freebsd-dev/sys/kern/kern_kse.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

1269 lines
31 KiB
C

/*
* Copyright (C) 2001 Julian Elischer <julian@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(s), this list of conditions and the following disclaimer as
* the first lines of this file unmodified other than the possible
* addition of one or more copyright notices.
* 2. Redistributions in binary form must reproduce the above copyright
* notice(s), 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 COPYRIGHT HOLDER(S) ``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 COPYRIGHT HOLDER(S) 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/systm.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/smp.h>
#include <sys/sysproto.h>
#include <sys/sched.h>
#include <sys/signalvar.h>
#include <sys/sleepqueue.h>
#include <sys/kse.h>
#include <sys/ktr.h>
#include <vm/uma.h>
/*
* KSEGRP related storage.
*/
static uma_zone_t upcall_zone;
/* DEBUG ONLY */
extern int virtual_cpu;
extern int thread_debug;
extern int max_threads_per_proc;
extern int max_groups_per_proc;
extern int max_threads_hits;
extern struct mtx kse_zombie_lock;
#define RANGEOF(type, start, end) (offsetof(type, end) - offsetof(type, start))
TAILQ_HEAD(, kse_upcall) zombie_upcalls =
TAILQ_HEAD_INITIALIZER(zombie_upcalls);
static int thread_update_usr_ticks(struct thread *td, int user);
static void thread_alloc_spare(struct thread *td, struct thread *spare);
/* move to proc.h */
extern void kse_purge(struct proc *p, struct thread *td);
extern void kse_purge_group(struct thread *td);
void kseinit(void);
void kse_GC(void);
struct kse_upcall *
upcall_alloc(void)
{
struct kse_upcall *ku;
ku = uma_zalloc(upcall_zone, M_WAITOK);
bzero(ku, sizeof(*ku));
return (ku);
}
void
upcall_free(struct kse_upcall *ku)
{
uma_zfree(upcall_zone, ku);
}
void
upcall_link(struct kse_upcall *ku, struct ksegrp *kg)
{
mtx_assert(&sched_lock, MA_OWNED);
TAILQ_INSERT_TAIL(&kg->kg_upcalls, ku, ku_link);
ku->ku_ksegrp = kg;
kg->kg_numupcalls++;
}
void
upcall_unlink(struct kse_upcall *ku)
{
struct ksegrp *kg = ku->ku_ksegrp;
mtx_assert(&sched_lock, MA_OWNED);
KASSERT(ku->ku_owner == NULL, ("%s: have owner", __func__));
TAILQ_REMOVE(&kg->kg_upcalls, ku, ku_link);
kg->kg_numupcalls--;
upcall_stash(ku);
}
void
upcall_remove(struct thread *td)
{
if (td->td_upcall) {
td->td_upcall->ku_owner = NULL;
upcall_unlink(td->td_upcall);
td->td_upcall = 0;
}
}
#ifndef _SYS_SYSPROTO_H_
struct kse_switchin_args {
const struct __mcontext *mcp;
long val;
long *loc;
};
#endif
int
kse_switchin(struct thread *td, struct kse_switchin_args *uap)
{
mcontext_t mc;
int error;
error = (uap->mcp == NULL) ? EINVAL : 0;
if (!error)
error = copyin(uap->mcp, &mc, sizeof(mc));
if (!error && uap->loc != NULL)
error = (suword(uap->loc, uap->val) != 0) ? EINVAL : 0;
if (!error)
error = set_mcontext(td, &mc);
return ((error == 0) ? EJUSTRETURN : error);
}
/*
struct kse_thr_interrupt_args {
struct kse_thr_mailbox * tmbx;
int cmd;
long data;
};
*/
int
kse_thr_interrupt(struct thread *td, struct kse_thr_interrupt_args *uap)
{
struct proc *p;
struct thread *td2;
p = td->td_proc;
if (!(p->p_flag & P_SA))
return (EINVAL);
switch (uap->cmd) {
case KSE_INTR_SENDSIG:
if (uap->data < 0 || uap->data > _SIG_MAXSIG)
return (EINVAL);
case KSE_INTR_INTERRUPT:
case KSE_INTR_RESTART:
PROC_LOCK(p);
mtx_lock_spin(&sched_lock);
