freebsd-dev/lib/libkse/thread/thr_detach.c
Daniel Eischen cc24e83605 Move idle kse wakeup to outside of regions where locks are held.
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
2003-07-23 02:11:07 +00:00

118 lines
4.0 KiB
C

/*
* Copyright (c) 1995 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.
*
* $FreeBSD$
*/
#include <sys/types.h>
#include <machine/atomic.h>
#include <errno.h>
#include <pthread.h>
#include "thr_private.h"
__weak_reference(_pthread_detach, pthread_detach);
int
_pthread_detach(pthread_t pthread)
{
struct pthread *curthread = _get_curthread();
struct kse_mailbox *kmbx = NULL;
struct pthread *joiner;
int rval = 0;
/* Check for invalid calling parameters: */
if (pthread == NULL || pthread->magic != THR_MAGIC)
/* Return an invalid argument error: */
rval = EINVAL;
else if ((rval = _thr_ref_add(curthread, pthread,
/*include dead*/1)) != 0) {
/* Return an error: */
}
/* Check if the thread is already detached: */
else if ((pthread->attr.flags & PTHREAD_DETACHED) != 0) {
/* Return an error: */
_thr_ref_delete(curthread, pthread);
rval = EINVAL;
} else {
/* Lock the detached thread: */
THR_SCHED_LOCK(curthread, pthread);
/* Flag the thread as detached: */
pthread->attr.flags |= PTHREAD_DETACHED;
/* Retrieve any joining thread and remove it: */
joiner = pthread->joiner;
if ((joiner != NULL) && (joiner->kseg == pthread->kseg)) {
/*
* We already own the scheduler lock for the joiner.
* Take advantage of that and make the joiner runnable.
*/
if (joiner->join_status.thread == pthread) {
/*
* Set the return value for the woken thread:
*/
joiner->join_status.error = ESRCH;
joiner->join_status.ret = NULL;
joiner->join_status.thread = NULL;
kmbx = _thr_setrunnable_unlocked(joiner);
}
joiner = NULL;
}
THR_SCHED_UNLOCK(curthread, pthread);
/* See if there is a thread waiting in pthread_join(): */
if ((joiner != NULL) &&
(_thr_ref_add(curthread, joiner, 0) == 0)) {
/* Lock the joiner before fiddling with it. */
THR_SCHED_LOCK(curthread, joiner);
if (joiner->join_status.thread == pthread) {
/*
* Set the return value for the woken thread:
*/
joiner->join_status.error = ESRCH;
joiner->join_status.ret = NULL;
joiner->join_status.thread = NULL;
kmbx = _thr_setrunnable_unlocked(joiner);
}
THR_SCHED_UNLOCK(curthread, joiner);
_thr_ref_delete(curthread, joiner);
}
_thr_ref_delete(curthread, pthread);
if (kmbx != NULL)
kse_wakeup(kmbx);
}
/* Return the completion status: */
return (rval);
}