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freebsd-dev/lib/libkse/thread/thr_kern.c
Daniel Eischen 396a73603d Set the tcb (thread control block) in the child process after a fork. 
This protects against a race with an upcall in the parent during the
fork which can clobber the parent's tcb before the vm space is copied
in the child.  The child then gets a corrupted tcb that is either null
or that points to another thread that doesn't exist in the child (after
a fork, only the fork()ing thread exists in the child).

Reported by:	Arno J. Klaassen (arno at heho / snv / jussieu / fr)
2007-12-06 06:04:01 +00:00

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/*
* Copyright (C) 2003 Daniel M. Eischen <deischen@freebsd.org>
* Copyright (C) 2002 Jonathon Mini <mini@freebsd.org>
* Copyright (c) 1995-1998 John Birrell <jb@cimlogic.com.au>
* 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, 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.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by John Birrell.
* 4. Neither the name of the author nor the names of any co-contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``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 OR CONTRIBUTORS 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/types.h>
#include <sys/kse.h>
#include <sys/ptrace.h>
#include <sys/signalvar.h>
#include <sys/queue.h>
#include <machine/atomic.h>
#include <machine/sigframe.h>
#include <assert.h>
#include <errno.h>
#include <signal.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <ucontext.h>
#include <unistd.h>
#include "atomic_ops.h"
#include "thr_private.h"
#include "libc_private.h"
#ifdef NOTYET
#include "spinlock.h"
#endif
/* #define DEBUG_THREAD_KERN */
#ifdef DEBUG_THREAD_KERN
#define DBG_MSG stdout_debug
#else
#define DBG_MSG(x...)
#endif
/*
* Define a high water mark for the maximum number of threads that
* will be cached. Once this level is reached, any extra threads
* will be free()'d.
*/
#define MAX_CACHED_THREADS 100
/*
* Define high water marks for the maximum number of KSEs and KSE groups
* that will be cached. Because we support 1:1 threading, there could have
* same number of KSEs and KSE groups as threads. Once these levels are
* reached, any extra KSE and KSE groups will be free()'d.
*/
#define MAX_CACHED_KSES ((_thread_scope_system <= 0) ? 50 : 100)
#define MAX_CACHED_KSEGS ((_thread_scope_system <= 0) ? 50 : 100)
#define KSE_SET_MBOX(kse, thrd) \
(kse)->k_kcb->kcb_kmbx.km_curthread = &(thrd)->tcb->tcb_tmbx
#define KSE_SET_EXITED(kse) (kse)->k_flags |= KF_EXITED
/*
* Macros for manipulating the run queues. The priority queue
* routines use the thread's pqe link and also handle the setting
* and clearing of the thread's THR_FLAGS_IN_RUNQ flag.
*/
#define KSE_RUNQ_INSERT_HEAD(kse, thrd) \
_pq_insert_head(&(kse)->k_schedq->sq_runq, thrd)
#define KSE_RUNQ_INSERT_TAIL(kse, thrd) \
_pq_insert_tail(&(kse)->k_schedq->sq_runq, thrd)
#define KSE_RUNQ_REMOVE(kse, thrd) \
_pq_remove(&(kse)->k_schedq->sq_runq, thrd)
#define KSE_RUNQ_FIRST(kse) \
((_libkse_debug == 0) ? \
_pq_first(&(kse)->k_schedq->sq_runq) : \
_pq_first_debug(&(kse)->k_schedq->sq_runq))
#define KSE_RUNQ_THREADS(kse) ((kse)->k_schedq->sq_runq.pq_threads)
#define THR_NEED_CANCEL(thrd) \
(((thrd)->cancelflags & THR_CANCELLING) != 0 && \
((thrd)->cancelflags & PTHREAD_CANCEL_DISABLE) == 0 && \
(((thrd)->cancelflags & THR_AT_CANCEL_POINT) != 0 || \
((thrd)->cancelflags & PTHREAD_CANCEL_ASYNCHRONOUS) != 0))
#define THR_NEED_ASYNC_CANCEL(thrd) \
(((thrd)->cancelflags & THR_CANCELLING) != 0 && \
((thrd)->cancelflags & PTHREAD_CANCEL_DISABLE) == 0 && \
(((thrd)->cancelflags & THR_AT_CANCEL_POINT) == 0 && \
((thrd)->cancelflags & PTHREAD_CANCEL_ASYNCHRONOUS) != 0))
/*
* We've got to keep track of everything that is allocated, not only
* to have a speedy free list, but also so they can be deallocated
* after a fork().
*/
static TAILQ_HEAD(, kse) active_kseq;
static TAILQ_HEAD(, kse) free_kseq;
static TAILQ_HEAD(, kse_group) free_kse_groupq;
static TAILQ_HEAD(, kse_group) active_kse_groupq;
static TAILQ_HEAD(, kse_group) gc_ksegq;
static struct lock kse_lock; /* also used for kseg queue */
static int free_kse_count = 0;
static int free_kseg_count = 0;
static TAILQ_HEAD(, pthread) free_threadq;
static struct lock thread_lock;
static int free_thread_count = 0;
static int inited = 0;
static int active_kse_count = 0;
static int active_kseg_count = 0;
static u_int64_t next_uniqueid = 1;
LIST_HEAD(thread_hash_head, pthread);
#define THREAD_HASH_QUEUES 127
static struct thread_hash_head thr_hashtable[THREAD_HASH_QUEUES];
#define THREAD_HASH(thrd) ((unsigned long)thrd % THREAD_HASH_QUEUES)
/* Lock for thread tcb constructor/destructor */
static pthread_mutex_t _tcb_mutex;
#ifdef DEBUG_THREAD_KERN
static void dump_queues(struct kse *curkse);
#endif
static void kse_check_completed(struct kse *kse);
static void kse_check_waitq(struct kse *kse);
static void kse_fini(struct kse *curkse);
static void kse_reinit(struct kse *kse, int sys_scope);
static void kse_sched_multi(struct kse_mailbox *kmbx);
static void kse_sched_single(struct kse_mailbox *kmbx);
static void kse_switchout_thread(struct kse *kse, struct pthread *thread);
static void kse_wait(struct kse *kse, struct pthread *td_wait, int sigseq);
static void kse_free_unlocked(struct kse *kse);
static void kse_destroy(struct kse *kse);
static void kseg_free_unlocked(struct kse_group *kseg);
static void kseg_init(struct kse_group *kseg);
static void kseg_reinit(struct kse_group *kseg);
static void kseg_destroy(struct kse_group *kseg);
static void kse_waitq_insert(struct pthread *thread);
static void kse_wakeup_multi(struct kse *curkse);
static struct kse_mailbox *kse_wakeup_one(struct pthread *thread);
static void thr_cleanup(struct kse *kse, struct pthread *curthread);
static void thr_link(struct pthread *thread);
static void thr_resume_wrapper(int sig, siginfo_t *, ucontext_t *);
static void thr_resume_check(struct pthread *curthread, ucontext_t *ucp);
static int thr_timedout(struct pthread *thread, struct timespec *curtime);
static void thr_unlink(struct pthread *thread);
static void thr_destroy(struct pthread *curthread, struct pthread *thread);
static void thread_gc(struct pthread *thread);
static void kse_gc(struct pthread *thread);
static void kseg_gc(struct pthread *thread);
static __inline void
thr_accounting(struct pthread *thread)
{
if ((thread->slice_usec != -1) &&
(thread->slice_usec <= TIMESLICE_USEC) &&
(thread->attr.sched_policy != SCHED_FIFO)) {
thread->slice_usec += (thread->tcb->tcb_tmbx.tm_uticks
+ thread->tcb->tcb_tmbx.tm_sticks) * _clock_res_usec;
/* Check for time quantum exceeded: */
if (thread->slice_usec > TIMESLICE_USEC)
thread->slice_usec = -1;
}
thread->tcb->tcb_tmbx.tm_uticks = 0;
thread->tcb->tcb_tmbx.tm_sticks = 0;
}
/*
* This is called after a fork().
* No locks need to be taken here since we are guaranteed to be
* single threaded.
*
* XXX
* POSIX says for threaded process, fork() function is used
* only to run new programs, and the effects of calling functions
* that require certain resources between the call to fork() and
* the call to an exec function are undefined.
*
* It is not safe to free memory after fork(), because these data
* structures may be in inconsistent state.
*/
void
_kse_single_thread(struct pthread *curthread)
{
#ifdef NOTYET
struct kse *kse;
struct kse_group *kseg;
struct pthread *thread;
_thr_spinlock_init();
*__malloc_lock = (spinlock_t)_SPINLOCK_INITIALIZER;
if (__isthreaded) {
_thr_rtld_fini();
_thr_signal_deinit();
}
__isthreaded = 0;
/*
* Restore signal mask early, so any memory problems could
* dump core.
*/
__sys_sigprocmask(SIG_SETMASK, &curthread->sigmask, NULL);
_thread_active_threads = 1;
curthread->kse->k_kcb->kcb_kmbx.km_curthread = NULL;
curthread->attr.flags &= ~PTHREAD_SCOPE_PROCESS;
curthread->attr.flags |= PTHREAD_SCOPE_SYSTEM;
/*
* Enter a loop to remove and free all threads other than
* the running thread from the active thread list:
*/
while ((thread = TAILQ_FIRST(&_thread_list)) != NULL) {
THR_GCLIST_REMOVE(thread);
/*
* Remove this thread from the list (the current
* thread will be removed but re-added by libpthread
* initialization.
*/
TAILQ_REMOVE(&_thread_list, thread, tle);
/* Make sure this isn't the running thread: */
if (thread != curthread) {
_thr_stack_free(&thread->attr);
if (thread->specific != NULL)
free(thread->specific);
thr_destroy(curthread, thread);
}
}
TAILQ_INIT(&curthread->mutexq); /* initialize mutex queue */
curthread->joiner = NULL; /* no joining threads yet */
curthread->refcount = 0;
SIGEMPTYSET(curthread->sigpend); /* clear pending signals */
/* Don't free thread-specific data as the caller may require it */
/* Free the free KSEs: */
while ((kse = TAILQ_FIRST(&free_kseq)) != NULL) {
TAILQ_REMOVE(&free_kseq, kse, k_qe);
kse_destroy(kse);
}
free_kse_count = 0;
/* Free the active KSEs: */
while ((kse = TAILQ_FIRST(&active_kseq)) != NULL) {
TAILQ_REMOVE(&active_kseq, kse, k_qe);
kse_destroy(kse);
}
active_kse_count = 0;
/* Free the free KSEGs: */
while ((kseg = TAILQ_FIRST(&free_kse_groupq)) != NULL) {
TAILQ_REMOVE(&free_kse_groupq, kseg, kg_qe);
kseg_destroy(kseg);
}
free_kseg_count = 0;
/* Free the active KSEGs: */
while ((kseg = TAILQ_FIRST(&active_kse_groupq)) != NULL) {
TAILQ_REMOVE(&active_kse_groupq, kseg, kg_qe);
kseg_destroy(kseg);
}
active_kseg_count = 0;
/* Free the free threads. */
while ((thread = TAILQ_FIRST(&free_threadq)) != NULL) {
TAILQ_REMOVE(&free_threadq, thread, tle);
thr_destroy(curthread, thread);
}
free_thread_count = 0;
/* Free the to-be-gc'd threads. */
while ((thread = TAILQ_FIRST(&_thread_gc_list)) != NULL) {
TAILQ_REMOVE(&_thread_gc_list, thread, gcle);
thr_destroy(curthread, thread);
}
TAILQ_INIT(&gc_ksegq);
_gc_count = 0;
if (inited != 0) {
/*
* Destroy these locks; they'll be recreated to assure they
* are in the unlocked state.