FOREACH_THREAD_IN_PROC(p, td2) {
if (td2->td_mailbox == uap->tmbx)
break;
}
if (td2 == NULL) {
mtx_unlock_spin(&sched_lock);
PROC_UNLOCK(p);
return (ESRCH);
}
if (uap->cmd == KSE_INTR_SENDSIG) {
if (uap->data > 0) {
td2->td_flags &= ~TDF_INTERRUPT;
mtx_unlock_spin(&sched_lock);
tdsignal(td2, (int)uap->data, SIGTARGET_TD);
} else {
mtx_unlock_spin(&sched_lock);
}
} else {
td2->td_flags |= TDF_INTERRUPT | TDF_ASTPENDING;
if (TD_CAN_UNBIND(td2))
td2->td_upcall->ku_flags |= KUF_DOUPCALL;
if (uap->cmd == KSE_INTR_INTERRUPT)
td2->td_intrval = EINTR;
else
td2->td_intrval = ERESTART;
if (TD_ON_SLEEPQ(td2) && (td2->td_flags & TDF_SINTR))
sleepq_abort(td2);
mtx_unlock_spin(&sched_lock);
}
PROC_UNLOCK(p);
break;
case KSE_INTR_SIGEXIT:
if (uap->data < 1 || uap->data > _SIG_MAXSIG)
return (EINVAL);
PROC_LOCK(p);
sigexit(td, (int)uap->data);
break;
default:
return (EINVAL);
}
return (0);
}
/*
struct kse_exit_args {
register_t dummy;
};
*/
int
kse_exit(struct thread *td, struct kse_exit_args *uap)
{
struct proc *p;
struct ksegrp *kg;
struct kse *ke;
struct kse_upcall *ku, *ku2;
int error, count;
p = td->td_proc;
/*
* Ensure that this is only called from the UTS
*/
if ((ku = td->td_upcall) == NULL || TD_CAN_UNBIND(td))
return (EINVAL);
kg = td->td_ksegrp;
count = 0;
/*
* Calculate the existing non-exiting upcalls in this ksegroup.
* If we are the last upcall but there are still other threads,
* then do not exit. We need the other threads to be able to
* complete whatever they are doing.
* XXX This relies on the userland knowing what to do if we return.
* It may be a better choice to convert ourselves into a kse_release
* ( or similar) and wait in the kernel to be needed.
*/
PROC_LOCK(p);
mtx_lock_spin(&sched_lock);
FOREACH_UPCALL_IN_GROUP(kg, ku2) {
if (ku2->ku_flags & KUF_EXITING)
count++;
}
if ((kg->kg_numupcalls - count) == 1 &&
(kg->kg_numthreads > 1)) {
mtx_unlock_spin(&sched_lock);
PROC_UNLOCK(p);
return (EDEADLK);
}
ku->ku_flags |= KUF_EXITING;
mtx_unlock_spin(&sched_lock);
PROC_UNLOCK(p);
/*
* Mark the UTS mailbox as having been finished with.
* If that fails then just go for a segfault.
* XXX need to check it that can be deliverred without a mailbox.
*/
error = suword(&ku->ku_mailbox->km_flags, ku->ku_mflags|KMF_DONE);
PROC_LOCK(p);
if (error)
psignal(p, SIGSEGV);
mtx_lock_spin(&sched_lock);
upcall_remove(td);
ke = td->td_kse;
if (p->p_numthreads == 1) {
kse_purge(p, td);
p->p_flag &= ~P_SA;
mtx_unlock_spin(&sched_lock);
PROC_UNLOCK(p);
} else {
if (kg->kg_numthreads == 1) { /* Shutdown a group */
kse_purge_group(td);
ke->ke_flags |= KEF_EXIT;
}
thread_stopped(p);
thread_exit();
/* NOTREACHED */
}
return (0);
}
/*
* Either becomes an upcall or waits for an awakening event and
* then becomes an upcall. Only error cases return.
*/
/*
struct kse_release_args {
struct timespec *timeout;
};
*/
int
kse_release(struct thread *td, struct kse_release_args *uap)
{
struct proc *p;
struct ksegrp *kg;
struct kse_upcall *ku;
struct timespec timeout;
struct timeval tv;
sigset_t sigset;
int error;
p = td->td_proc;
kg = td->td_ksegrp;
if ((ku = td->td_upcall) == NULL || TD_CAN_UNBIND(td))
return (EINVAL);
if (uap->timeout != NULL) {
if ((error = copyin(uap->timeout, &timeout, sizeof(timeout))))
return (error);
TIMESPEC_TO_TIMEVAL(&tv, &timeout);
}
if (td->td_pflags & TDP_SA)
td->td_pflags |= TDP_UPCALLING;
else {
ku->ku_mflags = fuword(&ku->ku_mailbox->km_flags);
