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Commit 4/14 of sched_lock decomposition.

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- Use thread_lock() rather than sched_lock for per-thread scheduling
   sychronization.
 - Use the per-process spinlock rather than the sched_lock for per-process
   scheduling synchronization.
 - Move some common code into thread_suspend_switch() to handle the
   mechanics of suspending a thread.  The locking here is incredibly
   convoluted and should be simplified.

Tested by:      kris, current@
Tested on:      i386, amd64, ULE, 4BSD, libthr, libkse, PREEMPTION, etc.
Discussed with: kris, attilio, kmacy, jhb, julian, bde (small parts each)
This commit is contained in:
Jeff Roberson 2007-06-04 23:52:24 +00:00
parent 2502c107ba
commit a54e85fdbf
2 changed files with 163 additions and 129 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

122
sys/kern/kern_sig.c
View File

@ -511,10 +511,10 @@ sigqueue_delete_set_proc(struct proc *p, sigset_t *set)
sigqueue_init(&worklist, NULL);
sigqueue_move_set(&p->p_sigqueue, &worklist, set);
mtx_lock_spin(&sched_lock);
PROC_SLOCK(p);
FOREACH_THREAD_IN_PROC(p, td0)
sigqueue_move_set(&td0->td_sigqueue, &worklist, set);
mtx_unlock_spin(&sched_lock);
PROC_SUNLOCK(p);
sigqueue_flush(&worklist);
}
@ -552,7 +552,7 @@ cursig(struct thread *td)
{
PROC_LOCK_ASSERT(td->td_proc, MA_OWNED);
mtx_assert(&td->td_proc->p_sigacts->ps_mtx, MA_OWNED);
mtx_assert(&sched_lock, MA_NOTOWNED);
THREAD_LOCK_ASSERT(td, MA_NOTOWNED);
return (SIGPENDING(td) ? issignal(td) : 0);
}
@ -588,9 +588,9 @@ signotify(struct thread *td)
if (! SIGISEMPTY(set))
sigqueue_move_set(&p->p_sigqueue, &td->td_sigqueue, &set);
if (SIGPENDING(td)) {
mtx_lock_spin(&sched_lock);
thread_lock(td);
td->td_flags |= TDF_NEEDSIGCHK | TDF_ASTPENDING;
mtx_unlock_spin(&sched_lock);
thread_unlock(td);
}
#ifdef KSE
if ((p->p_flag & P_SA) && !(p->p_flag & P_SIGEVENT)) {
@ -758,7 +758,9 @@ kern_sigaction(td, sig, act, oact, flags)
}
#endif
/* never to be seen again */
PROC_SLOCK(p);
sigqueue_delete_proc(p, sig);
PROC_SUNLOCK(p);
if (sig != SIGCONT)
/* easier in psignal */
SIGADDSET(ps->ps_sigignore, sig);
@ -954,7 +956,9 @@ execsigs(struct proc *p)
if (sigprop(sig) & SA_IGNORE) {
if (sig != SIGCONT)
SIGADDSET(ps->ps_sigignore, sig);
PROC_SLOCK(p);
sigqueue_delete_proc(p, sig);
PROC_SUNLOCK(p);
}
ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL;
}
@ -1849,7 +1853,7 @@ trapsignal(struct thread *td, ksiginfo_t *ksi)
thread_user_enter(td);
PROC_LOCK(p);
SIGDELSET(td->td_sigmask, sig);
mtx_lock_spin(&sched_lock);
thread_lock(td);
/*
* Force scheduling an upcall, so UTS has chance to
* process the signal before thread runs again in
@ -1857,7 +1861,7 @@ trapsignal(struct thread *td, ksiginfo_t *ksi)
*/
if (td->td_upcall)
td->td_upcall->ku_flags |= KUF_DOUPCALL;
mtx_unlock_spin(&sched_lock);
thread_unlock(td);
} else {
PROC_LOCK(p);
}
@ -1952,7 +1956,7 @@ sigtd(struct proc *p, int sig, int prop)
if (curproc == p && !SIGISMEMBER(curthread->td_sigmask, sig))
return (curthread);
signal_td = NULL;
mtx_lock_spin(&sched_lock);
PROC_SLOCK(p);
FOREACH_THREAD_IN_PROC(p, td) {
if (!SIGISMEMBER(td->td_sigmask, sig)) {
signal_td = td;
@ -1961,7 +1965,7 @@ sigtd(struct proc *p, int sig, int prop)
}
if (signal_td == NULL)
signal_td = FIRST_THREAD_IN_PROC(p);
mtx_unlock_spin(&sched_lock);
PROC_SUNLOCK(p);
return (signal_td);
}
@ -2128,7 +2132,9 @@ do_tdsignal(struct proc *p, struct thread *td, int sig, ksiginfo_t *ksi)
ksiginfo_tryfree(ksi);
return (ret);
}
PROC_SLOCK(p);
sigqueue_delete_proc(p, SIGCONT);
PROC_SUNLOCK(p);
if (p->p_flag & P_CONTINUED) {
p->p_flag &= ~P_CONTINUED;
PROC_LOCK(p->p_pptr);
@ -2166,6 +2172,7 @@ do_tdsignal(struct proc *p, struct thread *td, int sig, ksiginfo_t *ksi)
* waking up threads so that they can cross the user boundary.
