4f0db5e08c
next step is to allow > 1 to be allocated per process. This would give multi-processor threads. (when the rest of the infrastructure is in place) While doing this I noticed libkvm and sys/kern/kern_proc.c:fill_kinfo_proc are diverging more than they should.. corrective action needed soon.
863 lines
22 KiB
C
863 lines
22 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.
|
|
*
|
|
* $FreeBSD$
|
|
*/
|
|
|
|
#include <sys/param.h>
|
|
#include <sys/systm.h>
|
|
#include <sys/kernel.h>
|
|
#include <sys/lock.h>
|
|
#include <sys/malloc.h>
|
|
#include <sys/mutex.h>
|
|
#include <sys/proc.h>
|
|
#include <sys/sysctl.h>
|
|
#include <sys/filedesc.h>
|
|
#include <sys/tty.h>
|
|
#include <sys/signalvar.h>
|
|
#include <sys/sx.h>
|
|
#include <sys/user.h>
|
|
#include <sys/jail.h>
|
|
#include <sys/kse.h>
|
|
#include <sys/ktr.h>
|
|
|
|
#include <vm/vm.h>
|
|
#include <vm/vm_object.h>
|
|
#include <vm/pmap.h>
|
|
#include <vm/uma.h>
|
|
#include <vm/vm_map.h>
|
|
|
|
#include <machine/frame.h>
|
|
|
|
/*
|
|
* KSEGRP related storage.
|
|
*/
|
|
static uma_zone_t ksegrp_zone;
|
|
static uma_zone_t kse_zone;
|
|
static uma_zone_t thread_zone;
|
|
|
|
/* DEBUG ONLY */
|
|
SYSCTL_NODE(_kern, OID_AUTO, threads, CTLFLAG_RW, 0, "thread allocation");
|
|
static int oiks_debug = 1; /* 0 disable, 1 printf, 2 enter debugger */
|
|
SYSCTL_INT(_kern_threads, OID_AUTO, oiks, CTLFLAG_RW,
|
|
&oiks_debug, 0, "OIKS thread debug");
|
|
|
|
static int max_threads_per_proc = 4;
|
|
SYSCTL_INT(_kern_threads, OID_AUTO, max_per_proc, CTLFLAG_RW,
|
|
&max_threads_per_proc, 0, "Limit on threads per proc");
|
|
|
|
#define RANGEOF(type, start, end) (offsetof(type, end) - offsetof(type, start))
|
|
|
|
struct threadqueue zombie_threads = TAILQ_HEAD_INITIALIZER(zombie_threads);
|
|
struct mtx zombie_thread_lock;
|
|
MTX_SYSINIT(zombie_thread_lock, &zombie_thread_lock,
|
|
"zombie_thread_lock", MTX_SPIN);
|
|
|
|
/*
|
|
* Pepare a thread for use.
|
|
*/
|
|
static void
|
|
thread_ctor(void *mem, int size, void *arg)
|
|
{
|
|
struct thread *td;
|
|
|
|
KASSERT((size == sizeof(struct thread)),
|
|
("size mismatch: %d != %d\n", size, (int)sizeof(struct thread)));
|
|
|
|
td = (struct thread *)mem;
|
|
td->td_state = TDS_INACTIVE;
|
|
td->td_flags |= TDF_UNBOUND;
|
|
}
|
|
|
|
/*
|
|
* Reclaim a thread after use.
|
|
*/
|
|
static void
|
|
thread_dtor(void *mem, int size, void *arg)
|
|
{
|
|
struct thread *td;
|
|
|
|
KASSERT((size == sizeof(struct thread)),
|
|
("size mismatch: %d != %d\n", size, (int)sizeof(struct thread)));
|
|
|
|
td = (struct thread *)mem;
|
|
|
|
#ifdef INVARIANTS
|
|
/* Verify that this thread is in a safe state to free. */
|
|
switch (td->td_state) {
|
|
case TDS_INHIBITED:
|
|
case TDS_RUNNING:
|
|
case TDS_CAN_RUN:
|
|
case TDS_RUNQ:
|
|
/*
|
|
* We must never unlink a thread that is in one of
|
|
* these states, because it is currently active.
