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);
217 * Tear down type-stable parts of a thread (just before being discarded).
220 thread_fini(void *mem, int size)
224 td = (struct thread *)mem;
225 EVENTHANDLER_INVOKE(thread_fini, td);
226 rlqentry_free(td->td_rlqe);
227 turnstile_free(td->td_turnstile);
228 sleepq_free(td->td_sleepqueue);
229 umtx_thread_fini(td);
234 * For a newly created process,
235 * link up all the structures and its initial threads etc.
237 * {arch}/{arch}/machdep.c {arch}_init(), init386() etc.
238 * proc_dtor() (should go away)
242 proc_linkup0(struct proc *p, struct thread *td)
244 TAILQ_INIT(&p->p_threads); /* all threads in proc */
249 proc_linkup(struct proc *p, struct thread *td)
252 sigqueue_init(&p->p_sigqueue, p);
253 p->p_ksi = ksiginfo_alloc(1);
254 if (p->p_ksi != NULL) {
255 /* XXX p_ksi may be null if ksiginfo zone is not ready */
256 p->p_ksi->ksi_flags = KSI_EXT | KSI_INS;
258 LIST_INIT(&p->p_mqnotifier);
264 * Initialize global thread allocation resources.
270 mtx_init(&tid_lock, "TID lock", NULL, MTX_DEF);
273 * pid_max cannot be greater than PID_MAX.
274 * leave one number for thread0.
276 tid_unrhdr = new_unrhdr(PID_MAX + 2, INT_MAX, &tid_lock);
278 thread_zone = uma_zcreate("THREAD", sched_sizeof_thread(),
279 thread_ctor, thread_dtor, thread_init, thread_fini,
281 tidhashtbl = hashinit(maxproc / 2, M_TIDHASH, &tidhash);
282 rw_init(&tidhash_lock, "tidhash");
286 * Place an unused thread on the zombie list.
287 * Use the slpq as that must be unused by now.
290 thread_zombie(struct thread *td)
292 mtx_lock_spin(&zombie_lock);
293 TAILQ_INSERT_HEAD(&zombie_threads, td, td_slpq);
294 mtx_unlock_spin(&zombie_lock);
298 * Release a thread that has exited after cpu_throw().
301 thread_stash(struct thread *td)
303 atomic_subtract_rel_int(&td->td_proc->p_exitthreads, 1);
308 * Reap zombie resources.
313 struct thread *td_first, *td_next;
316 * Don't even bother to lock if none at this instant,
317 * we really don't care about the next instant..
319 if (!TAILQ_EMPTY(&zombie_threads)) {
320 mtx_lock_spin(&zombie_lock);
321 td_first = TAILQ_FIRST(&zombie_threads);
323 TAILQ_INIT(&zombie_threads);
324 mtx_unlock_spin(&zombie_lock);
326 td_next = TAILQ_NEXT(td_first, td_slpq);
327 if (td_first->td_ucred)
328 crfree(td_first->td_ucred);
329 thread_free(td_first);
339 thread_alloc(int pages)
343 thread_reap(); /* check if any zombies to get */
345 td = (struct thread *)uma_zalloc(thread_zone, M_WAITOK);
346 KASSERT(td->td_kstack == 0, ("thread_alloc got thread with kstack"));
347 if (!vm_thread_new(td, pages)) {
348 uma_zfree(thread_zone, td);
351 cpu_thread_alloc(td);
356 thread_alloc_stack(struct thread *td, int pages)
359 KASSERT(td->td_kstack == 0,
360 ("thread_alloc_stack called on a thread with kstack"));
361 if (!vm_thread_new(td, pages))
363 cpu_thread_alloc(td);
368 * Deallocate a thread.
371 thread_free(struct thread *td)
374 lock_profile_thread_exit(td);
376 cpuset_rel(td->td_cpuset);
377 td->td_cpuset = NULL;
379 if (td->td_kstack != 0)
380 vm_thread_dispose(td);
381 uma_zfree(thread_zone, td);
385 * Discard the current thread and exit from its context.
