NetBSD/sys/rump/librump/rumpkern/sleepq.c

182 lines
4.0 KiB
C

/* $NetBSD: sleepq.c,v 1.13 2011/01/28 17:57:03 pooka Exp $ */
/*
* Copyright (c) 2008 Antti Kantee. 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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.
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: sleepq.c,v 1.13 2011/01/28 17:57:03 pooka Exp $");
#include <sys/param.h>
#include <sys/condvar.h>
#include <sys/mutex.h>
#include <sys/once.h>
#include <sys/queue.h>
#include <sys/sleepq.h>
#include <sys/syncobj.h>
#include <sys/atomic.h>
#include "rump_private.h"
/*
* Flimsy and minimalistic sleepq implementation. This is implemented
* only for the use of callouts in kern_timeout.c. locking etc is
* completely incorrect, horrible, etc etc etc.
*/
syncobj_t sleep_syncobj;
static kcondvar_t sq_cv;
static int
sqinit1(void)
{
cv_init(&sq_cv, "sleepq");
return 0;
}
void
sleepq_init(sleepq_t *sq)
{
ONCE_DECL(sqctl);
RUN_ONCE(&sqctl, sqinit1);
TAILQ_INIT(sq);
}
void
sleepq_enqueue(sleepq_t *sq, wchan_t wc, const char *wmsg, syncobj_t *sob)
{
struct lwp *l = curlwp;
l->l_wchan = wc;
l->l_wmesg = wmsg;
l->l_sleepq = sq;
TAILQ_INSERT_TAIL(sq, l, l_sleepchain);
}
int
sleepq_block(int timo, bool catch)
{
struct lwp *l = curlwp;
int error = 0;
kmutex_t *mp = l->l_mutex;
int biglocks = l->l_biglocks;
while (l->l_wchan) {
l->l_mutex = mp; /* keep sleepq lock until woken up */
error = cv_timedwait(&sq_cv, mp, timo);
if (error == EWOULDBLOCK || error == EINTR) {
if (l->l_wchan) {
TAILQ_REMOVE(l->l_sleepq, l, l_sleepchain);
l->l_wchan = NULL;
l->l_wmesg = NULL;
}
}
}
mutex_spin_exit(mp);
if (biglocks)
KERNEL_LOCK(biglocks, curlwp);
return error;
}
lwp_t *
sleepq_wake(sleepq_t *sq, wchan_t wchan, u_int expected, kmutex_t *mp)
{
struct lwp *l, *l_next;
bool found = false;
if (__predict_false(expected != -1))
panic("sleepq_wake: \"expected\" not supported");
for (l = TAILQ_FIRST(sq); l; l = l_next) {
l_next = TAILQ_NEXT(l, l_sleepchain);
if (l->l_wchan == wchan) {
found = true;
l->l_wchan = NULL;
l->l_wmesg = NULL;
TAILQ_REMOVE(sq, l, l_sleepchain);
}
}
if (found)
cv_broadcast(&sq_cv);
mutex_spin_exit(mp);
return NULL;
}
void
sleepq_unsleep(struct lwp *l, bool cleanup)
{
l->l_wchan = NULL;
l->l_wmesg = NULL;
TAILQ_REMOVE(l->l_sleepq, l, l_sleepchain);
cv_broadcast(&sq_cv);
if (cleanup) {
mutex_spin_exit(l->l_mutex);
}
}
/*
* Thread scheduler handles priorities. Therefore no action here.
* (maybe do something if we're deperate?)
*/
void
sleepq_changepri(struct lwp *l, pri_t pri)
{
}
void
sleepq_lendpri(struct lwp *l, pri_t pri)
{
}
struct lwp *
syncobj_noowner(wchan_t wc)
{
return NULL;
}
void
lwp_unlock_to(struct lwp *l, kmutex_t *new)
{
kmutex_t *old;
KASSERT(mutex_owned(l->l_mutex));
old = l->l_mutex;
membar_exit();
l->l_mutex = new;
mutex_spin_exit(old);
}