common/disp/ts.c

/*
 * 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.
 */

/*	Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T	*/
/*	  All Rights Reserved  	*/

#pragma ident	"%Z%%M%	%I%	%E% SMI"	/* from SVr4.0 1.23 */

#include <sys/types.h>
#include <sys/param.h>
#include <sys/sysmacros.h>
#include <sys/cred.h>
#include <sys/proc.h>
#include <sys/session.h>
#include <sys/strsubr.h>
#include <sys/signal.h>
#include <sys/user.h>
#include <sys/priocntl.h>
#include <sys/class.h>
#include <sys/disp.h>
#include <sys/procset.h>
#include <sys/debug.h>
#include <sys/ts.h>
#include <sys/tspriocntl.h>
#include <sys/iapriocntl.h>
#include <sys/kmem.h>
#include <sys/errno.h>
#include <sys/cpuvar.h>
#include <sys/systm.h>		/* for lbolt */
#include <sys/vtrace.h>
#include <sys/vmsystm.h>
#include <sys/schedctl.h>
#include <sys/tnf_probe.h>
#include <sys/atomic.h>
#include <sys/policy.h>
#include <sys/sdt.h>
#include <sys/cpupart.h>
#include <vm/rm.h>
#include <vm/seg_kmem.h>
#include <sys/modctl.h>
#include <sys/cpucaps.h>

static pri_t ts_init(id_t, int, classfuncs_t **);

static struct sclass csw = {
	"TS",
	ts_init,
	0
};

static struct modlsched modlsched = {
	&mod_schedops, "time sharing sched class", &csw
};

static struct modlinkage modlinkage = {
	MODREV_1, (void *)&modlsched, NULL
};

int
_init()
{
	return (mod_install(&modlinkage));
}

int
_fini()
{
	return (EBUSY);		/* don't remove TS for now */
}

int
_info(struct modinfo *modinfop)
{
	return (mod_info(&modlinkage, modinfop));
}

/*
 * Class specific code for the time-sharing class
 */


/*
 * Extern declarations for variables defined in the ts master file
 */
#define	TSMAXUPRI 60

pri_t	ts_maxupri = TSMAXUPRI;	/* max time-sharing user priority */
pri_t	ts_maxumdpri;		/* maximum user mode ts priority */

pri_t	ia_maxupri = IAMAXUPRI;	/* max interactive user priority */
pri_t	ia_boost = IA_BOOST;	/* boost value for interactive */

tsdpent_t  *ts_dptbl;	/* time-sharing disp parameter table */
pri_t	*ts_kmdpris;	/* array of global pris used by ts procs when */
			/*  sleeping or running in kernel after sleep */

static id_t ia_cid;

int ts_sleep_promote = 1;

#define	tsmedumdpri	(ts_maxumdpri >> 1)

#define	TS_NEWUMDPRI(tspp) \
{ \
	pri_t pri; \
	pri = (tspp)->ts_cpupri + (tspp)->ts_upri + (tspp)->ts_boost; \
	if (pri > ts_maxumdpri) \
		(tspp)->ts_umdpri = ts_maxumdpri; \
	else if (pri < 0) \
		(tspp)->ts_umdpri = 0; \
	else \
		(tspp)->ts_umdpri = pri; \
	ASSERT((tspp)->ts_umdpri >= 0 && (tspp)->ts_umdpri <= ts_maxumdpri); \
}

/*
 * The tsproc_t structures are kept in an array of circular doubly linked
 * lists.  A hash on the thread pointer is used to determine which list
 * each thread should be placed.  Each list has a dummy "head" which is
 * never removed, so the list is never empty.  ts_update traverses these
 * lists to update the priorities of threads that have been waiting on
 * the run queue.
 */

#define	TS_LISTS 16		/* number of lists, must be power of 2 */

/* hash function, argument is a thread pointer */
#define	TS_LIST_HASH(tp)	(((uintptr_t)(tp) >> 9) & (TS_LISTS - 1))

/* iterate to the next list */
#define	TS_LIST_NEXT(i)		(((i) + 1) & (TS_LISTS - 1))

/*
 * Insert thread into the appropriate tsproc list.
 */
#define	TS_LIST_INSERT(tspp)				\
{							\
	int index = TS_LIST_HASH(tspp->ts_tp);		\
	kmutex_t *lockp = &ts_list_lock[index];		\
	tsproc_t *headp = &ts_plisthead[index];		\
	mutex_enter(lockp);				\
	tspp->ts_next = headp->ts_next;			\
	tspp->ts_prev = headp;				\
	headp->ts_next->ts_prev = tspp;			\
	headp->ts_next = tspp;				\
	mutex_exit(lockp);				\
}