if (ku->ku_mflags == -1) {
PROC_LOCK(p);
sigexit(td, SIGSEGV);
}
}
PROC_LOCK(p);
if (ku->ku_mflags & KMF_WAITSIGEVENT) {
/* UTS wants to wait for signal event */
if (!(p->p_flag & P_SIGEVENT) && !(ku->ku_flags & KUF_DOUPCALL)) {
td->td_kflags |= TDK_KSERELSIG;
error = msleep(&p->p_siglist, &p->p_mtx, PPAUSE|PCATCH,
"ksesigwait", (uap->timeout ? tvtohz(&tv) : 0));
td->td_kflags &= ~(TDK_KSERELSIG | TDK_WAKEUP);
}
p->p_flag &= ~P_SIGEVENT;
sigset = p->p_siglist;
PROC_UNLOCK(p);
error = copyout(&sigset, &ku->ku_mailbox->km_sigscaught,
sizeof(sigset));
} else {
if (! kg->kg_completed && !(ku->ku_flags & KUF_DOUPCALL)) {
kg->kg_upsleeps++;
td->td_kflags |= TDK_KSEREL;
error = msleep(&kg->kg_completed, &p->p_mtx,
PPAUSE|PCATCH, "kserel",
(uap->timeout ? tvtohz(&tv) : 0));
td->td_kflags &= ~(TDK_KSEREL | TDK_WAKEUP);
kg->kg_upsleeps--;
}
PROC_UNLOCK(p);
}
if (ku->ku_flags & KUF_DOUPCALL) {
mtx_lock_spin(&sched_lock);
ku->ku_flags &= ~KUF_DOUPCALL;
mtx_unlock_spin(&sched_lock);
}
return (0);
}
/* struct kse_wakeup_args {
struct kse_mailbox *mbx;
}; */
int
kse_wakeup(struct thread *td, struct kse_wakeup_args *uap)
{
struct proc *p;
struct ksegrp *kg;
struct kse_upcall *ku;
struct thread *td2;
p = td->td_proc;
td2 = NULL;
ku = NULL;
/* KSE-enabled processes only, please. */
if (!(p->p_flag & P_SA))
return (EINVAL);
PROC_LOCK(p);
mtx_lock_spin(&sched_lock);
if (uap->mbx) {
FOREACH_KSEGRP_IN_PROC(p, kg) {
FOREACH_UPCALL_IN_GROUP(kg, ku) {
if (ku->ku_mailbox == uap->mbx)
break;
}
if (ku)
break;
}
} else {
kg = td->td_ksegrp;
if (kg->kg_upsleeps) {
mtx_unlock_spin(&sched_lock);
wakeup_one(&kg->kg_completed);
PROC_UNLOCK(p);
return (0);
}
ku = TAILQ_FIRST(&kg->kg_upcalls);
}
if (ku == NULL) {
mtx_unlock_spin(&sched_lock);
PROC_UNLOCK(p);
return (ESRCH);
}
if ((td2 = ku->ku_owner) == NULL) {
mtx_unlock_spin(&sched_lock);
panic("%s: no owner", __func__);
} else if (td2->td_kflags & (TDK_KSEREL | TDK_KSERELSIG)) {
mtx_unlock_spin(&sched_lock);
if (!(td2->td_kflags & TDK_WAKEUP)) {
td2->td_kflags |= TDK_WAKEUP;
if (td2->td_kflags & TDK_KSEREL)
sleepq_remove(td2, &kg->kg_completed);
else
sleepq_remove(td2, &p->p_siglist);
}
} else {
ku->ku_flags |= KUF_DOUPCALL;
mtx_unlock_spin(&sched_lock);
}
PROC_UNLOCK(p);
return (0);
}
/*
* No new KSEG: first call: use current KSE, don't schedule an upcall
* All other situations, do allocate max new KSEs and schedule an upcall.
*/
/* struct kse_create_args {
struct kse_mailbox *mbx;
int newgroup;
}; */
int
kse_create(struct thread *td, struct kse_create_args *uap)
{
struct kse *newke;
struct ksegrp *newkg;
struct ksegrp *kg;
struct proc *p;
struct kse_mailbox mbx;
struct kse_upcall *newku;
int err, ncpus, sa = 0, first = 0;
struct thread *newtd;
p = td->td_proc;
if ((err = copyin(uap->mbx, &mbx, sizeof(mbx))))
return (err);
ncpus = mp_ncpus;
if (virtual_cpu != 0)
ncpus = virtual_cpu;
if (!(mbx.km_flags & KMF_BOUND))
sa = TDP_SA;
else
ncpus = 1;
PROC_LOCK(p);
if (!(p->p_flag & P_SA)) {
first = 1;
p->p_flag |= P_SA;
}
PROC_UNLOCK(p);
if (!sa && !uap->newgroup && !first)
return (EINVAL);
kg = td->td_ksegrp;
if (uap->newgroup) {
/* Have race condition but it is cheap */
if (p->p_numksegrps >= max_groups_per_proc)
return (EPROCLIM);
/*
* If we want a new KSEGRP it doesn't matter whether
* we have already fired up KSE mode before or not.
* We put the process in KSE mode and create a new KSEGRP.