*/
_lock_destroy(&kse_lock);
_lock_destroy(&thread_lock);
_lock_destroy(&_thread_list_lock);
inited = 0;
}
/* We're no longer part of any lists */
curthread->tlflags = 0;
/*
* After a fork, we are still operating on the thread's original
* stack. Don't clear the THR_FLAGS_USER from the thread's
* attribute flags.
*/
/* Initialize the threads library. */
curthread->kse = NULL;
curthread->kseg = NULL;
_kse_initial = NULL;
_libpthread_init(curthread);
#else
int i;
/* Reset the current thread and KSE lock data. */
for (i = 0; i < curthread->locklevel; i++) {
_lockuser_reinit(&curthread->lockusers[i], (void *)curthread);
}
curthread->locklevel = 0;
for (i = 0; i < curthread->kse->k_locklevel; i++) {
_lockuser_reinit(&curthread->kse->k_lockusers[i],
(void *)curthread->kse);
_LCK_SET_PRIVATE2(&curthread->kse->k_lockusers[i], NULL);
}
curthread->kse->k_locklevel = 0;
/*
* Reinitialize the thread and signal locks so that
* sigaction() will work after a fork().
*/
_lock_reinit(&curthread->lock, LCK_ADAPTIVE, _thr_lock_wait,
_thr_lock_wakeup);
_lock_reinit(&_thread_signal_lock, LCK_ADAPTIVE, _kse_lock_wait,
_kse_lock_wakeup);
_thr_spinlock_init();
if (__isthreaded) {
_thr_rtld_fini();
_thr_signal_deinit();
}
__isthreaded = 0;
curthread->kse->k_kcb->kcb_kmbx.km_curthread = NULL;
curthread->attr.flags |= PTHREAD_SCOPE_SYSTEM;
/*
* After a fork, it is possible that an upcall occurs in
* the parent KSE that fork()'d before the child process
* is fully created and before its vm space is copied.
* During the upcall, the tcb is set to null or to another
* thread, and this is what gets copied in the child process
* when the vm space is cloned sometime after the upcall
* occurs. Note that we shouldn't have to set the kcb, but
* we do it for completeness.
*/
_kcb_set(curthread->kse->k_kcb);
_tcb_set(curthread->kse->k_kcb, curthread->tcb);
/* After a fork(), there child should have no pending signals. */
sigemptyset(&curthread->sigpend);
/*
* Restore signal mask early, so any memory problems could
* dump core.
*/
sigprocmask(SIG_SETMASK, &curthread->sigmask, NULL);
_thread_active_threads = 1;
#endif
}
/*
* This is used to initialize housekeeping and to initialize the
* KSD for the KSE.
*/
void
_kse_init(void)
{
if (inited == 0) {
TAILQ_INIT(&active_kseq);
TAILQ_INIT(&active_kse_groupq);
TAILQ_INIT(&free_kseq);
TAILQ_INIT(&free_kse_groupq);
TAILQ_INIT(&free_threadq);
TAILQ_INIT(&gc_ksegq);
if (_lock_init(&kse_lock, LCK_ADAPTIVE,
_kse_lock_wait, _kse_lock_wakeup, calloc) != 0)
PANIC("Unable to initialize free KSE queue lock");
if (_lock_init(&thread_lock, LCK_ADAPTIVE,
_kse_lock_wait, _kse_lock_wakeup, calloc) != 0)
PANIC("Unable to initialize free thread queue lock");
if (_lock_init(&_thread_list_lock, LCK_ADAPTIVE,
_kse_lock_wait, _kse_lock_wakeup, calloc) != 0)
PANIC("Unable to initialize thread list lock");
_pthread_mutex_init(&_tcb_mutex, NULL);
active_kse_count = 0;
active_kseg_count = 0;
_gc_count = 0;
inited = 1;
}
}
/*
* This is called when the first thread (other than the initial
* thread) is created.
*/
int
_kse_setthreaded(int threaded)
{
sigset_t sigset;
if ((threaded != 0) && (__isthreaded == 0)) {
SIGFILLSET(sigset);
__sys_sigprocmask(SIG_SETMASK, &sigset, &_thr_initial->sigmask);
/*
* Tell the kernel to create a KSE for the initial thread
* and enable upcalls in it.
*/
_kse_initial->k_flags |= KF_STARTED;
if (_thread_scope_system <= 0) {
_thr_initial->attr.flags &= ~PTHREAD_SCOPE_SYSTEM;
_kse_initial->k_kseg->kg_flags &= ~KGF_SINGLE_THREAD;
_kse_initial->k_kcb->kcb_kmbx.km_curthread = NULL;
}
else {
/*
* For bound thread, kernel reads mailbox pointer
* once, we'd set it here before calling kse_create.
*/
_tcb_set(_kse_initial->k_kcb, _thr_initial->tcb);
KSE_SET_MBOX(_kse_initial, _thr_initial);
_kse_initial->k_kcb->kcb_kmbx.km_flags |= KMF_BOUND;
}
/*
* Locking functions in libc are required when there are
* threads other than the initial thread.
*/
_thr_rtld_init();
__isthreaded = 1;
if (kse_create(&_kse_initial->k_kcb->kcb_kmbx, 0) != 0) {
_kse_initial->k_flags &= ~KF_STARTED;
__isthreaded = 0;
PANIC("kse_create() failed\n");
return (-1);
}
_thr_initial->tcb->tcb_tmbx.tm_lwp =
_kse_initial->k_kcb->kcb_kmbx.km_lwp;
_thread_activated = 1;
#ifndef SYSTEM_SCOPE_ONLY
if (_thread_scope_system <= 0) {
/* Set current thread to initial thread */
_tcb_set(_kse_initial->k_kcb, _thr_initial->tcb);
KSE_SET_MBOX(_kse_initial, _thr_initial);
_thr_start_sig_daemon();
_thr_setmaxconcurrency();
}
else
#endif
__sys_sigprocmask(SIG_SETMASK, &_thr_initial->sigmask,
NULL);
}
return (0);
}
/*
* Lock wait and wakeup handlers for KSE locks. These are only used by
* KSEs, and should never be used by threads. KSE locks include the
* KSE group lock (used for locking the scheduling queue) and the
* kse_lock defined above.
*
* When a KSE lock attempt blocks, the entire KSE blocks allowing another
* KSE to run. For the most part, it doesn't make much sense to try and
* schedule another thread because you need to lock the scheduling queue
* in order to do that. And since the KSE lock is used to lock the scheduling
* queue, you would just end up blocking again.
*/
void
_kse_lock_wait(struct lock *lock __unused, struct lockuser *lu)
{
struct kse *curkse = (struct kse *)_LCK_GET_PRIVATE(lu);
struct timespec ts;
int saved_flags;
if (curkse->k_kcb->kcb_kmbx.km_curthread != NULL)
PANIC("kse_lock_wait does not disable upcall.\n");
/*
* Enter a loop to wait until we get the lock.
*/
ts.tv_sec = 0;
ts.tv_nsec = 1000000; /* 1 sec */
while (!_LCK_GRANTED(lu)) {
/*
* Yield the kse and wait to be notified when the lock
* is granted.
*/
saved_flags = curkse->k_kcb->kcb_kmbx.km_flags;
curkse->k_kcb->kcb_kmbx.km_flags |= KMF_NOUPCALL |
KMF_NOCOMPLETED;
kse_release(&ts);
curkse->k_kcb->kcb_kmbx.km_flags = saved_flags;
}
}
void
_kse_lock_wakeup(struct lock *lock, struct lockuser *lu)
{
struct kse *curkse;
struct kse *kse;
struct kse_mailbox *mbx;
curkse = _get_curkse();
kse = (struct kse *)_LCK_GET_PRIVATE(lu);
if (kse == curkse)
PANIC("KSE trying to wake itself up in lock");
else {
mbx = &kse->k_kcb->kcb_kmbx;
_lock_grant(lock, lu);
/*
* Notify the owning kse that it has the lock.
* It is safe to pass invalid address to kse_wakeup
* even if the mailbox is not in kernel at all,
* and waking up a wrong kse is also harmless.
*/
kse_wakeup(mbx);
}
}
/*
* Thread wait and wakeup handlers for thread locks. These are only used
* by threads, never by KSEs. Thread locks include the per-thread lock
* (defined in its structure), and condition variable and mutex locks.
*/
void
_thr_lock_wait(struct lock *lock __unused, struct lockuser *lu)
{
struct pthread *curthread = (struct pthread *)lu->lu_private;
do {
THR_LOCK_SWITCH(curthread);
THR_SET_STATE(curthread, PS_LOCKWAIT);
_thr_sched_switch_unlocked(curthread);
} while (!_LCK_GRANTED(lu));
}
void
_thr_lock_wakeup(struct lock *lock __unused, struct lockuser *lu)
{
struct pthread *thread;
struct pthread *curthread;
struct kse_mailbox *kmbx;
curthread = _get_curthread();
thread = (struct pthread *)_LCK_GET_PRIVATE(lu);
THR_SCHED_LOCK(curthread, thread);
_lock_grant(lock, lu);
kmbx = _thr_setrunnable_unlocked(thread);
THR_SCHED_UNLOCK(curthread, thread);
if (kmbx != NULL)
kse_wakeup(kmbx);
}
kse_critical_t
_kse_critical_enter(void)
{
kse_critical_t crit;
crit = (kse_critical_t)_kcb_critical_enter();
return (crit);
}
void
_kse_critical_leave(kse_critical_t crit)
{
struct pthread *curthread;
_kcb_critical_leave((struct kse_thr_mailbox *)crit);
if ((crit != NULL) && ((curthread = _get_curthread()) != NULL))
THR_YIELD_CHECK(curthread);
}
int
_kse_in_critical(void)
{
return (_kcb_in_critical());
}
void
_thr_critical_enter(struct pthread *thread)
{
thread->critical_count++;
}
void
_thr_critical_leave(struct pthread *thread)
{
thread->critical_count--;
THR_YIELD_CHECK(thread);
}
void
_thr_sched_switch(struct pthread *curthread)
{
struct kse *curkse;
(void)_kse_critical_enter();
curkse = _get_curkse();
KSE_SCHED_LOCK(curkse, curkse->k_kseg);
_thr_sched_switch_unlocked(curthread);
}
/*
* XXX - We may need to take the scheduling lock before calling
* this, or perhaps take the lock within here before
* doing anything else.
