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/rangelock.h>
43 #include <sys/resourcevar.h>
46 #include <sys/sched.h>
47 #include <sys/sleepqueue.h>
48 #include <sys/selinfo.h>
49 #include <sys/turnstile.h>
51 #include <sys/rwlock.h>
53 #include <sys/cpuset.h>
55 #include <sys/pmckern.h>
58 #include <security/audit/audit.h>
61 #include <vm/vm_extern.h>
63 #include <sys/eventhandler.h>
65 SDT_PROVIDER_DECLARE(proc);
66 SDT_PROBE_DEFINE(proc, , , lwp__exit);
70 * thread related storage.
72 static uma_zone_t thread_zone;
74 TAILQ_HEAD(, thread) zombie_threads = TAILQ_HEAD_INITIALIZER(zombie_threads);
75 static struct mtx zombie_lock;
76 MTX_SYSINIT(zombie_lock, &zombie_lock, "zombie lock", MTX_SPIN);
78 static void thread_zombie(struct thread *);
80 #define TID_BUFFER_SIZE 1024
83 static struct unrhdr *tid_unrhdr;
84 static lwpid_t tid_buffer[TID_BUFFER_SIZE];
85 static int tid_head, tid_tail;
86 static MALLOC_DEFINE(M_TIDHASH, "tidhash", "thread hash");
88 struct tidhashhead *tidhashtbl;
90 struct rwlock tidhash_lock;
97 tid = alloc_unr(tid_unrhdr);
101 if (tid_head == tid_tail) {
102 mtx_unlock(&tid_lock);
105 tid = tid_buffer[tid_head];
106 tid_head = (tid_head + 1) % TID_BUFFER_SIZE;
107 mtx_unlock(&tid_lock);
112 tid_free(lwpid_t tid)
114 lwpid_t tmp_tid = -1;
117 if ((tid_tail + 1) % TID_BUFFER_SIZE == tid_head) {
118 tmp_tid = tid_buffer[tid_head];
119 tid_head = (tid_head + 1) % TID_BUFFER_SIZE;
121 tid_buffer[tid_tail] = tid;
122 tid_tail = (tid_tail + 1) % TID_BUFFER_SIZE;
123 mtx_unlock(&tid_lock);
125 free_unr(tid_unrhdr, tmp_tid);
129 * Prepare a thread for use.
132 thread_ctor(void *mem, int size, void *arg, int flags)
136 td = (struct thread *)mem;
137 td->td_state = TDS_INACTIVE;
138 td->td_oncpu = NOCPU;
140 td->td_tid = tid_alloc();
143 * Note that td_critnest begins life as 1 because the thread is not
144 * running and is thereby implicitly waiting to be on the receiving
145 * end of a context switch.
148 td->td_lend_user_pri = PRI_MAX;
149 EVENTHANDLER_INVOKE(thread_ctor, td);
151 audit_thread_alloc(td);
153 umtx_thread_alloc(td);
158 * Reclaim a thread after use.
161 thread_dtor(void *mem, int size, void *arg)
165 td = (struct thread *)mem;
168 /* Verify that this thread is in a safe state to free. */
169 switch (td->td_state) {
175 * We must never unlink a thread that is in one of
176 * these states, because it is currently active.
178 panic("bad state for thread unlinking");
183 panic("bad thread state");
188 audit_thread_free(td);
190 /* Free all OSD associated to this thread. */
193 EVENTHANDLER_INVOKE(thread_dtor, td);
194 tid_free(td->td_tid);
198 * Initialize type-stable parts of a thread (when newly created).
201 thread_init(void *mem, int size, int flags)
205 td = (struct thread *)mem;
207 td->td_sleepqueue = sleepq_alloc();
208 td->td_turnstile = turnstile_alloc();
210 td->td_vp_reserv = 0;
211 EVENTHANDLER_INVOKE(thread_init, td);
212 td->td_sched = (struct td_sched *)&td[1];
213 umtx_thread_init(td);
220 * Tear down type-stable parts of a thread (just before being discarded).
223 thread_fini(void *mem, int size)
227 td = (struct thread *)mem;
228 EVENTHANDLER_INVOKE(thread_fini, td);
229 rlqentry_free(td->td_rlqe);
230 turnstile_free(td->td_turnstile);
231 sleepq_free(td->td_sleepqueue);
232 umtx_thread_fini(td);
237 * For a newly created process,
238 * link up all the structures and its initial threads etc.