* We try do the per-process part here.
*/
PROC_SLOCK(p);
if (P_SHOULDSTOP(p)) {
/*
* The process is in stopped mode. All the threads should be
@ -2177,6 +2184,7 @@ do_tdsignal(struct proc *p, struct thread *td, int sig, ksiginfo_t *ksi)
* so no further action is necessary.
* No signal can restart us.
*/
PROC_SUNLOCK(p);
goto out;
}
@ -2203,15 +2211,21 @@ do_tdsignal(struct proc *p, struct thread *td, int sig, ksiginfo_t *ksi)
*/
p->p_flag &= ~P_STOPPED_SIG;
if (p->p_numthreads == p->p_suspcount) {
PROC_SUNLOCK(p);
p->p_flag |= P_CONTINUED;
p->p_xstat = SIGCONT;
PROC_LOCK(p->p_pptr);
childproc_continued(p);
PROC_UNLOCK(p->p_pptr);
PROC_SLOCK(p);
}
if (action == SIG_DFL) {
thread_unsuspend(p);
PROC_SUNLOCK(p);
sigqueue_delete(sigqueue, sig);
} else if (action == SIG_CATCH) {
goto out;
}
if (action == SIG_CATCH) {
#ifdef KSE
/*
* The process wants to catch it so it needs
@ -2223,20 +2237,18 @@ do_tdsignal(struct proc *p, struct thread *td, int sig, ksiginfo_t *ksi)
* single thread is runnable asap.
* XXXKSE for now however, make them all run.
*/
#else
#endif
/*
* The process wants to catch it so it needs
* to run at least one thread, but which one?
*/
#endif
goto runfast;
}
/*
* The signal is not ignored or caught.
*/
mtx_lock_spin(&sched_lock);
thread_unsuspend(p);
mtx_unlock_spin(&sched_lock);
PROC_SUNLOCK(p);
goto out;
}
@ -2246,6 +2258,7 @@ do_tdsignal(struct proc *p, struct thread *td, int sig, ksiginfo_t *ksi)
* (If we did the shell could get confused).
* Just make sure the signal STOP bit set.
*/
PROC_SUNLOCK(p);
p->p_flag |= P_STOPPED_SIG;
sigqueue_delete(sigqueue, sig);
goto out;
@ -2259,10 +2272,11 @@ do_tdsignal(struct proc *p, struct thread *td, int sig, ksiginfo_t *ksi)
* the PROCESS runnable, leave it stopped.
* It may run a bit until it hits a thread_suspend_check().
*/
mtx_lock_spin(&sched_lock);
thread_lock(td);
if (TD_ON_SLEEPQ(td) && (td->td_flags & TDF_SINTR))
sleepq_abort(td, intrval);
mtx_unlock_spin(&sched_lock);
thread_unlock(td);
PROC_SUNLOCK(p);
goto out;
/*
* Mutexes are short lived. Threads waiting on them will
@ -2270,9 +2284,10 @@ do_tdsignal(struct proc *p, struct thread *td, int sig, ksiginfo_t *ksi)
*/
} else if (p->p_state == PRS_NORMAL) {
if (p->p_flag & P_TRACED || action == SIG_CATCH) {
mtx_lock_spin(&sched_lock);
thread_lock(td);
tdsigwakeup(td, sig, action, intrval);
mtx_unlock_spin(&sched_lock);
thread_unlock(td);
PROC_SUNLOCK(p);
goto out;
}
@ -2283,7 +2298,6 @@ do_tdsignal(struct proc *p, struct thread *td, int sig, ksiginfo_t *ksi)
goto out;
p->p_flag |= P_STOPPED_SIG;
p->p_xstat = sig;
mtx_lock_spin(&sched_lock);
sig_suspend_threads(td, p, 1);
if (p->p_numthreads == p->p_suspcount) {
/*
@ -2294,10 +2308,10 @@ do_tdsignal(struct proc *p, struct thread *td, int sig, ksiginfo_t *ksi)
* should never be equal to p_suspcount.
