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);
417 * drop FPU & debug register state storage, or any other
418 * architecture specific resources that
419 * would not be on a new untouched process.
421 cpu_thread_exit(td); /* XXXSMP */
424 * The last thread is left attached to the process
425 * So that the whole bundle gets recycled. Skip
426 * all this stuff if we never had threads.
427 * EXIT clears all sign of other threads when
428 * it goes to single threading, so the last thread always
429 * takes the short path.
431 if (p->p_flag & P_HADTHREADS) {
432 if (p->p_numthreads > 1) {
433 atomic_add_int(&td->td_proc->p_exitthreads, 1);
435 td2 = FIRST_THREAD_IN_PROC(p);
436 sched_exit_thread(td2, td);
439 * The test below is NOT true if we are the
440 * sole exiting thread. P_STOPPED_SINGLE is unset
441 * in exit1() after it is the only survivor.
443 if (P_SHOULDSTOP(p) == P_STOPPED_SINGLE) {
444 if (p->p_numthreads == p->p_suspcount) {
445 thread_lock(p->p_singlethread);
446 wakeup_swapper = thread_unsuspend_one(
447 p->p_singlethread, p);
448 thread_unlock(p->p_singlethread);
454 PCPU_SET(deadthread, td);
457 * The last thread is exiting.. but not through exit()
459 panic ("thread_exit: Last thread exiting on its own");
464 * If this thread is part of a process that is being tracked by hwpmc(4),
465 * inform the module of the thread's impending exit.
467 if (PMC_PROC_IS_USING_PMCS(td->td_proc))
468 PMC_SWITCH_CONTEXT(td, PMC_FN_CSW_OUT);
475 /* Do the same timestamp bookkeeping that mi_switch() would do. */
476 new_switchtime = cpu_ticks();
477 runtime = new_switchtime - PCPU_GET(switchtime);
478 td->td_runtime += runtime;
479 td->td_incruntime += runtime;
480 PCPU_SET(switchtime, new_switchtime);
481 PCPU_SET(switchticks, ticks);
482 PCPU_INC(cnt.v_swtch);
484 /* Save our resource usage in our process. */
485 td->td_ru.ru_nvcsw++;
487 rucollect(&p->p_ru, &td->td_ru);
490 td->td_state = TDS_INACTIVE;
492 witness_thread_exit(td);
494 CTR1(KTR_PROC, "thread_exit: cpu_throw() thread %p", td);
496 panic("I'm a teapot!");
501 * Do any thread specific cleanups that may be needed in wait()
502 * called with Giant, proc and schedlock not held.
505 thread_wait(struct proc *p)
509 mtx_assert(&Giant, MA_NOTOWNED);
510 KASSERT(p->p_numthreads == 1, ("multiple threads in thread_wait()"));
511 KASSERT(p->p_exitthreads == 0, ("p_exitthreads leaking"));
512 td = FIRST_THREAD_IN_PROC(p);
513 /* Lock the last thread so we spin until it exits cpu_throw(). */
516 lock_profile_thread_exit(td);
517 cpuset_rel(td->td_cpuset);
518 td->td_cpuset = NULL;
519 cpu_thread_clean(td);
520 crfree(td->td_ucred);
521 thread_reap(); /* check for zombie threads etc. */
525 * Link a thread to a process.
526 * set up anything that needs to be initialized for it to
527 * be used by the process.
530 thread_link(struct thread *td, struct proc *p)
534 * XXX This can't be enabled because it's called for proc0 before
535 * its lock has been created.