/*
 * Remove thread from tsproc list.
 */
#define	TS_LIST_DELETE(tspp)				\
{							\
	int index = TS_LIST_HASH(tspp->ts_tp);		\
	kmutex_t *lockp = &ts_list_lock[index];		\
	mutex_enter(lockp);				\
	tspp->ts_prev->ts_next = tspp->ts_next;		\
	tspp->ts_next->ts_prev = tspp->ts_prev;		\
	mutex_exit(lockp);				\
}


static int	ts_admin(caddr_t, cred_t *);
static int	ts_enterclass(kthread_t *, id_t, void *, cred_t *, void *);
static int	ts_fork(kthread_t *, kthread_t *, void *);
static int	ts_getclinfo(void *);
static int	ts_getclpri(pcpri_t *);
static int	ts_parmsin(void *);
static int	ts_parmsout(void *, pc_vaparms_t *);
static int	ts_vaparmsin(void *, pc_vaparms_t *);
static int	ts_vaparmsout(void *, pc_vaparms_t *);
static int	ts_parmsset(kthread_t *, void *, id_t, cred_t *);
static void	ts_exit(kthread_t *);
static int	ts_donice(kthread_t *, cred_t *, int, int *);
static int	ts_doprio(kthread_t *, cred_t *, int, int *);
static void	ts_exitclass(void *);
static int	ts_canexit(kthread_t *, cred_t *);
static void	ts_forkret(kthread_t *, kthread_t *);
static void	ts_nullsys();
static void	ts_parmsget(kthread_t *, void *);
static void	ts_preempt(kthread_t *);
static void	ts_setrun(kthread_t *);
static void	ts_sleep(kthread_t *);
static pri_t	ts_swapin(kthread_t *, int);
static pri_t	ts_swapout(kthread_t *, int);
static void	ts_tick(kthread_t *);
static void	ts_trapret(kthread_t *);
static void	ts_update(void *);
static int	ts_update_list(int);
static void	ts_wakeup(kthread_t *);
static pri_t	ts_globpri(kthread_t *);
static void	ts_yield(kthread_t *);
extern tsdpent_t *ts_getdptbl(void);
extern pri_t	*ts_getkmdpris(void);
extern pri_t	td_getmaxumdpri(void);
static int	ts_alloc(void **, int);
static void	ts_free(void *);

pri_t		ia_init(id_t, int, classfuncs_t **);
static int	ia_getclinfo(void *);
static int	ia_getclpri(pcpri_t *);
static int	ia_parmsin(void *);
static int	ia_vaparmsin(void *, pc_vaparms_t *);
static int	ia_vaparmsout(void *, pc_vaparms_t *);
static int	ia_parmsset(kthread_t *, void *, id_t, cred_t *);
static void	ia_parmsget(kthread_t *, void *);
static void	ia_set_process_group(pid_t, pid_t, pid_t);

static void	ts_change_priority(kthread_t *, tsproc_t *);

extern pri_t	ts_maxkmdpri;	/* maximum kernel mode ts priority */
static pri_t	ts_maxglobpri;	/* maximum global priority used by ts class */
static kmutex_t	ts_dptblock;	/* protects time sharing dispatch table */
static kmutex_t	ts_list_lock[TS_LISTS];	/* protects tsproc lists */
static tsproc_t	ts_plisthead[TS_LISTS];	/* dummy tsproc at head of lists */

static gid_t	IA_gid = 0;

static struct classfuncs ts_classfuncs = {
	/* class functions */
	ts_admin,
	ts_getclinfo,
	ts_parmsin,
	ts_parmsout,
	ts_vaparmsin,
	ts_vaparmsout,
	ts_getclpri,
	ts_alloc,
	ts_free,

	/* thread functions */
	ts_enterclass,
	ts_exitclass,
	ts_canexit,
	ts_fork,
	ts_forkret,
	ts_parmsget,
	ts_parmsset,
	ts_nullsys,	/* stop */
	ts_exit,
	ts_nullsys,	/* active */
	ts_nullsys,	/* inactive */
	ts_swapin,
	ts_swapout,
	ts_trapret,
	ts_preempt,
	ts_setrun,
	ts_sleep,
	ts_tick,
	ts_wakeup,
	ts_donice,
	ts_globpri,
	ts_nullsys,	/* set_process_group */
	ts_yield,
	ts_doprio,
};

/*
 * ia_classfuncs is used for interactive class threads; IA threads are stored
 * on the same class list as TS threads, and most of the class functions are
 * identical, but a few have different enough functionality to require their
 * own functions.
 */
static struct classfuncs ia_classfuncs = {
	/* class functions */
	ts_admin,
	ia_getclinfo,
	ia_parmsin,
	ts_parmsout,
	ia_vaparmsin,
	ia_vaparmsout,
	ia_getclpri,
	ts_alloc,
	ts_free,