*/
thread_stopped(p);
mtx_unlock_spin(&sched_lock);
PROC_SUNLOCK(p);
sigqueue_delete_proc(p, p->p_xstat);
} else
mtx_unlock_spin(&sched_lock);
PROC_SUNLOCK(p);
goto out;
}
else
@ -2305,6 +2319,7 @@ do_tdsignal(struct proc *p, struct thread *td, int sig, ksiginfo_t *ksi)
/* NOTREACHED */
} else {
/* Not in "NORMAL" state. discard the signal. */
PROC_SUNLOCK(p);
sigqueue_delete(sigqueue, sig);
goto out;
}
@ -2315,13 +2330,14 @@ do_tdsignal(struct proc *p, struct thread *td, int sig, ksiginfo_t *ksi)
*/
runfast:
mtx_lock_spin(&sched_lock);
thread_lock(td);
tdsigwakeup(td, sig, action, intrval);
thread_unlock(td);
thread_unsuspend(p);
mtx_unlock_spin(&sched_lock);
PROC_SUNLOCK(p);
out:
/* If we jump here, sched_lock should not be owned. */
mtx_assert(&sched_lock, MA_NOTOWNED);
/* If we jump here, proc slock should not be owned. */
PROC_SLOCK_ASSERT(p, MA_NOTOWNED);
return (ret);
}
@ -2337,7 +2353,8 @@ tdsigwakeup(struct thread *td, int sig, sig_t action, int intrval)
register int prop;
PROC_LOCK_ASSERT(p, MA_OWNED);
mtx_assert(&sched_lock, MA_OWNED);
PROC_SLOCK_ASSERT(p, MA_OWNED);
THREAD_LOCK_ASSERT(td, MA_OWNED);
prop = sigprop(sig);
/*
@ -2366,14 +2383,16 @@ tdsigwakeup(struct thread *td, int sig, sig_t action, int intrval)
* be awakened.
*/
if ((prop & SA_CONT) && action == SIG_DFL) {
mtx_unlock_spin(&sched_lock);
thread_unlock(td);
PROC_SUNLOCK(p);
sigqueue_delete(&p->p_sigqueue, sig);
/*
* It may be on either list in this state.
* Remove from both for now.
*/
sigqueue_delete(&td->td_sigqueue, sig);
mtx_lock_spin(&sched_lock);
PROC_SLOCK(p);
thread_lock(td);
return;
}
@ -2403,9 +2422,10 @@ sig_suspend_threads(struct thread *td, struct proc *p, int sending)
struct thread *td2;
PROC_LOCK_ASSERT(p, MA_OWNED);
mtx_assert(&sched_lock, MA_OWNED);
PROC_SLOCK_ASSERT(p, MA_OWNED);
FOREACH_THREAD_IN_PROC(p, td2) {
thread_lock(td2);
if ((TD_IS_SLEEPING(td2) || TD_IS_SWAPPED(td2)) &&
(td2->td_flags & TDF_SINTR) &&
!TD_IS_SUSPENDED(td2)) {
@ -2418,6 +2438,7 @@ sig_suspend_threads(struct thread *td, struct proc *p, int sending)
forward_signal(td2);
#endif
}
thread_unlock(td2);
}
}
@ -2430,15 +2451,17 @@ ptracestop(struct thread *td, int sig)
WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK,
&p->p_mtx.lock_object, "Stopping for traced signal");
mtx_lock_spin(&sched_lock);
thread_lock(td);
td->td_flags |= TDF_XSIG;
mtx_unlock_spin(&sched_lock);
thread_unlock(td);
td->td_xsig = sig;
PROC_SLOCK(p);
while ((p->p_flag & P_TRACED) && (td->td_flags & TDF_XSIG)) {
if (p->p_flag & P_SINGLE_EXIT) {
mtx_lock_spin(&sched_lock);
thread_lock(td);
td->td_flags &= ~TDF_XSIG;
mtx_unlock_spin(&sched_lock);
thread_unlock(td);
PROC_SUNLOCK(p);
return (sig);
}
/*