*/
newkg = ksegrp_alloc();
bzero(&newkg->kg_startzero, RANGEOF(struct ksegrp,
kg_startzero, kg_endzero));
bcopy(&kg->kg_startcopy, &newkg->kg_startcopy,
RANGEOF(struct ksegrp, kg_startcopy, kg_endcopy));
PROC_LOCK(p);
mtx_lock_spin(&sched_lock);
if (p->p_numksegrps >= max_groups_per_proc) {
mtx_unlock_spin(&sched_lock);
PROC_UNLOCK(p);
ksegrp_free(newkg);
return (EPROCLIM);
}
ksegrp_link(newkg, p);
sched_fork_ksegrp(kg, newkg);
mtx_unlock_spin(&sched_lock);
PROC_UNLOCK(p);
} else {
if (!first && ((td->td_pflags & TDP_SA) ^ sa) != 0)
return (EINVAL);
newkg = kg;
}
/*
* Creating upcalls more than number of physical cpu does
* not help performance.
*/
if (newkg->kg_numupcalls >= ncpus)
return (EPROCLIM);
if (newkg->kg_numupcalls == 0) {
/*
* Initialize KSE group
*
* For multiplxed group, create KSEs as many as physical
* cpus. This increases concurrent even if userland
* is not MP safe and can only run on single CPU.
* In ideal world, every physical cpu should execute a thread.
* If there is enough KSEs, threads in kernel can be
* executed parallel on different cpus with full speed,
* Concurrent in kernel shouldn't be restricted by number of
* upcalls userland provides. Adding more upcall structures
* only increases concurrent in userland.
*
* For bound thread group, because there is only thread in the
* group, we only create one KSE for the group. Thread in this
* kind of group will never schedule an upcall when blocked,
* this intends to simulate pthread system scope thread.
*/
while (newkg->kg_kses < ncpus) {
newke = kse_alloc();
bzero(&newke->ke_startzero, RANGEOF(struct kse,
ke_startzero, ke_endzero));
#if 0
mtx_lock_spin(&sched_lock);
bcopy(&ke->ke_startcopy, &newke->ke_startcopy,
RANGEOF(struct kse, ke_startcopy, ke_endcopy));
mtx_unlock_spin(&sched_lock);
#endif
mtx_lock_spin(&sched_lock);
kse_link(newke, newkg);
sched_fork_kse(td->td_kse, newke);
/* Add engine */
kse_reassign(newke);
mtx_unlock_spin(&sched_lock);
}
}
newku = upcall_alloc();
newku->ku_mailbox = uap->mbx;
newku->ku_func = mbx.km_func;
bcopy(&mbx.km_stack, &newku->ku_stack, sizeof(stack_t));
/* For the first call this may not have been set */
if (td->td_standin == NULL)
thread_alloc_spare(td, NULL);
PROC_LOCK(p);
if (newkg->kg_numupcalls >= ncpus) {
PROC_UNLOCK(p);
upcall_free(newku);
return (EPROCLIM);
}
if (first && sa) {
SIGSETOR(p->p_siglist, td->td_siglist);
SIGEMPTYSET(td->td_siglist);
SIGFILLSET(td->td_sigmask);
SIG_CANTMASK(td->td_sigmask);
}
mtx_lock_spin(&sched_lock);
PROC_UNLOCK(p);
upcall_link(newku, newkg);
if (mbx.km_quantum)
newkg->kg_upquantum = max(1, mbx.km_quantum/tick);
/*
* Each upcall structure has an owner thread, find which
* one owns it.
*/
if (uap->newgroup) {
/*
* Because new ksegrp hasn't thread,
* create an initial upcall thread to own it.
*/
newtd = thread_schedule_upcall(td, newku);
} else {
/*
* If current thread hasn't an upcall structure,
* just assign the upcall to it.
*/
if (td->td_upcall == NULL) {
newku->ku_owner = td;
td->td_upcall = newku;
newtd = td;
} else {
/*
* Create a new upcall thread to own it.
*/
newtd = thread_schedule_upcall(td, newku);
}
}
if (!sa) {
newtd->td_mailbox = mbx.km_curthread;
newtd->td_pflags &= ~TDP_SA;
if (newtd != td) {
mtx_unlock_spin(&sched_lock);
cpu_set_upcall_kse(newtd, newku);
mtx_lock_spin(&sched_lock);
}
} else {
newtd->td_pflags |= TDP_SA;
}
if (newtd != td)
setrunqueue(newtd);
mtx_unlock_spin(&sched_lock);
return (0);
}
/*
* Initialize global thread allocation resources.
*/
void
kseinit(void)
{
upcall_zone = uma_zcreate("UPCALL", sizeof(struct kse_upcall),
NULL, NULL, NULL, NULL, UMA_ALIGN_CACHE, 0);
}
/*
* Stash an embarasingly extra upcall into the zombie upcall queue.
*/
void
upcall_stash(struct kse_upcall *ku)
{
mtx_lock_spin(&kse_zombie_lock);
TAILQ_INSERT_HEAD(&zombie_upcalls, ku, ku_link);
mtx_unlock_spin(&kse_zombie_lock);
}
/*
* Reap zombie kse resource.