240 * {arch}/{arch}/machdep.c ia64_init(), init386() etc.
241 * proc_dtor() (should go away)
245 proc_linkup0(struct proc *p, struct thread *td)
247 TAILQ_INIT(&p->p_threads); /* all threads in proc */
252 proc_linkup(struct proc *p, struct thread *td)
255 sigqueue_init(&p->p_sigqueue, p);
256 p->p_ksi = ksiginfo_alloc(1);
257 if (p->p_ksi != NULL) {
258 /* XXX p_ksi may be null if ksiginfo zone is not ready */
259 p->p_ksi->ksi_flags = KSI_EXT | KSI_INS;
261 LIST_INIT(&p->p_mqnotifier);
267 * Initialize global thread allocation resources.
273 mtx_init(&tid_lock, "TID lock", NULL, MTX_DEF);
276 * pid_max cannot be greater than PID_MAX.
277 * leave one number for thread0.
279 tid_unrhdr = new_unrhdr(PID_MAX + 2, INT_MAX, &tid_lock);
281 thread_zone = uma_zcreate("THREAD", sched_sizeof_thread(),
282 thread_ctor, thread_dtor, thread_init, thread_fini,
284 tidhashtbl = hashinit(maxproc / 2, M_TIDHASH, &tidhash);
285 rw_init(&tidhash_lock, "tidhash");
289 * Place an unused thread on the zombie list.
290 * Use the slpq as that must be unused by now.
293 thread_zombie(struct thread *td)
295 mtx_lock_spin(&zombie_lock);
296 TAILQ_INSERT_HEAD(&zombie_threads, td, td_slpq);
297 mtx_unlock_spin(&zombie_lock);
301 * Release a thread that has exited after cpu_throw().
304 thread_stash(struct thread *td)
306 atomic_subtract_rel_int(&td->td_proc->p_exitthreads, 1);
311 * Reap zombie resources.
316 struct thread *td_first, *td_next;
319 * Don't even bother to lock if none at this instant,
320 * we really don't care about the next instant..
322 if (!TAILQ_EMPTY(&zombie_threads)) {
323 mtx_lock_spin(&zombie_lock);
324 td_first = TAILQ_FIRST(&zombie_threads);
326 TAILQ_INIT(&zombie_threads);
327 mtx_unlock_spin(&zombie_lock);
329 td_next = TAILQ_NEXT(td_first, td_slpq);
330 if (td_first->td_ucred)
331 crfree(td_first->td_ucred);
332 thread_free(td_first);
342 thread_alloc(int pages)
346 thread_reap(); /* check if any zombies to get */
348 td = (struct thread *)uma_zalloc(thread_zone, M_WAITOK);
349 KASSERT(td->td_kstack == 0, ("thread_alloc got thread with kstack"));
350 if (!vm_thread_new(td, pages)) {
351 uma_zfree(thread_zone, td);
354 cpu_thread_alloc(td);
359 thread_alloc_stack(struct thread *td, int pages)
362 KASSERT(td->td_kstack == 0,
363 ("thread_alloc_stack called on a thread with kstack"));
364 if (!vm_thread_new(td, pages))
366 cpu_thread_alloc(td);
371 * Deallocate a thread.
374 thread_free(struct thread *td)
377 lock_profile_thread_exit(td);
379 cpuset_rel(td->td_cpuset);
380 td->td_cpuset = NULL;
382 if (td->td_kstack != 0)
383 vm_thread_dispose(td);
384 uma_zfree(thread_zone, td);
388 * Discard the current thread and exit from its context.
389 * Always called with scheduler locked.
391 * Because we can't free a thread while we're operating under its context,
392 * push the current thread into our CPU's deadthread holder. This means
393 * we needn't worry about someone else grabbing our context before we
399 uint64_t runtime, new_switchtime;
408 PROC_SLOCK_ASSERT(p, MA_OWNED);
409 mtx_assert(&Giant, MA_NOTOWNED);
411 PROC_LOCK_ASSERT(p, MA_OWNED);
412 KASSERT(p != NULL, ("thread exiting without a process"));
413 CTR3(KTR_PROC, "thread_exit: thread %p (pid %ld, %s)", td,
414 (long)p->p_pid, td->td_name);
415 KASSERT(TAILQ_EMPTY(&td->td_sigqueue.sq_list), ("signal pending"));
418 AUDIT_SYSCALL_EXIT(0, td);
420 umtx_thread_exit(td);
422 * drop FPU & debug register state storage, or any other
423 * architecture specific resources that
424 * would not be on a new untouched process.