|
|
*/
|
|
panic("bad state for thread unlinking");
|
|
/* NOTREACHED */
|
|
case TDS_INACTIVE:
|
|
break;
|
|
default:
|
|
panic("bad thread state");
|
|
/* NOTREACHED */
|
|
}
|
|
#endif
|
|
}
|
|
|
|
/*
|
|
* Initialize type-stable parts of a thread (when newly created).
|
|
*/
|
|
static void
|
|
thread_init(void *mem, int size)
|
|
{
|
|
struct thread *td;
|
|
|
|
KASSERT((size == sizeof(struct thread)),
|
|
("size mismatch: %d != %d\n", size, (int)sizeof(struct thread)));
|
|
|
|
td = (struct thread *)mem;
|
|
mtx_lock(&Giant);
|
|
pmap_new_thread(td);
|
|
mtx_unlock(&Giant);
|
|
cpu_thread_setup(td);
|
|
}
|
|
|
|
/*
|
|
* Tear down type-stable parts of a thread (just before being discarded).
|
|
*/
|
|
static void
|
|
thread_fini(void *mem, int size)
|
|
{
|
|
struct thread *td;
|
|
|
|
KASSERT((size == sizeof(struct thread)),
|
|
("size mismatch: %d != %d\n", size, (int)sizeof(struct thread)));
|
|
|
|
td = (struct thread *)mem;
|
|
pmap_dispose_thread(td);
|
|
}
|
|
|
|
/*
|
|
* Initialize global thread allocation resources.
|
|
*/
|
|
void
|
|
threadinit(void)
|
|
{
|
|
|
|
thread_zone = uma_zcreate("THREAD", sizeof (struct thread),
|
|
thread_ctor, thread_dtor, thread_init, thread_fini,
|
|
UMA_ALIGN_CACHE, 0);
|
|
ksegrp_zone = uma_zcreate("KSEGRP", sizeof (struct ksegrp),
|
|
NULL, NULL, NULL, NULL,
|
|
UMA_ALIGN_CACHE, 0);
|
|
kse_zone = uma_zcreate("KSE", sizeof (struct kse),
|
|
NULL, NULL, NULL, NULL,
|
|
UMA_ALIGN_CACHE, 0);
|
|
}
|
|
|
|
/*
|
|
* Stash an embarasingly extra thread into the zombie thread queue.
|
|
*/
|
|
void
|
|
thread_stash(struct thread *td)
|
|
{
|
|
mtx_lock_spin(&zombie_thread_lock);
|
|
TAILQ_INSERT_HEAD(&zombie_threads, td, td_runq);
|
|
mtx_unlock_spin(&zombie_thread_lock);
|
|
}
|
|
|
|
/*
|
|
* reap any zombie threads.
|
|
*/
|
|
void
|
|
thread_reap(void)
|
|
{
|
|
struct thread *td_reaped;
|
|
|
|
/*
|
|
* don't even bother to lock if none at this instant
|
|
* We really don't care about the next instant..
|
|
*/
|
|
if (!TAILQ_EMPTY(&zombie_threads)) {
|
|
mtx_lock_spin(&zombie_thread_lock);
|
|
while (!TAILQ_EMPTY(&zombie_threads)) {
|
|
td_reaped = TAILQ_FIRST(&zombie_threads);
|
|
TAILQ_REMOVE(&zombie_threads, td_reaped, td_runq);
|
|
mtx_unlock_spin(&zombie_thread_lock);
|
|
thread_free(td_reaped);
|
|
mtx_lock_spin(&zombie_thread_lock);
|
|
}
|
|
mtx_unlock_spin(&zombie_thread_lock);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Allocate a ksegrp.
|
|
*/
|
|
struct ksegrp *
|
|
ksegrp_alloc(void)
|
|
{
|
|
return (uma_zalloc(ksegrp_zone, M_WAITOK));
|
|
}
|
|
|
|
/*
|
|
* Allocate a kse.
|
|
*/
|
|
struct kse *
|
|
kse_alloc(void)
|
|
{
|
|
return (uma_zalloc(kse_zone, M_WAITOK));
|
|
}
|
|
|
|
/*
|
|
* Allocate a thread.