*/
void
_thr_sched_switch_unlocked(struct pthread *curthread)
{
struct kse *curkse;
volatile int resume_once = 0;
ucontext_t *uc;
/* We're in the scheduler, 5 by 5: */
curkse = curthread->kse;
curthread->need_switchout = 1; /* The thread yielded on its own. */
curthread->critical_yield = 0; /* No need to yield anymore. */
/* Thread can unlock the scheduler lock. */
curthread->lock_switch = 1;
if (curthread->attr.flags & PTHREAD_SCOPE_SYSTEM)
kse_sched_single(&curkse->k_kcb->kcb_kmbx);
else {
if (__predict_false(_libkse_debug != 0)) {
/*
* Because debugger saves single step status in thread
* mailbox's tm_dflags, we can safely clear single
* step status here. the single step status will be
* restored by kse_switchin when the thread is
* switched in again. This also lets uts run in full
* speed.
*/
ptrace(PT_CLEARSTEP, curkse->k_kcb->kcb_kmbx.km_lwp,
(caddr_t) 1, 0);
}
KSE_SET_SWITCH(curkse);
_thread_enter_uts(curthread->tcb, curkse->k_kcb);
}
/*
* Unlock the scheduling queue and leave the
* critical region.
*/
/* Don't trust this after a switch! */
curkse = curthread->kse;
curthread->lock_switch = 0;
KSE_SCHED_UNLOCK(curkse, curkse->k_kseg);
_kse_critical_leave(&curthread->tcb->tcb_tmbx);
/*
* This thread is being resumed; check for cancellations.
*/
if (THR_NEED_ASYNC_CANCEL(curthread) && !THR_IN_CRITICAL(curthread)) {
uc = alloca(sizeof(ucontext_t));
resume_once = 0;
THR_GETCONTEXT(uc);
if (resume_once == 0) {
resume_once = 1;
curthread->check_pending = 0;
thr_resume_check(curthread, uc);
}
}
THR_ACTIVATE_LAST_LOCK(curthread);
}
/*
* This is the scheduler for a KSE which runs a scope system thread.
* The multi-thread KSE scheduler should also work for a single threaded
* KSE, but we use a separate scheduler so that it can be fine-tuned
* to be more efficient (and perhaps not need a separate stack for
* the KSE, allowing it to use the thread's stack).
*/
static void
kse_sched_single(struct kse_mailbox *kmbx)
{
struct kse *curkse;
struct pthread *curthread;
struct timespec ts;
sigset_t sigmask;
int i, sigseqno, level, first = 0;
curkse = (struct kse *)kmbx->km_udata;
curthread = curkse->k_curthread;
if (__predict_false((curkse->k_flags & KF_INITIALIZED) == 0)) {
/* Setup this KSEs specific data. */
_kcb_set(curkse->k_kcb);
_tcb_set(curkse->k_kcb, curthread->tcb);
curkse->k_flags |= KF_INITIALIZED;
first = 1;
curthread->active = 1;
/* Setup kernel signal masks for new thread. */
__sys_sigprocmask(SIG_SETMASK, &curthread->sigmask, NULL);
/*
* Enter critical region, this is meanless for bound thread,
* It is used to let other code work, those code want mailbox
* to be cleared.
*/
(void)_kse_critical_enter();
} else {
/*
* Bound thread always has tcb set, this prevent some
* code from blindly setting bound thread tcb to NULL,
* buggy code ?
*/
_tcb_set(curkse->k_kcb, curthread->tcb);
}
curthread->critical_yield = 0;
curthread->need_switchout = 0;
/*
* Lock the scheduling queue.
*
* There is no scheduling queue for single threaded KSEs,
* but we need a lock for protection regardless.
*/
if (curthread->lock_switch == 0)
KSE_SCHED_LOCK(curkse, curkse->k_kseg);
/*
* This has to do the job of kse_switchout_thread(), only
* for a single threaded KSE/KSEG.
*/
switch (curthread->state) {
case PS_MUTEX_WAIT:
case PS_COND_WAIT:
if (THR_NEED_CANCEL(curthread)) {
curthread->interrupted = 1;
curthread->continuation = _thr_finish_cancellation;
THR_SET_STATE(curthread, PS_RUNNING);
}
break;
case PS_LOCKWAIT:
/*
* This state doesn't timeout.
*/
curthread->wakeup_time.tv_sec = -1;
curthread->wakeup_time.tv_nsec = -1;
level = curthread->locklevel - 1;
if (_LCK_GRANTED(&curthread->lockusers[level]))
THR_SET_STATE(curthread, PS_RUNNING);
break;
case PS_DEAD:
/* Unlock the scheduling queue and exit the KSE and thread. */
thr_cleanup(curkse, curthread);
KSE_SCHED_UNLOCK(curkse, curkse->k_kseg);
PANIC("bound thread shouldn't get here\n");
break;
case PS_JOIN:
if (THR_NEED_CANCEL(curthread)) {
curthread->join_status.thread = NULL;
THR_SET_STATE(curthread, PS_RUNNING);
} else {
/*
* This state doesn't timeout.
*/
curthread->wakeup_time.tv_sec = -1;
curthread->wakeup_time.tv_nsec = -1;
}
break;
case PS_SUSPENDED:
if (THR_NEED_CANCEL(curthread)) {
curthread->interrupted = 1;
THR_SET_STATE(curthread, PS_RUNNING);
} else {
/*
* These states don't timeout.
*/
curthread->wakeup_time.tv_sec = -1;
curthread->wakeup_time.tv_nsec = -1;
}
break;
case PS_RUNNING:
if ((curthread->flags & THR_FLAGS_SUSPENDED) != 0 &&
!THR_NEED_CANCEL(curthread)) {
THR_SET_STATE(curthread, PS_SUSPENDED);
/*
* These states don't timeout.
*/
curthread->wakeup_time.tv_sec = -1;
curthread->wakeup_time.tv_nsec = -1;
}
break;
case PS_SIGWAIT:
PANIC("bound thread does not have SIGWAIT state\n");
case PS_SLEEP_WAIT:
PANIC("bound thread does not have SLEEP_WAIT state\n");
case PS_SIGSUSPEND:
PANIC("bound thread does not have SIGSUSPEND state\n");
case PS_DEADLOCK:
/*
* These states don't timeout and don't need
* to be in the waiting queue.
*/
curthread->wakeup_time.tv_sec = -1;
curthread->wakeup_time.tv_nsec = -1;
break;
default:
PANIC("Unknown state\n");
break;
}
while (curthread->state != PS_RUNNING) {
sigseqno = curkse->k_sigseqno;
if (curthread->check_pending != 0) {
/*
* Install pending signals into the frame, possible
* cause mutex or condvar backout.
*/
curthread->check_pending = 0;
SIGFILLSET(sigmask);
/*
* Lock out kernel signal code when we are processing
* signals, and get a fresh copy of signal mask.
*/
__sys_sigprocmask(SIG_SETMASK, &sigmask,
&curthread->sigmask);
for (i = 1; i <= _SIG_MAXSIG; i++) {
if (SIGISMEMBER(curthread->sigmask, i))
continue;
if (SIGISMEMBER(curthread->sigpend, i))
(void)_thr_sig_add(curthread, i,
&curthread->siginfo[i-1]);
}
__sys_sigprocmask(SIG_SETMASK, &curthread->sigmask,
NULL);
/* The above code might make thread runnable */
if (curthread->state == PS_RUNNING)
break;
}
THR_DEACTIVATE_LAST_LOCK(curthread);
kse_wait(curkse, curthread, sigseqno);
THR_ACTIVATE_LAST_LOCK(curthread);
if (curthread->wakeup_time.tv_sec >= 0) {
KSE_GET_TOD(curkse, &ts);
if (thr_timedout(curthread, &ts)) {
/* Indicate the thread timedout: */
curthread->timeout = 1;
/* Make the thread runnable. */
THR_SET_STATE(curthread, PS_RUNNING);
}
}
}
if (curthread->lock_switch == 0) {
/* Unlock the scheduling queue. */
KSE_SCHED_UNLOCK(curkse, curkse->k_kseg);
}
DBG_MSG("Continuing bound thread %p\n", curthread);
if (first) {
_kse_critical_leave(&curthread->tcb->tcb_tmbx);
pthread_exit(curthread->start_routine(curthread->arg));
}
}
#ifdef DEBUG_THREAD_KERN
static void
dump_queues(struct kse *curkse)
{
struct pthread *thread;
DBG_MSG("Threads in waiting queue:\n");
TAILQ_FOREACH(thread, &curkse->k_kseg->kg_schedq.sq_waitq, pqe) {
DBG_MSG(" thread %p, state %d, blocked %d\n",
thread, thread->state, thread->blocked);
}
}
#endif
/*
* This is the scheduler for a KSE which runs multiple threads.
*/
static void
kse_sched_multi(struct kse_mailbox *kmbx)
{
struct kse *curkse;
struct pthread *curthread, *td_wait;
int ret;
curkse = (struct kse *)kmbx->km_udata;
THR_ASSERT(curkse->k_kcb->kcb_kmbx.km_curthread == NULL,
"Mailbox not null in kse_sched_multi");
/* Check for first time initialization: */
if (__predict_false((curkse->k_flags & KF_INITIALIZED) == 0)) {
/* Setup this KSEs specific data. */
_kcb_set(curkse->k_kcb);
/* Set this before grabbing the context. */
curkse->k_flags |= KF_INITIALIZED;
}
/*
* No current thread anymore, calling _get_curthread in UTS
* should dump core
*/
_tcb_set(curkse->k_kcb, NULL);
/* If this is an upcall; take the scheduler lock. */
if (!KSE_IS_SWITCH(curkse))
KSE_SCHED_LOCK(curkse, curkse->k_kseg);
else
KSE_CLEAR_SWITCH(curkse);
if (KSE_IS_IDLE(curkse)) {
KSE_CLEAR_IDLE(curkse);
curkse->k_kseg->kg_idle_kses--;
}
/*
* Now that the scheduler lock is held, get the current
* thread. The KSE's current thread cannot be safely
* examined without the lock because it could have returned
* as completed on another KSE. See kse_check_completed().