386 * Always called with scheduler locked.
388 * Because we can't free a thread while we're operating under its context,
389 * push the current thread into our CPU's deadthread holder. This means
390 * we needn't worry about someone else grabbing our context before we
396 uint64_t runtime, new_switchtime;
405 PROC_SLOCK_ASSERT(p, MA_OWNED);
406 mtx_assert(&Giant, MA_NOTOWNED);
408 PROC_LOCK_ASSERT(p, MA_OWNED);
409 KASSERT(p != NULL, ("thread exiting without a process"));
410 CTR3(KTR_PROC, "thread_exit: thread %p (pid %ld, %s)", td,
411 (long)p->p_pid, td->td_name);
412 KASSERT(TAILQ_EMPTY(&td->td_sigqueue.sq_list), ("signal pending"));
415 AUDIT_SYSCALL_EXIT(0, 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(
448 p->p_singlethread, p);
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 || mode == SINGLE_ALLPROC)
580 remaining = p->p_numthreads - p->p_suspcount;
582 panic("calc_remaining: wrong mode %d", mode);
587 remain_for_mode(int mode)
590 return (mode == SINGLE_ALLPROC ? 0 : 1);
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, p);
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, p);
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, p);
619 if (TD_ON_SLEEPQ(td2) && (td2->td_flags & TDF_SINTR) != 0)
620 wakeup_swapper |= sleepq_abort(td2, ERESTART);
624 * ALLPROC suspend tries to avoid spurious EINTR for
625 * threads sleeping interruptable, by suspending the
626 * thread directly, similarly to sig_suspend_threads().
627 * Since such sleep is not performed at the user
628 * boundary, TDF_BOUNDARY flag is not set, and TDF_ALLPROCSUSP
629 * is used to avoid immediate un-suspend.
631 if (TD_IS_SUSPENDED(td2) && (td2->td_flags & (TDF_BOUNDARY |
632 TDF_ALLPROCSUSP)) == 0)
633 wakeup_swapper |= thread_unsuspend_one(td2, p);
634 if (TD_ON_SLEEPQ(td2) && (td2->td_flags & TDF_SINTR) != 0) {
635 if ((td2->td_flags & TDF_SBDRY) == 0) {
636 thread_suspend_one(td2);
637 td2->td_flags |= TDF_ALLPROCSUSP;
639 wakeup_swapper |= sleepq_abort(td2, ERESTART);
644 return (wakeup_swapper);
648 * Enforce single-threading.
650 * Returns 1 if the caller must abort (another thread is waiting to
651 * exit the process or similar). Process is locked!
652 * Returns 0 when you are successfully the only thread running.
653 * A process has successfully single threaded in the suspend mode when
654 * There are no threads in user mode. Threads in the kernel must be
655 * allowed to continue until they get to the user boundary. They may even
656 * copy out their return values and data before suspending. They may however be
657 * accelerated in reaching the user boundary as we will wake up
658 * any sleeping threads that are interruptable. (PCATCH).
661 thread_single(struct proc *p, int mode)
665 int remaining, wakeup_swapper;
668 KASSERT(mode == SINGLE_EXIT || mode == SINGLE_BOUNDARY ||
669 mode == SINGLE_ALLPROC || mode == SINGLE_NO_EXIT,
670 ("invalid mode %d", mode));
672 * If allowing non-ALLPROC singlethreading for non-curproc
673 * callers, calc_remaining() and remain_for_mode() should be
674 * adjusted to also account for td->td_proc != p. For now
675 * this is not implemented because it is not used.