*/
void
kse_GC(void)
{
struct kse_upcall *ku_first, *ku_next;
/*
* Don't even bother to lock if none at this instant,
* we really don't care about the next instant..
*/
if (!TAILQ_EMPTY(&zombie_upcalls)) {
mtx_lock_spin(&kse_zombie_lock);
ku_first = TAILQ_FIRST(&zombie_upcalls);
if (ku_first)
TAILQ_INIT(&zombie_upcalls);
mtx_unlock_spin(&kse_zombie_lock);
while (ku_first) {
ku_next = TAILQ_NEXT(ku_first, ku_link);
upcall_free(ku_first);
ku_first = ku_next;
}
}
}
/*
* Store the thread context in the UTS's mailbox.
* then add the mailbox at the head of a list we are building in user space.
* The list is anchored in the ksegrp structure.
*/
int
thread_export_context(struct thread *td, int willexit)
{
struct proc *p;
struct ksegrp *kg;
uintptr_t mbx;
void *addr;
int error = 0, temp, sig;
mcontext_t mc;
p = td->td_proc;
kg = td->td_ksegrp;
/* Export the user/machine context. */
get_mcontext(td, &mc, 0);
addr = (void *)(&td->td_mailbox->tm_context.uc_mcontext);
error = copyout(&mc, addr, sizeof(mcontext_t));
if (error)
goto bad;
/* Exports clock ticks in kernel mode */
addr = (caddr_t)(&td->td_mailbox->tm_sticks);
temp = fuword32(addr) + td->td_usticks;
if (suword32(addr, temp)) {
error = EFAULT;
goto bad;
}
/*
* Post sync signal, or process SIGKILL and SIGSTOP.
* For sync signal, it is only possible when the signal is not
* caught by userland or process is being debugged.
*/
PROC_LOCK(p);
if (td->td_flags & TDF_NEEDSIGCHK) {
mtx_lock_spin(&sched_lock);
td->td_flags &= ~TDF_NEEDSIGCHK;
mtx_unlock_spin(&sched_lock);
mtx_lock(&p->p_sigacts->ps_mtx);
while ((sig = cursig(td)) != 0)
postsig(sig);
mtx_unlock(&p->p_sigacts->ps_mtx);
}
if (willexit)
SIGFILLSET(td->td_sigmask);
PROC_UNLOCK(p);
/* Get address in latest mbox of list pointer */
addr = (void *)(&td->td_mailbox->tm_next);
/*
* Put the saved address of the previous first
* entry into this one
*/
for (;;) {
mbx = (uintptr_t)kg->kg_completed;
if (suword(addr, mbx)) {
error = EFAULT;
goto bad;
}
PROC_LOCK(p);
if (mbx == (uintptr_t)kg->kg_completed) {
kg->kg_completed = td->td_mailbox;
/*
* The thread context may be taken away by
* other upcall threads when we unlock
* process lock. it's no longer valid to
* use it again in any other places.
*/
td->td_mailbox = NULL;
PROC_UNLOCK(p);
break;
}
PROC_UNLOCK(p);
}
td->td_usticks = 0;
return (0);
bad:
PROC_LOCK(p);
sigexit(td, SIGILL);
return (error);
}
/*
* Take the list of completed mailboxes for this KSEGRP and put them on this
* upcall's mailbox as it's the next one going up.
*/
static int
thread_link_mboxes(struct ksegrp *kg, struct kse_upcall *ku)
{
struct proc *p = kg->kg_proc;
void *addr;
uintptr_t mbx;
addr = (void *)(&ku->ku_mailbox->km_completed);
for (;;) {
mbx = (uintptr_t)kg->kg_completed;
if (suword(addr, mbx)) {
PROC_LOCK(p);
psignal(p, SIGSEGV);
PROC_UNLOCK(p);
return (EFAULT);
}
PROC_LOCK(p);
if (mbx == (uintptr_t)kg->kg_completed) {
kg->kg_completed = NULL;
PROC_UNLOCK(p);
break;
}
PROC_UNLOCK(p);
}
return (0);
}
/*
* This function should be called at statclock interrupt time
*/
int
thread_statclock(int user)
{
struct thread *td = curthread;
struct ksegrp *kg = td->td_ksegrp;
if (kg->kg_numupcalls == 0 || !(td->td_pflags & TDP_SA))
return (0);
if (user) {
/* Current always do via ast() */
mtx_lock_spin(&sched_lock);
td->td_flags |= (TDF_USTATCLOCK|TDF_ASTPENDING);
mtx_unlock_spin(&sched_lock);
td->td_uuticks++;
} else {
if (td->td_mailbox != NULL)
td->td_usticks++;
else {
/* XXXKSE
* We will call thread_user_enter() for every
* kernel entry in future, so if the thread mailbox
* is NULL, it must be a UTS kernel, don't account
* clock ticks for it.