*/
curthread = curkse->k_curthread;
/*
* If the current thread was completed in another KSE, then
* it will be in the run queue. Don't mark it as being blocked.
*/
if ((curthread != NULL) &&
((curthread->flags & THR_FLAGS_IN_RUNQ) == 0) &&
(curthread->need_switchout == 0)) {
/*
* Assume the current thread is blocked; when the
* completed threads are checked and if the current
* thread is among the completed, the blocked flag
* will be cleared.
*/
curthread->blocked = 1;
DBG_MSG("Running thread %p is now blocked in kernel.\n",
curthread);
}
/* Check for any unblocked threads in the kernel. */
kse_check_completed(curkse);
/*
* Check for threads that have timed-out.
*/
kse_check_waitq(curkse);
/*
* Switchout the current thread, if necessary, as the last step
* so that it is inserted into the run queue (if it's runnable)
* _after_ any other threads that were added to it above.
*/
if (curthread == NULL)
; /* Nothing to do here. */
else if ((curthread->need_switchout == 0) && DBG_CAN_RUN(curthread) &&
(curthread->blocked == 0) && (THR_IN_CRITICAL(curthread))) {
/*
* Resume the thread and tell it to yield when
* it leaves the critical region.
*/
curthread->critical_yield = 1;
curthread->active = 1;
if ((curthread->flags & THR_FLAGS_IN_RUNQ) != 0)
KSE_RUNQ_REMOVE(curkse, curthread);
curkse->k_curthread = curthread;
curthread->kse = curkse;
DBG_MSG("Continuing thread %p in critical region\n",
curthread);
kse_wakeup_multi(curkse);
KSE_SCHED_UNLOCK(curkse, curkse->k_kseg);
ret = _thread_switch(curkse->k_kcb, curthread->tcb, 1);
if (ret != 0)
PANIC("Can't resume thread in critical region\n");
}
else if ((curthread->flags & THR_FLAGS_IN_RUNQ) == 0) {
curthread->tcb->tcb_tmbx.tm_lwp = 0;
kse_switchout_thread(curkse, curthread);
}
curkse->k_curthread = NULL;
#ifdef DEBUG_THREAD_KERN
dump_queues(curkse);
#endif
/* Check if there are no threads ready to run: */
while (((curthread = KSE_RUNQ_FIRST(curkse)) == NULL) &&
(curkse->k_kseg->kg_threadcount != 0) &&
((curkse->k_flags & KF_TERMINATED) == 0)) {
/*
* Wait for a thread to become active or until there are
* no more threads.
*/
td_wait = KSE_WAITQ_FIRST(curkse);
kse_wait(curkse, td_wait, 0);
kse_check_completed(curkse);
kse_check_waitq(curkse);
}
/* Check for no more threads: */
if ((curkse->k_kseg->kg_threadcount == 0) ||
((curkse->k_flags & KF_TERMINATED) != 0)) {
/*
* Normally this shouldn't return, but it will if there
* are other KSEs running that create new threads that
* are assigned to this KSE[G]. For instance, if a scope
* system thread were to create a scope process thread
* and this kse[g] is the initial kse[g], then that newly
* created thread would be assigned to us (the initial
* kse[g]).
*/
kse_wakeup_multi(curkse);
KSE_SCHED_UNLOCK(curkse, curkse->k_kseg);
kse_fini(curkse);
/* never returns */
}
THR_ASSERT(curthread != NULL,
"Return from kse_wait/fini without thread.");
THR_ASSERT(curthread->state != PS_DEAD,
"Trying to resume dead thread!");
KSE_RUNQ_REMOVE(curkse, curthread);
/*
* Make the selected thread the current thread.
*/
curkse->k_curthread = curthread;
/*
* Make sure the current thread's kse points to this kse.
*/
curthread->kse = curkse;
/*
* Reset the time slice if this thread is running for the first
* time or running again after using its full time slice allocation.
*/
if (curthread->slice_usec == -1)
curthread->slice_usec = 0;
/* Mark the thread active. */
curthread->active = 1;
/*
* The thread's current signal frame will only be NULL if it
* is being resumed after being blocked in the kernel. In
* this case, and if the thread needs to run down pending
* signals or needs a cancellation check, we need to add a
* signal frame to the thread's context.
*/
if (curthread->lock_switch == 0 && curthread->state == PS_RUNNING &&
(curthread->check_pending != 0 ||
THR_NEED_ASYNC_CANCEL(curthread)) &&
!THR_IN_CRITICAL(curthread)) {
curthread->check_pending = 0;
signalcontext(&curthread->tcb->tcb_tmbx.tm_context, 0,
(__sighandler_t *)thr_resume_wrapper);
}
kse_wakeup_multi(curkse);
/*
* Continue the thread at its current frame:
*/
if (curthread->lock_switch != 0) {
/*
* This thread came from a scheduler switch; it will
* unlock the scheduler lock and set the mailbox.
*/
ret = _thread_switch(curkse->k_kcb, curthread->tcb, 0);
} else {
/* This thread won't unlock the scheduler lock. */
KSE_SCHED_UNLOCK(curkse, curkse->k_kseg);
ret = _thread_switch(curkse->k_kcb, curthread->tcb, 1);
}
if (ret != 0)
PANIC("Thread has returned from _thread_switch");
/* This point should not be reached. */
PANIC("Thread has returned from _thread_switch");
}
static void
thr_resume_wrapper(int sig __unused, siginfo_t *siginfo __unused,
ucontext_t *ucp)
{
struct pthread *curthread = _get_curthread();
struct kse *curkse;
int ret, err_save = errno;
DBG_MSG(">>> sig wrapper\n");
if (curthread->lock_switch)
PANIC("thr_resume_wrapper, lock_switch != 0\n");
thr_resume_check(curthread, ucp);
errno = err_save;
_kse_critical_enter();
curkse = curthread->kse;
curthread->tcb->tcb_tmbx.tm_context = *ucp;
ret = _thread_switch(curkse->k_kcb, curthread->tcb, 1);
if (ret != 0)
PANIC("thr_resume_wrapper: thread has returned "
"from _thread_switch");
/* THR_SETCONTEXT(ucp); */ /* not work, why ? */
}
static void
thr_resume_check(struct pthread *curthread, ucontext_t *ucp)
{
_thr_sig_rundown(curthread, ucp);
if (THR_NEED_ASYNC_CANCEL(curthread))
pthread_testcancel();
}
/*
* Clean up a thread. This must be called with the thread's KSE
* scheduling lock held. The thread must be a thread from the
* KSE's group.
*/
static void
thr_cleanup(struct kse *curkse, struct pthread *thread)
{
struct pthread *joiner;
struct kse_mailbox *kmbx = NULL;
int sys_scope;
thread->active = 0;
thread->need_switchout = 0;
thread->lock_switch = 0;
thread->check_pending = 0;
if ((joiner = thread->joiner) != NULL) {
/* Joinee scheduler lock held; joiner won't leave. */
if (joiner->kseg == curkse->k_kseg) {
if (joiner->join_status.thread == thread) {
joiner->join_status.thread = NULL;
joiner->join_status.ret = thread->ret;
(void)_thr_setrunnable_unlocked(joiner);
}
} else {
KSE_SCHED_UNLOCK(curkse, curkse->k_kseg);
/* The joiner may have removed itself and exited. */
if (_thr_ref_add(thread, joiner, 0) == 0) {
KSE_SCHED_LOCK(curkse, joiner->kseg);
if (joiner->join_status.thread == thread) {
joiner->join_status.thread = NULL;
joiner->join_status.ret = thread->ret;
kmbx = _thr_setrunnable_unlocked(joiner);
}
KSE_SCHED_UNLOCK(curkse, joiner->kseg);
_thr_ref_delete(thread, joiner);
if (kmbx != NULL)
kse_wakeup(kmbx);
}
KSE_SCHED_LOCK(curkse, curkse->k_kseg);
}
thread->attr.flags |= PTHREAD_DETACHED;
}
if (!(sys_scope = (thread->attr.flags & PTHREAD_SCOPE_SYSTEM))) {
/*
* Remove the thread from the KSEG's list of threads.
*/
KSEG_THRQ_REMOVE(thread->kseg, thread);
/*
* Migrate the thread to the main KSE so that this
* KSE and KSEG can be cleaned when their last thread
* exits.
*/
thread->kseg = _kse_initial->k_kseg;
thread->kse = _kse_initial;
}
/*
* We can't hold the thread list lock while holding the
* scheduler lock.
*/
KSE_SCHED_UNLOCK(curkse, curkse->k_kseg);
DBG_MSG("Adding thread %p to GC list\n", thread);
KSE_LOCK_ACQUIRE(curkse, &_thread_list_lock);
thread->tlflags |= TLFLAGS_GC_SAFE;
THR_GCLIST_ADD(thread);
KSE_LOCK_RELEASE(curkse, &_thread_list_lock);
if (sys_scope) {
/*
* System scope thread is single thread group,
* when thread is exited, its kse and ksegrp should
* be recycled as well.
* kse upcall stack belongs to thread, clear it here.
*/
curkse->k_stack.ss_sp = 0;
curkse->k_stack.ss_size = 0;
kse_exit();
PANIC("kse_exit() failed for system scope thread");
}
KSE_SCHED_LOCK(curkse, curkse->k_kseg);
}
void
_thr_gc(struct pthread *curthread)
{
thread_gc(curthread);
kse_gc(curthread);
kseg_gc(curthread);
}
static void
thread_gc(struct pthread *curthread)
{
struct pthread *td, *td_next;
kse_critical_t crit;
TAILQ_HEAD(, pthread) worklist;
TAILQ_INIT(&worklist);
crit = _kse_critical_enter();
KSE_LOCK_ACQUIRE(curthread->kse, &_thread_list_lock);
/* Check the threads waiting for GC. */
for (td = TAILQ_FIRST(&_thread_gc_list); td != NULL; td = td_next) {
td_next = TAILQ_NEXT(td, gcle);
if ((td->tlflags & TLFLAGS_GC_SAFE) == 0)
continue;
else if (((td->attr.flags & PTHREAD_SCOPE_SYSTEM) != 0) &&
((td->kse->k_kcb->kcb_kmbx.km_flags & KMF_DONE) == 0)) {
/*
* The thread and KSE are operating on the same
* stack. Wait for the KSE to exit before freeing
* the thread's stack as well as everything else.
*/
continue;
}
/*
* Remove the thread from the GC list. If the thread
* isn't yet detached, it will get added back to the
* GC list at a later time.
*/
THR_GCLIST_REMOVE(td);
DBG_MSG("Freeing thread %p stack\n", td);
/*
* We can free the thread stack since it's no longer
* in use.
