NetBSD/sys/dev/sysmon/sysmon_taskq.c

212 lines
5.7 KiB
C

/* $NetBSD: sysmon_taskq.c,v 1.14 2008/09/05 22:06:52 gmcgarry Exp $ */
/*
* Copyright (c) 2001, 2003 Wasabi Systems, Inc.
* All rights reserved.
*
* Written by Jason R. Thorpe for Wasabi Systems, Inc.
*
* 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 for the NetBSD Project by
* Wasabi Systems, Inc.
* 4. The name of Wasabi Systems, Inc. may not be used to endorse
* or promote products derived from this software without specific prior
* written permission.
*
* THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``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 WASABI SYSTEMS, INC
* 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.
*/
/*
* General purpose task queue for sysmon back-ends. This can be
* used to run callbacks that require thread context.
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: sysmon_taskq.c,v 1.14 2008/09/05 22:06:52 gmcgarry Exp $");
#include <sys/param.h>
#include <sys/malloc.h>
#include <sys/queue.h>
#include <sys/proc.h>
#include <sys/kthread.h>
#include <sys/systm.h>
#include <dev/sysmon/sysmon_taskq.h>
struct sysmon_task {
TAILQ_ENTRY(sysmon_task) st_list;
void (*st_func)(void *);
void *st_arg;
u_int st_pri;
};
static TAILQ_HEAD(, sysmon_task) sysmon_task_queue =
TAILQ_HEAD_INITIALIZER(sysmon_task_queue);
static kmutex_t sysmon_task_queue_mtx;
static kmutex_t sysmon_task_queue_init_mtx;
static kcondvar_t sysmon_task_queue_cv;
static int sysmon_task_queue_initialized;
static int sysmon_task_queue_cleanup_sem;
static struct lwp *sysmon_task_queue_lwp;
static void sysmon_task_queue_thread(void *);
void
sysmon_task_queue_preinit(void)
{
mutex_init(&sysmon_task_queue_mtx, MUTEX_DEFAULT, IPL_VM);
mutex_init(&sysmon_task_queue_init_mtx, MUTEX_DEFAULT, IPL_NONE);
cv_init(&sysmon_task_queue_cv, "smtaskq");
}
/*
* sysmon_task_queue_init:
*
* Initialize the sysmon task queue.
*/
void
sysmon_task_queue_init(void)
{
int error;
mutex_enter(&sysmon_task_queue_init_mtx);
if (sysmon_task_queue_initialized) {
mutex_exit(&sysmon_task_queue_init_mtx);
return;
}
sysmon_task_queue_initialized = 1;
mutex_exit(&sysmon_task_queue_init_mtx);
error = kthread_create(PRI_NONE, KTHREAD_MPSAFE, NULL,
sysmon_task_queue_thread, NULL, &sysmon_task_queue_lwp, "sysmon");
if (error) {
printf("Unable to create sysmon task queue thread, "
"error = %d\n", error);
panic("sysmon_task_queue_init");
}
}
/*
* sysmon_task_queue_fini:
*
* Tear town the sysmon task queue.
*/
void
sysmon_task_queue_fini(void)
{
mutex_enter(&sysmon_task_queue_mtx);
sysmon_task_queue_cleanup_sem = 1;
cv_signal(&sysmon_task_queue_cv);
while (sysmon_task_queue_cleanup_sem != 0)
cv_wait(&sysmon_task_queue_cv,
&sysmon_task_queue_mtx);
mutex_exit(&sysmon_task_queue_mtx);
}
/*
* sysmon_task_queue_thread:
*
* The sysmon task queue execution thread. We execute callbacks that
* have been queued for us.
*/
static void
sysmon_task_queue_thread(void *arg)
{
struct sysmon_task *st;
/*
* Run through all the tasks before we check for the exit
* condition; it's probably more important to actually run
* all the tasks before we exit.
*/
mutex_enter(&sysmon_task_queue_mtx);
for (;;) {
st = TAILQ_FIRST(&sysmon_task_queue);
if (st != NULL) {
TAILQ_REMOVE(&sysmon_task_queue, st, st_list);
mutex_exit(&sysmon_task_queue_mtx);
(*st->st_func)(st->st_arg);
free(st, M_TEMP);
mutex_enter(&sysmon_task_queue_mtx);
} else {
/* Check for the exit condition. */
if (sysmon_task_queue_cleanup_sem != 0)
break;
cv_wait(&sysmon_task_queue_cv, &sysmon_task_queue_mtx);
}
}
/* Time to die. */
sysmon_task_queue_cleanup_sem = 0;
cv_broadcast(&sysmon_task_queue_cv);
mutex_exit(&sysmon_task_queue_mtx);
kthread_exit(0);
}
/*
* sysmon_task_queue_sched:
*
* Schedule a task for deferred execution.
*/
int
sysmon_task_queue_sched(u_int pri, void (*func)(void *), void *arg)
{
struct sysmon_task *st, *lst;
if (sysmon_task_queue_lwp == NULL)
aprint_debug("WARNING: Callback scheduled before sysmon "
"task queue thread present\n");
if (func == NULL)
return EINVAL;
st = malloc(sizeof(*st), M_TEMP, M_NOWAIT);
if (st == NULL)
return ENOMEM;
st->st_func = func;
st->st_arg = arg;
st->st_pri = pri;
mutex_enter(&sysmon_task_queue_mtx);
TAILQ_FOREACH(lst, &sysmon_task_queue, st_list) {
if (st->st_pri > lst->st_pri) {
TAILQ_INSERT_BEFORE(lst, st, st_list);
break;
}
}
if (lst == NULL)
TAILQ_INSERT_TAIL(&sysmon_task_queue, st, st_list);
cv_broadcast(&sysmon_task_queue_cv);
mutex_exit(&sysmon_task_queue_mtx);
return 0;
}