536 * PROC_LOCK_ASSERT(p, MA_OWNED);
538 td->td_state = TDS_INACTIVE;
540 td->td_flags = TDF_INMEM;
542 LIST_INIT(&td->td_contested);
543 LIST_INIT(&td->td_lprof[0]);
544 LIST_INIT(&td->td_lprof[1]);
545 sigqueue_init(&td->td_sigqueue, p);
546 callout_init(&td->td_slpcallout, CALLOUT_MPSAFE);
547 TAILQ_INSERT_TAIL(&p->p_threads, td, td_plist);
556 thread_unlink(struct thread *td)
558 struct proc *p = td->td_proc;
560 PROC_LOCK_ASSERT(p, MA_OWNED);
561 TAILQ_REMOVE(&p->p_threads, td, td_plist);
563 /* could clear a few other things here */
564 /* Must NOT clear links to proc! */
568 calc_remaining(struct proc *p, int mode)
572 PROC_LOCK_ASSERT(p, MA_OWNED);
573 PROC_SLOCK_ASSERT(p, MA_OWNED);
574 if (mode == SINGLE_EXIT)
575 remaining = p->p_numthreads;
576 else if (mode == SINGLE_BOUNDARY)
577 remaining = p->p_numthreads - p->p_boundary_count;
578 else if (mode == SINGLE_NO_EXIT || mode == SINGLE_ALLPROC)
579 remaining = p->p_numthreads - p->p_suspcount;
581 panic("calc_remaining: wrong mode %d", mode);
586 remain_for_mode(int mode)
589 return (mode == SINGLE_ALLPROC ? 0 : 1);
593 weed_inhib(int mode, struct thread *td2, struct proc *p)
597 PROC_LOCK_ASSERT(p, MA_OWNED);
598 PROC_SLOCK_ASSERT(p, MA_OWNED);
599 THREAD_LOCK_ASSERT(td2, MA_OWNED);
604 if (TD_IS_SUSPENDED(td2))
605 wakeup_swapper |= thread_unsuspend_one(td2, p);
606 if (TD_ON_SLEEPQ(td2) && (td2->td_flags & TDF_SINTR) != 0)
607 wakeup_swapper |= sleepq_abort(td2, EINTR);
609 case SINGLE_BOUNDARY:
610 if (TD_IS_SUSPENDED(td2) && (td2->td_flags & TDF_BOUNDARY) == 0)
611 wakeup_swapper |= thread_unsuspend_one(td2, p);
612 if (TD_ON_SLEEPQ(td2) && (td2->td_flags & TDF_SINTR) != 0)
613 wakeup_swapper |= sleepq_abort(td2, ERESTART);
616 if (TD_IS_SUSPENDED(td2) && (td2->td_flags & TDF_BOUNDARY) == 0)
617 wakeup_swapper |= thread_unsuspend_one(td2, p);
618 if (TD_ON_SLEEPQ(td2) && (td2->td_flags & TDF_SINTR) != 0)
619 wakeup_swapper |= sleepq_abort(td2, ERESTART);
623 * ALLPROC suspend tries to avoid spurious EINTR for
624 * threads sleeping interruptable, by suspending the
625 * thread directly, similarly to sig_suspend_threads().
626 * Since such sleep is not performed at the user
627 * boundary, TDF_BOUNDARY flag is not set, and TDF_ALLPROCSUSP
628 * is used to avoid immediate un-suspend.
630 if (TD_IS_SUSPENDED(td2) && (td2->td_flags & (TDF_BOUNDARY |
631 TDF_ALLPROCSUSP)) == 0)
632 wakeup_swapper |= thread_unsuspend_one(td2, p);
633 if (TD_ON_SLEEPQ(td2) && (td2->td_flags & TDF_SINTR) != 0) {
634 if ((td2->td_flags & TDF_SBDRY) == 0) {
635 thread_suspend_one(td2);
636 td2->td_flags |= TDF_ALLPROCSUSP;
638 wakeup_swapper |= sleepq_abort(td2, ERESTART);
643 return (wakeup_swapper);
647 * Enforce single-threading.
649 * Returns 1 if the caller must abort (another thread is waiting to
650 * exit the process or similar). Process is locked!
651 * Returns 0 when you are successfully the only thread running.
652 * A process has successfully single threaded in the suspend mode when
653 * There are no threads in user mode. Threads in the kernel must be
654 * allowed to continue until they get to the user boundary. They may even
655 * copy out their return values and data before suspending. They may however be
656 * accelerated in reaching the user boundary as we will wake up
657 * any sleeping threads that are interruptable. (PCATCH).
660 thread_single(struct proc *p, int mode)
664 int remaining, wakeup_swapper;
667 KASSERT(mode == SINGLE_EXIT || mode == SINGLE_BOUNDARY ||
668 mode == SINGLE_ALLPROC || mode == SINGLE_NO_EXIT,
669 ("invalid mode %d", mode));
671 * If allowing non-ALLPROC singlethreading for non-curproc
672 * callers, calc_remaining() and remain_for_mode() should be
673 * adjusted to also account for td->td_proc != p. For now
674 * this is not implemented because it is not used.