*/
_thr_stack_free(&td->attr);
if (((td->attr.flags & PTHREAD_DETACHED) != 0) &&
(td->refcount == 0)) {
/*
* The thread has detached and is no longer
* referenced. It is safe to remove all
* remnants of the thread.
*/
THR_LIST_REMOVE(td);
TAILQ_INSERT_HEAD(&worklist, td, gcle);
}
}
KSE_LOCK_RELEASE(curthread->kse, &_thread_list_lock);
_kse_critical_leave(crit);
while ((td = TAILQ_FIRST(&worklist)) != NULL) {
TAILQ_REMOVE(&worklist, td, gcle);
/*
* XXX we don't free initial thread and its kse
* (if thread is a bound thread), because there might
* have some code referencing initial thread and kse.
*/
if (td == _thr_initial) {
DBG_MSG("Initial thread won't be freed\n");
continue;
}
if ((td->attr.flags & PTHREAD_SCOPE_SYSTEM) != 0) {
crit = _kse_critical_enter();
KSE_LOCK_ACQUIRE(curthread->kse, &kse_lock);
kse_free_unlocked(td->kse);
kseg_free_unlocked(td->kseg);
KSE_LOCK_RELEASE(curthread->kse, &kse_lock);
_kse_critical_leave(crit);
}
DBG_MSG("Freeing thread %p\n", td);
_thr_free(curthread, td);
}
}
static void
kse_gc(struct pthread *curthread)
{
kse_critical_t crit;
TAILQ_HEAD(, kse) worklist;
struct kse *kse;
if (free_kse_count <= MAX_CACHED_KSES)
return;
TAILQ_INIT(&worklist);
crit = _kse_critical_enter();
KSE_LOCK_ACQUIRE(curthread->kse, &kse_lock);
while (free_kse_count > MAX_CACHED_KSES) {
kse = TAILQ_FIRST(&free_kseq);
TAILQ_REMOVE(&free_kseq, kse, k_qe);
TAILQ_INSERT_HEAD(&worklist, kse, k_qe);
free_kse_count--;
}
KSE_LOCK_RELEASE(curthread->kse, &kse_lock);
_kse_critical_leave(crit);
while ((kse = TAILQ_FIRST(&worklist))) {
TAILQ_REMOVE(&worklist, kse, k_qe);
kse_destroy(kse);
}
}
static void
kseg_gc(struct pthread *curthread)
{
kse_critical_t crit;
TAILQ_HEAD(, kse_group) worklist;
struct kse_group *kseg;
if (free_kseg_count <= MAX_CACHED_KSEGS)
return;
TAILQ_INIT(&worklist);
crit = _kse_critical_enter();
KSE_LOCK_ACQUIRE(curthread->kse, &kse_lock);
while (free_kseg_count > MAX_CACHED_KSEGS) {
kseg = TAILQ_FIRST(&free_kse_groupq);
TAILQ_REMOVE(&free_kse_groupq, kseg, kg_qe);
free_kseg_count--;
TAILQ_INSERT_HEAD(&worklist, kseg, kg_qe);
}
KSE_LOCK_RELEASE(curthread->kse, &kse_lock);
_kse_critical_leave(crit);
while ((kseg = TAILQ_FIRST(&worklist))) {
TAILQ_REMOVE(&worklist, kseg, kg_qe);
kseg_destroy(kseg);
}
}
/*
* Only new threads that are running or suspended may be scheduled.
*/
int
_thr_schedule_add(struct pthread *curthread, struct pthread *newthread)
{
kse_critical_t crit;
int ret;
/* Add the new thread. */
thr_link(newthread);
/*
* If this is the first time creating a thread, make sure
* the mailbox is set for the current thread.
*/
if ((newthread->attr.flags & PTHREAD_SCOPE_SYSTEM) != 0) {
/* We use the thread's stack as the KSE's stack. */
newthread->kse->k_kcb->kcb_kmbx.km_stack.ss_sp =
newthread->attr.stackaddr_attr;
newthread->kse->k_kcb->kcb_kmbx.km_stack.ss_size =
newthread->attr.stacksize_attr;
/*
* No need to lock the scheduling queue since the
* KSE/KSEG pair have not yet been started.
*/
KSEG_THRQ_ADD(newthread->kseg, newthread);
/* this thread never gives up kse */
newthread->active = 1;
newthread->kse->k_curthread = newthread;
newthread->kse->k_kcb->kcb_kmbx.km_flags = KMF_BOUND;
newthread->kse->k_kcb->kcb_kmbx.km_func =
(kse_func_t *)kse_sched_single;
newthread->kse->k_kcb->kcb_kmbx.km_quantum = 0;
KSE_SET_MBOX(newthread->kse, newthread);
/*
* This thread needs a new KSE and KSEG.
*/
newthread->kse->k_flags &= ~KF_INITIALIZED;
newthread->kse->k_flags |= KF_STARTED;
/* Fire up! */
ret = kse_create(&newthread->kse->k_kcb->kcb_kmbx, 1);
if (ret != 0)
ret = errno;
}
else {
/*
* Lock the KSE and add the new thread to its list of
* assigned threads. If the new thread is runnable, also
* add it to the KSE's run queue.
*/
crit = _kse_critical_enter();
KSE_SCHED_LOCK(curthread->kse, newthread->kseg);
KSEG_THRQ_ADD(newthread->kseg, newthread);
if (newthread->state == PS_RUNNING)
THR_RUNQ_INSERT_TAIL(newthread);
if ((newthread->kse->k_flags & KF_STARTED) == 0) {
/*
* This KSE hasn't been started yet. Start it
* outside of holding the lock.
*/
newthread->kse->k_flags |= KF_STARTED;
newthread->kse->k_kcb->kcb_kmbx.km_func =
(kse_func_t *)kse_sched_multi;
newthread->kse->k_kcb->kcb_kmbx.km_flags = 0;
kse_create(&newthread->kse->k_kcb->kcb_kmbx, 0);
} else if ((newthread->state == PS_RUNNING) &&
KSE_IS_IDLE(newthread->kse)) {
/*
* The thread is being scheduled on another KSEG.
*/
kse_wakeup_one(newthread);
}
KSE_SCHED_UNLOCK(curthread->kse, newthread->kseg);
_kse_critical_leave(crit);
ret = 0;
}
if (ret != 0)
thr_unlink(newthread);
return (ret);
}
void
kse_waitq_insert(struct pthread *thread)
{
struct pthread *td;
if (thread->wakeup_time.tv_sec == -1)
TAILQ_INSERT_TAIL(&thread->kse->k_schedq->sq_waitq, thread,
pqe);
else {
td = TAILQ_FIRST(&thread->kse->k_schedq->sq_waitq);
while ((td != NULL) && (td->wakeup_time.tv_sec != -1) &&
((td->wakeup_time.tv_sec < thread->wakeup_time.tv_sec) ||
((td->wakeup_time.tv_sec == thread->wakeup_time.tv_sec) &&
(td->wakeup_time.tv_nsec <= thread->wakeup_time.tv_nsec))))
td = TAILQ_NEXT(td, pqe);
if (td == NULL)
TAILQ_INSERT_TAIL(&thread->kse->k_schedq->sq_waitq,
thread, pqe);
else
TAILQ_INSERT_BEFORE(td, thread, pqe);
}
thread->flags |= THR_FLAGS_IN_WAITQ;
}
/*
* This must be called with the scheduling lock held.
*/
static void
kse_check_completed(struct kse *kse)
{
struct pthread *thread;
struct kse_thr_mailbox *completed;
int sig;
if ((completed = kse->k_kcb->kcb_kmbx.km_completed) != NULL) {
kse->k_kcb->kcb_kmbx.km_completed = NULL;
while (completed != NULL) {
thread = completed->tm_udata;
DBG_MSG("Found completed thread %p, name %s\n",
thread,
(thread->name == NULL) ? "none" : thread->name);
thread->blocked = 0;
if (thread != kse->k_curthread) {
thr_accounting(thread);
if ((thread->flags & THR_FLAGS_SUSPENDED) != 0)
THR_SET_STATE(thread, PS_SUSPENDED);
else
KSE_RUNQ_INSERT_TAIL(kse, thread);
if ((thread->kse != kse) &&
(thread->kse->k_curthread == thread)) {
/*
* Remove this thread from its
* previous KSE so that it (the KSE)
* doesn't think it is still active.
*/
thread->kse->k_curthread = NULL;
thread->active = 0;
}
}
if ((sig = thread->tcb->tcb_tmbx.tm_syncsig.si_signo)
!= 0) {
if (SIGISMEMBER(thread->sigmask, sig))
SIGADDSET(thread->sigpend, sig);
else if (THR_IN_CRITICAL(thread))
kse_thr_interrupt(NULL, KSE_INTR_SIGEXIT, sig);
else
(void)_thr_sig_add(thread, sig,
&thread->tcb->tcb_tmbx.tm_syncsig);
thread->tcb->tcb_tmbx.tm_syncsig.si_signo = 0;
}
completed = completed->tm_next;
}
}
}
/*
* This must be called with the scheduling lock held.
*/
static void
kse_check_waitq(struct kse *kse)
{
struct pthread *pthread;
struct timespec ts;
KSE_GET_TOD(kse, &ts);
/*
* Wake up threads that have timedout. This has to be
* done before adding the current thread to the run queue
* so that a CPU intensive thread doesn't get preference
* over waiting threads.
*/
while (((pthread = KSE_WAITQ_FIRST(kse)) != NULL) &&
thr_timedout(pthread, &ts)) {
/* Remove the thread from the wait queue: */
KSE_WAITQ_REMOVE(kse, pthread);
DBG_MSG("Found timedout thread %p in waitq\n", pthread);
/* Indicate the thread timedout: */
pthread->timeout = 1;
/* Add the thread to the priority queue: */
if ((pthread->flags & THR_FLAGS_SUSPENDED) != 0)
THR_SET_STATE(pthread, PS_SUSPENDED);
else {
THR_SET_STATE(pthread, PS_RUNNING);
KSE_RUNQ_INSERT_TAIL(kse, pthread);
}
}
}
static int
thr_timedout(struct pthread *thread, struct timespec *curtime)
{
if (thread->wakeup_time.tv_sec < 0)
return (0);
else if (thread->wakeup_time.tv_sec > curtime->tv_sec)
return (0);
else if ((thread->wakeup_time.tv_sec == curtime->tv_sec) &&
(thread->wakeup_time.tv_nsec > curtime->tv_nsec))
return (0);
else
return (1);
}
/*
* This must be called with the scheduling lock held.
*
* Each thread has a time slice, a wakeup time (used when it wants
* to wait for a specified amount of time), a run state, and an
* active flag.