	/* thread functions */
	ts_enterclass,
	ts_exitclass,
	ts_canexit,
	ts_fork,
	ts_forkret,
	ia_parmsget,
	ia_parmsset,
	ts_nullsys,	/* stop */
	ts_exit,
	ts_nullsys,	/* active */
	ts_nullsys,	/* inactive */
	ts_swapin,
	ts_swapout,
	ts_trapret,
	ts_preempt,
	ts_setrun,
	ts_sleep,
	ts_tick,
	ts_wakeup,
	ts_donice,
	ts_globpri,
	ia_set_process_group,
	ts_yield,
	ts_doprio,
};


/*
 * Time sharing class initialization.  Called by dispinit() at boot time.
 * We can ignore the clparmsz argument since we know that the smallest
 * possible parameter buffer is big enough for us.
 */
/* ARGSUSED */
static pri_t
ts_init(id_t cid, int clparmsz, classfuncs_t **clfuncspp)
{
	int i;
	extern pri_t ts_getmaxumdpri(void);

	ts_dptbl = ts_getdptbl();
	ts_kmdpris = ts_getkmdpris();
	ts_maxumdpri = ts_getmaxumdpri();
	ts_maxglobpri = MAX(ts_kmdpris[0], ts_dptbl[ts_maxumdpri].ts_globpri);

	/*
	 * Initialize the tsproc lists.
	 */
	for (i = 0; i < TS_LISTS; i++) {
		ts_plisthead[i].ts_next = ts_plisthead[i].ts_prev =
		    &ts_plisthead[i];
	}

	/*
	 * We're required to return a pointer to our classfuncs
	 * structure and the highest global priority value we use.
	 */
	*clfuncspp = &ts_classfuncs;
	return (ts_maxglobpri);
}


/*
 * Interactive class scheduler initialization
 */
/* ARGSUSED */
pri_t
ia_init(id_t cid, int clparmsz, classfuncs_t **clfuncspp)
{
	/*
	 * We're required to return a pointer to our classfuncs
	 * structure and the highest global priority value we use.
	 */
	ia_cid = cid;
	*clfuncspp = &ia_classfuncs;
	return (ts_maxglobpri);
}


/*
 * Get or reset the ts_dptbl values per the user's request.
 */
static int
ts_admin(caddr_t uaddr, cred_t *reqpcredp)
{
	tsadmin_t	tsadmin;
	tsdpent_t	*tmpdpp;
	int		userdpsz;
	int		i;
	size_t		tsdpsz;

	if (get_udatamodel() == DATAMODEL_NATIVE) {
		if (copyin(uaddr, &tsadmin, sizeof (tsadmin_t)))
			return (EFAULT);
	}
#ifdef _SYSCALL32_IMPL
	else {
		/* get tsadmin struct from ILP32 caller */
		tsadmin32_t tsadmin32;
		if (copyin(uaddr, &tsadmin32, sizeof (tsadmin32_t)))
			return (EFAULT);
		tsadmin.ts_dpents =
		    (struct tsdpent *)(uintptr_t)tsadmin32.ts_dpents;
		tsadmin.ts_ndpents = tsadmin32.ts_ndpents;
		tsadmin.ts_cmd = tsadmin32.ts_cmd;
	}
#endif /* _SYSCALL32_IMPL */

	tsdpsz = (ts_maxumdpri + 1) * sizeof (tsdpent_t);

	switch (tsadmin.ts_cmd) {
	case TS_GETDPSIZE:
		tsadmin.ts_ndpents = ts_maxumdpri + 1;

		if (get_udatamodel() == DATAMODEL_NATIVE) {
			if (copyout(&tsadmin, uaddr, sizeof (tsadmin_t)))
				return (EFAULT);
		}
#ifdef _SYSCALL32_IMPL
		else {
			/* return tsadmin struct to ILP32 caller */
			tsadmin32_t tsadmin32;
			tsadmin32.ts_dpents =
			    (caddr32_t)(uintptr_t)tsadmin.ts_dpents;
			tsadmin32.ts_ndpents = tsadmin.ts_ndpents;
			tsadmin32.ts_cmd = tsadmin.ts_cmd;
			if (copyout(&tsadmin32, uaddr, sizeof (tsadmin32_t)))
				return (EFAULT);
		}
#endif /* _SYSCALL32_IMPL */
		break;

	case TS_GETDPTBL:
		userdpsz = MIN(tsadmin.ts_ndpents * sizeof (tsdpent_t),
		    tsdpsz);
		if (copyout(ts_dptbl, tsadmin.ts_dpents, userdpsz))
			return (EFAULT);

