
375 cpuset_rel(td->td_cpuset);
376 td->td_cpuset = NULL;
378 if (td->td_kstack != 0)
379 vm_thread_dispose(td);
380 uma_zfree(thread_zone, td);
384 * Discard the current thread and exit from its context.
385 * Always called with scheduler locked.
387 * Because we can't free a thread while we're operating under its context,
388 * push the current thread into our CPU's deadthread holder. This means
389 * we needn't worry about someone else grabbing our context before we
395 uint64_t runtime, new_switchtime;
404 PROC_SLOCK_ASSERT(p, MA_OWNED);
405 mtx_assert(&Giant, MA_NOTOWNED);
407 PROC_LOCK_ASSERT(p, MA_OWNED);
408 KASSERT(p != NULL, ("thread exiting without a process"));
409 CTR3(KTR_PROC, "thread_exit: thread %p (pid %ld, %s)", td,
410 (long)p->p_pid, td->td_name);
411 KASSERT(TAILQ_EMPTY(&td->td_sigqueue.sq_list), ("signal pending"));
414 AUDIT_SYSCALL_EXIT(0, td);
416 umtx_thread_exit(td);
418 * drop FPU & debug register state storage, or any other
419 * architecture specific resources that
420 * would not be on a new untouched process.
422 cpu_thread_exit(td); /* XXXSMP */
425 * The last thread is left attached to the process
426 * So that the whole bundle gets recycled. Skip
427 * all this stuff if we never had threads.
428 * EXIT clears all sign of other threads when
429 * it goes to single threading, so the last thread always
430 * takes the short path.
432 if (p->p_flag & P_HADTHREADS) {
433 if (p->p_numthreads > 1) {
434 atomic_add_int(&td->td_proc->p_exitthreads, 1);
436 td2 = FIRST_THREAD_IN_PROC(p);
437 sched_exit_thread(td2, td);
440 * The test below is NOT true if we are the
441 * sole exiting thread. P_STOPPED_SINGLE is unset
442 * in exit1() after it is the only survivor.
444 if (P_SHOULDSTOP(p) == P_STOPPED_SINGLE) {
445 if (p->p_numthreads == p->p_suspcount) {
446 thread_lock(p->p_singlethread);
447 wakeup_swapper = thread_unsuspend_one(
449 thread_unlock(p->p_singlethread);
455 PCPU_SET(deadthread, td);
458 * The last thread is exiting.. but not through exit()
460 panic ("thread_exit: Last thread exiting on its own");
465 * If this thread is part of a process that is being tracked by hwpmc(4),
466 * inform the module of the thread's impending exit.
468 if (PMC_PROC_IS_USING_PMCS(td->td_proc))
469 PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_OUT);
476 /* Do the same timestamp bookkeeping that mi_switch() would do. */
477 new_switchtime = cpu_ticks();
478 runtime = new_switchtime - PCPU_GET(switchtime);
479 td->td_runtime += runtime;
480 td->td_incruntime += runtime;
481 PCPU_SET(switchtime, new_switchtime);
482 PCPU_SET(switchticks, ticks);
483 PCPU_INC(cnt.v_swtch);
485 /* Save our resource usage in our process. */
486 td->td_ru.ru_nvcsw++;
488 rucollect(&p->p_ru, &td->td_ru);
491 td->td_state = TDS_INACTIVE;
493 witness_thread_exit(td);
495 CTR1(KTR_PROC, "thread_exit: cpu_throw() thread %p", td);
497 panic("I'm a teapot!");
502 * Do any thread specific cleanups that may be needed in wait()
503 * called with Giant, proc and schedlock not held.
506 thread_wait(struct proc *p)
510 mtx_assert(&Giant, MA_NOTOWNED);
511 KASSERT(p->p_numthreads == 1, ("multiple threads in thread_wait()"));
512 KASSERT(p->p_exitthreads == 0, ("p_exitthreads leaking"));
513 td = FIRST_THREAD_IN_PROC(p);
514 /* Lock the last thread so we spin until it exits cpu_throw(). */
517 lock_profile_thread_exit(td);
518 cpuset_rel(td->td_cpuset);
519 td->td_cpuset = NULL;
520 cpu_thread_clean(td);
521 crfree(td->td_ucred);
522 thread_reap(); /* check for zombie threads etc. */
526 * Link a thread to a process.
527 * set up anything that needs to be initialized for it to
528 * be used by the process.
531 thread_link(struct thread *td, struct proc *p)
535 * XXX This can't be enabled because it's called for proc0 before
536 * its lock has been created.