677 KASSERT((mode == SINGLE_ALLPROC && td->td_proc != p) ||
678 (mode != SINGLE_ALLPROC && td->td_proc == p),
679 ("mode %d proc %p curproc %p", mode, p, td->td_proc));
680 mtx_assert(&Giant, MA_NOTOWNED);
681 PROC_LOCK_ASSERT(p, MA_OWNED);
683 if ((p->p_flag & P_HADTHREADS) == 0 && mode != SINGLE_ALLPROC)
686 /* Is someone already single threading? */
687 if (p->p_singlethread != NULL && p->p_singlethread != td)
690 if (mode == SINGLE_EXIT) {
691 p->p_flag |= P_SINGLE_EXIT;
692 p->p_flag &= ~P_SINGLE_BOUNDARY;
694 p->p_flag &= ~P_SINGLE_EXIT;
695 if (mode == SINGLE_BOUNDARY)
696 p->p_flag |= P_SINGLE_BOUNDARY;
698 p->p_flag &= ~P_SINGLE_BOUNDARY;
700 if (mode == SINGLE_ALLPROC)
701 p->p_flag |= P_TOTAL_STOP;
702 p->p_flag |= P_STOPPED_SINGLE;
704 p->p_singlethread = td;
705 remaining = calc_remaining(p, mode);
706 while (remaining != remain_for_mode(mode)) {
707 if (P_SHOULDSTOP(p) != P_STOPPED_SINGLE)
710 FOREACH_THREAD_IN_PROC(p, td2) {
714 td2->td_flags |= TDF_ASTPENDING | TDF_NEEDSUSPCHK;
715 if (TD_IS_INHIBITED(td2)) {
716 wakeup_swapper |= weed_inhib(mode, td2, p);
718 } else if (TD_IS_RUNNING(td2) && td != td2) {
726 remaining = calc_remaining(p, mode);
729 * Maybe we suspended some threads.. was it enough?
731 if (remaining == remain_for_mode(mode))
736 * Wake us up when everyone else has suspended.
737 * In the mean time we suspend as well.
739 thread_suspend_switch(td, p);
740 remaining = calc_remaining(p, mode);
742 if (mode == SINGLE_EXIT) {
744 * Convert the process to an unthreaded process. The
745 * SINGLE_EXIT is called by exit1() or execve(), in
746 * both cases other threads must be retired.
748 KASSERT(p->p_numthreads == 1, ("Unthreading with >1 threads"));
749 p->p_singlethread = NULL;
750 p->p_flag &= ~(P_STOPPED_SINGLE | P_SINGLE_EXIT | P_HADTHREADS);
753 * Wait for any remaining threads to exit cpu_throw().
755 while (p->p_exitthreads != 0) {
758 sched_relinquish(td);
768 thread_suspend_check_needed(void)
775 PROC_LOCK_ASSERT(p, MA_OWNED);
776 return (P_SHOULDSTOP(p) || ((p->p_flag & P_TRACED) != 0 &&
777 (td->td_dbgflags & TDB_SUSPEND) != 0));
781 * Called in from locations that can safely check to see
782 * whether we have to suspend or at least throttle for a
783 * single-thread event (e.g. fork).
785 * Such locations include userret().
786 * If the "return_instead" argument is non zero, the thread must be able to
787 * accept 0 (caller may continue), or 1 (caller must abort) as a result.
789 * The 'return_instead' argument tells the function if it may do a
790 * thread_exit() or suspend, or whether the caller must abort and back
793 * If the thread that set the single_threading request has set the
794 * P_SINGLE_EXIT bit in the process flags then this call will never return
795 * if 'return_instead' is false, but will exit.
797 * P_SINGLE_EXIT | return_instead == 0| return_instead != 0
798 *---------------+--------------------+---------------------
799 * 0 | returns 0 | returns 0 or 1
800 * | when ST ends | immediately
801 *---------------+--------------------+---------------------
802 * 1 | thread exits | returns 1
804 * 0 = thread_exit() or suspension ok,
805 * other = return error instead of stopping the thread.
807 * While a full suspension is under effect, even a single threading
808 * thread would be suspended if it made this call (but it shouldn't).
809 * This call should only be made from places where
810 * thread_exit() would be safe as that may be the outcome unless
811 * return_instead is set.