|
|
*/
|
|
struct thread *
|
|
thread_alloc(void)
|
|
{
|
|
thread_reap(); /* check if any zombies to get */
|
|
return (uma_zalloc(thread_zone, M_WAITOK));
|
|
}
|
|
|
|
/*
|
|
* Deallocate a ksegrp.
|
|
*/
|
|
void
|
|
ksegrp_free(struct ksegrp *td)
|
|
{
|
|
uma_zfree(ksegrp_zone, td);
|
|
}
|
|
|
|
/*
|
|
* Deallocate a kse.
|
|
*/
|
|
void
|
|
kse_free(struct kse *td)
|
|
{
|
|
uma_zfree(kse_zone, td);
|
|
}
|
|
|
|
/*
|
|
* Deallocate a thread.
|
|
*/
|
|
void
|
|
thread_free(struct thread *td)
|
|
{
|
|
uma_zfree(thread_zone, td);
|
|
}
|
|
|
|
/*
|
|
* Store the thread context in the UTS's mailbox.
|
|
*/
|
|
int
|
|
thread_export_context(struct thread *td)
|
|
{
|
|
struct kse *ke;
|
|
uintptr_t td2_mbx;
|
|
void *addr1;
|
|
void *addr2;
|
|
int error;
|
|
|
|
#ifdef __ia64__
|
|
td2_mbx = 0; /* pacify gcc (!) */
|
|
#endif
|
|
/* Export the register contents. */
|
|
error = cpu_export_context(td);
|
|
|
|
ke = td->td_kse;
|
|
addr1 = (caddr_t)ke->ke_mailbox
|
|
+ offsetof(struct kse_mailbox, kmbx_completed_threads);
|
|
addr2 = (caddr_t)td->td_mailbox
|
|
+ offsetof(struct thread_mailbox , next_completed);
|
|
/* Then link it into it's KSE's list of completed threads. */
|
|
if (!error) {
|
|
error = td2_mbx = fuword(addr1);
|
|
if (error == -1)
|
|
error = EFAULT;
|
|
else
|
|
error = 0;
|
|
}
|
|
if (!error)
|
|
error = suword(addr2, td2_mbx);
|
|
if (!error)
|
|
error = suword(addr1, (u_long)td->td_mailbox);
|
|
if (error == -1)
|
|
error = EFAULT;
|
|
return (error);
|
|
}
|
|
|
|
|
|
/*
|
|
* Discard the current thread and exit from its context.
|
|
*
|
|
* Because we can't free a thread while we're operating under its context,
|
|
* push the current thread into our KSE's ke_tdspare slot, freeing the
|
|
* thread that might be there currently. Because we know that only this
|
|
* processor will run our KSE, we needn't worry about someone else grabbing
|
|
* our context before we do a cpu_throw.
|
|
*/
|
|
void
|
|
thread_exit(void)
|
|
{
|
|
struct thread *td;
|
|
struct kse *ke;
|
|
struct proc *p;
|
|
struct ksegrp *kg;
|
|
|
|
td = curthread;
|
|
kg = td->td_ksegrp;
|
|
p = td->td_proc;
|
|
ke = td->td_kse;
|
|
|
|
mtx_assert(&sched_lock, MA_OWNED);
|
|
KASSERT(p != NULL, ("thread exiting without a process"));
|
|
KASSERT(ke != NULL, ("thread exiting without a kse"));
|
|
KASSERT(kg != NULL, ("thread exiting without a kse group"));
|
|
PROC_LOCK_ASSERT(p, MA_OWNED);
|
|
CTR1(KTR_PROC, "thread_exit: thread %p", td);
|
|
KASSERT(!mtx_owned(&Giant), ("dying thread owns giant"));
|
|
|
|
if (ke->ke_tdspare != NULL) {
|
|
thread_stash(ke->ke_tdspare);
|
|
ke->ke_tdspare = NULL;
|
|
}
|
|
cpu_thread_exit(td); /* XXXSMP */
|
|
|
|
/*
|
|
* The last thread is left attached to the process
|
|
* So that the whole bundle gets recycled. Skip
|
|
* all this stuff.