676 KASSERT((mode == SINGLE_ALLPROC && td->td_proc != p) ||
677 (mode != SINGLE_ALLPROC && td->td_proc == p),
678 ("mode %d proc %p curproc %p", mode, p, td->td_proc));
679 mtx_assert(&Giant, MA_NOTOWNED);
680 PROC_LOCK_ASSERT(p, MA_OWNED);
682 if ((p->p_flag & P_HADTHREADS) == 0 && mode != SINGLE_ALLPROC)
685 /* Is someone already single threading? */
686 if (p->p_singlethread != NULL && p->p_singlethread != td)
689 if (mode == SINGLE_EXIT) {
690 p->p_flag |= P_SINGLE_EXIT;
691 p->p_flag &= ~P_SINGLE_BOUNDARY;
693 p->p_flag &= ~P_SINGLE_EXIT;
694 if (mode == SINGLE_BOUNDARY)
695 p->p_flag |= P_SINGLE_BOUNDARY;
697 p->p_flag &= ~P_SINGLE_BOUNDARY;
699 if (mode == SINGLE_ALLPROC)
700 p->p_flag |= P_TOTAL_STOP;
701 p->p_flag |= P_STOPPED_SINGLE;
703 p->p_singlethread = td;
704 remaining = calc_remaining(p, mode);
705 while (remaining != remain_for_mode(mode)) {
706 if (P_SHOULDSTOP(p) != P_STOPPED_SINGLE)
709 FOREACH_THREAD_IN_PROC(p, td2) {
713 td2->td_flags |= TDF_ASTPENDING | TDF_NEEDSUSPCHK;
714 if (TD_IS_INHIBITED(td2)) {
715 wakeup_swapper |= weed_inhib(mode, td2, p);
717 } else if (TD_IS_RUNNING(td2) && td != td2) {
725 remaining = calc_remaining(p, mode);
728 * Maybe we suspended some threads.. was it enough?
730 if (remaining == remain_for_mode(mode))
735 * Wake us up when everyone else has suspended.
736 * In the mean time we suspend as well.
738 thread_suspend_switch(td, p);
739 remaining = calc_remaining(p, mode);
741 if (mode == SINGLE_EXIT) {
743 * Convert the process to an unthreaded process. The
744 * SINGLE_EXIT is called by exit1() or execve(), in
745 * both cases other threads must be retired.
747 KASSERT(p->p_numthreads == 1, ("Unthreading with >1 threads"));
748 p->p_singlethread = NULL;
749 p->p_flag &= ~(P_STOPPED_SINGLE | P_SINGLE_EXIT | P_HADTHREADS);
752 * Wait for any remaining threads to exit cpu_throw().
754 while (p->p_exitthreads != 0) {
757 sched_relinquish(td);
767 thread_suspend_check_needed(void)
774 PROC_LOCK_ASSERT(p, MA_OWNED);
775 return (P_SHOULDSTOP(p) || ((p->p_flag & P_TRACED) != 0 &&
776 (td->td_dbgflags & TDB_SUSPEND) != 0));
780 * Called in from locations that can safely check to see
781 * whether we have to suspend or at least throttle for a
782 * single-thread event (e.g. fork).
784 * Such locations include userret().
785 * If the "return_instead" argument is non zero, the thread must be able to
786 * accept 0 (caller may continue), or 1 (caller must abort) as a result.
788 * The 'return_instead' argument tells the function if it may do a
789 * thread_exit() or suspend, or whether the caller must abort and back
792 * If the thread that set the single_threading request has set the
793 * P_SINGLE_EXIT bit in the process flags then this call will never return
794 * if 'return_instead' is false, but will exit.
796 * P_SINGLE_EXIT | return_instead == 0| return_instead != 0
797 *---------------+--------------------+---------------------
798 * 0 | returns 0 | returns 0 or 1
799 * | when ST ends | immediately
800 *---------------+--------------------+---------------------
801 * 1 | thread exits | returns 1
803 * 0 = thread_exit() or suspension ok,
804 * other = return error instead of stopping the thread.