@ -2448,26 +2471,19 @@ ptracestop(struct thread *td, int sig)
p->p_xstat = sig;
p->p_xthread = td;
p->p_flag |= (P_STOPPED_SIG|P_STOPPED_TRACE);
mtx_lock_spin(&sched_lock);
sig_suspend_threads(td, p, 0);
stopme:
thread_stopped(p);
thread_suspend_one(td);
PROC_UNLOCK(p);
DROP_GIANT();
mi_switch(SW_VOL, NULL);
mtx_unlock_spin(&sched_lock);
PICKUP_GIANT();
PROC_LOCK(p);
if (!(p->p_flag & P_TRACED))
thread_suspend_switch(td);
if (!(p->p_flag & P_TRACED)) {
break;
}
if (td->td_flags & TDF_DBSUSPEND) {
if (p->p_flag & P_SINGLE_EXIT)
break;
mtx_lock_spin(&sched_lock);
goto stopme;
}
}
PROC_SUNLOCK(p);
return (td->td_xsig);
}
@ -2621,16 +2637,10 @@ issignal(td)
&p->p_mtx.lock_object, "Catching SIGSTOP");
p->p_flag |= P_STOPPED_SIG;
p->p_xstat = sig;
mtx_lock_spin(&sched_lock);
PROC_SLOCK(p);
sig_suspend_threads(td, p, 0);
thread_stopped(p);
thread_suspend_one(td);
PROC_UNLOCK(p);
DROP_GIANT();
mi_switch(SW_INVOL, NULL);
mtx_unlock_spin(&sched_lock);
PICKUP_GIANT();
PROC_LOCK(p);
thread_suspend_switch(td);
PROC_SUNLOCK(p);
mtx_lock(&ps->ps_mtx);
break;
} else if (prop & SA_IGNORE) {
@ -2672,18 +2682,18 @@ thread_stopped(struct proc *p)
int n;
PROC_LOCK_ASSERT(p, MA_OWNED);
mtx_assert(&sched_lock, MA_OWNED);
PROC_SLOCK_ASSERT(p, MA_OWNED);
n = p->p_suspcount;
if (p == curproc)
n++;
if ((p->p_flag & P_STOPPED_SIG) && (n == p->p_numthreads)) {
mtx_unlock_spin(&sched_lock);
PROC_SUNLOCK(p);
p->p_flag &= ~P_WAITED;
PROC_LOCK(p->p_pptr);
childproc_stopped(p, (p->p_flag & P_TRACED) ?
CLD_TRAPPED : CLD_STOPPED);
PROC_UNLOCK(p->p_pptr);
mtx_lock_spin(&sched_lock);
PROC_SLOCK(p);
}
}

170
sys/kern/kern_thread.c
View File

@ -70,8 +70,8 @@ int virtual_cpu;
#endif
TAILQ_HEAD(, thread) zombie_threads = TAILQ_HEAD_INITIALIZER(zombie_threads);
struct mtx kse_zombie_lock;
MTX_SYSINIT(kse_zombie_lock, &kse_zombie_lock, "kse zombie lock", MTX_SPIN);
struct mtx zombie_lock;
MTX_SYSINIT(zombie_lock, &zombie_lock, "zombie lock", MTX_SPIN);
#ifdef KSE
static int
@ -121,14 +121,7 @@ thread_ctor(void *mem, int size, void *arg, int flags)
/*
* Note that td_critnest begins life as 1 because the thread is not
* running and is thereby implicitly waiting to be on the receiving
* end of a context switch. A context switch must occur inside a
* critical section, and in fact, includes hand-off of the sched_lock.
* After a context switch to a newly created thread, it will release
* sched_lock for the first time, and its td_critnest will hit 0 for
* the first time. This happens on the far end of a context switch,
* and when it context switches away from itself, it will in fact go
* back into a critical section, and hand off the sched lock to the
* next thread.
* end of a context switch.
