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cc24e83605
This eliminates ping-ponging of locks, where the idle KSE wakes up only to find the lock it needs is being held. This gives little or no gain to M:N mode but greatly speeds up 1:1 mode. Reviewed & Tested by: davidxu
118 lines
4.0 KiB
C
118 lines
4.0 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 <sys/types.h>
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#include <machine/atomic.h>
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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_detach, pthread_detach);
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int
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_pthread_detach(pthread_t pthread)
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{
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struct pthread *curthread = _get_curthread();
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struct kse_mailbox *kmbx = NULL;
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struct pthread *joiner;
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int rval = 0;
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/* Check for invalid calling parameters: */
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if (pthread == NULL || pthread->magic != THR_MAGIC)
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/* Return an invalid argument error: */
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rval = EINVAL;
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else if ((rval = _thr_ref_add(curthread, pthread,
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/*include dead*/1)) != 0) {
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/* Return an error: */
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}
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/* Check if the thread is already detached: */
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else if ((pthread->attr.flags & PTHREAD_DETACHED) != 0) {
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/* Return an error: */
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_thr_ref_delete(curthread, pthread);
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rval = EINVAL;
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} else {
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/* Lock the detached thread: */
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THR_SCHED_LOCK(curthread, pthread);
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/* Flag the thread as detached: */
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pthread->attr.flags |= PTHREAD_DETACHED;
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/* Retrieve any joining thread and remove it: */
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joiner = pthread->joiner;
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if ((joiner != NULL) && (joiner->kseg == pthread->kseg)) {
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/*
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* We already own the scheduler lock for the joiner.
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* Take advantage of that and make the joiner runnable.
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*/
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if (joiner->join_status.thread == pthread) {
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/*
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* Set the return value for the woken thread:
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*/
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joiner->join_status.error = ESRCH;
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joiner->join_status.ret = NULL;
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joiner->join_status.thread = NULL;
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kmbx = _thr_setrunnable_unlocked(joiner);
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}
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joiner = NULL;
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}
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THR_SCHED_UNLOCK(curthread, pthread);
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/* See if there is a thread waiting in pthread_join(): */
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if ((joiner != NULL) &&
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(_thr_ref_add(curthread, joiner, 0) == 0)) {
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/* Lock the joiner before fiddling with it. */
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THR_SCHED_LOCK(curthread, joiner);
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if (joiner->join_status.thread == pthread) {
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/*
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* Set the return value for the woken thread:
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*/
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joiner->join_status.error = ESRCH;
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joiner->join_status.ret = NULL;
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joiner->join_status.thread = NULL;
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kmbx = _thr_setrunnable_unlocked(joiner);
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}
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THR_SCHED_UNLOCK(curthread, joiner);
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_thr_ref_delete(curthread, joiner);
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}
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_thr_ref_delete(curthread, pthread);
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if (kmbx != NULL)
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kse_wakeup(kmbx);
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}
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/* Return the completion status: */
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return (rval);
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}
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