		tsadmin.ts_ndpents = userdpsz / sizeof (tsdpent_t);

		if (get_udatamodel() == DATAMODEL_NATIVE) {
			if (copyout(&tsadmin, uaddr, sizeof (tsadmin_t)))
				return (EFAULT);
		}
#ifdef _SYSCALL32_IMPL
		else {
			/* return tsadmin struct to ILP32 callers */
			tsadmin32_t tsadmin32;
			tsadmin32.ts_dpents =
			    (caddr32_t)(uintptr_t)tsadmin.ts_dpents;
			tsadmin32.ts_ndpents = tsadmin.ts_ndpents;
			tsadmin32.ts_cmd = tsadmin.ts_cmd;
			if (copyout(&tsadmin32, uaddr, sizeof (tsadmin32_t)))
				return (EFAULT);
		}
#endif /* _SYSCALL32_IMPL */
		break;

	case TS_SETDPTBL:
		/*
		 * We require that the requesting process has sufficient
		 * priveleges.  We also require that the table supplied by
		 * the user exactly match the current ts_dptbl in size.
		 */
		if (secpolicy_dispadm(reqpcredp) != 0)
			return (EPERM);

		if (tsadmin.ts_ndpents * sizeof (tsdpent_t) != tsdpsz) {
			return (EINVAL);
		}

		/*
		 * We read the user supplied table into a temporary buffer
		 * where it is validated before being copied over the
		 * ts_dptbl.
		 */
		tmpdpp = kmem_alloc(tsdpsz, KM_SLEEP);
		if (copyin((caddr_t)tsadmin.ts_dpents, (caddr_t)tmpdpp,
		    tsdpsz)) {
			kmem_free(tmpdpp, tsdpsz);
			return (EFAULT);
		}
		for (i = 0; i < tsadmin.ts_ndpents; i++) {

			/*
			 * Validate the user supplied values.  All we are doing
			 * here is verifying that the values are within their
			 * allowable ranges and will not panic the system.  We
			 * make no attempt to ensure that the resulting
			 * configuration makes sense or results in reasonable
			 * performance.
			 */
			if (tmpdpp[i].ts_quantum <= 0) {
				kmem_free(tmpdpp, tsdpsz);
				return (EINVAL);
			}
			if (tmpdpp[i].ts_tqexp > ts_maxumdpri ||
			    tmpdpp[i].ts_tqexp < 0) {
				kmem_free(tmpdpp, tsdpsz);
				return (EINVAL);
			}
			if (tmpdpp[i].ts_slpret > ts_maxumdpri ||
			    tmpdpp[i].ts_slpret < 0) {
				kmem_free(tmpdpp, tsdpsz);
				return (EINVAL);
			}
			if (tmpdpp[i].ts_maxwait < 0) {
				kmem_free(tmpdpp, tsdpsz);
				return (EINVAL);
			}
			if (tmpdpp[i].ts_lwait > ts_maxumdpri ||
			    tmpdpp[i].ts_lwait < 0) {
				kmem_free(tmpdpp, tsdpsz);
				return (EINVAL);
			}
		}

		/*
		 * Copy the user supplied values over the current ts_dptbl
		 * values.  The ts_globpri member is read-only so we don't
		 * overwrite it.
		 */
		mutex_enter(&ts_dptblock);
		for (i = 0; i < tsadmin.ts_ndpents; i++) {
			ts_dptbl[i].ts_quantum = tmpdpp[i].ts_quantum;
			ts_dptbl[i].ts_tqexp = tmpdpp[i].ts_tqexp;
			ts_dptbl[i].ts_slpret = tmpdpp[i].ts_slpret;
			ts_dptbl[i].ts_maxwait = tmpdpp[i].ts_maxwait;
			ts_dptbl[i].ts_lwait = tmpdpp[i].ts_lwait;
		}
		mutex_exit(&ts_dptblock);
		kmem_free(tmpdpp, tsdpsz);
		break;

	default:
		return (EINVAL);
	}
	return (0);
}


/*
 * Allocate a time-sharing class specific thread structure and
 * initialize it with the parameters supplied. Also move the thread
 * to specified time-sharing priority.
 */
static int
ts_enterclass(kthread_t *t, id_t cid, void *parmsp,
	cred_t *reqpcredp, void *bufp)
{
	tsparms_t	*tsparmsp = (tsparms_t *)parmsp;
	tsproc_t	*tspp;
	pri_t		reqtsuprilim;
	pri_t		reqtsupri;
	static uint32_t	tspexists = 0;	/* set on first occurrence of */
					/*   a time-sharing process */

	tspp = (tsproc_t *)bufp;
	ASSERT(tspp != NULL);