537 * PROC_LOCK_ASSERT(p, MA_OWNED);
539 td->td_state = TDS_INACTIVE;
541 td->td_flags = TDF_INMEM;
543 LIST_INIT(&td->td_contested);
544 LIST_INIT(&td->td_lprof[0]);
545 LIST_INIT(&td->td_lprof[1]);
546 sigqueue_init(&td->td_sigqueue, p);
547 callout_init(&td->td_slpcallout, CALLOUT_MPSAFE);
548 TAILQ_INSERT_TAIL(&p->p_threads, td, td_plist);
557 thread_unlink(struct thread *td)
559 struct proc *p = td->td_proc;
561 PROC_LOCK_ASSERT(p, MA_OWNED);
562 TAILQ_REMOVE(&p->p_threads, td, td_plist);
564 /* could clear a few other things here */
565 /* Must NOT clear links to proc! */
569 calc_remaining(struct proc *p, int mode)
573 PROC_LOCK_ASSERT(p, MA_OWNED);
574 PROC_SLOCK_ASSERT(p, MA_OWNED);
575 if (mode == SINGLE_EXIT)
576 remaining = p->p_numthreads;
577 else if (mode == SINGLE_BOUNDARY)
578 remaining = p->p_numthreads - p->p_boundary_count;
579 else if (mode == SINGLE_NO_EXIT)
580 remaining = p->p_numthreads - p->p_suspcount;
582 panic("calc_remaining: wrong mode %d", mode);
587 remain_for_mode(int mode)
594 weed_inhib(int mode, struct thread *td2, struct proc *p)
598 PROC_LOCK_ASSERT(p, MA_OWNED);
599 PROC_SLOCK_ASSERT(p, MA_OWNED);
600 THREAD_LOCK_ASSERT(td2, MA_OWNED);
605 if (TD_IS_SUSPENDED(td2))
606 wakeup_swapper |= thread_unsuspend_one(td2);
607 if (TD_ON_SLEEPQ(td2) && (td2->td_flags & TDF_SINTR) != 0)
608 wakeup_swapper |= sleepq_abort(td2, EINTR);
610 case SINGLE_BOUNDARY:
611 if (TD_IS_SUSPENDED(td2) && (td2->td_flags & TDF_BOUNDARY) == 0)
612 wakeup_swapper |= thread_unsuspend_one(td2);
613 if (TD_ON_SLEEPQ(td2) && (td2->td_flags & TDF_SINTR) != 0)
614 wakeup_swapper |= sleepq_abort(td2, ERESTART);
617 if (TD_IS_SUSPENDED(td2) && (td2->td_flags & TDF_BOUNDARY) == 0)
618 wakeup_swapper |= thread_unsuspend_one(td2);
619 if (TD_ON_SLEEPQ(td2) && (td2->td_flags & TDF_SINTR) != 0)
620 wakeup_swapper |= sleepq_abort(td2, ERESTART);
623 return (wakeup_swapper);
627 * Enforce single-threading.
629 * Returns 1 if the caller must abort (another thread is waiting to
630 * exit the process or similar). Process is locked!
631 * Returns 0 when you are successfully the only thread running.
632 * A process has successfully single threaded in the suspend mode when
633 * There are no threads in user mode. Threads in the kernel must be
634 * allowed to continue until they get to the user boundary. They may even
635 * copy out their return values and data before suspending. They may however be
636 * accelerated in reaching the user boundary as we will wake up
637 * any sleeping threads that are interruptable. (PCATCH).
640 thread_single(int mode)
645 int remaining, wakeup_swapper;
649 mtx_assert(&Giant, MA_NOTOWNED);
650 PROC_LOCK_ASSERT(p, MA_OWNED);
652 if ((p->p_flag & P_HADTHREADS) == 0)
655 /* Is someone already single threading? */
656 if (p->p_singlethread != NULL && p->p_singlethread != td)
659 if (mode == SINGLE_EXIT) {
660 p->p_flag |= P_SINGLE_EXIT;
661 p->p_flag &= ~P_SINGLE_BOUNDARY;
663 p->p_flag &= ~P_SINGLE_EXIT;
664 if (mode == SINGLE_BOUNDARY)
665 p->p_flag |= P_SINGLE_BOUNDARY;
667 p->p_flag &= ~P_SINGLE_BOUNDARY;
669 p->p_flag |= P_STOPPED_SINGLE;
671 p->p_singlethread = td;
672 remaining = calc_remaining(p, mode);
673 while (remaining != remain_for_mode(mode)) {
674 if (P_SHOULDSTOP(p) != P_STOPPED_SINGLE)
677 FOREACH_THREAD_IN_PROC(p, td2) {
681 td2->td_flags |= TDF_ASTPENDING | TDF_NEEDSUSPCHK;
682 if (TD_IS_INHIBITED(td2))
683 wakeup_swapper |= weed_inhib(mode, td2, p);
685 else if (TD_IS_RUNNING(td2) && td != td2) {
693 remaining = calc_remaining(p, mode);
696 * Maybe we suspended some threads.. was it enough?
