55613576f5
KSEs when it's thread exits; allow the GC handler to do that.
o Make spinlock/spinlock critical regions.
The following were submitted by davidxu
o Alow thr_switch() to take a null mailbox argument.
o Better protect cancellation checks.
o Don't set KSE specific data when creating new KSEs; rely on the
first upcall of the KSE to set it.
o Add the ability to set the maximum concurrency level and do this
automatically. We should have a way to enable/disable this with
some sort of tunable because some applications may not want this
to be the default.
o Hold the scheduling lock across thread switch calls.
o If scheduling of a thread fails, make sure to remove it from the list
of active threads.
o Better protect accesses to a joining threads when the target thread is
exited and detached.
o Remove some macro definitions that are now provided by <sys/kse.h>.
o Don't leave the library in threaded mode if creation of the initial
KSE fails.
o Wakeup idle KSEs when there are threads ready to run.
o Maintain the number of threads active in the priority queue.
148 lines
4.8 KiB
C
148 lines
4.8 KiB
C
/*
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* Copyright (c) 1995 John Birrell <jb@cimlogic.com.au>.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by John Birrell.
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* 4. Neither the name of the author nor the names of any co-contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#include <errno.h>
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#include <pthread.h>
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#include "thr_private.h"
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__weak_reference(_pthread_join, pthread_join);
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int
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_pthread_join(pthread_t pthread, void **thread_return)
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{
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struct pthread *curthread = _get_curthread();
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kse_critical_t crit;
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int ret = 0;
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_thr_enter_cancellation_point(curthread);
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/* Check if the caller has specified an invalid thread: */
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if (pthread == NULL || pthread->magic != THR_MAGIC) {
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/* Invalid thread: */
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_thr_leave_cancellation_point(curthread);
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return (EINVAL);
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}
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/* Check if the caller has specified itself: */
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if (pthread == curthread) {
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/* Avoid a deadlock condition: */
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_thr_leave_cancellation_point(curthread);
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return (EDEADLK);
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}
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/*
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* Find the thread in the list of active threads or in the
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* list of dead threads:
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*/
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if ((ret = _thr_ref_add(curthread, pthread, /*include dead*/1)) != 0) {
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/* Return an error: */
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_thr_leave_cancellation_point(curthread);
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return (ESRCH);
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}
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THR_SCHED_LOCK(curthread, pthread);
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/* Check if this thread has been detached: */
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if ((pthread->attr.flags & PTHREAD_DETACHED) != 0) {
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THR_SCHED_UNLOCK(curthread, pthread);
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/* Remove the reference and return an error: */
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_thr_ref_delete(curthread, pthread);
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ret = ESRCH;
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} else {
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/* Lock the target thread while checking its state. */
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if (pthread->state == PS_DEAD) {
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if (thread_return != NULL)
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/* Return the thread's return value: */
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*thread_return = pthread->ret;
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/* Detach the thread. */
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pthread->attr.flags |= PTHREAD_DETACHED;
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/* Unlock the thread. */
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THR_SCHED_UNLOCK(curthread, pthread);
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/*
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* Remove the thread from the list of active
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* threads and add it to the GC list.
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*/
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crit = _kse_critical_enter();
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KSE_LOCK_ACQUIRE(curthread->kse, &_thread_list_lock);
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THR_LIST_REMOVE(pthread);
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THR_GCLIST_ADD(pthread);
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KSE_LOCK_RELEASE(curthread->kse, &_thread_list_lock);
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_kse_critical_leave(crit);
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/* Remove the reference. */
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_thr_ref_delete(curthread, pthread);
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}
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else if (pthread->joiner != NULL) {
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/* Unlock the thread and remove the reference. */
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THR_SCHED_UNLOCK(curthread, pthread);
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_thr_ref_delete(curthread, pthread);
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/* Multiple joiners are not supported. */
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ret = ENOTSUP;
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}
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else {
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/* Set the running thread to be the joiner: */
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pthread->joiner = curthread;
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/* Keep track of which thread we're joining to: */
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curthread->join_status.thread = pthread;
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/* Unlock the thread and remove the reference. */
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THR_SCHED_UNLOCK(curthread, pthread);
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_thr_ref_delete(curthread, pthread);
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THR_LOCK_SWITCH(curthread);
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while (curthread->join_status.thread == pthread) {
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THR_SET_STATE(curthread, PS_JOIN);
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/* Schedule the next thread: */
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_thr_sched_switch(curthread);
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}
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THR_UNLOCK_SWITCH(curthread);
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/*
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* The thread return value and error are set by the
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* thread we're joining to when it exits or detaches:
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*/
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ret = curthread->join_status.error;
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if ((ret == 0) && (thread_return != NULL))
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*thread_return = curthread->join_status.ret;
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}
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}
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_thr_leave_cancellation_point(curthread);
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/* Return the completion status: */
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return (ret);
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}
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