*/
td->td_critnest = 1;
@ -222,6 +215,7 @@ thread_fini(void *mem, int size)
void
proc_linkup(struct proc *p, struct thread *td)
{
TAILQ_INIT(&p->p_threads); /* all threads in proc */
TAILQ_INIT(&p->p_upcalls); /* upcall list */
sigqueue_init(&p->p_sigqueue, p);
@ -260,9 +254,9 @@ threadinit(void)
void
thread_stash(struct thread *td)
{
mtx_lock_spin(&kse_zombie_lock);
mtx_lock_spin(&zombie_lock);
TAILQ_INSERT_HEAD(&zombie_threads, td, td_slpq);
mtx_unlock_spin(&kse_zombie_lock);
mtx_unlock_spin(&zombie_lock);
}
/*
@ -278,11 +272,11 @@ thread_reap(void)
* we really don't care about the next instant..
*/
if (!TAILQ_EMPTY(&zombie_threads)) {
mtx_lock_spin(&kse_zombie_lock);
mtx_lock_spin(&zombie_lock);
td_first = TAILQ_FIRST(&zombie_threads);
if (td_first)
TAILQ_INIT(&zombie_threads);
mtx_unlock_spin(&kse_zombie_lock);
mtx_unlock_spin(&zombie_lock);
while (td_first) {
td_next = TAILQ_NEXT(td_first, td_slpq);
if (td_first->td_ucred)
@ -358,8 +352,9 @@ thread_exit(void)
td = curthread;
p = td->td_proc;
mtx_assert(&sched_lock, MA_OWNED);
PROC_SLOCK_ASSERT(p, MA_OWNED);
mtx_assert(&Giant, MA_NOTOWNED);
PROC_LOCK_ASSERT(p, MA_OWNED);
KASSERT(p != NULL, ("thread exiting without a process"));
CTR3(KTR_PROC, "thread_exit: thread %p (pid %ld, %s)", td,
@ -390,28 +385,13 @@ thread_exit(void)
*/
cpu_thread_exit(td); /* XXXSMP */
#ifdef KSE
/*
* The thread is exiting. scheduler can release its stuff
* and collect stats etc.
* XXX this is not very right, since PROC_UNLOCK may still
* need scheduler stuff.
*/
sched_thread_exit(td);
#endif
/* Do the same timestamp bookkeeping that mi_switch() would do. */
new_switchtime = cpu_ticks();
p->p_rux.rux_runtime += (new_switchtime - PCPU_GET(switchtime));
PCPU_SET(switchtime, new_switchtime);
PCPU_SET(switchticks, ticks);
PCPU_INC(cnt.v_swtch);
/*
* Aggregate this thread's tick stats in the parent so they are not
* lost. Also add the child usage to our own when the final thread
* exits.
*/
ruxagg(&p->p_rux, td);
/* Add the child usage to our own when the final thread exits. */
if (p->p_numthreads == 1)
ruadd(p->p_ru, &p->p_rux, &p->p_stats->p_cru, &p->p_crux);
/*
@ -424,7 +404,13 @@ thread_exit(void)
*/
if (p->p_flag & P_HADTHREADS) {
if (p->p_numthreads > 1) {
thread_lock(td);
#ifdef KSE
kse_unlink(td);
#else
thread_unlink(td);
#endif
thread_unlock(td);
/* Impart our resource usage on another thread */
td2 = FIRST_THREAD_IN_PROC(p);
rucollect(&td2->td_ru, &td->td_ru);
@ -437,7 +423,9 @@ thread_exit(void)
*/
if (P_SHOULDSTOP(p) == P_STOPPED_SINGLE) {
if (p->p_numthreads == p->p_suspcount) {
thread_lock(p->p_singlethread);
thread_unsuspend_one(p->p_singlethread);
thread_unlock(p->p_singlethread);
}
}
@ -454,8 +442,6 @@ thread_exit(void)
*/
upcall_remove(td);
#endif
PROC_UNLOCK(p);
PCPU_SET(deadthread, td);
} else {
/*
@ -473,17 +459,15 @@ thread_exit(void)
*/
panic ("thread_exit: Last thread exiting on its own");
}
} else {
/*
* non threaded process comes here.
* This includes an EX threaded process that is coming
* here via exit1(). (exit1 dethreads the proc first).
*/
PROC_UNLOCK(p);
}
}
PROC_UNLOCK(p);
thread_lock(td);
/* Aggregate our tick statistics into our parents rux. */
ruxagg(&p->p_rux, td);
PROC_SUNLOCK(p);
td->td_state = TDS_INACTIVE;
CTR1(KTR_PROC, "thread_exit: cpu_throw() thread %p", td);
cpu_throw(td, choosethread());
sched_throw(td);
panic("I'm a teapot!");
/* NOTREACHED */
}
@ -532,6 +516,11 @@ void
thread_link(struct thread *td, struct proc *p)
{
/*
* XXX This can't be enabled because it's called for proc0 before
* it's spinlock has been created.
