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freebsd/sys/kern/kern_thr.c
Marcel Moolenaar 247aba2474 Allocate TIDs in thread_init() and deallocate them in thread_fini().
The overhead of unconditionally allocating TIDs (and likewise,
unconditionally deallocating them), is amortized across multiple
thread creations by the way UMA makes it possible to have type-stable
storage.
Previously the cost was kept down by having threads created as part
of a fork operation use the process' PID as the TID. While this had
some nice properties, it also introduced complexity in the way TIDs
were allocated. Most importantly, by using the type-stable storage
that UMA gives us this was also unnecessary.

This change affects how core dumps are created and in particular how
the PRSTATUS notes are dumped. Since we don't have a thread with a
TID equalling the PID, we now need a different way to preserve the
old and previous behavior. We do this by having the given thread (i.e.
the thread passed to the core dump code in td) dump it's state first
and fill in pr_pid with the actual PID. All other threads will have
pr_pid contain their TIDs. The upshot of all this is that the debugger
will now likely select the right LWP (=TID) as the initial thread.

Credits to: julian@ for spotting how we can utilize UMA.
Thanks to: all who provided julian@ with test results.
2004-06-26 18:58:22 +00:00

315 lines
7.1 KiB
C

/*
* Copyright (c) 2003, Jeffrey Roberson <jeff@freebsd.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice unmodified, this list of conditions, and the following
* disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/resourcevar.h>
#include <sys/sched.h>
#include <sys/sysent.h>
#include <sys/systm.h>
#include <sys/sysproto.h>
#include <sys/signalvar.h>
#include <sys/ucontext.h>
#include <sys/thr.h>
#include <machine/frame.h>
/*
* Back end support functions.
*/
void
thr_exit1(void)
{
struct ksegrp *kg;
struct thread *td;
struct kse *ke;
struct proc *p;
td = curthread;
p = td->td_proc;
kg = td->td_ksegrp;
ke = td->td_kse;
mtx_assert(&sched_lock, MA_OWNED);
PROC_LOCK_ASSERT(p, MA_OWNED);
KASSERT(!mtx_owned(&Giant), ("dying thread owns giant"));
/*
* Shutting down last thread in the proc. This will actually
* call exit() in the trampoline when it returns.
*/
if (p->p_numthreads == 1) {
PROC_UNLOCK(p);
return;
}
/*
* XXX Undelivered process wide signals should be reposted to the
* proc.
*/
/* Clean up cpu resources. */
cpu_thread_exit(td);
/* Unlink the thread from the process and kseg. */
thread_unlink(td);
ke->ke_state = KES_UNQUEUED;
ke->ke_thread = NULL;
kse_unlink(ke);
sched_exit_kse(TAILQ_NEXT(ke, ke_kglist), ke);
/*
* If we were stopped while waiting for all threads to exit and this
* is the last thread wakeup the exiting thread.
*/
if (P_SHOULDSTOP(p) == P_STOPPED_SINGLE)
if (p->p_numthreads == 1)
thread_unsuspend_one(p->p_singlethread);
PROC_UNLOCK(p);
td->td_kse = NULL;
td->td_state = TDS_INACTIVE;
#if 0
td->td_proc = NULL;
#endif
td->td_ksegrp = NULL;
td->td_last_kse = NULL;
sched_exit_thread(TAILQ_NEXT(td, td_kglist), td);
thread_stash(td);
cpu_throw(td, choosethread());
}
#define RANGEOF(type, start, end) (offsetof(type, end) - offsetof(type, start))
/*
* System call interface.
*/
int
thr_create(struct thread *td, struct thr_create_args *uap)
/* ucontext_t *ctx, thr_id_t *id, int flags */
{
struct kse *ke0;
struct thread *td0;
ucontext_t ctx;
int error;
if ((error = copyin(uap->ctx, &ctx, sizeof(ctx))))
return (error);
/* Initialize our td. */
td0 = thread_alloc();
/*