*
* When a thread gets run by the scheduler, the active flag is
* set to non-zero (1). When a thread performs an explicit yield
* or schedules a state change, it enters the scheduler and the
* active flag is cleared. When the active flag is still seen
* set in the scheduler, that means that the thread is blocked in
* the kernel (because it is cleared before entering the scheduler
* in all other instances).
*
* The wakeup time is only set for those states that can timeout.
* It is set to (-1, -1) for all other instances.
*
* The thread's run state, aside from being useful when debugging,
* is used to place the thread in an appropriate queue. There
* are 2 basic queues:
*
* o run queue - queue ordered by priority for all threads
* that are runnable
* o waiting queue - queue sorted by wakeup time for all threads
* that are not otherwise runnable (not blocked
* in kernel, not waiting for locks)
*
* The thread's time slice is used for round-robin scheduling
* (the default scheduling policy). While a SCHED_RR thread
* is runnable it's time slice accumulates. When it reaches
* the time slice interval, it gets reset and added to the end
* of the queue of threads at its priority. When a thread no
* longer becomes runnable (blocks in kernel, waits, etc), its
* time slice is reset.
*
* The job of kse_switchout_thread() is to handle all of the above.
*/
static void
kse_switchout_thread(struct kse *kse, struct pthread *thread)
{
int level;
int i;
int restart;
siginfo_t siginfo;
/*
* Place the currently running thread into the
* appropriate queue(s).
*/
DBG_MSG("Switching out thread %p, state %d\n", thread, thread->state);
THR_DEACTIVATE_LAST_LOCK(thread);
if (thread->blocked != 0) {
thread->active = 0;
thread->need_switchout = 0;
/* This thread must have blocked in the kernel. */
/*
* Check for pending signals and cancellation for
* this thread to see if we need to interrupt it
* in the kernel.
*/
if (THR_NEED_CANCEL(thread)) {
kse_thr_interrupt(&thread->tcb->tcb_tmbx,
KSE_INTR_INTERRUPT, 0);
} else if (thread->check_pending != 0) {
for (i = 1; i <= _SIG_MAXSIG; ++i) {
if (SIGISMEMBER(thread->sigpend, i) &&
!SIGISMEMBER(thread->sigmask, i)) {
restart = _thread_sigact[i - 1].sa_flags & SA_RESTART;
kse_thr_interrupt(&thread->tcb->tcb_tmbx,
restart ? KSE_INTR_RESTART : KSE_INTR_INTERRUPT, 0);
break;
}
}
}
}
else {
switch (thread->state) {
case PS_MUTEX_WAIT:
case PS_COND_WAIT:
if (THR_NEED_CANCEL(thread)) {
thread->interrupted = 1;
thread->continuation = _thr_finish_cancellation;
THR_SET_STATE(thread, PS_RUNNING);
} else {
/* Insert into the waiting queue: */
KSE_WAITQ_INSERT(kse, thread);
}
break;
case PS_LOCKWAIT:
/*
* This state doesn't timeout.
*/
thread->wakeup_time.tv_sec = -1;
thread->wakeup_time.tv_nsec = -1;
level = thread->locklevel - 1;
if (!_LCK_GRANTED(&thread->lockusers[level]))
KSE_WAITQ_INSERT(kse, thread);
else
THR_SET_STATE(thread, PS_RUNNING);
break;
case PS_SLEEP_WAIT:
case PS_SIGWAIT:
if (THR_NEED_CANCEL(thread)) {
thread->interrupted = 1;
THR_SET_STATE(thread, PS_RUNNING);
} else {
KSE_WAITQ_INSERT(kse, thread);
}
break;
case PS_JOIN:
if (THR_NEED_CANCEL(thread)) {
thread->join_status.thread = NULL;
THR_SET_STATE(thread, PS_RUNNING);
} else {
/*
* This state doesn't timeout.
*/
thread->wakeup_time.tv_sec = -1;
thread->wakeup_time.tv_nsec = -1;
/* Insert into the waiting queue: */
KSE_WAITQ_INSERT(kse, thread);
}
break;
case PS_SIGSUSPEND:
case PS_SUSPENDED:
if (THR_NEED_CANCEL(thread)) {
thread->interrupted = 1;
THR_SET_STATE(thread, PS_RUNNING);
} else {
/*
* These states don't timeout.
*/
thread->wakeup_time.tv_sec = -1;
thread->wakeup_time.tv_nsec = -1;
/* Insert into the waiting queue: */
KSE_WAITQ_INSERT(kse, thread);
}
break;
case PS_DEAD:
/*
* The scheduler is operating on a different
* stack. It is safe to do garbage collecting
* here.
*/
thr_cleanup(kse, thread);
return;
break;
case PS_RUNNING:
if ((thread->flags & THR_FLAGS_SUSPENDED) != 0 &&
!THR_NEED_CANCEL(thread))
THR_SET_STATE(thread, PS_SUSPENDED);
break;
case PS_DEADLOCK:
/*
* These states don't timeout.
*/
thread->wakeup_time.tv_sec = -1;
thread->wakeup_time.tv_nsec = -1;
/* Insert into the waiting queue: */
KSE_WAITQ_INSERT(kse, thread);
break;
default:
PANIC("Unknown state\n");
break;
}
thr_accounting(thread);
if (thread->state == PS_RUNNING) {
if (thread->slice_usec == -1) {
/*
* The thread exceeded its time quantum or
* it yielded the CPU; place it at the tail
* of the queue for its priority.
*/
KSE_RUNQ_INSERT_TAIL(kse, thread);
} else {
/*
* The thread hasn't exceeded its interval
* Place it at the head of the queue for its
* priority.
*/
KSE_RUNQ_INSERT_HEAD(kse, thread);
}
}
}
thread->active = 0;
thread->need_switchout = 0;
if (thread->check_pending != 0) {
/* Install pending signals into the frame. */
thread->check_pending = 0;
KSE_LOCK_ACQUIRE(kse, &_thread_signal_lock);
for (i = 1; i <= _SIG_MAXSIG; i++) {
if (SIGISMEMBER(thread->sigmask, i))
continue;
if (SIGISMEMBER(thread->sigpend, i))
(void)_thr_sig_add(thread, i,
&thread->siginfo[i-1]);
else if (SIGISMEMBER(_thr_proc_sigpending, i) &&
_thr_getprocsig_unlocked(i, &siginfo)) {
(void)_thr_sig_add(thread, i, &siginfo);
}
}
KSE_LOCK_RELEASE(kse, &_thread_signal_lock);
}
}
/*
* This function waits for the smallest timeout value of any waiting
* thread, or until it receives a message from another KSE.
*
* This must be called with the scheduling lock held.
*/
static void
kse_wait(struct kse *kse, struct pthread *td_wait, int sigseqno)
{
struct timespec ts, ts_sleep;
int saved_flags;
if ((td_wait == NULL) || (td_wait->wakeup_time.tv_sec < 0)) {
/* Limit sleep to no more than 1 minute. */
ts_sleep.tv_sec = 60;
ts_sleep.tv_nsec = 0;
} else {
KSE_GET_TOD(kse, &ts);
TIMESPEC_SUB(&ts_sleep, &td_wait->wakeup_time, &ts);
if (ts_sleep.tv_sec > 60) {
ts_sleep.tv_sec = 60;
ts_sleep.tv_nsec = 0;
}
}
/* Don't sleep for negative times. */
if ((ts_sleep.tv_sec >= 0) && (ts_sleep.tv_nsec >= 0)) {
KSE_SET_IDLE(kse);
kse->k_kseg->kg_idle_kses++;
KSE_SCHED_UNLOCK(kse, kse->k_kseg);
if ((kse->k_kseg->kg_flags & KGF_SINGLE_THREAD) &&
(kse->k_sigseqno != sigseqno))
; /* don't sleep */
else {
saved_flags = kse->k_kcb->kcb_kmbx.km_flags;
kse->k_kcb->kcb_kmbx.km_flags |= KMF_NOUPCALL;
kse_release(&ts_sleep);
kse->k_kcb->kcb_kmbx.km_flags = saved_flags;
}
KSE_SCHED_LOCK(kse, kse->k_kseg);
if (KSE_IS_IDLE(kse)) {
KSE_CLEAR_IDLE(kse);
kse->k_kseg->kg_idle_kses--;
}
}
}
/*
* Avoid calling this kse_exit() so as not to confuse it with the
* system call of the same name.
*/
static void
kse_fini(struct kse *kse)
{
/* struct kse_group *free_kseg = NULL; */
struct timespec ts;
struct pthread *td;
/*
* Check to see if this is one of the main kses.
*/
if (kse->k_kseg != _kse_initial->k_kseg) {
PANIC("shouldn't get here");
/* This is for supporting thread groups. */
#ifdef NOT_YET
/* Remove this KSE from the KSEG's list of KSEs. */
KSE_SCHED_LOCK(kse, kse->k_kseg);
TAILQ_REMOVE(&kse->k_kseg->kg_kseq, kse, k_kgqe);
kse->k_kseg->kg_ksecount--;
if (TAILQ_EMPTY(&kse->k_kseg->kg_kseq))
free_kseg = kse->k_kseg;
KSE_SCHED_UNLOCK(kse, kse->k_kseg);
/*
* Add this KSE to the list of free KSEs along with
* the KSEG if is now orphaned.
*/
KSE_LOCK_ACQUIRE(kse, &kse_lock);
if (free_kseg != NULL)
kseg_free_unlocked(free_kseg);
kse_free_unlocked(kse);
KSE_LOCK_RELEASE(kse, &kse_lock);
kse_exit();
/* Never returns. */
PANIC("kse_exit()");
#endif
} else {
/*
* We allow program to kill kse in initial group (by
* lowering the concurrency).
*/
if ((kse != _kse_initial) &&
((kse->k_flags & KF_TERMINATED) != 0)) {
KSE_SCHED_LOCK(kse, kse->k_kseg);
TAILQ_REMOVE(&kse->k_kseg->kg_kseq, kse, k_kgqe);
kse->k_kseg->kg_ksecount--;
/*
* Migrate thread to _kse_initial if its lastest
* kse it ran on is the kse.