426 cpu_thread_exit(td); /* XXXSMP */
429 * The last thread is left attached to the process
430 * So that the whole bundle gets recycled. Skip
431 * all this stuff if we never had threads.
432 * EXIT clears all sign of other threads when
433 * it goes to single threading, so the last thread always
434 * takes the short path.
436 if (p->p_flag & P_HADTHREADS) {
437 if (p->p_numthreads > 1) {
439 td2 = FIRST_THREAD_IN_PROC(p);
440 sched_exit_thread(td2, td);
443 * The test below is NOT true if we are the
444 * sole exiting thread. P_STOPPED_SINGLE is unset
445 * in exit1() after it is the only survivor.
447 if (P_SHOULDSTOP(p) == P_STOPPED_SINGLE) {
448 if (p->p_numthreads == p->p_suspcount) {
449 thread_lock(p->p_singlethread);
450 wakeup_swapper = thread_unsuspend_one(
452 thread_unlock(p->p_singlethread);
458 atomic_add_int(&td->td_proc->p_exitthreads, 1);
459 PCPU_SET(deadthread, td);
462 * The last thread is exiting.. but not through exit()
464 panic ("thread_exit: Last thread exiting on its own");
469 * If this thread is part of a process that is being tracked by hwpmc(4),
470 * inform the module of the thread's impending exit.
472 if (PMC_PROC_IS_USING_PMCS(td->td_proc))
473 PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_OUT);
477 /* Do the same timestamp bookkeeping that mi_switch() would do. */
478 new_switchtime = cpu_ticks();
479 runtime = new_switchtime - PCPU_GET(switchtime);
480 td->td_runtime += runtime;
481 td->td_incruntime += runtime;
482 PCPU_SET(switchtime, new_switchtime);
483 PCPU_SET(switchticks, ticks);
484 PCPU_INC(cnt.v_swtch);
486 /* Save our resource usage in our process. */
487 td->td_ru.ru_nvcsw++;
489 rucollect(&p->p_ru, &td->td_ru);
493 td->td_state = TDS_INACTIVE;
495 witness_thread_exit(td);
497 CTR1(KTR_PROC, "thread_exit: cpu_throw() thread %p", td);
499 panic("I'm a teapot!");
504 * Do any thread specific cleanups that may be needed in wait()
505 * called with Giant, proc and schedlock not held.
508 thread_wait(struct proc *p)
512 mtx_assert(&Giant, MA_NOTOWNED);
513 KASSERT((p->p_numthreads == 1), ("Multiple threads in wait1()"));
514 td = FIRST_THREAD_IN_PROC(p);
515 /* Lock the last thread so we spin until it exits cpu_throw(). */
518 /* Wait for any remaining threads to exit cpu_throw(). */
519 while (p->p_exitthreads)
520 sched_relinquish(curthread);
521 lock_profile_thread_exit(td);
522 cpuset_rel(td->td_cpuset);
523 td->td_cpuset = NULL;
524 cpu_thread_clean(td);
525 crfree(td->td_ucred);
526 thread_reap(); /* check for zombie threads etc. */
530 * Link a thread to a process.
531 * set up anything that needs to be initialized for it to
532 * be used by the process.
535 thread_link(struct thread *td, struct proc *p)
539 * XXX This can't be enabled because it's called for proc0 before
540 * its lock has been created.
541 * PROC_LOCK_ASSERT(p, MA_OWNED);
543 td->td_state = TDS_INACTIVE;
545 td->td_flags = TDF_INMEM;
547 LIST_INIT(&td->td_contested);
548 LIST_INIT(&td->td_lprof[0]);
549 LIST_INIT(&td->td_lprof[1]);
550 sigqueue_init(&td->td_sigqueue, p);
551 callout_init(&td->td_slpcallout, CALLOUT_MPSAFE);
552 TAILQ_INSERT_HEAD(&p->p_threads, td, td_plist);
557 * Convert a process with one thread to an unthreaded process.