814 thread_suspend_check(int return_instead)
822 mtx_assert(&Giant, MA_NOTOWNED);
823 PROC_LOCK_ASSERT(p, MA_OWNED);
824 while (thread_suspend_check_needed()) {
825 if (P_SHOULDSTOP(p) == P_STOPPED_SINGLE) {
826 KASSERT(p->p_singlethread != NULL,
827 ("singlethread not set"));
829 * The only suspension in action is a
830 * single-threading. Single threader need not stop.
831 * XXX Should be safe to access unlocked
832 * as it can only be set to be true by us.
834 if (p->p_singlethread == td)
835 return (0); /* Exempt from stopping. */
837 if ((p->p_flag & P_SINGLE_EXIT) && return_instead)
840 /* Should we goto user boundary if we didn't come from there? */
841 if (P_SHOULDSTOP(p) == P_STOPPED_SINGLE &&
842 (p->p_flag & P_SINGLE_BOUNDARY) && return_instead)
846 * Ignore suspend requests for stop signals if they
849 if ((P_SHOULDSTOP(p) == P_STOPPED_SIG ||
850 (p->p_flag & P_TOTAL_STOP) != 0) &&
851 (td->td_flags & TDF_SBDRY) != 0) {
852 KASSERT(return_instead,
853 ("TDF_SBDRY set for unsafe thread_suspend_check"));
858 * If the process is waiting for us to exit,
859 * this thread should just suicide.
860 * Assumes that P_SINGLE_EXIT implies P_STOPPED_SINGLE.
862 if ((p->p_flag & P_SINGLE_EXIT) && (p->p_singlethread != td)) {
867 umtx_thread_exit(td);
875 if (P_SHOULDSTOP(p) == P_STOPPED_SINGLE) {
876 if (p->p_numthreads == p->p_suspcount + 1) {
877 thread_lock(p->p_singlethread);
879 thread_unsuspend_one(p->p_singlethread, p);
880 thread_unlock(p->p_singlethread);
888 * When a thread suspends, it just
889 * gets taken off all queues.
891 thread_suspend_one(td);
892 if (return_instead == 0) {
893 p->p_boundary_count++;
894 td->td_flags |= TDF_BOUNDARY;
897 mi_switch(SW_INVOL | SWT_SUSPEND, NULL);
898 if (return_instead == 0)
899 td->td_flags &= ~TDF_BOUNDARY;
902 if (return_instead == 0) {
904 p->p_boundary_count--;
912 thread_suspend_switch(struct thread *td, struct proc *p)
915 KASSERT(!TD_IS_SUSPENDED(td), ("already suspended"));
916 PROC_LOCK_ASSERT(p, MA_OWNED);
917 PROC_SLOCK_ASSERT(p, MA_OWNED);
919 * We implement thread_suspend_one in stages here to avoid
920 * dropping the proc lock while the thread lock is owned.
922 if (p == td->td_proc) {
928 td->td_flags &= ~TDF_NEEDSUSPCHK;
929 TD_SET_SUSPENDED(td);
933 mi_switch(SW_VOL | SWT_SUSPEND, NULL);
941 thread_suspend_one(struct thread *td)
946 PROC_SLOCK_ASSERT(p, MA_OWNED);
947 THREAD_LOCK_ASSERT(td, MA_OWNED);
948 KASSERT(!TD_IS_SUSPENDED(td), ("already suspended"));
950 td->td_flags &= ~TDF_NEEDSUSPCHK;
951 TD_SET_SUSPENDED(td);
956 thread_unsuspend_one(struct thread *td, struct proc *p)
959 THREAD_LOCK_ASSERT(td, MA_OWNED);
960 KASSERT(TD_IS_SUSPENDED(td), ("Thread not suspended"));
961 TD_CLR_SUSPENDED(td);
962 td->td_flags &= ~TDF_ALLPROCSUSP;
963 if (td->td_proc == p) {
964 PROC_SLOCK_ASSERT(p, MA_OWNED);
967 return (setrunnable(td));
971 * Allow all threads blocked by single threading to continue running.