*/
td = TAILQ_FIRST(&kse->k_kseg->kg_threadq);
while (td != NULL) {
if (td->kse == kse)
td->kse = _kse_initial;
td = TAILQ_NEXT(td, kle);
}
KSE_SCHED_UNLOCK(kse, kse->k_kseg);
KSE_LOCK_ACQUIRE(kse, &kse_lock);
kse_free_unlocked(kse);
KSE_LOCK_RELEASE(kse, &kse_lock);
/* Make sure there is always at least one is awake */
KSE_WAKEUP(_kse_initial);
kse_exit();
/* Never returns. */
PANIC("kse_exit() failed for initial kseg");
}
KSE_SCHED_LOCK(kse, kse->k_kseg);
KSE_SET_IDLE(kse);
kse->k_kseg->kg_idle_kses++;
KSE_SCHED_UNLOCK(kse, kse->k_kseg);
ts.tv_sec = 120;
ts.tv_nsec = 0;
kse->k_kcb->kcb_kmbx.km_flags = 0;
kse_release(&ts);
/* Never reach */
}
}
void
_thr_set_timeout(const struct timespec *timeout)
{
struct pthread *curthread = _get_curthread();
struct timespec ts;
/* Reset the timeout flag for the running thread: */
curthread->timeout = 0;
/* Check if the thread is to wait forever: */
if (timeout == NULL) {
/*
* Set the wakeup time to something that can be recognised as
* different to an actual time of day:
*/
curthread->wakeup_time.tv_sec = -1;
curthread->wakeup_time.tv_nsec = -1;
}
/* Check if no waiting is required: */
else if ((timeout->tv_sec == 0) && (timeout->tv_nsec == 0)) {
/* Set the wake up time to 'immediately': */
curthread->wakeup_time.tv_sec = 0;
curthread->wakeup_time.tv_nsec = 0;
} else {
/* Calculate the time for the current thread to wakeup: */
KSE_GET_TOD(curthread->kse, &ts);
TIMESPEC_ADD(&curthread->wakeup_time, &ts, timeout);
}
}
void
_thr_panic_exit(char *file, int line, char *msg)
{
char buf[256];
snprintf(buf, sizeof(buf), "(%s:%d) %s\n", file, line, msg);
__sys_write(2, buf, strlen(buf));
abort();
}
void
_thr_setrunnable(struct pthread *curthread, struct pthread *thread)
{
kse_critical_t crit;
struct kse_mailbox *kmbx;
crit = _kse_critical_enter();
KSE_SCHED_LOCK(curthread->kse, thread->kseg);
kmbx = _thr_setrunnable_unlocked(thread);
KSE_SCHED_UNLOCK(curthread->kse, thread->kseg);
_kse_critical_leave(crit);
if ((kmbx != NULL) && (__isthreaded != 0))
kse_wakeup(kmbx);
}
struct kse_mailbox *
_thr_setrunnable_unlocked(struct pthread *thread)
{
struct kse_mailbox *kmbx = NULL;
if ((thread->kseg->kg_flags & KGF_SINGLE_THREAD) != 0) {
/* No silly queues for these threads. */
if ((thread->flags & THR_FLAGS_SUSPENDED) != 0)
THR_SET_STATE(thread, PS_SUSPENDED);
else {
THR_SET_STATE(thread, PS_RUNNING);
kmbx = kse_wakeup_one(thread);
}
} else if (thread->state != PS_RUNNING) {
if ((thread->flags & THR_FLAGS_IN_WAITQ) != 0)
KSE_WAITQ_REMOVE(thread->kse, thread);
if ((thread->flags & THR_FLAGS_SUSPENDED) != 0)
THR_SET_STATE(thread, PS_SUSPENDED);
else {
THR_SET_STATE(thread, PS_RUNNING);
if ((thread->blocked == 0) && (thread->active == 0) &&
(thread->flags & THR_FLAGS_IN_RUNQ) == 0)
THR_RUNQ_INSERT_TAIL(thread);
/*
* XXX - Threads are not yet assigned to specific
* KSEs; they are assigned to the KSEG. So
* the fact that a thread's KSE is waiting
* doesn't necessarily mean that it will be
* the KSE that runs the thread after the
* lock is granted. But we don't know if the
* other KSEs within the same KSEG are also
* in a waiting state or not so we err on the
* side of caution and wakeup the thread's
* last known KSE. We ensure that the
* threads KSE doesn't change while it's
* scheduling lock is held so it is safe to
* reference it (the KSE). If the KSE wakes
* up and doesn't find any more work it will
* again go back to waiting so no harm is
* done.
*/
kmbx = kse_wakeup_one(thread);
}
}
return (kmbx);
}
static struct kse_mailbox *
kse_wakeup_one(struct pthread *thread)
{
struct kse *ke;
if (KSE_IS_IDLE(thread->kse)) {
KSE_CLEAR_IDLE(thread->kse);
thread->kseg->kg_idle_kses--;
return (&thread->kse->k_kcb->kcb_kmbx);
} else {
TAILQ_FOREACH(ke, &thread->kseg->kg_kseq, k_kgqe) {
if (KSE_IS_IDLE(ke)) {
KSE_CLEAR_IDLE(ke);
ke->k_kseg->kg_idle_kses--;
return (&ke->k_kcb->kcb_kmbx);
}
}
}
return (NULL);
}
static void
kse_wakeup_multi(struct kse *curkse)
{
struct kse *ke;
int tmp;
if ((tmp = KSE_RUNQ_THREADS(curkse)) && curkse->k_kseg->kg_idle_kses) {
TAILQ_FOREACH(ke, &curkse->k_kseg->kg_kseq, k_kgqe) {
if (KSE_IS_IDLE(ke)) {
KSE_CLEAR_IDLE(ke);
ke->k_kseg->kg_idle_kses--;
KSE_WAKEUP(ke);
if (--tmp == 0)
break;
}
}
}
}
/*
* Allocate a new KSEG.
*
* We allow the current thread to be NULL in the case that this
* is the first time a KSEG is being created (library initialization).
* In this case, we don't need to (and can't) take any locks.
*/
struct kse_group *
_kseg_alloc(struct pthread *curthread)
{
struct kse_group *kseg = NULL;
kse_critical_t crit;
if ((curthread != NULL) && (free_kseg_count > 0)) {
/* Use the kse lock for the kseg queue. */
crit = _kse_critical_enter();
KSE_LOCK_ACQUIRE(curthread->kse, &kse_lock);
if ((kseg = TAILQ_FIRST(&free_kse_groupq)) != NULL) {
TAILQ_REMOVE(&free_kse_groupq, kseg, kg_qe);
free_kseg_count--;
active_kseg_count++;
TAILQ_INSERT_TAIL(&active_kse_groupq, kseg, kg_qe);
}
KSE_LOCK_RELEASE(curthread->kse, &kse_lock);
_kse_critical_leave(crit);
if (kseg)
kseg_reinit(kseg);
}
/*
* If requested, attempt to allocate a new KSE group only if the
* KSE allocation was successful and a KSE group wasn't found in
* the free list.
*/
if ((kseg == NULL) &&
((kseg = (struct kse_group *)malloc(sizeof(*kseg))) != NULL)) {
if (_pq_alloc(&kseg->kg_schedq.sq_runq,
THR_MIN_PRIORITY, THR_LAST_PRIORITY) != 0) {
free(kseg);
kseg = NULL;
} else {
kseg_init(kseg);
/* Add the KSEG to the list of active KSEGs. */
if (curthread != NULL) {
crit = _kse_critical_enter();
KSE_LOCK_ACQUIRE(curthread->kse, &kse_lock);
active_kseg_count++;
TAILQ_INSERT_TAIL(&active_kse_groupq,
kseg, kg_qe);
KSE_LOCK_RELEASE(curthread->kse, &kse_lock);
_kse_critical_leave(crit);
} else {
active_kseg_count++;
TAILQ_INSERT_TAIL(&active_kse_groupq,
kseg, kg_qe);
}
}
}
return (kseg);
}
static void
kseg_init(struct kse_group *kseg)
{
kseg_reinit(kseg);
_lock_init(&kseg->kg_lock, LCK_ADAPTIVE, _kse_lock_wait,
_kse_lock_wakeup, calloc);
}
static void
kseg_reinit(struct kse_group *kseg)
{
TAILQ_INIT(&kseg->kg_kseq);
TAILQ_INIT(&kseg->kg_threadq);
TAILQ_INIT(&kseg->kg_schedq.sq_waitq);
kseg->kg_threadcount = 0;
kseg->kg_ksecount = 0;
kseg->kg_idle_kses = 0;
kseg->kg_flags = 0;
}
/*
* This must be called with the kse lock held and when there are
* no more threads that reference it.
*/
static void
kseg_free_unlocked(struct kse_group *kseg)
{
TAILQ_REMOVE(&active_kse_groupq, kseg, kg_qe);
TAILQ_INSERT_HEAD(&free_kse_groupq, kseg, kg_qe);
free_kseg_count++;
active_kseg_count--;
}
void
_kseg_free(struct kse_group *kseg)
{
struct kse *curkse;
kse_critical_t crit;
crit = _kse_critical_enter();
curkse = _get_curkse();
KSE_LOCK_ACQUIRE(curkse, &kse_lock);
kseg_free_unlocked(kseg);
KSE_LOCK_RELEASE(curkse, &kse_lock);
_kse_critical_leave(crit);
}
static void
kseg_destroy(struct kse_group *kseg)
{
_lock_destroy(&kseg->kg_lock);
_pq_free(&kseg->kg_schedq.sq_runq);
free(kseg);
}
/*
* Allocate a new KSE.
*
* We allow the current thread to be NULL in the case that this
* is the first time a KSE is being created (library initialization).
* In this case, we don't need to (and can't) take any locks.
*/
struct kse *
_kse_alloc(struct pthread *curthread, int sys_scope)
{
struct kse *kse = NULL;
char *stack;
kse_critical_t crit;
int i;
if ((curthread != NULL) && (free_kse_count > 0)) {
crit = _kse_critical_enter();
KSE_LOCK_ACQUIRE(curthread->kse, &kse_lock);
/* Search for a finished KSE. */
kse = TAILQ_FIRST(&free_kseq);
while ((kse != NULL) &&
((kse->k_kcb->kcb_kmbx.km_flags & KMF_DONE) == 0)) {
kse = TAILQ_NEXT(kse, k_qe);
}
if (kse != NULL) {
DBG_MSG("found an unused kse.\n");
TAILQ_REMOVE(&free_kseq, kse, k_qe);
free_kse_count--;
TAILQ_INSERT_TAIL(&active_kseq, kse, k_qe);
active_kse_count++;
}
KSE_LOCK_RELEASE(curthread->kse, &kse_lock);
_kse_critical_leave(crit);
if (kse != NULL)
kse_reinit(kse, sys_scope);
}
if ((kse == NULL) &&
((kse = (struct kse *)malloc(sizeof(*kse))) != NULL)) {
if (sys_scope != 0)
stack = NULL;
else if ((stack = malloc(KSE_STACKSIZE)) == NULL) {
free(kse);
return (NULL);
}
bzero(kse, sizeof(*kse));
/* Initialize KCB without the lock. */
if ((kse->k_kcb = _kcb_ctor(kse)) == NULL) {
if (stack != NULL)
free(stack);
free(kse);
return (NULL);
}
/* Initialize the lockusers. */
for (i = 0; i < MAX_KSE_LOCKLEVEL; i++) {
_lockuser_init(&kse->k_lockusers[i], (void *)kse);
_LCK_SET_PRIVATE2(&kse->k_lockusers[i], NULL);
}
/* _lock_init(kse->k_lock, ...) */
if (curthread != NULL) {
crit = _kse_critical_enter();
KSE_LOCK_ACQUIRE(curthread->kse, &kse_lock);
}
kse->k_flags = 0;
TAILQ_INSERT_TAIL(&active_kseq, kse, k_qe);
active_kse_count++;
if (curthread != NULL) {
KSE_LOCK_RELEASE(curthread->kse, &kse_lock);
_kse_critical_leave(crit);
}
/*
* Create the KSE context.