560 thread_unthread(struct thread *td)
562 struct proc *p = td->td_proc;
564 KASSERT((p->p_numthreads == 1), ("Unthreading with >1 threads"));
565 p->p_flag &= ~P_HADTHREADS;
573 thread_unlink(struct thread *td)
575 struct proc *p = td->td_proc;
577 PROC_LOCK_ASSERT(p, MA_OWNED);
578 TAILQ_REMOVE(&p->p_threads, td, td_plist);
580 /* could clear a few other things here */
581 /* Must NOT clear links to proc! */
585 calc_remaining(struct proc *p, int mode)
589 PROC_LOCK_ASSERT(p, MA_OWNED);
590 PROC_SLOCK_ASSERT(p, MA_OWNED);
591 if (mode == SINGLE_EXIT)
592 remaining = p->p_numthreads;
593 else if (mode == SINGLE_BOUNDARY)
594 remaining = p->p_numthreads - p->p_boundary_count;
595 else if (mode == SINGLE_NO_EXIT)
596 remaining = p->p_numthreads - p->p_suspcount;
598 panic("calc_remaining: wrong mode %d", mode);
603 * Enforce single-threading.
605 * Returns 1 if the caller must abort (another thread is waiting to
606 * exit the process or similar). Process is locked!
607 * Returns 0 when you are successfully the only thread running.
608 * A process has successfully single threaded in the suspend mode when
609 * There are no threads in user mode. Threads in the kernel must be
610 * allowed to continue until they get to the user boundary. They may even
611 * copy out their return values and data before suspending. They may however be
612 * accelerated in reaching the user boundary as we will wake up
613 * any sleeping threads that are interruptable. (PCATCH).
616 thread_single(int mode)
621 int remaining, wakeup_swapper;
625 mtx_assert(&Giant, MA_NOTOWNED);
626 PROC_LOCK_ASSERT(p, MA_OWNED);
628 if ((p->p_flag & P_HADTHREADS) == 0)
631 /* Is someone already single threading? */
632 if (p->p_singlethread != NULL && p->p_singlethread != td)
635 if (mode == SINGLE_EXIT) {
636 p->p_flag |= P_SINGLE_EXIT;
637 p->p_flag &= ~P_SINGLE_BOUNDARY;
639 p->p_flag &= ~P_SINGLE_EXIT;
640 if (mode == SINGLE_BOUNDARY)
641 p->p_flag |= P_SINGLE_BOUNDARY;
643 p->p_flag &= ~P_SINGLE_BOUNDARY;
645 p->p_flag |= P_STOPPED_SINGLE;
647 p->p_singlethread = td;
648 remaining = calc_remaining(p, mode);
649 while (remaining != 1) {
650 if (P_SHOULDSTOP(p) != P_STOPPED_SINGLE)
653 FOREACH_THREAD_IN_PROC(p, td2) {
657 td2->td_flags |= TDF_ASTPENDING | TDF_NEEDSUSPCHK;
658 if (TD_IS_INHIBITED(td2)) {
661 if (TD_IS_SUSPENDED(td2))
663 thread_unsuspend_one(td2);
664 if (TD_ON_SLEEPQ(td2) &&
665 (td2->td_flags & TDF_SINTR))
667 sleepq_abort(td2, EINTR);
669 case SINGLE_BOUNDARY:
670 if (TD_IS_SUSPENDED(td2) &&
671 !(td2->td_flags & TDF_BOUNDARY))
673 thread_unsuspend_one(td2);
674 if (TD_ON_SLEEPQ(td2) &&
675 (td2->td_flags & TDF_SINTR))
677 sleepq_abort(td2, ERESTART);
680 if (TD_IS_SUSPENDED(td2) &&
681 !(td2->td_flags & TDF_BOUNDARY))
683 thread_unsuspend_one(td2);
684 if (TD_ON_SLEEPQ(td2) &&
685 (td2->td_flags & TDF_SINTR))
687 sleepq_abort(td2, ERESTART);
694 else if (TD_IS_RUNNING(td2) && td != td2) {
702 remaining = calc_remaining(p, mode);
705 * Maybe we suspended some threads.. was it enough?
712 * Wake us up when everyone else has suspended.
713 * In the mean time we suspend as well.