* PROC_SLOCK_ASSERT(p, MA_OWNED);
*/
td->td_state = TDS_INACTIVE;
td->td_proc = p;
td->td_flags = 0;
@ -579,7 +568,7 @@ thread_unlink(struct thread *td)
{
struct proc *p = td->td_proc;
mtx_assert(&sched_lock, MA_OWNED);
PROC_SLOCK_ASSERT(p, MA_OWNED);
TAILQ_REMOVE(&p->p_threads, td, td_plist);
p->p_numthreads--;
/* could clear a few other things here */
@ -631,7 +620,7 @@ thread_single(int mode)
p->p_flag &= ~P_SINGLE_BOUNDARY;
}
p->p_flag |= P_STOPPED_SINGLE;
mtx_lock_spin(&sched_lock);
PROC_SLOCK(p);
p->p_singlethread = td;
if (mode == SINGLE_EXIT)
remaining = p->p_numthreads;
@ -645,6 +634,7 @@ thread_single(int mode)
FOREACH_THREAD_IN_PROC(p, td2) {
if (td2 == td)
continue;
thread_lock(td2);
td2->td_flags |= TDF_ASTPENDING;
if (TD_IS_INHIBITED(td2)) {
switch (mode) {
@ -666,8 +656,10 @@ thread_single(int mode)
sleepq_abort(td2, ERESTART);
break;
default:
if (TD_IS_SUSPENDED(td2))
if (TD_IS_SUSPENDED(td2)) {
thread_unlock(td2);
continue;
}
/*
* maybe other inhibited states too?
*/
@ -683,6 +675,7 @@ thread_single(int mode)
forward_signal(td2);
}
#endif
thread_unlock(td2);
}
if (mode == SINGLE_EXIT)
remaining = p->p_numthreads;
@ -702,13 +695,7 @@ stopme:
* Wake us up when everyone else has suspended.
* In the mean time we suspend as well.
*/
thread_stopped(p);
thread_suspend_one(td);
PROC_UNLOCK(p);
mi_switch(SW_VOL, NULL);
mtx_unlock_spin(&sched_lock);
PROC_LOCK(p);
mtx_lock_spin(&sched_lock);
thread_suspend_switch(td);
if (mode == SINGLE_EXIT)
remaining = p->p_numthreads;
else if (mode == SINGLE_BOUNDARY)
@ -727,7 +714,7 @@ stopme:
p->p_flag &= ~(P_STOPPED_SINGLE | P_SINGLE_EXIT);
thread_unthread(td);
}
mtx_unlock_spin(&sched_lock);
PROC_SUNLOCK(p);
return (0);
}
@ -800,7 +787,7 @@ thread_suspend_check(int return_instead)
if ((p->p_flag & P_SINGLE_EXIT) && (p->p_singlethread != td))
sigqueue_flush(&td->td_sigqueue);
mtx_lock_spin(&sched_lock);
PROC_SLOCK(p);
thread_stopped(p);
/*
* If the process is waiting for us to exit,
@ -809,7 +796,15 @@ thread_suspend_check(int return_instead)
*/
if ((p->p_flag & P_SINGLE_EXIT) && (p->p_singlethread != td))
thread_exit();
if (P_SHOULDSTOP(p) == P_STOPPED_SINGLE) {
if (p->p_numthreads == p->p_suspcount + 1) {
thread_lock(p->p_singlethread);
thread_unsuspend_one(p->p_singlethread);
thread_unlock(p->p_singlethread);
}
}
PROC_UNLOCK(p);
thread_lock(td);
/*
* When a thread suspends, it just
* gets taken off all queues.
@ -819,29 +814,52 @@ thread_suspend_check(int return_instead)
p->p_boundary_count++;
td->td_flags |= TDF_BOUNDARY;
}
if (P_SHOULDSTOP(p) == P_STOPPED_SINGLE) {
if (p->p_numthreads == p->p_suspcount)
thread_unsuspend_one(p->p_singlethread);
}
PROC_UNLOCK(p);
PROC_SUNLOCK(p);
mi_switch(SW_INVOL, NULL);
if (return_instead == 0) {
p->p_boundary_count--;
if (return_instead == 0)
td->td_flags &= ~TDF_BOUNDARY;
}
mtx_unlock_spin(&sched_lock);
thread_unlock(td);
PROC_LOCK(p);
if (return_instead == 0)
p->p_boundary_count--;
}
return (0);
}
void
thread_suspend_switch(struct thread *td)
{
struct proc *p;
p = td->td_proc;
KASSERT(!TD_IS_SUSPENDED(td), ("already suspended"));
PROC_LOCK_ASSERT(p, MA_OWNED);
PROC_SLOCK_ASSERT(p, MA_OWNED);
/*
* We implement thread_suspend_one in stages here to avoid
* dropping the proc lock while the thread lock is owned.