* Try the copyout as soon as we allocate the td so we don't have to
* tear things down in a failure case below.
*/
if ((error = copyout(&td0, uap->id, sizeof(thr_id_t)))) {
thread_free(td0);
return (error);
}
bzero(&td0->td_startzero,
(unsigned)RANGEOF(struct thread, td_startzero, td_endzero));
bcopy(&td->td_startcopy, &td0->td_startcopy,
(unsigned) RANGEOF(struct thread, td_startcopy, td_endcopy));
td0->td_proc = td->td_proc;
PROC_LOCK(td->td_proc);
td0->td_sigmask = td->td_sigmask;
PROC_UNLOCK(td->td_proc);
td0->td_ucred = crhold(td->td_ucred);
/* Initialize our kse structure. */
ke0 = kse_alloc();
bzero(&ke0->ke_startzero,
RANGEOF(struct kse, ke_startzero, ke_endzero));
/* Set up our machine context. */
cpu_set_upcall(td0, td);
error = set_mcontext(td0, &ctx.uc_mcontext);
if (error != 0) {
kse_free(ke0);
thread_free(td0);
goto out;
}
/* Link the thread and kse into the ksegrp and make it runnable. */
mtx_lock_spin(&sched_lock);
thread_link(td0, td->td_ksegrp);
kse_link(ke0, td->td_ksegrp);
/* Bind this thread and kse together. */
td0->td_kse = ke0;
ke0->ke_thread = td0;
sched_fork_kse(td->td_kse, ke0);
sched_fork_thread(td, td0);
TD_SET_CAN_RUN(td0);
if ((uap->flags & THR_SUSPENDED) == 0)
setrunqueue(td0);
mtx_unlock_spin(&sched_lock);
out:
return (error);
}
int
thr_self(struct thread *td, struct thr_self_args *uap)
/* thr_id_t *id */
{
int error;
if ((error = copyout(&td, uap->id, sizeof(thr_id_t))))
return (error);
return (0);
}
int
thr_exit(struct thread *td, struct thr_exit_args *uap)
/* NULL */
{
struct proc *p;
p = td->td_proc;
PROC_LOCK(p);
mtx_lock_spin(&sched_lock);
/*
* This unlocks proc and doesn't return unless this is the last
* thread.
*/
thr_exit1();
mtx_unlock_spin(&sched_lock);
return (0);
}
int
thr_kill(struct thread *td, struct thr_kill_args *uap)
/* thr_id_t id, int sig */
{
struct thread *ttd;
struct proc *p;
int error;
p = td->td_proc;
error = 0;
PROC_LOCK(p);
FOREACH_THREAD_IN_PROC(p, ttd) {
if (ttd == uap->id)
break;
}
if (ttd == NULL) {
error = ESRCH;
goto out;
}
if (uap->sig == 0)
goto out;
if (!_SIG_VALID(uap->sig)) {
error = EINVAL;
goto out;
}
tdsignal(ttd, uap->sig, SIGTARGET_TD);
out:
PROC_UNLOCK(p);
return (error);
}
int
thr_suspend(struct thread *td, struct thr_suspend_args *uap)
/* const struct timespec *timeout */
{
struct timespec ts;
struct timeval tv;
int error;
int hz;
hz = 0;
error = 0;
if (uap->timeout != NULL) {
error = copyin((const void *)uap->timeout, (void *)&ts,
sizeof(struct timespec));
if (error != 0)
return (error);
if (ts.tv_nsec < 0 || ts.tv_nsec > 1000000000)
return (EINVAL);
if (ts.tv_sec == 0 && ts.tv_nsec == 0)
return (ETIMEDOUT);
TIMESPEC_TO_TIMEVAL(&tv, &ts);
hz = tvtohz(&tv);
}
PROC_LOCK(td->td_proc);
mtx_lock_spin(&sched_lock);
if ((td->td_flags & TDF_THRWAKEUP) == 0) {
mtx_unlock_spin(&sched_lock);
error = msleep((void *)td, &td->td_proc->p_mtx,
td->td_priority | PCATCH, "lthr", hz);
mtx_lock_spin(&sched_lock);
}
td->td_flags &= ~TDF_THRWAKEUP;
mtx_unlock_spin(&sched_lock);
PROC_UNLOCK(td->td_proc);
return (error == EWOULDBLOCK ? ETIMEDOUT : error);
}
int
thr_wake(struct thread *td, struct thr_wake_args *uap)
/* thr_id_t id */
{
struct thread *tdsleeper, *ttd;
tdsleeper = ((struct thread *)uap->id);
PROC_LOCK(td->td_proc);
FOREACH_THREAD_IN_PROC(td->td_proc, ttd) {
if (ttd == tdsleeper)
break;
}
if (ttd == NULL) {
PROC_UNLOCK(td->td_proc);
return (ESRCH);
}
mtx_lock_spin(&sched_lock);
tdsleeper->td_flags |= TDF_THRWAKEUP;
mtx_unlock_spin(&sched_lock);
wakeup_one((void *)tdsleeper);
PROC_UNLOCK(td->td_proc);
return (0);
}