698 if (remaining == remain_for_mode(mode))
703 * Wake us up when everyone else has suspended.
704 * In the mean time we suspend as well.
706 thread_suspend_switch(td);
707 remaining = calc_remaining(p, mode);
709 if (mode == SINGLE_EXIT) {
711 * Convert the process to an unthreaded process. The
712 * SINGLE_EXIT is called by exit1() or execve(), in
713 * both cases other threads must be retired.
715 KASSERT(p->p_numthreads == 1, ("Unthreading with >1 threads"));
716 p->p_singlethread = NULL;
717 p->p_flag &= ~(P_STOPPED_SINGLE | P_SINGLE_EXIT | P_HADTHREADS);
720 * Wait for any remaining threads to exit cpu_throw().
722 while (p->p_exitthreads != 0) {
725 sched_relinquish(td);
735 thread_suspend_check_needed(void)
742 PROC_LOCK_ASSERT(p, MA_OWNED);
743 return (P_SHOULDSTOP(p) || ((p->p_flag & P_TRACED) != 0 &&
744 (td->td_dbgflags & TDB_SUSPEND) != 0));
748 * Called in from locations that can safely check to see
749 * whether we have to suspend or at least throttle for a
750 * single-thread event (e.g. fork).
752 * Such locations include userret().
753 * If the "return_instead" argument is non zero, the thread must be able to
754 * accept 0 (caller may continue), or 1 (caller must abort) as a result.
756 * The 'return_instead' argument tells the function if it may do a
757 * thread_exit() or suspend, or whether the caller must abort and back
760 * If the thread that set the single_threading request has set the
761 * P_SINGLE_EXIT bit in the process flags then this call will never return
762 * if 'return_instead' is false, but will exit.
764 * P_SINGLE_EXIT | return_instead == 0| return_instead != 0
765 *---------------+--------------------+---------------------
766 * 0 | returns 0 | returns 0 or 1
767 * | when ST ends | immediately
768 *---------------+--------------------+---------------------
769 * 1 | thread exits | returns 1
771 * 0 = thread_exit() or suspension ok,
772 * other = return error instead of stopping the thread.
774 * While a full suspension is under effect, even a single threading
775 * thread would be suspended if it made this call (but it shouldn't).
776 * This call should only be made from places where
777 * thread_exit() would be safe as that may be the outcome unless
778 * return_instead is set.
781 thread_suspend_check(int return_instead)
789 mtx_assert(&Giant, MA_NOTOWNED);
790 PROC_LOCK_ASSERT(p, MA_OWNED);
791 while (thread_suspend_check_needed()) {
792 if (P_SHOULDSTOP(p) == P_STOPPED_SINGLE) {
793 KASSERT(p->p_singlethread != NULL,
794 ("singlethread not set"));
796 * The only suspension in action is a
797 * single-threading. Single threader need not stop.
798 * XXX Should be safe to access unlocked
799 * as it can only be set to be true by us.
801 if (p->p_singlethread == td)
802 return (0); /* Exempt from stopping. */
804 if ((p->p_flag & P_SINGLE_EXIT) && return_instead)
807 /* Should we goto user boundary if we didn't come from there? */
808 if (P_SHOULDSTOP(p) == P_STOPPED_SINGLE &&
809 (p->p_flag & P_SINGLE_BOUNDARY) && return_instead)
813 * Ignore suspend requests for stop signals if they
816 if (P_SHOULDSTOP(p) == P_STOPPED_SIG &&
817 td->td_flags & TDF_SBDRY) {
818 KASSERT(return_instead,
819 ("TDF_SBDRY set for unsafe thread_suspend_check"));
824 * If the process is waiting for us to exit,
825 * this thread should just suicide.
826 * Assumes that P_SINGLE_EXIT implies P_STOPPED_SINGLE.
828 if ((p->p_flag & P_SINGLE_EXIT) && (p->p_singlethread != td)) {
840 if (P_SHOULDSTOP(p) == P_STOPPED_SINGLE) {
841 if (p->p_numthreads == p->p_suspcount + 1) {
842 thread_lock(p->p_singlethread);
844 thread_unsuspend_one(p->p_singlethread);
845 thread_unlock(p->p_singlethread);
853 * When a thread suspends, it just
854 * gets taken off all queues.
856 thread_suspend_one(td);
857 if (return_instead == 0) {
858 p->p_boundary_count++;
859 td->td_flags |= TDF_BOUNDARY;
862 mi_switch(SW_INVOL | SWT_SUSPEND, NULL);
863 if (return_instead == 0)
864 td->td_flags &= ~TDF_BOUNDARY;
867 if (return_instead == 0) {
869 p->p_boundary_count--;
877 thread_suspend_switch(struct thread *td)
882 KASSERT(!TD_IS_SUSPENDED(td), ("already suspended"));
883 PROC_LOCK_ASSERT(p, MA_OWNED);
884 PROC_SLOCK_ASSERT(p, MA_OWNED);
886 * We implement thread_suspend_one in stages here to avoid
887 * dropping the proc lock while the thread lock is owned.