	/*
	 * Initialize the tsproc structure.
	 */
	tspp->ts_cpupri = tsmedumdpri;
	if (cid == ia_cid) {
		/*
		 * Check to make sure caller is either privileged or the
		 * window system.  When the window system is converted
		 * to using privileges, the second check can go away.
		 */
		if (reqpcredp != NULL && !groupmember(IA_gid, reqpcredp) &&
		    secpolicy_setpriority(reqpcredp) != 0)
			return (EPERM);
		/*
		 * Belongs to IA "class", so set appropriate flags.
		 * Mark as 'on' so it will not be a swap victim
		 * while forking.
		 */
		tspp->ts_flags = TSIA | TSIASET;
		tspp->ts_boost = ia_boost;
	} else {
		tspp->ts_flags = 0;
		tspp->ts_boost = 0;
	}

	if (tsparmsp == NULL) {
		/*
		 * Use default values.
		 */
		tspp->ts_uprilim = tspp->ts_upri = 0;
		tspp->ts_nice = NZERO;
	} else {
		/*
		 * Use supplied values.
		 */
		if (tsparmsp->ts_uprilim == TS_NOCHANGE)
			reqtsuprilim = 0;
		else {
			if (tsparmsp->ts_uprilim > 0 &&
			    secpolicy_setpriority(reqpcredp) != 0)
				return (EPERM);
			reqtsuprilim = tsparmsp->ts_uprilim;
		}

		if (tsparmsp->ts_upri == TS_NOCHANGE) {
			reqtsupri = reqtsuprilim;
		} else {
			if (tsparmsp->ts_upri > 0 &&
			    secpolicy_setpriority(reqpcredp) != 0)
				return (EPERM);
			/*
			 * Set the user priority to the requested value
			 * or the upri limit, whichever is lower.
			 */
			reqtsupri = tsparmsp->ts_upri;
			if (reqtsupri > reqtsuprilim)
				reqtsupri = reqtsuprilim;
		}


		tspp->ts_uprilim = reqtsuprilim;
		tspp->ts_upri = reqtsupri;
		tspp->ts_nice = NZERO - (NZERO * reqtsupri) / ts_maxupri;
	}
	TS_NEWUMDPRI(tspp);

	tspp->ts_dispwait = 0;
	tspp->ts_timeleft = ts_dptbl[tspp->ts_cpupri].ts_quantum;
	tspp->ts_tp = t;
	cpucaps_sc_init(&tspp->ts_caps);

	/*
	 * Reset priority. Process goes to a "user mode" priority
	 * here regardless of whether or not it has slept since
	 * entering the kernel.
	 */
	thread_lock(t);			/* get dispatcher lock on thread */
	t->t_clfuncs = &(sclass[cid].cl_funcs->thread);
	t->t_cid = cid;
	t->t_cldata = (void *)tspp;
	t->t_schedflag &= ~TS_RUNQMATCH;
	ts_change_priority(t, tspp);
	thread_unlock(t);

	/*
	 * Link new structure into tsproc list.
	 */
	TS_LIST_INSERT(tspp);

	/*
	 * If this is the first time-sharing thread to occur since
	 * boot we set up the initial call to ts_update() here.
	 * Use an atomic compare-and-swap since that's easier and
	 * faster than a mutex (but check with an ordinary load first
	 * since most of the time this will already be done).
	 */
	if (tspexists == 0 && cas32(&tspexists, 0, 1) == 0)
		(void) timeout(ts_update, NULL, hz);

	return (0);
}


/*
 * Free tsproc structure of thread.
 */
static void
ts_exitclass(void *procp)
{
	tsproc_t *tspp = (tsproc_t *)procp;

	/* Remove tsproc_t structure from list */
	TS_LIST_DELETE(tspp);
	kmem_free(tspp, sizeof (tsproc_t));
}

/* ARGSUSED */
static int
ts_canexit(kthread_t *t, cred_t *cred)
{
	/*
	 * A thread can always leave a TS/IA class
	 */
	return (0);
}

static int
ts_fork(kthread_t *t, kthread_t *ct, void *bufp)
{
	tsproc_t	*ptspp;		/* ptr to parent's tsproc structure */
	tsproc_t	*ctspp;		/* ptr to child's tsproc structure */