* Scope system threads (one thread per KSE) are not required
* to have a stack for an unneeded kse upcall.
*/
if (!sys_scope) {
kse->k_kcb->kcb_kmbx.km_func = (kse_func_t *)kse_sched_multi;
kse->k_stack.ss_sp = stack;
kse->k_stack.ss_size = KSE_STACKSIZE;
} else {
kse->k_kcb->kcb_kmbx.km_func = (kse_func_t *)kse_sched_single;
kse->k_stack.ss_sp = NULL;
kse->k_stack.ss_size = 0;
}
kse->k_kcb->kcb_kmbx.km_udata = (void *)kse;
kse->k_kcb->kcb_kmbx.km_quantum = 20000;
/*
* We need to keep a copy of the stack in case it
* doesn't get used; a KSE running a scope system
* thread will use that thread's stack.
*/
kse->k_kcb->kcb_kmbx.km_stack = kse->k_stack;
}
return (kse);
}
static void
kse_reinit(struct kse *kse, int sys_scope)
{
if (!sys_scope) {
kse->k_kcb->kcb_kmbx.km_func = (kse_func_t *)kse_sched_multi;
if (kse->k_stack.ss_sp == NULL) {
/* XXX check allocation failure */
kse->k_stack.ss_sp = (char *) malloc(KSE_STACKSIZE);
kse->k_stack.ss_size = KSE_STACKSIZE;
}
kse->k_kcb->kcb_kmbx.km_quantum = 20000;
} else {
kse->k_kcb->kcb_kmbx.km_func = (kse_func_t *)kse_sched_single;
if (kse->k_stack.ss_sp)
free(kse->k_stack.ss_sp);
kse->k_stack.ss_sp = NULL;
kse->k_stack.ss_size = 0;
kse->k_kcb->kcb_kmbx.km_quantum = 0;
}
kse->k_kcb->kcb_kmbx.km_stack = kse->k_stack;
kse->k_kcb->kcb_kmbx.km_udata = (void *)kse;
kse->k_kcb->kcb_kmbx.km_curthread = NULL;
kse->k_kcb->kcb_kmbx.km_flags = 0;
kse->k_curthread = NULL;
kse->k_kseg = 0;
kse->k_schedq = 0;
kse->k_locklevel = 0;
kse->k_flags = 0;
kse->k_error = 0;
kse->k_cpu = 0;
kse->k_sigseqno = 0;
}
void
kse_free_unlocked(struct kse *kse)
{
TAILQ_REMOVE(&active_kseq, kse, k_qe);
active_kse_count--;
kse->k_kseg = NULL;
kse->k_kcb->kcb_kmbx.km_quantum = 20000;
kse->k_flags = 0;
TAILQ_INSERT_HEAD(&free_kseq, kse, k_qe);
free_kse_count++;
}
void
_kse_free(struct pthread *curthread, struct kse *kse)
{
kse_critical_t crit;
if (curthread == NULL)
kse_free_unlocked(kse);
else {
crit = _kse_critical_enter();
KSE_LOCK_ACQUIRE(curthread->kse, &kse_lock);
kse_free_unlocked(kse);
KSE_LOCK_RELEASE(curthread->kse, &kse_lock);
_kse_critical_leave(crit);
}
}
static void
kse_destroy(struct kse *kse)
{
int i;
if (kse->k_stack.ss_sp != NULL)
free(kse->k_stack.ss_sp);
_kcb_dtor(kse->k_kcb);
for (i = 0; i < MAX_KSE_LOCKLEVEL; ++i)
_lockuser_destroy(&kse->k_lockusers[i]);
_lock_destroy(&kse->k_lock);
free(kse);
}
struct pthread *
_thr_alloc(struct pthread *curthread)
{
kse_critical_t crit;
struct pthread *thread = NULL;
int i;
if (curthread != NULL) {
if (GC_NEEDED())
_thr_gc(curthread);
if (free_thread_count > 0) {
crit = _kse_critical_enter();
KSE_LOCK_ACQUIRE(curthread->kse, &thread_lock);
if ((thread = TAILQ_FIRST(&free_threadq)) != NULL) {
TAILQ_REMOVE(&free_threadq, thread, tle);
free_thread_count--;
}
KSE_LOCK_RELEASE(curthread->kse, &thread_lock);
_kse_critical_leave(crit);
}
}
if ((thread == NULL) &&
((thread = malloc(sizeof(struct pthread))) != NULL)) {
bzero(thread, sizeof(struct pthread));
thread->siginfo = calloc(_SIG_MAXSIG, sizeof(siginfo_t));
if (thread->siginfo == NULL) {
free(thread);
return (NULL);
}
if (curthread) {
_pthread_mutex_lock(&_tcb_mutex);
thread->tcb = _tcb_ctor(thread, 0 /* not initial tls */);
_pthread_mutex_unlock(&_tcb_mutex);
} else {
thread->tcb = _tcb_ctor(thread, 1 /* initial tls */);
}
if (thread->tcb == NULL) {
free(thread->siginfo);
free(thread);
return (NULL);
}
/*
* Initialize thread locking.
* Lock initializing needs malloc, so don't
* enter critical region before doing this!
*/
if (_lock_init(&thread->lock, LCK_ADAPTIVE,
_thr_lock_wait, _thr_lock_wakeup, calloc) != 0)
PANIC("Cannot initialize thread lock");
for (i = 0; i < MAX_THR_LOCKLEVEL; i++) {
_lockuser_init(&thread->lockusers[i], (void *)thread);
_LCK_SET_PRIVATE2(&thread->lockusers[i],
(void *)thread);
}
}
return (thread);
}
void
_thr_free(struct pthread *curthread, struct pthread *thread)
{
kse_critical_t crit;
DBG_MSG("Freeing thread %p\n", thread);
if (thread->name) {
free(thread->name);
thread->name = NULL;
}
if ((curthread == NULL) || (free_thread_count >= MAX_CACHED_THREADS)) {
thr_destroy(curthread, thread);
} else {
/* Add the thread to the free thread list. */
crit = _kse_critical_enter();
KSE_LOCK_ACQUIRE(curthread->kse, &thread_lock);
TAILQ_INSERT_TAIL(&free_threadq, thread, tle);
free_thread_count++;
KSE_LOCK_RELEASE(curthread->kse, &thread_lock);
_kse_critical_leave(crit);
}
}
static void
thr_destroy(struct pthread *curthread, struct pthread *thread)
{
int i;
for (i = 0; i < MAX_THR_LOCKLEVEL; i++)
_lockuser_destroy(&thread->lockusers[i]);
_lock_destroy(&thread->lock);
if (curthread) {
_pthread_mutex_lock(&_tcb_mutex);
_tcb_dtor(thread->tcb);
_pthread_mutex_unlock(&_tcb_mutex);
} else {
_tcb_dtor(thread->tcb);
}
free(thread->siginfo);
free(thread);
}
/*
* Add an active thread:
*
* o Assign the thread a unique id (which GDB uses to track
* threads.
* o Add the thread to the list of all threads and increment
* number of active threads.
*/
static void
thr_link(struct pthread *thread)
{
kse_critical_t crit;
struct kse *curkse;
crit = _kse_critical_enter();
curkse = _get_curkse();
KSE_LOCK_ACQUIRE(curkse, &_thread_list_lock);
/*
* Initialize the unique id (which GDB uses to track
* threads), add the thread to the list of all threads,
* and
*/
thread->uniqueid = next_uniqueid++;
THR_LIST_ADD(thread);
_thread_active_threads++;
KSE_LOCK_RELEASE(curkse, &_thread_list_lock);
_kse_critical_leave(crit);
}
/*
* Remove an active thread.
*/
static void
thr_unlink(struct pthread *thread)
{
kse_critical_t crit;
struct kse *curkse;
crit = _kse_critical_enter();
curkse = _get_curkse();
KSE_LOCK_ACQUIRE(curkse, &_thread_list_lock);
THR_LIST_REMOVE(thread);
_thread_active_threads--;
KSE_LOCK_RELEASE(curkse, &_thread_list_lock);
_kse_critical_leave(crit);
}
void
_thr_hash_add(struct pthread *thread)
{
struct thread_hash_head *head;
head = &thr_hashtable[THREAD_HASH(thread)];
LIST_INSERT_HEAD(head, thread, hle);
}
void
_thr_hash_remove(struct pthread *thread)
{
LIST_REMOVE(thread, hle);
}
struct pthread *
_thr_hash_find(struct pthread *thread)
{
struct pthread *td;
struct thread_hash_head *head;
head = &thr_hashtable[THREAD_HASH(thread)];
LIST_FOREACH(td, head, hle) {
if (td == thread)
return (thread);
}
return (NULL);
}
void
_thr_debug_check_yield(struct pthread *curthread)
{
/*
* Note that TMDF_SUSPEND is set after process is suspended.
* When we are being debugged, every suspension in process
* will cause all KSEs to schedule an upcall in kernel, unless the
* KSE is in critical region.
* If the function is being called, it means the KSE is no longer
* in critical region, if the TMDF_SUSPEND is set by debugger
* before KSE leaves critical region, we will catch it here, else
* if the flag is changed during testing, it also not a problem,
* because the change only occurs after a process suspension event
* occurs. A suspension event will always cause KSE to schedule an
* upcall, in the case, because we are not in critical region,
* upcall will be scheduled sucessfully, the flag will be checked
* again in kse_sched_multi, we won't back until the flag
* is cleared by debugger, the flag will be cleared in next
* suspension event.
*/
if (!DBG_CAN_RUN(curthread)) {
if ((curthread->attr.flags & PTHREAD_SCOPE_SYSTEM) == 0)
_thr_sched_switch(curthread);
else
kse_thr_interrupt(&curthread->tcb->tcb_tmbx,
KSE_INTR_DBSUSPEND, 0);
}
}
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