|
|
*/
|
|
if (p->p_numthreads > 1) {
|
|
/* Reassign this thread's KSE. */
|
|
ke->ke_thread = NULL;
|
|
td->td_kse = NULL;
|
|
ke->ke_state = KES_UNQUEUED;
|
|
kse_reassign(ke);
|
|
|
|
/* Unlink this thread from its proc. and the kseg */
|
|
TAILQ_REMOVE(&p->p_threads, td, td_plist);
|
|
p->p_numthreads--;
|
|
TAILQ_REMOVE(&kg->kg_threads, td, td_kglist);
|
|
kg->kg_numthreads--;
|
|
/*
|
|
* The test below is NOT true if we are the
|
|
* sole exiting thread. P_STOPPED_SNGL is unset
|
|
* in exit1() after it is the only survivor.
|
|
*/
|
|
if (P_SHOULDSTOP(p) == P_STOPPED_SINGLE) {
|
|
if (p->p_numthreads == p->p_suspcount) {
|
|
thread_unsuspend_one(p->p_singlethread);
|
|
}
|
|
}
|
|
PROC_UNLOCK(p);
|
|
td->td_state = TDS_INACTIVE;
|
|
td->td_proc = NULL;
|
|
td->td_ksegrp = NULL;
|
|
td->td_last_kse = NULL;
|
|
ke->ke_tdspare = td;
|
|
} else {
|
|
PROC_UNLOCK(p);
|
|
}
|
|
|
|
cpu_throw();
|
|
/* NOTREACHED */
|
|
}
|
|
|
|
/*
|
|
* Link a thread to a process.
|
|
* set up anything that needs to be initialized for it to
|
|
* be used by the process.
|
|
*
|
|
* Note that we do not link to the proc's ucred here.
|
|
* The thread is linked as if running but no KSE assigned.
|
|
*/
|
|
void
|
|
thread_link(struct thread *td, struct ksegrp *kg)
|
|
{
|
|
struct proc *p;
|
|
|
|
p = kg->kg_proc;
|
|
td->td_state = TDS_INACTIVE;
|
|
td->td_proc = p;
|
|
td->td_ksegrp = kg;
|
|
td->td_last_kse = NULL;
|
|
|
|
LIST_INIT(&td->td_contested);
|
|
callout_init(&td->td_slpcallout, 1);
|
|
TAILQ_INSERT_HEAD(&p->p_threads, td, td_plist);
|
|
TAILQ_INSERT_HEAD(&kg->kg_threads, td, td_kglist);
|
|
p->p_numthreads++;
|
|
kg->kg_numthreads++;
|
|
if (oiks_debug && p->p_numthreads > max_threads_per_proc) {
|
|
printf("OIKS %d\n", p->p_numthreads);
|
|
if (oiks_debug > 1)
|
|
Debugger("OIKS");
|
|
}
|
|
td->td_kse = NULL;
|
|
}
|
|
|
|
/*
|
|
* Set up the upcall pcb in either a given thread or a new one
|
|
* if none given. Use the upcall for the given KSE
|
|
* XXXKSE possibly fix cpu_set_upcall() to not need td->td_kse set.
|
|
*/
|
|
struct thread *
|
|
thread_schedule_upcall(struct thread *td, struct kse *ke)
|
|
{
|
|
struct thread *td2;
|
|
|
|
mtx_assert(&sched_lock, MA_OWNED);
|
|
if (ke->ke_tdspare != NULL) {
|
|
td2 = ke->ke_tdspare;
|
|
ke->ke_tdspare = NULL;
|
|
} else {
|
|
mtx_unlock_spin(&sched_lock);
|
|
td2 = thread_alloc();
|
|
mtx_lock_spin(&sched_lock);
|
|
}
|
|
CTR3(KTR_PROC, "thread_schedule_upcall: thread %p (pid %d, %s)",
|
|
td, td->td_proc->p_pid, td->td_proc->p_comm);
|
|
bzero(&td2->td_startzero,
|
|
(unsigned)RANGEOF(struct thread, td_startzero, td_endzero));
|
|
bcopy(&td->td_startcopy, &td2->td_startcopy,
|
|
(unsigned) RANGEOF(struct thread, td_startcopy, td_endcopy));
|
|
thread_link(td2, ke->ke_ksegrp);
|
|
cpu_set_upcall(td2, ke->ke_pcb);
|
|
td2->td_ucred = crhold(td->td_ucred);
|
|
td2->td_flags = TDF_UNBOUND|TDF_UPCALLING;
|
|
TD_SET_CAN_RUN(td2);
|
|
setrunqueue(td2);
|
|
return (td2);
|
|
}
|
|
|
|
/*
|
|
* 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 we will have no thread mailbox registered). The only
|
|
* traps we suport will have set the mailbox. We will clear it here.