974 thread_unsuspend(struct proc *p)
979 PROC_LOCK_ASSERT(p, MA_OWNED);
980 PROC_SLOCK_ASSERT(p, MA_OWNED);
982 if (!P_SHOULDSTOP(p)) {
983 FOREACH_THREAD_IN_PROC(p, td) {
985 if (TD_IS_SUSPENDED(td)) {
986 wakeup_swapper |= thread_unsuspend_one(td, p);
990 } else if ((P_SHOULDSTOP(p) == P_STOPPED_SINGLE) &&
991 (p->p_numthreads == p->p_suspcount)) {
993 * Stopping everything also did the job for the single
994 * threading request. Now we've downgraded to single-threaded,
997 if (p->p_singlethread->td_proc == p) {
998 thread_lock(p->p_singlethread);
999 wakeup_swapper = thread_unsuspend_one(
1000 p->p_singlethread, p);
1001 thread_unlock(p->p_singlethread);
1009 * End the single threading mode..
1012 thread_single_end(struct proc *p, int mode)
1017 KASSERT(mode == SINGLE_EXIT || mode == SINGLE_BOUNDARY ||
1018 mode == SINGLE_ALLPROC || mode == SINGLE_NO_EXIT,
1019 ("invalid mode %d", mode));
1020 PROC_LOCK_ASSERT(p, MA_OWNED);
1021 KASSERT((mode == SINGLE_ALLPROC && (p->p_flag & P_TOTAL_STOP) != 0) ||
1022 (mode != SINGLE_ALLPROC && (p->p_flag & P_TOTAL_STOP) == 0),
1023 ("mode %d does not match P_TOTAL_STOP", mode));
1024 p->p_flag &= ~(P_STOPPED_SINGLE | P_SINGLE_EXIT | P_SINGLE_BOUNDARY |
1027 p->p_singlethread = NULL;
1030 * If there are other threads they may now run,
1031 * unless of course there is a blanket 'stop order'
1032 * on the process. The single threader must be allowed
1033 * to continue however as this is a bad place to stop.
1035 if (p->p_numthreads != remain_for_mode(mode) && !P_SHOULDSTOP(p)) {
1036 FOREACH_THREAD_IN_PROC(p, td) {
1038 if (TD_IS_SUSPENDED(td)) {
1039 wakeup_swapper |= thread_unsuspend_one(td, p);
1050 thread_find(struct proc *p, lwpid_t tid)
1054 PROC_LOCK_ASSERT(p, MA_OWNED);
1055 FOREACH_THREAD_IN_PROC(p, td) {
1056 if (td->td_tid == tid)
1062 /* Locate a thread by number; return with proc lock held. */
1064 tdfind(lwpid_t tid, pid_t pid)
1066 #define RUN_THRESH 16
1070 rw_rlock(&tidhash_lock);
1071 LIST_FOREACH(td, TIDHASH(tid), td_hash) {
1072 if (td->td_tid == tid) {
1073 if (pid != -1 && td->td_proc->p_pid != pid) {
1077 PROC_LOCK(td->td_proc);
1078 if (td->td_proc->p_state == PRS_NEW) {
1079 PROC_UNLOCK(td->td_proc);
1083 if (run > RUN_THRESH) {
1084 if (rw_try_upgrade(&tidhash_lock)) {
1085 LIST_REMOVE(td, td_hash);
1086 LIST_INSERT_HEAD(TIDHASH(td->td_tid),
1088 rw_wunlock(&tidhash_lock);
1096 rw_runlock(&tidhash_lock);
1101 tidhash_add(struct thread *td)
1103 rw_wlock(&tidhash_lock);
1104 LIST_INSERT_HEAD(TIDHASH(td->td_tid), td, td_hash);
1105 rw_wunlock(&tidhash_lock);
1109 tidhash_remove(struct thread *td)
1111 rw_wlock(&tidhash_lock);
1112 LIST_REMOVE(td, td_hash);
1113 rw_wunlock(&tidhash_lock);