715 thread_suspend_switch(td);
716 remaining = calc_remaining(p, mode);
718 if (mode == SINGLE_EXIT) {
720 * We have gotten rid of all the other threads and we
721 * are about to either exit or exec. In either case,
722 * we try our utmost to revert to being a non-threaded
725 p->p_singlethread = NULL;
726 p->p_flag &= ~(P_STOPPED_SINGLE | P_SINGLE_EXIT);
734 * Called in from locations that can safely check to see
735 * whether we have to suspend or at least throttle for a
736 * single-thread event (e.g. fork).
738 * Such locations include userret().
739 * If the "return_instead" argument is non zero, the thread must be able to
740 * accept 0 (caller may continue), or 1 (caller must abort) as a result.
742 * The 'return_instead' argument tells the function if it may do a
743 * thread_exit() or suspend, or whether the caller must abort and back
746 * If the thread that set the single_threading request has set the
747 * P_SINGLE_EXIT bit in the process flags then this call will never return
748 * if 'return_instead' is false, but will exit.
750 * P_SINGLE_EXIT | return_instead == 0| return_instead != 0
751 *---------------+--------------------+---------------------
752 * 0 | returns 0 | returns 0 or 1
753 * | when ST ends | immediatly
754 *---------------+--------------------+---------------------
755 * 1 | thread exits | returns 1
757 * 0 = thread_exit() or suspension ok,
758 * other = return error instead of stopping the thread.
760 * While a full suspension is under effect, even a single threading
761 * thread would be suspended if it made this call (but it shouldn't).
762 * This call should only be made from places where
763 * thread_exit() would be safe as that may be the outcome unless
764 * return_instead is set.
767 thread_suspend_check(int return_instead)
775 mtx_assert(&Giant, MA_NOTOWNED);
776 PROC_LOCK_ASSERT(p, MA_OWNED);
777 while (P_SHOULDSTOP(p) ||
778 ((p->p_flag & P_TRACED) && (td->td_dbgflags & TDB_SUSPEND))) {
779 if (P_SHOULDSTOP(p) == P_STOPPED_SINGLE) {
780 KASSERT(p->p_singlethread != NULL,
781 ("singlethread not set"));
783 * The only suspension in action is a
784 * single-threading. Single threader need not stop.
785 * XXX Should be safe to access unlocked
786 * as it can only be set to be true by us.
788 if (p->p_singlethread == td)
789 return (0); /* Exempt from stopping. */
791 if ((p->p_flag & P_SINGLE_EXIT) && return_instead)
794 /* Should we goto user boundary if we didn't come from there? */
795 if (P_SHOULDSTOP(p) == P_STOPPED_SINGLE &&
796 (p->p_flag & P_SINGLE_BOUNDARY) && return_instead)
800 * Ignore suspend requests for stop signals if they
803 if (P_SHOULDSTOP(p) == P_STOPPED_SIG &&
804 td->td_flags & TDF_SBDRY) {
805 KASSERT(return_instead,
806 ("TDF_SBDRY set for unsafe thread_suspend_check"));
811 * If the process is waiting for us to exit,
812 * this thread should just suicide.
813 * Assumes that P_SINGLE_EXIT implies P_STOPPED_SINGLE.
815 if ((p->p_flag & P_SINGLE_EXIT) && (p->p_singlethread != td)) {
827 if (P_SHOULDSTOP(p) == P_STOPPED_SINGLE) {
828 if (p->p_numthreads == p->p_suspcount + 1) {
829 thread_lock(p->p_singlethread);
831 thread_unsuspend_one(p->p_singlethread);
832 thread_unlock(p->p_singlethread);
840 * When a thread suspends, it just
841 * gets taken off all queues.
843 thread_suspend_one(td);
844 if (return_instead == 0) {
845 p->p_boundary_count++;
846 td->td_flags |= TDF_BOUNDARY;
849 mi_switch(SW_INVOL | SWT_SUSPEND, NULL);
850 if (return_instead == 0)
851 td->td_flags &= ~TDF_BOUNDARY;
854 if (return_instead == 0) {
856 p->p_boundary_count--;
864 thread_suspend_switch(struct thread *td)
869 KASSERT(!TD_IS_SUSPENDED(td), ("already suspended"));
870 PROC_LOCK_ASSERT(p, MA_OWNED);
871 PROC_SLOCK_ASSERT(p, MA_OWNED);
873 * We implement thread_suspend_one in stages here to avoid
874 * dropping the proc lock while the thread lock is owned.