893 td->td_flags &= ~TDF_NEEDSUSPCHK;
894 TD_SET_SUSPENDED(td);
898 mi_switch(SW_VOL | SWT_SUSPEND, NULL);
906 thread_suspend_one(struct thread *td)
908 struct proc *p = td->td_proc;
910 PROC_SLOCK_ASSERT(p, MA_OWNED);
911 THREAD_LOCK_ASSERT(td, MA_OWNED);
912 KASSERT(!TD_IS_SUSPENDED(td), ("already suspended"));
914 td->td_flags &= ~TDF_NEEDSUSPCHK;
915 TD_SET_SUSPENDED(td);
920 thread_unsuspend_one(struct thread *td)
922 struct proc *p = td->td_proc;
924 PROC_SLOCK_ASSERT(p, MA_OWNED);
925 THREAD_LOCK_ASSERT(td, MA_OWNED);
926 KASSERT(TD_IS_SUSPENDED(td), ("Thread not suspended"));
927 TD_CLR_SUSPENDED(td);
929 return (setrunnable(td));
933 * Allow all threads blocked by single threading to continue running.
936 thread_unsuspend(struct proc *p)
941 PROC_LOCK_ASSERT(p, MA_OWNED);
942 PROC_SLOCK_ASSERT(p, MA_OWNED);
944 if (!P_SHOULDSTOP(p)) {
945 FOREACH_THREAD_IN_PROC(p, td) {
947 if (TD_IS_SUSPENDED(td)) {
948 wakeup_swapper |= thread_unsuspend_one(td);
952 } else if ((P_SHOULDSTOP(p) == P_STOPPED_SINGLE) &&
953 (p->p_numthreads == p->p_suspcount)) {
955 * Stopping everything also did the job for the single
956 * threading request. Now we've downgraded to single-threaded,
959 thread_lock(p->p_singlethread);
960 wakeup_swapper = thread_unsuspend_one(p->p_singlethread);
961 thread_unlock(p->p_singlethread);
968 * End the single threading mode..
971 thread_single_end(void)
978 PROC_LOCK_ASSERT(p, MA_OWNED);
979 p->p_flag &= ~(P_STOPPED_SINGLE | P_SINGLE_EXIT | P_SINGLE_BOUNDARY);
981 p->p_singlethread = NULL;
984 * If there are other threads they may now run,
985 * unless of course there is a blanket 'stop order'
986 * on the process. The single threader must be allowed
987 * to continue however as this is a bad place to stop.
989 if (p->p_numthreads != remain_for_mode(SINGLE_EXIT) &&
991 FOREACH_THREAD_IN_PROC(p, td) {
993 if (TD_IS_SUSPENDED(td)) {
994 wakeup_swapper |= thread_unsuspend_one(td);
1005 thread_find(struct proc *p, lwpid_t tid)
1009 PROC_LOCK_ASSERT(p, MA_OWNED);
1010 FOREACH_THREAD_IN_PROC(p, td) {
1011 if (td->td_tid == tid)
1017 /* Locate a thread by number; return with proc lock held. */
1019 tdfind(lwpid_t tid, pid_t pid)
1021 #define RUN_THRESH 16
1025 rw_rlock(&tidhash_lock);
1026 LIST_FOREACH(td, TIDHASH(tid), td_hash) {
1027 if (td->td_tid == tid) {
1028 if (pid != -1 && td->td_proc->p_pid != pid) {
1032 PROC_LOCK(td->td_proc);
1033 if (td->td_proc->p_state == PRS_NEW) {
1034 PROC_UNLOCK(td->td_proc);
1038 if (run > RUN_THRESH) {
1039 if (rw_try_upgrade(&tidhash_lock)) {
1040 LIST_REMOVE(td, td_hash);
1041 LIST_INSERT_HEAD(TIDHASH(td->td_tid),
1043 rw_wunlock(&tidhash_lock);
1051 rw_runlock(&tidhash_lock);
1056 tidhash_add(struct thread *td)
1058 rw_wlock(&tidhash_lock);
1059 LIST_INSERT_HEAD(TIDHASH(td->td_tid), td, td_hash);
1060 rw_wunlock(&tidhash_lock);
1064 tidhash_remove(struct thread *td)
1066 rw_wlock(&tidhash_lock);
1067 LIST_REMOVE(td, td_hash);
1068 rw_wunlock(&tidhash_lock);