	ASSERT(MUTEX_HELD(&ttoproc(t)->p_lock));

	ctspp = (tsproc_t *)bufp;
	ASSERT(ctspp != NULL);
	ptspp = (tsproc_t *)t->t_cldata;
	/*
	 * Initialize child's tsproc structure.
	 */
	thread_lock(t);
	ctspp->ts_timeleft = ts_dptbl[ptspp->ts_cpupri].ts_quantum;
	ctspp->ts_cpupri = ptspp->ts_cpupri;
	ctspp->ts_boost = ptspp->ts_boost;
	ctspp->ts_uprilim = ptspp->ts_uprilim;
	ctspp->ts_upri = ptspp->ts_upri;
	TS_NEWUMDPRI(ctspp);
	ctspp->ts_nice = ptspp->ts_nice;
	ctspp->ts_dispwait = 0;
	ctspp->ts_flags = ptspp->ts_flags & ~(TSKPRI | TSBACKQ | TSRESTORE);
	ctspp->ts_tp = ct;
	cpucaps_sc_init(&ctspp->ts_caps);
	thread_unlock(t);

	/*
	 * Link new structure into tsproc list.
	 */
	ct->t_cldata = (void *)ctspp;
	TS_LIST_INSERT(ctspp);
	return (0);
}


/*
 * Child is placed at back of dispatcher queue and parent gives
 * up processor so that the child runs first after the fork.
 * This allows the child immediately execing to break the multiple
 * use of copy on write pages with no disk home. The parent will
 * get to steal them back rather than uselessly copying them.
 */
static void
ts_forkret(kthread_t *t, kthread_t *ct)
{
	proc_t	*pp = ttoproc(t);
	proc_t	*cp = ttoproc(ct);
	tsproc_t *tspp;

	ASSERT(t == curthread);
	ASSERT(MUTEX_HELD(&pidlock));

	/*
	 * Grab the child's p_lock before dropping pidlock to ensure
	 * the process does not disappear before we set it running.
	 */
	mutex_enter(&cp->p_lock);
	mutex_exit(&pidlock);
	continuelwps(cp);
	mutex_exit(&cp->p_lock);

	mutex_enter(&pp->p_lock);
	continuelwps(pp);
	mutex_exit(&pp->p_lock);

	thread_lock(t);
	tspp = (tsproc_t *)(t->t_cldata);
	tspp->ts_cpupri = ts_dptbl[tspp->ts_cpupri].ts_tqexp;
	TS_NEWUMDPRI(tspp);
	tspp->ts_timeleft = ts_dptbl[tspp->ts_cpupri].ts_quantum;
	tspp->ts_dispwait = 0;
	t->t_pri = ts_dptbl[tspp->ts_umdpri].ts_globpri;
	ASSERT(t->t_pri >= 0 && t->t_pri <= ts_maxglobpri);
	tspp->ts_flags &= ~TSKPRI;
	THREAD_TRANSITION(t);
	ts_setrun(t);
	thread_unlock(t);

	swtch();
}


/*
 * Get information about the time-sharing class into the buffer
 * pointed to by tsinfop. The maximum configured user priority
 * is the only information we supply.  ts_getclinfo() is called
 * for TS threads, and ia_getclinfo() is called for IA threads.
 */
static int
ts_getclinfo(void *infop)
{
	tsinfo_t *tsinfop = (tsinfo_t *)infop;
	tsinfop->ts_maxupri = ts_maxupri;
	return (0);
}

static int
ia_getclinfo(void *infop)
{
	iainfo_t *iainfop = (iainfo_t *)infop;
	iainfop->ia_maxupri = ia_maxupri;
	return (0);
}


/*
 * Return the user mode scheduling priority range.
 */
static int
ts_getclpri(pcpri_t *pcprip)
{
	pcprip->pc_clpmax = ts_maxupri;
	pcprip->pc_clpmin = -ts_maxupri;
	return (0);
}


static int
ia_getclpri(pcpri_t *pcprip)
{
	pcprip->pc_clpmax = ia_maxupri;
	pcprip->pc_clpmin = -ia_maxupri;
	return (0);
}


static void
ts_nullsys()
{}


/*
 * Get the time-sharing parameters of the thread pointed to by
 * tsprocp into the buffer pointed to by tsparmsp.  ts_parmsget()
 * is called for TS threads, and ia_parmsget() is called for IA
 * threads.
 */
static void
ts_parmsget(kthread_t *t, void *parmsp)
{
	tsproc_t *tspp = (tsproc_t *)t->t_cldata;
	tsparms_t *tsparmsp = (tsparms_t *)parmsp;

	tsparmsp->ts_uprilim = tspp->ts_uprilim;
	tsparmsp->ts_upri = tspp->ts_upri;
}

static void
ia_parmsget(kthread_t *t, void *parmsp)
{
	tsproc_t *tspp = (tsproc_t *)t->t_cldata;
	iaparms_t *iaparmsp = (iaparms_t *)parmsp;

	iaparmsp->ia_uprilim = tspp->ts_uprilim;
	iaparmsp->ia_upri = tspp->ts_upri;
	if (tspp->ts_flags & TSIASET)
		iaparmsp->ia_mode = IA_SET_INTERACTIVE;
	else
		iaparmsp->ia_mode = IA_INTERACTIVE_OFF;
}