880 td->td_flags &= ~TDF_NEEDSUSPCHK;
881 TD_SET_SUSPENDED(td);
885 mi_switch(SW_VOL | SWT_SUSPEND, NULL);
893 thread_suspend_one(struct thread *td)
895 struct proc *p = td->td_proc;
897 PROC_SLOCK_ASSERT(p, MA_OWNED);
898 THREAD_LOCK_ASSERT(td, MA_OWNED);
899 KASSERT(!TD_IS_SUSPENDED(td), ("already suspended"));
901 td->td_flags &= ~TDF_NEEDSUSPCHK;
902 TD_SET_SUSPENDED(td);
907 thread_unsuspend_one(struct thread *td)
909 struct proc *p = td->td_proc;
911 PROC_SLOCK_ASSERT(p, MA_OWNED);
912 THREAD_LOCK_ASSERT(td, MA_OWNED);
913 KASSERT(TD_IS_SUSPENDED(td), ("Thread not suspended"));
914 TD_CLR_SUSPENDED(td);
916 return (setrunnable(td));
920 * Allow all threads blocked by single threading to continue running.
923 thread_unsuspend(struct proc *p)
928 PROC_LOCK_ASSERT(p, MA_OWNED);
929 PROC_SLOCK_ASSERT(p, MA_OWNED);
931 if (!P_SHOULDSTOP(p)) {
932 FOREACH_THREAD_IN_PROC(p, td) {
934 if (TD_IS_SUSPENDED(td)) {
935 wakeup_swapper |= thread_unsuspend_one(td);
939 } else if ((P_SHOULDSTOP(p) == P_STOPPED_SINGLE) &&
940 (p->p_numthreads == p->p_suspcount)) {
942 * Stopping everything also did the job for the single
943 * threading request. Now we've downgraded to single-threaded,
946 thread_lock(p->p_singlethread);
947 wakeup_swapper = thread_unsuspend_one(p->p_singlethread);
948 thread_unlock(p->p_singlethread);
955 * End the single threading mode..
958 thread_single_end(void)
966 PROC_LOCK_ASSERT(p, MA_OWNED);
967 p->p_flag &= ~(P_STOPPED_SINGLE | P_SINGLE_EXIT | P_SINGLE_BOUNDARY);
969 p->p_singlethread = NULL;
972 * If there are other threads they may now run,
973 * unless of course there is a blanket 'stop order'
974 * on the process. The single threader must be allowed
975 * to continue however as this is a bad place to stop.
977 if ((p->p_numthreads != 1) && (!P_SHOULDSTOP(p))) {
978 FOREACH_THREAD_IN_PROC(p, td) {
980 if (TD_IS_SUSPENDED(td)) {
981 wakeup_swapper |= thread_unsuspend_one(td);
992 thread_find(struct proc *p, lwpid_t tid)
996 PROC_LOCK_ASSERT(p, MA_OWNED);
997 FOREACH_THREAD_IN_PROC(p, td) {
998 if (td->td_tid == tid)
1004 /* Locate a thread by number; return with proc lock held. */
1006 tdfind(lwpid_t tid, pid_t pid)
1008 #define RUN_THRESH 16
1012 rw_rlock(&tidhash_lock);
1013 LIST_FOREACH(td, TIDHASH(tid), td_hash) {
1014 if (td->td_tid == tid) {
1015 if (pid != -1 && td->td_proc->p_pid != pid) {
1019 PROC_LOCK(td->td_proc);
1020 if (td->td_proc->p_state == PRS_NEW) {
1021 PROC_UNLOCK(td->td_proc);
1025 if (run > RUN_THRESH) {
1026 if (rw_try_upgrade(&tidhash_lock)) {
1027 LIST_REMOVE(td, td_hash);
1028 LIST_INSERT_HEAD(TIDHASH(td->td_tid),
1030 rw_wunlock(&tidhash_lock);
1038 rw_runlock(&tidhash_lock);
1043 tidhash_add(struct thread *td)
1045 rw_wlock(&tidhash_lock);
1046 LIST_INSERT_HEAD(TIDHASH(td->td_tid), td, td_hash);
1047 rw_wunlock(&tidhash_lock);
1051 tidhash_remove(struct thread *td)
1053 rw_wlock(&tidhash_lock);
1054 LIST_REMOVE(td, td_hash);
1055 rw_wunlock(&tidhash_lock);