*/
}
}
return (0);
}
/*
* Export state clock ticks for userland
*/
static int
thread_update_usr_ticks(struct thread *td, int user)
{
struct proc *p = td->td_proc;
struct kse_thr_mailbox *tmbx;
struct kse_upcall *ku;
struct ksegrp *kg;
caddr_t addr;
u_int uticks;
if ((ku = td->td_upcall) == NULL)
return (-1);
tmbx = (void *)fuword((void *)&ku->ku_mailbox->km_curthread);
if ((tmbx == NULL) || (tmbx == (void *)-1))
return (-1);
if (user) {
uticks = td->td_uuticks;
td->td_uuticks = 0;
addr = (caddr_t)&tmbx->tm_uticks;
} else {
uticks = td->td_usticks;
td->td_usticks = 0;
addr = (caddr_t)&tmbx->tm_sticks;
}
if (uticks) {
if (suword32(addr, uticks+fuword32(addr))) {
PROC_LOCK(p);
psignal(p, SIGSEGV);
PROC_UNLOCK(p);
return (-2);
}
}
kg = td->td_ksegrp;
if (kg->kg_upquantum && ticks >= kg->kg_nextupcall) {
mtx_lock_spin(&sched_lock);
td->td_upcall->ku_flags |= KUF_DOUPCALL;
mtx_unlock_spin(&sched_lock);
}
return (0);
}
/*
* This function is intended to be used to initialize a spare thread
* for upcall. Initialize thread's large data area outside sched_lock
* for thread_schedule_upcall().
*/
void
thread_alloc_spare(struct thread *td, struct thread *spare)
{
if (td->td_standin)
return;
if (spare == NULL)
spare = thread_alloc();
td->td_standin = spare;
bzero(&spare->td_startzero,
(unsigned)RANGEOF(struct thread, td_startzero, td_endzero));
spare->td_proc = td->td_proc;
spare->td_ucred = crhold(td->td_ucred);
}
/*
* Create a thread and schedule it for upcall on the KSE given.
* Use our thread's standin so that we don't have to allocate one.
*/
struct thread *
thread_schedule_upcall(struct thread *td, struct kse_upcall *ku)
{
struct thread *td2;
mtx_assert(&sched_lock, MA_OWNED);
/*
* Schedule an upcall thread on specified kse_upcall,
* the kse_upcall must be free.
* td must have a spare thread.
*/
KASSERT(ku->ku_owner == NULL, ("%s: upcall has owner", __func__));
if ((td2 = td->td_standin) != NULL) {
td->td_standin = NULL;
} else {
panic("no reserve thread when scheduling an upcall");
return (NULL);
}
CTR3(KTR_PROC, "thread_schedule_upcall: thread %p (pid %d, %s)",
td2, td->td_proc->p_pid, td->td_proc->p_comm);
bcopy(&td->td_startcopy, &td2->td_startcopy,
(unsigned) RANGEOF(struct thread, td_startcopy, td_endcopy));
thread_link(td2, ku->ku_ksegrp);
/* inherit parts of blocked thread's context as a good template */
cpu_set_upcall(td2, td);
/* Let the new thread become owner of the upcall */
ku->ku_owner = td2;
td2->td_upcall = ku;
td2->td_flags = 0;
td2->td_pflags = TDP_SA|TDP_UPCALLING;
td2->td_kse = NULL;
td2->td_state = TDS_CAN_RUN;
td2->td_inhibitors = 0;
SIGFILLSET(td2->td_sigmask);
SIG_CANTMASK(td2->td_sigmask);
sched_fork_thread(td, td2);
return (td2); /* bogus.. should be a void function */
}
/*
* It is only used when thread generated a trap and process is being
* debugged.
*/
void
thread_signal_add(struct thread *td, int sig)
{
struct proc *p;
siginfo_t siginfo;
struct sigacts *ps;
int error;
p = td->td_proc;
PROC_LOCK_ASSERT(p, MA_OWNED);
ps = p->p_sigacts;
mtx_assert(&ps->ps_mtx, MA_OWNED);
cpu_thread_siginfo(sig, 0, &siginfo);
mtx_unlock(&ps->ps_mtx);
PROC_UNLOCK(p);
error = copyout(&siginfo, &td->td_mailbox->tm_syncsig, sizeof(siginfo));
if (error) {
PROC_LOCK(p);
sigexit(td, SIGILL);
}
PROC_LOCK(p);
SIGADDSET(td->td_sigmask, sig);
mtx_lock(&ps->ps_mtx);
}
void
thread_switchout(struct thread *td)
{
struct kse_upcall *ku;
struct thread *td2;
mtx_assert(&sched_lock, MA_OWNED);
/*
* If the outgoing thread is in threaded group and has never
* scheduled an upcall, decide whether this is a short
* or long term event and thus whether or not to schedule
* an upcall.