/*
 * Check the validity of the time-sharing parameters in the buffer
 * pointed to by tsparmsp.
 * ts_parmsin() is called for TS threads, and ia_parmsin() is called
 * for IA threads.
 */
static int
ts_parmsin(void *parmsp)
{
	tsparms_t	*tsparmsp = (tsparms_t *)parmsp;
	/*
	 * Check validity of parameters.
	 */
	if ((tsparmsp->ts_uprilim > ts_maxupri ||
	    tsparmsp->ts_uprilim < -ts_maxupri) &&
	    tsparmsp->ts_uprilim != TS_NOCHANGE)
		return (EINVAL);

	if ((tsparmsp->ts_upri > ts_maxupri ||
	    tsparmsp->ts_upri < -ts_maxupri) &&
	    tsparmsp->ts_upri != TS_NOCHANGE)
		return (EINVAL);

	return (0);
}

static int
ia_parmsin(void *parmsp)
{
	iaparms_t	*iaparmsp = (iaparms_t *)parmsp;

	if ((iaparmsp->ia_uprilim > ia_maxupri ||
	    iaparmsp->ia_uprilim < -ia_maxupri) &&
	    iaparmsp->ia_uprilim != IA_NOCHANGE) {
		return (EINVAL);
	}

	if ((iaparmsp->ia_upri > ia_maxupri ||
	    iaparmsp->ia_upri < -ia_maxupri) &&
	    iaparmsp->ia_upri != IA_NOCHANGE) {
		return (EINVAL);
	}

	return (0);
}


/*
 * Check the validity of the time-sharing parameters in the pc_vaparms_t
 * structure vaparmsp and put them in the buffer pointed to by tsparmsp.
 * pc_vaparms_t contains (key, value) pairs of parameter.
 * ts_vaparmsin() is called for TS threads, and ia_vaparmsin() is called
 * for IA threads. ts_vaparmsin() is the variable parameter version of
 * ts_parmsin() and ia_vaparmsin() is the variable parameter version of
 * ia_parmsin().
 */
static int
ts_vaparmsin(void *parmsp, pc_vaparms_t *vaparmsp)
{
	tsparms_t	*tsparmsp = (tsparms_t *)parmsp;
	int		priflag = 0;
	int		limflag = 0;
	uint_t		cnt;
	pc_vaparm_t	*vpp = &vaparmsp->pc_parms[0];


	/*
	 * TS_NOCHANGE (-32768) is outside of the range of values for
	 * ts_uprilim and ts_upri. If the structure tsparms_t is changed,
	 * TS_NOCHANGE should be replaced by a flag word (in the same manner
	 * as in rt.c).
	 */
	tsparmsp->ts_uprilim = TS_NOCHANGE;
	tsparmsp->ts_upri = TS_NOCHANGE;

	/*
	 * Get the varargs parameter and check validity of parameters.
	 */
	if (vaparmsp->pc_vaparmscnt > PC_VAPARMCNT)
		return (EINVAL);

	for (cnt = 0; cnt < vaparmsp->pc_vaparmscnt; cnt++, vpp++) {

		switch (vpp->pc_key) {
		case TS_KY_UPRILIM:
			if (limflag++)
				return (EINVAL);
			tsparmsp->ts_uprilim = (pri_t)vpp->pc_parm;
			if (tsparmsp->ts_uprilim > ts_maxupri ||
			    tsparmsp->ts_uprilim < -ts_maxupri)
				return (EINVAL);
			break;

		case TS_KY_UPRI:
			if (priflag++)
				return (EINVAL);
			tsparmsp->ts_upri = (pri_t)vpp->pc_parm;
			if (tsparmsp->ts_upri > ts_maxupri ||
			    tsparmsp->ts_upri < -ts_maxupri)
				return (EINVAL);
			break;

		default:
			return (EINVAL);
		}
	}

	if (vaparmsp->pc_vaparmscnt == 0) {
		/*
		 * Use default parameters.
		 */
		tsparmsp->ts_upri = tsparmsp->ts_uprilim = 0;
	}

	return (0);
}

static int
ia_vaparmsin(void *parmsp, pc_vaparms_t *vaparmsp)
{
	iaparms_t	*iaparmsp = (iaparms_t *)parmsp;
	int		priflag = 0;
	int		limflag = 0;
	int		mflag = 0;
	uint_t		cnt;
	pc_vaparm_t	*vpp = &vaparmsp->pc_parms[0];

