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/*
* Copyright (c) 2003 Daniel M. Eischen <deischen@freebsd.org>
* Copyright (c) 2003 Sergey Osokin <osa@freebsd.org.ru>.
* 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. 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 THE AUTHORS 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 <errno.h>
#include <pthread.h>
#include <sys/types.h>
#include <sys/sysctl.h>
#include "thr_private.h"
/*#define DEBUG_CONCURRENCY */
#ifdef DEBUG_CONCURRENCY
#define DBG_MSG stdout_debug
#else
#define DBG_MSG(x...)
#endif
static int level = 0;
__weak_reference(_pthread_getconcurrency, pthread_getconcurrency);
__weak_reference(_pthread_setconcurrency, pthread_setconcurrency);
int
_pthread_getconcurrency(void)
{
return (level);
}
int
_pthread_setconcurrency(int new_level)
{
int ret;
if (new_level < 0)
ret = EINVAL;
else if (new_level == level)
ret = 0;
else if (new_level == 0) {
level = 0;
ret = 0;
} else if ((_kse_isthreaded() == 0) && (_kse_setthreaded(1) != 0)) {
DBG_MSG("Can't enable threading.\n");
ret = EAGAIN;
} else {
ret = _thr_setconcurrency(new_level);
if (ret == 0)
level = new_level;
}
return (ret);
}
int
_thr_setconcurrency(int new_level)
{
struct pthread *curthread;
struct kse *newkse, *kse;
kse_critical_t crit;
int kse_count;
int i;
int ret;
ret = 0;
curthread = _get_curthread();
/* Race condition, but so what. */
kse_count = _kse_initial->k_kseg->kg_ksecount;
if (new_level > kse_count) {
for (i = kse_count; i < new_level; i++) {
newkse = _kse_alloc(curthread, 0);
if (newkse == NULL) {
DBG_MSG("Can't alloc new KSE.\n");
ret = EAGAIN;
break;
}
newkse->k_kseg = _kse_initial->k_kseg;
newkse->k_schedq = _kse_initial->k_schedq;
newkse->k_curthread = NULL;
crit = _kse_critical_enter();
KSE_SCHED_LOCK(curthread->kse, newkse->k_kseg);
TAILQ_INSERT_TAIL(&newkse->k_kseg->kg_kseq,
newkse, k_kgqe);
newkse->k_kseg->kg_ksecount++;
newkse->k_flags |= KF_STARTED;
KSE_SCHED_UNLOCK(curthread->kse, newkse->k_kseg);
if (kse_create(&newkse->k_kcb->kcb_kmbx, 0) != 0) {
KSE_SCHED_LOCK(curthread->kse, newkse->k_kseg);
TAILQ_REMOVE(&newkse->k_kseg->kg_kseq,
newkse, k_kgqe);
newkse->k_kseg->kg_ksecount--;
KSE_SCHED_UNLOCK(curthread->kse,
newkse->k_kseg);
_kse_critical_leave(crit);
_kse_free(curthread, newkse);
DBG_MSG("kse_create syscall failed.\n");
ret = EAGAIN;
break;
} else {
_kse_critical_leave(crit);
}
}
} else if (new_level < kse_count) {
kse_count = 0;
crit = _kse_critical_enter();
KSE_SCHED_LOCK(curthread->kse, _kse_initial->k_kseg);
/* Count the number of active KSEs */
TAILQ_FOREACH(kse, &_kse_initial->k_kseg->kg_kseq, k_kgqe) {
if ((kse->k_flags & KF_TERMINATED) == 0)
kse_count++;
}
/* Reduce the number of active KSEs appropriately. */
kse = TAILQ_FIRST(&_kse_initial->k_kseg->kg_kseq);
while ((kse != NULL) && (kse_count > new_level)) {
if ((kse != _kse_initial) &&
((kse->k_flags & KF_TERMINATED) == 0)) {
kse->k_flags |= KF_TERMINATED;
kse_count--;
/* Wakup the KSE in case it is idle. */
kse_wakeup(&kse->k_kcb->kcb_kmbx);
}
kse = TAILQ_NEXT(kse, k_kgqe);
}
KSE_SCHED_UNLOCK(curthread->kse, _kse_initial->k_kseg);
_kse_critical_leave(crit);
}
return (ret);
}
int
_thr_setmaxconcurrency(void)
{
int vcpu;
size_t len;
int ret;
len = sizeof(vcpu);
ret = sysctlbyname("kern.threads.virtual_cpu", &vcpu, &len, NULL, 0);
if (ret == 0 && vcpu > 0)
ret = _thr_setconcurrency(vcpu);
return (ret);
}
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