* If it is a short term event, just suspend it in
* a way that takes its KSE with it.
* Select the events for which we want to schedule upcalls.
* For now it's just sleep.
* XXXKSE eventually almost any inhibition could do.
*/
if (TD_CAN_UNBIND(td) && (td->td_standin) && TD_ON_SLEEPQ(td)) {
/*
* Release ownership of upcall, and schedule an upcall
* thread, this new upcall thread becomes the owner of
* the upcall structure.
*/
ku = td->td_upcall;
ku->ku_owner = NULL;
td->td_upcall = NULL;
td->td_flags &= ~TDF_CAN_UNBIND;
td2 = thread_schedule_upcall(td, ku);
setrunqueue(td2);
}
}
/*
* Setup done on the thread when it enters the kernel.
* XXXKSE Presently only for syscalls but eventually all kernel entries.
*/
void
thread_user_enter(struct proc *p, struct thread *td)
{
struct ksegrp *kg;
struct kse_upcall *ku;
struct kse_thr_mailbox *tmbx;
uint32_t tflags;
kg = td->td_ksegrp;
/*
* First check that we shouldn't just abort.
* But check if we are the single thread first!
*/
if (p->p_flag & P_SINGLE_EXIT) {
PROC_LOCK(p);
mtx_lock_spin(&sched_lock);
thread_stopped(p);
thread_exit();
/* NOTREACHED */
}
/*
* If we are doing a syscall in a KSE environment,
* note where our mailbox is. There is always the
* possibility that we could do this lazily (in kse_reassign()),
* but for now do it every time.
*/
kg = td->td_ksegrp;
if (td->td_pflags & TDP_SA) {
ku = td->td_upcall;
KASSERT(ku, ("%s: no upcall owned", __func__));
KASSERT((ku->ku_owner == td), ("%s: wrong owner", __func__));
KASSERT(!TD_CAN_UNBIND(td), ("%s: can unbind", __func__));
ku->ku_mflags = fuword32((void *)&ku->ku_mailbox->km_flags);
tmbx = (void *)fuword((void *)&ku->ku_mailbox->km_curthread);
if ((tmbx == NULL) || (tmbx == (void *)-1L) ||
(ku->ku_mflags & KMF_NOUPCALL)) {
td->td_mailbox = NULL;
} else {
if (td->td_standin == NULL)
thread_alloc_spare(td, NULL);
tflags = fuword32(&tmbx->tm_flags);
/*
* On some architectures, TP register points to thread
* mailbox but not points to kse mailbox, and userland
* can not atomically clear km_curthread, but can
* use TP register, and set TMF_NOUPCALL in thread
* flag to indicate a critical region.
*/
if (tflags & TMF_NOUPCALL) {
td->td_mailbox = NULL;
} else {
td->td_mailbox = tmbx;
mtx_lock_spin(&sched_lock);
td->td_flags |= TDF_CAN_UNBIND;
mtx_unlock_spin(&sched_lock);
}
}
}
}
/*
* The extra work we go through if we are a threaded process when we
* return to userland.
*
* If we are a KSE process and returning to user mode, check for
* extra work to do before we return (e.g. for more syscalls
* to complete first). If we were in a critical section, we should
* just return to let it finish. Same if we were in the UTS (in
* which case the mailbox's context's busy indicator will be set).
* The only traps we suport will have set the mailbox.
* We will clear it here.
*/
int
thread_userret(struct thread *td, struct trapframe *frame)
{
int error = 0, upcalls, uts_crit;
struct kse_upcall *ku;
struct ksegrp *kg, *kg2;
struct proc *p;
struct timespec ts;
p = td->td_proc;
kg = td->td_ksegrp;
ku = td->td_upcall;
/* Nothing to do with bound thread */
if (!(td->td_pflags & TDP_SA))
return (0);
/*
* Stat clock interrupt hit in userland, it
* is returning from interrupt, charge thread's
* userland time for UTS.
*/
if (td->td_flags & TDF_USTATCLOCK) {
thread_update_usr_ticks(td, 1);
mtx_lock_spin(&sched_lock);
td->td_flags &= ~TDF_USTATCLOCK;
mtx_unlock_spin(&sched_lock);
if (kg->kg_completed ||
(td->td_upcall->ku_flags & KUF_DOUPCALL))
thread_user_enter(p, td);
}
uts_crit = (td->td_mailbox == NULL);
/*
* Optimisation:
* This thread has not started any upcall.
* If there is no work to report other than ourself,
* then it can return direct to userland.
