freebsd-dev/lib/libthr/thread/thr_getschedparam.c
David Xu e2dc286c1c Caching scheduling policy and priority in userland, a critical but baddly
written application is frequently changing thread priority for SCHED_OTHER
policy.
2006-07-13 22:45:19 +00:00

76 lines
2.7 KiB
C

/*
* Copyright (c) 1998 Daniel Eischen <eischen@vigrid.com>.
* 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 Daniel Eischen.
* 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 DANIEL EISCHEN 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 "namespace.h"
#include <errno.h>
#include <pthread.h>
#include "un-namespace.h"
#include "thr_private.h"
__weak_reference(_pthread_getschedparam, pthread_getschedparam);
int
_pthread_getschedparam(pthread_t pthread, int *policy,
struct sched_param *param)
{
struct pthread *curthread = _get_curthread();
int ret;
if (policy == NULL || param == NULL)
return (EINVAL);
if (pthread == curthread) {
/*
* Avoid searching the thread list when it is the current
* thread.
*/
THR_LOCK(curthread);
*policy = curthread->attr.sched_policy;
param->sched_priority = curthread->attr.prio;
THR_UNLOCK(curthread);
ret = 0;
}
/* Find the thread in the list of active threads. */
else if ((ret = _thr_ref_add(curthread, pthread, /*include dead*/0))
== 0) {
THR_THREAD_LOCK(curthread, pthread);
*policy = pthread->attr.sched_policy;
param->sched_priority = pthread->attr.prio;
THR_THREAD_UNLOCK(curthread, pthread);
_thr_ref_delete(curthread, pthread);
}
return (ret);
}