*/
thread_stopped(p);
p->p_suspcount++;
PROC_UNLOCK(p);
thread_lock(td);
TD_SET_SUSPENDED(td);
PROC_SUNLOCK(p);
DROP_GIANT();
mi_switch(SW_VOL, NULL);
thread_unlock(td);
PICKUP_GIANT();
PROC_LOCK(p);
PROC_SLOCK(p);
}
void
thread_suspend_one(struct thread *td)
{
struct proc *p = td->td_proc;
mtx_assert(&sched_lock, MA_OWNED);
PROC_LOCK_ASSERT(p, MA_OWNED);
PROC_SLOCK_ASSERT(p, MA_OWNED);
THREAD_LOCK_ASSERT(td, MA_OWNED);
KASSERT(!TD_IS_SUSPENDED(td), ("already suspended"));
p->p_suspcount++;
TD_SET_SUSPENDED(td);
@ -852,8 +870,8 @@ thread_unsuspend_one(struct thread *td)
{
struct proc *p = td->td_proc;
mtx_assert(&sched_lock, MA_OWNED);
PROC_LOCK_ASSERT(p, MA_OWNED);
PROC_SLOCK_ASSERT(p, MA_OWNED);
THREAD_LOCK_ASSERT(td, MA_OWNED);
KASSERT(TD_IS_SUSPENDED(td), ("Thread not suspended"));
TD_CLR_SUSPENDED(td);
p->p_suspcount--;
@ -868,13 +886,15 @@ thread_unsuspend(struct proc *p)
{
struct thread *td;
mtx_assert(&sched_lock, MA_OWNED);
PROC_LOCK_ASSERT(p, MA_OWNED);
PROC_SLOCK_ASSERT(p, MA_OWNED);
if (!P_SHOULDSTOP(p)) {
FOREACH_THREAD_IN_PROC(p, td) {
thread_lock(td);
if (TD_IS_SUSPENDED(td)) {
thread_unsuspend_one(td);
}
thread_unlock(td);
}
} else if ((P_SHOULDSTOP(p) == P_STOPPED_SINGLE) &&
(p->p_numthreads == p->p_suspcount)) {
@ -883,7 +903,9 @@ thread_unsuspend(struct proc *p)
* threading request. Now we've downgraded to single-threaded,
* let it continue.
*/
thread_lock(p->p_singlethread);
thread_unsuspend_one(p->p_singlethread);
thread_unlock(p->p_singlethread);
}
}
@ -900,7 +922,7 @@ thread_single_end(void)
p = td->td_proc;
PROC_LOCK_ASSERT(p, MA_OWNED);
p->p_flag &= ~(P_STOPPED_SINGLE | P_SINGLE_EXIT | P_SINGLE_BOUNDARY);
mtx_lock_spin(&sched_lock);
PROC_SLOCK(p);
p->p_singlethread = NULL;
/*
* If there are other threads they mey now run,
@ -910,12 +932,14 @@ thread_single_end(void)
*/
if ((p->p_numthreads != 1) && (!P_SHOULDSTOP(p))) {
FOREACH_THREAD_IN_PROC(p, td) {
thread_lock(td);
if (TD_IS_SUSPENDED(td)) {
thread_unsuspend_one(td);
}
thread_unlock(td);
}
}
mtx_unlock_spin(&sched_lock);
PROC_SUNLOCK(p);
}
struct thread *
@ -924,11 +948,11 @@ thread_find(struct proc *p, lwpid_t tid)
struct thread *td;
PROC_LOCK_ASSERT(p, MA_OWNED);
mtx_lock_spin(&sched_lock);
PROC_SLOCK(p);
FOREACH_THREAD_IN_PROC(p, td) {
if (td->td_tid == tid)
break;
}
mtx_unlock_spin(&sched_lock);
PROC_SUNLOCK(p);
return (td);
}