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/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2008 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
#pragma ident "%Z%%M% %I% %E% SMI"
/*
* Routines to support shuttle synchronization objects
*/
#include <sys/types.h>
#include <sys/proc.h>
#include <sys/thread.h>
#include <sys/class.h>
#include <sys/debug.h>
#include <sys/sobject.h>
#include <sys/cpuvar.h>
#include <sys/schedctl.h>
#include <sys/sdt.h>
static disp_lock_t shuttle_lock; /* lock on shuttle objects */
/*
* Place the thread in question on the run q.
*/
static void
shuttle_unsleep(kthread_t *t)
{
ASSERT(THREAD_LOCK_HELD(t));
/* Waiting on a shuttle */
ASSERT(t->t_wchan0 == (caddr_t)1 && t->t_wchan == NULL);
t->t_flag &= ~T_WAKEABLE;
t->t_wchan0 = NULL;
t->t_sobj_ops = NULL;
THREAD_TRANSITION(t);
CL_SETRUN(t);
}
static kthread_t *
shuttle_owner()
{
return (NULL);
}
/*ARGSUSED*/
static void
shuttle_change_pri(kthread_t *t, pri_t p, pri_t *t_prip)
{
ASSERT(THREAD_LOCK_HELD(t));
*t_prip = p;
}
static sobj_ops_t shuttle_sobj_ops = {
SOBJ_SHUTTLE, shuttle_owner, shuttle_unsleep, shuttle_change_pri
};
/*
* Mark the current thread as sleeping on a shuttle object, and
* resume the specified thread. The 't' thread must be marked as ONPROC.
*
* No locks other than 'l' should be held at this point.
*/
void
shuttle_resume(kthread_t *t, kmutex_t *l)
{
klwp_t *lwp = ttolwp(curthread);
cpu_t *cp;
disp_lock_t *oldtlp;
thread_lock(curthread);
disp_lock_enter_high(&shuttle_lock);
if (lwp != NULL) {
lwp->lwp_asleep = 1; /* /proc */
lwp->lwp_sysabort = 0; /* /proc */
lwp->lwp_ru.nvcsw++;
}
curthread->t_flag |= T_WAKEABLE;
curthread->t_sobj_ops = &shuttle_sobj_ops;
/*
* setting cpu_dispthread before changing thread state
* so that kernel preemption will be deferred to after swtch_to()
*/
cp = CPU;
cp->cpu_dispthread = t;
cp->cpu_dispatch_pri = DISP_PRIO(t);
/*
* Set the wchan0 field so that /proc won't just do a setrun
* on this thread when trying to stop a process. Instead,
* /proc will mark the thread as VSTOPPED similar to threads
* that are blocked on user level condition variables.
*/
curthread->t_wchan0 = (caddr_t)1;
CL_INACTIVE(curthread);
DTRACE_SCHED1(wakeup, kthread_t *, t);
DTRACE_SCHED(sleep);
THREAD_SLEEP(curthread, &shuttle_lock);
disp_lock_exit_high(&shuttle_lock);
/*
* Update ustate records (there is no waitrq obviously)
*/
(void) new_mstate(curthread, LMS_SLEEP);
thread_lock_high(t);
oldtlp = t->t_lockp;
t->t_flag &= ~T_WAKEABLE;
t->t_wchan0 = NULL;
t->t_sobj_ops = NULL;
/*
* Make sure we end up on the right CPU if we are dealing with bound
* CPU's or processor partitions.
*/
if (t->t_bound_cpu != NULL || t->t_cpupart != cp->cpu_part) {
aston(t);
cp->cpu_runrun = 1;
}
/*
* We re-assign t_disp_queue and t_lockp of 't' here because
* 't' could have been preempted.
*/
if (t->t_disp_queue != cp->cpu_disp) {
t->t_disp_queue = cp->cpu_disp;
thread_onproc(t, cp);
}
/*
* We can't call thread_unlock_high() here because t's thread lock
* could have changed by thread_onproc() call above to point to
* CPU->cpu_thread_lock.
*/
disp_lock_exit_high(oldtlp);
mutex_exit(l);
/*
* Make sure we didn't receive any important events while
* we weren't looking
*/
if (lwp && (ISSIG(curthread, JUSTLOOKING) ||
MUSTRETURN(curproc, curthread) || schedctl_cancel_pending()))
setrun(curthread);
swtch_to(t);
/*
* Caller must check for ISSIG/lwp_sysabort conditions
* and clear lwp->lwp_asleep/lwp->lwp_sysabort
*/
}
/*
* Mark the current thread as sleeping on a shuttle object, and
* switch to a new thread.
* No locks other than 'l' should be held at this point.
*/
void
shuttle_swtch(kmutex_t *l)
{
klwp_t *lwp = ttolwp(curthread);
thread_lock(curthread);
disp_lock_enter_high(&shuttle_lock);
lwp->lwp_asleep = 1; /* /proc */
lwp->lwp_sysabort = 0; /* /proc */
lwp->lwp_ru.nvcsw++;
curthread->t_flag |= T_WAKEABLE;
curthread->t_sobj_ops = &shuttle_sobj_ops;
curthread->t_wchan0 = (caddr_t)1;
CL_INACTIVE(curthread);
DTRACE_SCHED(sleep);
THREAD_SLEEP(curthread, &shuttle_lock);
(void) new_mstate(curthread, LMS_SLEEP);
disp_lock_exit_high(&shuttle_lock);
mutex_exit(l);
if (ISSIG(curthread, JUSTLOOKING) ||
MUSTRETURN(curproc, curthread) || schedctl_cancel_pending())
setrun(curthread);
swtch();
/*
* Caller must check for ISSIG/lwp_sysabort conditions
* and clear lwp->lwp_asleep/lwp->lwp_sysabort
*/
}
/*
* Mark the specified thread as once again sleeping on a shuttle object. This
* routine is called to put a server thread -- one that was dequeued but for
* which shuttle_resume() was _not_ called -- back to sleep on a shuttle
* object. Because we don't hit the sched:::wakeup DTrace probe until
* shuttle_resume(), we do _not_ have a sched:::sleep probe here.
*/
void
shuttle_sleep(kthread_t *t)
{
klwp_t *lwp = ttolwp(t);
proc_t *p = ttoproc(t);
thread_lock(t);
disp_lock_enter_high(&shuttle_lock);
if (lwp != NULL) {
lwp->lwp_asleep = 1; /* /proc */
lwp->lwp_sysabort = 0; /* /proc */
lwp->lwp_ru.nvcsw++;
}
t->t_flag |= T_WAKEABLE;
t->t_sobj_ops = &shuttle_sobj_ops;
t->t_wchan0 = (caddr_t)1;
CL_INACTIVE(t);
ASSERT(t->t_mstate == LMS_SLEEP);
THREAD_SLEEP(t, &shuttle_lock);
disp_lock_exit_high(&shuttle_lock);
if (lwp && (ISSIG(t, JUSTLOOKING) || MUSTRETURN(p, t)))
setrun(t);
}
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