|
|
*/
|
|
int
|
|
thread_userret(struct proc *p, struct ksegrp *kg, struct kse *ke,
|
|
struct thread *td, struct trapframe *frame)
|
|
{
|
|
int error = 0;
|
|
|
|
if (ke->ke_tdspare == NULL) {
|
|
ke->ke_tdspare = thread_alloc();
|
|
}
|
|
if (td->td_flags & TDF_UNBOUND) {
|
|
/*
|
|
* Are we returning from a thread that had a mailbox?
|
|
*
|
|
* XXX Maybe this should be in a separate function.
|
|
*/
|
|
if (((td->td_flags & TDF_UPCALLING) == 0) && td->td_mailbox) {
|
|
/*
|
|
* [XXXKSE Future enhancement]
|
|
* We could also go straight back to the syscall
|
|
* if we never had to do an upcall since then.
|
|
* If the KSE's copy is == the thread's copy..
|
|
* AND there are no other completed threads.
|
|
*/
|
|
/*
|
|
* We will go back as an upcall or go do another thread.
|
|
* Either way we need to save the context back to
|
|
* the user thread mailbox.
|
|
* So the UTS can restart it later.
|
|
*/
|
|
error = thread_export_context(td);
|
|
td->td_mailbox = NULL;
|
|
if (error) {
|
|
/*
|
|
* Failing to do the KSE
|
|
* operation just defaults operation
|
|
* back to synchonous operation.
|
|
*/
|
|
goto cont;
|
|
}
|
|
|
|
if (TAILQ_FIRST(&kg->kg_runq)) {
|
|
/*
|
|
* Uh-oh.. don't return to the user.
|
|
* Instead, switch to the thread that
|
|
* needs to run. The question is:
|
|
* What do we do with the thread we have now?
|
|
* We have put the completion block
|
|
* on the kse mailbox. If we had more energy,
|
|
* we could lazily do so, assuming someone
|
|
* else might get to userland earlier
|
|
* and deliver it earlier than we could.
|
|
* To do that we could save it off the KSEG.
|
|
* An upcalling KSE would 'reap' all completed
|
|
* threads.
|
|
* Being in a hurry, we'll do nothing and
|
|
* leave it on the current KSE for now.
|
|
*
|
|
* As for the other threads to run;
|
|
* we COULD rush through all the threads
|
|
* in this KSEG at this priority, or we
|
|
* could throw the ball back into the court
|
|
* and just run the highest prio kse available.
|
|
* What is OUR priority?
|
|
* the priority of the highest sycall waiting
|
|
* to be returned?
|
|
* For now, just let another KSE run (easiest).
|
|
*/
|
|
PROC_LOCK(p);
|
|
mtx_lock_spin(&sched_lock);
|
|
thread_exit(); /* Abandon current thread. */
|
|
/* NOTREACHED */
|
|
} else { /* if (number of returning syscalls = 1) */
|
|
/*
|
|
* Swap our frame for the upcall frame.
|
|
*
|
|
* XXXKSE Assumes we are going to user land
|
|
* and not nested in the kernel
|
|
*/
|
|
td->td_flags |= TDF_UPCALLING;
|
|
}
|
|
}
|
|
/*
|
|
* This is NOT just an 'else' clause for the above test...
|
|
*/
|
|
if (td->td_flags & TDF_UPCALLING) {
|
|
CTR3(KTR_PROC, "userret: upcall thread %p (pid %d, %s)",
|
|
td, p->p_pid, p->p_comm);
|
|
/*
|
|
* Make sure that it has the correct frame loaded.