806 * While a full suspension is under effect, even a single threading
807 * thread would be suspended if it made this call (but it shouldn't).
808 * This call should only be made from places where
809 * thread_exit() would be safe as that may be the outcome unless
810 * return_instead is set.
813 thread_suspend_check(int return_instead)
821 mtx_assert(&Giant, MA_NOTOWNED);
822 PROC_LOCK_ASSERT(p, MA_OWNED);
823 while (thread_suspend_check_needed()) {
824 if (P_SHOULDSTOP(p) == P_STOPPED_SINGLE) {
825 KASSERT(p->p_singlethread != NULL,
826 ("singlethread not set"));
828 * The only suspension in action is a
829 * single-threading. Single threader need not stop.
830 * XXX Should be safe to access unlocked
831 * as it can only be set to be true by us.
833 if (p->p_singlethread == td)
834 return (0); /* Exempt from stopping. */
836 if ((p->p_flag & P_SINGLE_EXIT) && return_instead)
839 /* Should we goto user boundary if we didn't come from there? */
840 if (P_SHOULDSTOP(p) == P_STOPPED_SINGLE &&
841 (p->p_flag & P_SINGLE_BOUNDARY) && return_instead)
845 * Ignore suspend requests for stop signals if they
848 if ((P_SHOULDSTOP(p) == P_STOPPED_SIG ||
849 (p->p_flag & P_TOTAL_STOP) != 0) &&
850 (td->td_flags & TDF_SBDRY) != 0) {
851 KASSERT(return_instead,
852 ("TDF_SBDRY set for unsafe thread_suspend_check"));
857 * If the process is waiting for us to exit,
858 * this thread should just suicide.
859 * Assumes that P_SINGLE_EXIT implies P_STOPPED_SINGLE.
861 if ((p->p_flag & P_SINGLE_EXIT) && (p->p_singlethread != td)) {
866 umtx_thread_exit(td);
874 if (P_SHOULDSTOP(p) == P_STOPPED_SINGLE) {
875 if (p->p_numthreads == p->p_suspcount + 1) {
876 thread_lock(p->p_singlethread);
878 thread_unsuspend_one(p->p_singlethread, p);
879 thread_unlock(p->p_singlethread);
887 * When a thread suspends, it just
888 * gets taken off all queues.
890 thread_suspend_one(td);
891 if (return_instead == 0) {
892 p->p_boundary_count++;
893 td->td_flags |= TDF_BOUNDARY;
896 mi_switch(SW_INVOL | SWT_SUSPEND, NULL);
897 if (return_instead == 0)
898 td->td_flags &= ~TDF_BOUNDARY;
901 if (return_instead == 0) {
903 p->p_boundary_count--;
911 thread_suspend_switch(struct thread *td, struct proc *p)
914 KASSERT(!TD_IS_SUSPENDED(td), ("already suspended"));
915 PROC_LOCK_ASSERT(p, MA_OWNED);
916 PROC_SLOCK_ASSERT(p, MA_OWNED);
918 * We implement thread_suspend_one in stages here to avoid
919 * dropping the proc lock while the thread lock is owned.
921 if (p == td->td_proc) {
927 td->td_flags &= ~TDF_NEEDSUSPCHK;
928 TD_SET_SUSPENDED(td);
932 mi_switch(SW_VOL | SWT_SUSPEND, NULL);
940 thread_suspend_one(struct thread *td)
945 PROC_SLOCK_ASSERT(p, MA_OWNED);
946 THREAD_LOCK_ASSERT(td, MA_OWNED);
947 KASSERT(!TD_IS_SUSPENDED(td), ("already suspended"));
949 td->td_flags &= ~TDF_NEEDSUSPCHK;
950 TD_SET_SUSPENDED(td);
955 thread_unsuspend_one(struct thread *td, struct proc *p)
958 THREAD_LOCK_ASSERT(td, MA_OWNED);
959 KASSERT(TD_IS_SUSPENDED(td), ("Thread not suspended"));
960 TD_CLR_SUSPENDED(td);
961 td->td_flags &= ~TDF_ALLPROCSUSP;
962 if (td->td_proc == p) {
963 PROC_SLOCK_ASSERT(p, MA_OWNED);
966 return (setrunnable(td));
970 * Allow all threads blocked by single threading to continue running.