*/
if (TD_CAN_UNBIND(td)) {
mtx_lock_spin(&sched_lock);
td->td_flags &= ~TDF_CAN_UNBIND;
if ((td->td_flags & TDF_NEEDSIGCHK) == 0 &&
(kg->kg_completed == NULL) &&
(ku->ku_flags & KUF_DOUPCALL) == 0 &&
(kg->kg_upquantum && ticks < kg->kg_nextupcall)) {
mtx_unlock_spin(&sched_lock);
thread_update_usr_ticks(td, 0);
nanotime(&ts);
error = copyout(&ts,
(caddr_t)&ku->ku_mailbox->km_timeofday,
sizeof(ts));
td->td_mailbox = 0;
ku->ku_mflags = 0;
if (error)
goto out;
return (0);
}
mtx_unlock_spin(&sched_lock);
thread_export_context(td, 0);
/*
* There is something to report, and we own an upcall
* strucuture, we can go to userland.
* Turn ourself into an upcall thread.
*/
td->td_pflags |= TDP_UPCALLING;
} else if (td->td_mailbox && (ku == NULL)) {
thread_export_context(td, 1);
PROC_LOCK(p);
/*
* There are upcall threads waiting for
* work to do, wake one of them up.
* XXXKSE Maybe wake all of them up.
*/
if (kg->kg_upsleeps)
wakeup_one(&kg->kg_completed);
mtx_lock_spin(&sched_lock);
thread_stopped(p);
thread_exit();
/* NOTREACHED */
}
KASSERT(ku != NULL, ("upcall is NULL\n"));
KASSERT(TD_CAN_UNBIND(td) == 0, ("can unbind"));
if (p->p_numthreads > max_threads_per_proc) {
max_threads_hits++;
PROC_LOCK(p);
mtx_lock_spin(&sched_lock);
p->p_maxthrwaits++;
while (p->p_numthreads > max_threads_per_proc) {
upcalls = 0;
FOREACH_KSEGRP_IN_PROC(p, kg2) {
if (kg2->kg_numupcalls == 0)
upcalls++;
else
upcalls += kg2->kg_numupcalls;
}
if (upcalls >= max_threads_per_proc)
break;
mtx_unlock_spin(&sched_lock);
if (msleep(&p->p_numthreads, &p->p_mtx, PPAUSE|PCATCH,
"maxthreads", 0)) {
mtx_lock_spin(&sched_lock);
break;
} else {
mtx_lock_spin(&sched_lock);
}
}
p->p_maxthrwaits--;
mtx_unlock_spin(&sched_lock);
PROC_UNLOCK(p);
}
if (td->td_pflags & TDP_UPCALLING) {
uts_crit = 0;
kg->kg_nextupcall = ticks+kg->kg_upquantum;
/*
* There is no more work to do and we are going to ride
* this thread up to userland as an upcall.
* Do the last parts of the setup needed for the upcall.
*/
CTR3(KTR_PROC, "userret: upcall thread %p (pid %d, %s)",
td, td->td_proc->p_pid, td->td_proc->p_comm);
td->td_pflags &= ~TDP_UPCALLING;
if (ku->ku_flags & KUF_DOUPCALL) {
mtx_lock_spin(&sched_lock);
ku->ku_flags &= ~KUF_DOUPCALL;
mtx_unlock_spin(&sched_lock);
}
/*
* Set user context to the UTS
*/
if (!(ku->ku_mflags & KMF_NOUPCALL)) {
cpu_set_upcall_kse(td, ku);
error = suword(&ku->ku_mailbox->km_curthread, 0);
if (error)
goto out;
}
/*
* Unhook the list of completed threads.
* anything that completes after this gets to
* come in next time.
* Put the list of completed thread mailboxes on
* this KSE's mailbox.
*/
if (!(ku->ku_mflags & KMF_NOCOMPLETED) &&
(error = thread_link_mboxes(kg, ku)) != 0)
goto out;
}
if (!uts_crit) {
nanotime(&ts);
error = copyout(&ts, &ku->ku_mailbox->km_timeofday, sizeof(ts));
}
out:
if (error) {
/*
* Things are going to be so screwed we should just kill
* the process.
* how do we do that?
*/
PROC_LOCK(td->td_proc);
psignal(td->td_proc, SIGSEGV);
PROC_UNLOCK(td->td_proc);
} else {
/*
* Optimisation:
* Ensure that we have a spare thread available,
* for when we re-enter the kernel.
*/
if (td->td_standin == NULL)
thread_alloc_spare(td, NULL);
}
ku->ku_mflags = 0;
/*
* Clear thread mailbox first, then clear system tick count.
* The order is important because thread_statclock() use
* mailbox pointer to see if it is an userland thread or
* an UTS kernel thread.
*/
td->td_mailbox = NULL;
td->td_usticks = 0;
return (error); /* go sync */
}
int
thread_upcall_check(struct thread *td)
{
PROC_LOCK_ASSERT(td->td_proc, MA_OWNED);
if (td->td_kflags & TDK_WAKEUP)
return (1);
else
return (0);
}