|
|
* While we know that we are on the same KSEGRP
|
|
* as we were created on, we could very easily
|
|
* have come in on another KSE. We therefore need
|
|
* to do the copy of the frame after the last
|
|
* possible switch() (the one above).
|
|
*/
|
|
bcopy(ke->ke_frame, frame, sizeof(struct trapframe));
|
|
|
|
/*
|
|
* Decide what we are sending to the user
|
|
* upcall sets one argument. The address of the mbox.
|
|
*/
|
|
cpu_set_args(td, ke);
|
|
|
|
/*
|
|
* There is no more work to do and we are going to ride
|
|
* this thead/KSE up to userland. Make sure the user's
|
|
* pointer to the thread mailbox is cleared before we
|
|
* re-enter the kernel next time for any reason..
|
|
* We might as well do it here.
|
|
*/
|
|
td->td_flags &= ~TDF_UPCALLING; /* Hmmmm. */
|
|
error = suword((caddr_t)td->td_kse->ke_mailbox +
|
|
offsetof(struct kse_mailbox, kmbx_current_thread),
|
|
0);
|
|
}
|
|
/*
|
|
* Stop any chance that we may be separated from
|
|
* the KSE we are currently on. This is "biting the bullet",
|
|
* we are committing to go to user space as as THIS KSE here.
|
|
*/
|
|
cont:
|
|
td->td_flags &= ~TDF_UNBOUND;
|
|
}
|
|
return (error);
|
|
}
|
|
|
|
/*
|
|
* Enforce single-threading.
|
|
*
|
|
* Returns 1 if the caller must abort (another thread is waiting to
|
|
* exit the process or similar). Process is locked!
|
|
* Returns 0 when you are successfully the only thread running.
|
|
* A process has successfully single threaded in the suspend mode when
|
|
* There are no threads in user mode. Threads in the kernel must be
|
|
* allowed to continue until they get to the user boundary. They may even
|
|
* copy out their return values and data before suspending. They may however be
|
|
* accellerated in reaching the user boundary as we will wake up
|
|
* any sleeping threads that are interruptable. (PCATCH).
|
|
*/
|
|
int
|
|
thread_single(int force_exit)
|
|
{
|
|
struct thread *td;
|
|
struct thread *td2;
|
|
struct proc *p;
|
|
|
|
td = curthread;
|
|
p = td->td_proc;
|
|
PROC_LOCK_ASSERT(p, MA_OWNED);
|
|
KASSERT((td != NULL), ("curthread is NULL"));
|
|
|
|
if ((p->p_flag & P_KSES) == 0)
|
|
return (0);
|
|
|
|
/* Is someone already single threading? */
|
|
if (p->p_singlethread)
|
|
return (1);
|
|
|
|
if (force_exit == SINGLE_EXIT)
|
|
p->p_flag |= P_SINGLE_EXIT;
|
|
else
|
|
p->p_flag &= ~P_SINGLE_EXIT;
|
|
p->p_flag |= P_STOPPED_SINGLE;
|
|
p->p_singlethread = td;
|
|
while ((p->p_numthreads - p->p_suspcount) != 1) {
|
|
mtx_lock_spin(&sched_lock);
|
|
FOREACH_THREAD_IN_PROC(p, td2) {
|
|
if (td2 == td)
|
|
continue;
|
|
if (TD_IS_INHIBITED(td2)) {
|
|
if (TD_IS_SUSPENDED(td2)) {
|
|
if (force_exit == SINGLE_EXIT) {
|
|
thread_unsuspend_one(td2);
|
|
}
|
|
}
|
|
if ( TD_IS_SLEEPING(td2)) {
|
|
if (td2->td_flags & TDF_CVWAITQ)
|
|
cv_waitq_remove(td2);
|
|
else
|
|
unsleep(td2);
|
|
break;
|
|
}
|
|
if (TD_CAN_RUN(td2))
|
|
setrunqueue(td2);
|
|
}
|
|
}
|
|
/*
|
|
* Wake us up when everyone else has suspended.
|
|
* In the mean time we suspend as well.
