7f206ad4bb
lock held (_thr_sched_switch_unlocked()) and use this to avoid dropping the scheduler lock and having the scheduler retake the same lock again. Add a better way of detecting if a low-level lock is in use. When switching out a thread due to blocking in the UTS, don't switch to the KSE's scheduler stack only to switch back to another thread. If possible switch to the new thread directly from the old thread and avoid the overhead of the extra context switch. Check for pending signals on a thread when entering the scheduler and add them to the threads signal frame. This includes some other minor signal fixes. Most of this was a joint effor between davidxu and myself. Reviewed by: davidxu Approved by: re@ (blanket for libpthread)
150 lines
4.9 KiB
C
150 lines
4.9 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_SCHED_LOCK(curthread, 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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THR_SCHED_UNLOCK(curthread, curthread);
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/* Schedule the next thread: */
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_thr_sched_switch(curthread);
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THR_SCHED_LOCK(curthread, curthread);
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}
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THR_SCHED_UNLOCK(curthread, 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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