	/*
	 * IA_NOCHANGE (-32768) is outside of the range of values for
	 * ia_uprilim, ia_upri and ia_mode. If the structure iaparms_t is
	 * changed, IA_NOCHANGE should be replaced by a flag word (in the
	 * same manner as in rt.c).
	 */
	iaparmsp->ia_uprilim = IA_NOCHANGE;
	iaparmsp->ia_upri = IA_NOCHANGE;
	iaparmsp->ia_mode = IA_NOCHANGE;

	/*
	 * Get the varargs parameter and check validity of parameters.
	 */
	if (vaparmsp->pc_vaparmscnt > PC_VAPARMCNT)
		return (EINVAL);

	for (cnt = 0; cnt < vaparmsp->pc_vaparmscnt; cnt++, vpp++) {

		switch (vpp->pc_key) {
		case IA_KY_UPRILIM:
			if (limflag++)
				return (EINVAL);
			iaparmsp->ia_uprilim = (pri_t)vpp->pc_parm;
			if (iaparmsp->ia_uprilim > ia_maxupri ||
			    iaparmsp->ia_uprilim < -ia_maxupri)
				return (EINVAL);
			break;

		case IA_KY_UPRI:
			if (priflag++)
				return (EINVAL);
			iaparmsp->ia_upri = (pri_t)vpp->pc_parm;
			if (iaparmsp->ia_upri > ia_maxupri ||
			    iaparmsp->ia_upri < -ia_maxupri)
				return (EINVAL);
			break;

		case IA_KY_MODE:
			if (mflag++)
				return (EINVAL);
			iaparmsp->ia_mode = (int)vpp->pc_parm;
			if (iaparmsp->ia_mode != IA_SET_INTERACTIVE &&
			    iaparmsp->ia_mode != IA_INTERACTIVE_OFF)
				return (EINVAL);
			break;

		default:
			return (EINVAL);
		}
	}

	if (vaparmsp->pc_vaparmscnt == 0) {
		/*
		 * Use default parameters.
		 */
		iaparmsp->ia_upri = iaparmsp->ia_uprilim = 0;
		iaparmsp->ia_mode = IA_SET_INTERACTIVE;
	}

	return (0);
}

/*
 * Nothing to do here but return success.
 */
/* ARGSUSED */
static int
ts_parmsout(void *parmsp, pc_vaparms_t *vaparmsp)
{
	return (0);
}


/*
 * Copy all selected time-sharing class parameters to the user.
 * The parameters are specified by a key.
 */
static int
ts_vaparmsout(void *prmsp, pc_vaparms_t *vaparmsp)
{
	tsparms_t	*tsprmsp = (tsparms_t *)prmsp;
	int		priflag = 0;
	int		limflag = 0;
	uint_t		cnt;
	pc_vaparm_t	*vpp = &vaparmsp->pc_parms[0];

	ASSERT(MUTEX_NOT_HELD(&curproc->p_lock));

	if (vaparmsp->pc_vaparmscnt > PC_VAPARMCNT)
		return (EINVAL);

	for (cnt = 0; cnt < vaparmsp->pc_vaparmscnt; cnt++, vpp++) {

		switch (vpp->pc_key) {
		case TS_KY_UPRILIM:
			if (limflag++)
				return (EINVAL);
			if (copyout(&tsprmsp->ts_uprilim,
			    (caddr_t)(uintptr_t)vpp->pc_parm, sizeof (pri_t)))
				return (EFAULT);
			break;

		case TS_KY_UPRI:
			if (priflag++)
				return (EINVAL);
			if (copyout(&tsprmsp->ts_upri,
			    (caddr_t)(uintptr_t)vpp->pc_parm, sizeof (pri_t)))
				return (EFAULT);
			break;

		default:
			return (EINVAL);
		}
	}

	return (0);
}


/*
 * Copy all selected interactive class parameters to the user.
 * The parameters are specified by a key.
 */
static int
ia_vaparmsout(void *prmsp, pc_vaparms_t *vaparmsp)
{
	iaparms_t	*iaprmsp = (iaparms_t *)prmsp;
	int		priflag = 0;
	int		limflag = 0;
	int		mflag = 0;
	uint_t		cnt;
	pc_vaparm_t	*vpp = &vaparmsp->pc_parms[0];

	ASSERT(MUTEX_NOT_HELD(&curproc->p_lock));

	if (vaparmsp->pc_vaparmscnt > PC_VAPARMCNT)
		return (EINVAL);

	for (cnt = 0; cnt < vaparmsp->pc_vaparmscnt; cnt++, vpp++) {

		switch (vpp->pc_key) {
		case IA_KY_UPRILIM:
			if (limflag++)
				return (EINVAL);
			if (copyout(&