|
|
*/
|
|
thread_suspend_one(td);
|
|
mtx_unlock(&Giant);
|
|
PROC_UNLOCK(p);
|
|
mi_switch();
|
|
mtx_unlock_spin(&sched_lock);
|
|
mtx_lock(&Giant);
|
|
PROC_LOCK(p);
|
|
}
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* Called in from locations that can safely check to see
|
|
* whether we have to suspend or at least throttle for a
|
|
* single-thread event (e.g. fork).
|
|
*
|
|
* Such locations include userret().
|
|
* If the "return_instead" argument is non zero, the thread must be able to
|
|
* accept 0 (caller may continue), or 1 (caller must abort) as a result.
|
|
*
|
|
* The 'return_instead' argument tells the function if it may do a
|
|
* thread_exit() or suspend, or whether the caller must abort and back
|
|
* out instead.
|
|
*
|
|
* If the thread that set the single_threading request has set the
|
|
* P_SINGLE_EXIT bit in the process flags then this call will never return
|
|
* if 'return_instead' is false, but will exit.
|
|
*
|
|
* P_SINGLE_EXIT | return_instead == 0| return_instead != 0
|
|
*---------------+--------------------+---------------------
|
|
* 0 | returns 0 | returns 0 or 1
|
|
* | when ST ends | immediatly
|
|
*---------------+--------------------+---------------------
|
|
* 1 | thread exits | returns 1
|
|
* | | immediatly
|
|
* 0 = thread_exit() or suspension ok,
|
|
* other = return error instead of stopping the thread.
|
|
*
|
|
* While a full suspension is under effect, even a single threading
|
|
* thread would be suspended if it made this call (but it shouldn't).
|
|
* This call should only be made from places where
|
|
* thread_exit() would be safe as that may be the outcome unless
|
|
* return_instead is set.
|
|
*/
|
|
int
|
|
thread_suspend_check(int return_instead)
|
|
{
|
|
struct thread *td = curthread;
|
|
struct proc *p = td->td_proc;
|
|
|
|
td = curthread;
|
|
p = td->td_proc;
|
|
PROC_LOCK_ASSERT(p, MA_OWNED);
|
|
while (P_SHOULDSTOP(p)) {
|
|
if (P_SHOULDSTOP(p) == P_STOPPED_SINGLE) {
|
|
KASSERT(p->p_singlethread != NULL,
|
|
("singlethread not set"));
|
|
/*
|
|
* The only suspension in action is a
|
|
* single-threading. Single threader need not stop.
|
|
* XXX Should be safe to access unlocked
|
|
* as it can only be set to be true by us.
|
|
*/
|
|
if (p->p_singlethread == td)
|
|
return (0); /* Exempt from stopping. */
|
|
}
|
|
if (return_instead)
|
|
return (1);
|
|
|
|
/*
|
|
* If the process is waiting for us to exit,
|
|
* this thread should just suicide.
|
|
* Assumes that P_SINGLE_EXIT implies P_STOPPED_SINGLE.
|
|
*/
|
|
if ((p->p_flag & P_SINGLE_EXIT) && (p->p_singlethread != td)) {
|
|
mtx_lock_spin(&sched_lock);
|
|
while (mtx_owned(&Giant))
|
|
mtx_unlock(&Giant);
|
|
thread_exit();
|
|
}
|
|
|
|
/*
|
|
* When a thread suspends, it just
|
|
* moves to the processes's suspend queue
|
|
* and stays there.
|
|
*
|
|
* XXXKSE if TDF_BOUND is true
|
|
* it will not release it's KSE which might
|
|
* lead to deadlock if there are not enough KSEs
|
|
* to complete all waiting threads.
|
|
* Maybe be able to 'lend' it out again.
|
|
* (lent kse's can not go back to userland?)
|
|
* and can only be lent in STOPPED state.