973 thread_unsuspend(struct proc *p)
978 PROC_LOCK_ASSERT(p, MA_OWNED);
979 PROC_SLOCK_ASSERT(p, MA_OWNED);
981 if (!P_SHOULDSTOP(p)) {
982 FOREACH_THREAD_IN_PROC(p, td) {
984 if (TD_IS_SUSPENDED(td)) {
985 wakeup_swapper |= thread_unsuspend_one(td, p);
989 } else if ((P_SHOULDSTOP(p) == P_STOPPED_SINGLE) &&
990 (p->p_numthreads == p->p_suspcount)) {
992 * Stopping everything also did the job for the single
993 * threading request. Now we've downgraded to single-threaded,
996 if (p->p_singlethread->td_proc == p) {
997 thread_lock(p->p_singlethread);
998 wakeup_swapper = thread_unsuspend_one(
999 p->p_singlethread, p);
1000 thread_unlock(p->p_singlethread);
1008 * End the single threading mode..
1011 thread_single_end(struct proc *p, int mode)
1016 KASSERT(mode == SINGLE_EXIT || mode == SINGLE_BOUNDARY ||
1017 mode == SINGLE_ALLPROC || mode == SINGLE_NO_EXIT,
1018 ("invalid mode %d", mode));
1019 PROC_LOCK_ASSERT(p, MA_OWNED);
1020 KASSERT((mode == SINGLE_ALLPROC && (p->p_flag & P_TOTAL_STOP) != 0) ||
1021 (mode != SINGLE_ALLPROC && (p->p_flag & P_TOTAL_STOP) == 0),
1022 ("mode %d does not match P_TOTAL_STOP", mode));
1023 p->p_flag &= ~(P_STOPPED_SINGLE | P_SINGLE_EXIT | P_SINGLE_BOUNDARY |
1026 p->p_singlethread = NULL;
1029 * If there are other threads they may now run,
1030 * unless of course there is a blanket 'stop order'
1031 * on the process. The single threader must be allowed
1032 * to continue however as this is a bad place to stop.
1034 if (p->p_numthreads != remain_for_mode(mode) && !P_SHOULDSTOP(p)) {
1035 FOREACH_THREAD_IN_PROC(p, td) {
1037 if (TD_IS_SUSPENDED(td)) {
1038 wakeup_swapper |= thread_unsuspend_one(td, p);
1049 thread_find(struct proc *p, lwpid_t tid)
1053 PROC_LOCK_ASSERT(p, MA_OWNED);
1054 FOREACH_THREAD_IN_PROC(p, td) {
1055 if (td->td_tid == tid)
1061 /* Locate a thread by number; return with proc lock held. */
1063 tdfind(lwpid_t tid, pid_t pid)
1065 #define RUN_THRESH 16
1069 rw_rlock(&tidhash_lock);
1070 LIST_FOREACH(td, TIDHASH(tid), td_hash) {
1071 if (td->td_tid == tid) {
1072 if (pid != -1 && td->td_proc->p_pid != pid) {
1076 PROC_LOCK(td->td_proc);
1077 if (td->td_proc->p_state == PRS_NEW) {
1078 PROC_UNLOCK(td->td_proc);
1082 if (run > RUN_THRESH) {
1083 if (rw_try_upgrade(&tidhash_lock)) {
1084 LIST_REMOVE(td, td_hash);
1085 LIST_INSERT_HEAD(TIDHASH(td->td_tid),
1087 rw_wunlock(&tidhash_lock);
1095 rw_runlock(&tidhash_lock);
1100 tidhash_add(struct thread *td)
1102 rw_wlock(&tidhash_lock);
1103 LIST_INSERT_HEAD(TIDHASH(td->td_tid), td, td_hash);
1104 rw_wunlock(&tidhash_lock);
1108 tidhash_remove(struct thread *td)
1110 rw_wlock(&tidhash_lock);
1111 LIST_REMOVE(td, td_hash);
1112 rw_wunlock(&tidhash_lock);