|
|
*/
|
|
mtx_lock_spin(&sched_lock);
|
|
if ((p->p_flag & P_STOPPED_SIG) &&
|
|
(p->p_suspcount+1 == p->p_numthreads)) {
|
|
mtx_unlock_spin(&sched_lock);
|
|
PROC_LOCK(p->p_pptr);
|
|
if ((p->p_pptr->p_procsig->ps_flag &
|
|
PS_NOCLDSTOP) == 0) {
|
|
psignal(p->p_pptr, SIGCHLD);
|
|
}
|
|
PROC_UNLOCK(p->p_pptr);
|
|
mtx_lock_spin(&sched_lock);
|
|
}
|
|
mtx_assert(&Giant, MA_NOTOWNED);
|
|
thread_suspend_one(td);
|
|
PROC_UNLOCK(p);
|
|
if (P_SHOULDSTOP(p) == P_STOPPED_SINGLE) {
|
|
if (p->p_numthreads == p->p_suspcount) {
|
|
thread_unsuspend_one(p->p_singlethread);
|
|
}
|
|
}
|
|
p->p_stats->p_ru.ru_nivcsw++;
|
|
mi_switch();
|
|
mtx_unlock_spin(&sched_lock);
|
|
PROC_LOCK(p);
|
|
}
|
|
return (0);
|
|
}
|
|
|
|
void
|
|
thread_suspend_one(struct thread *td)
|
|
{
|
|
struct proc *p = td->td_proc;
|
|
|
|
mtx_assert(&sched_lock, MA_OWNED);
|
|
p->p_suspcount++;
|
|
TD_SET_SUSPENDED(td);
|
|
TAILQ_INSERT_TAIL(&p->p_suspended, td, td_runq);
|
|
/*
|
|
* Hack: If we are suspending but are on the sleep queue
|
|
* then we are in msleep or the cv equivalent. We
|
|
* want to look like we have two Inhibitors.
|
|
*/
|
|
if (TD_ON_SLEEPQ(td))
|
|
TD_SET_SLEEPING(td);
|
|
}
|
|
|
|
void
|
|
thread_unsuspend_one(struct thread *td)
|
|
{
|
|
struct proc *p = td->td_proc;
|
|
|
|
mtx_assert(&sched_lock, MA_OWNED);
|
|
TAILQ_REMOVE(&p->p_suspended, td, td_runq);
|
|
TD_CLR_SUSPENDED(td);
|
|
p->p_suspcount--;
|
|
setrunnable(td);
|
|
}
|
|
|
|
/*
|
|
* Allow all threads blocked by single threading to continue running.
|
|
*/
|
|
void
|
|
thread_unsuspend(struct proc *p)
|
|
{
|
|
struct thread *td;
|
|
|
|
mtx_assert(&sched_lock, MA_OWNED);
|
|
PROC_LOCK_ASSERT(p, MA_OWNED);
|
|
if (!P_SHOULDSTOP(p)) {
|
|
while (( td = TAILQ_FIRST(&p->p_suspended))) {
|
|
thread_unsuspend_one(td);
|
|
}
|
|
} else if ((P_SHOULDSTOP(p) == P_STOPPED_SINGLE) &&
|
|
(p->p_numthreads == p->p_suspcount)) {
|
|
/*
|
|
* Stopping everything also did the job for the single
|
|
* threading request. Now we've downgraded to single-threaded,
|
|
* let it continue.
|
|
*/
|
|
thread_unsuspend_one(p->p_singlethread);
|
|
}
|
|
}
|
|
|
|
void
|
|
thread_single_end(void)
|
|
{
|
|
struct thread *td;
|
|
struct proc *p;
|
|
|
|
td = curthread;
|
|
p = td->td_proc;
|
|
PROC_LOCK_ASSERT(p, MA_OWNED);
|
|
p->p_flag &= ~P_STOPPED_SINGLE;
|
|
p->p_singlethread = NULL;
|
|
/*
|
|
* If there are other threads they mey now run,
|
|
* unless of course there is a blanket 'stop order'
|
|
* on the process. The single threader must be allowed
|
|
* to continue however as this is a bad place to stop.
|
|
*/
|
|
if ((p->p_numthreads != 1) && (!P_SHOULDSTOP(p))) {
|
|
mtx_lock_spin(&sched_lock);
|
|
while (( td = TAILQ_FIRST(&p->p_suspended))) {
|
|
thread_unsuspend_one(td);
|
|
}
|
|
mtx_unlock_spin(&sched_lock);
|
|
}
|
|
}
|
|
|
|
|