common/disp/ts.c

	ts.c revision 9ac8606f19e304e832a685ae7060cc3c284b9779
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (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 2005 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>

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 int  ts_donice(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_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_nullsys, /* 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,
};

/*
 * 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,
    ts_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_nullsys, /* 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,
};


/*
 * 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;

    /*
     * 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;
    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 global scheduling priority ranges for the timesharing
 * class in pcpri_t structure.
 */
static int
ts_getclpri(pcpri_t *pcprip)
{
    pcprip->pc_clpmax = ts_dptbl[ts_maxumdpri].ts_globpri;
    pcprip->pc_clpmin = ts_dptbl[0].ts_globpri;
    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;
    iaparmsp->ia_nice = tspp->ts_nice;
}


/*
 * 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(&iaprmsp->ia_uprilim,
                (caddr_t)(uintptr_t)vpp->pc_parm, sizeof (pri_t)))
                return (EFAULT);
            break;

        case IA_KY_UPRI:
            if (priflag++)
                return (EINVAL);
            if (copyout(&iaprmsp->ia_upri,
                (caddr_t)(uintptr_t)vpp->pc_parm, sizeof (pri_t)))
                return (EFAULT);
            break;

        case IA_KY_MODE:
            if (mflag++)
                return (EINVAL);
            if (copyout(&iaprmsp->ia_mode,
                (caddr_t)(uintptr_t)vpp->pc_parm, sizeof (int)))
                return (EFAULT);
            break;

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


/*
 * Set the scheduling parameters of the thread pointed to by tsprocp
 * to those specified in the buffer pointed to by tsparmsp.
 * ts_parmsset() is called for TS threads, and ia_parmsset() is
 * called for IA threads.
 */
/* ARGSUSED */
static int
ts_parmsset(kthread_t *tx, void *parmsp, id_t reqpcid, cred_t *reqpcredp)
{
    char        nice;
    pri_t       reqtsuprilim;
    pri_t       reqtsupri;
    tsparms_t   *tsparmsp = (tsparms_t *)parmsp;
    tsproc_t    *tspp = (tsproc_t *)tx->t_cldata;

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

    if (tsparmsp->ts_uprilim == TS_NOCHANGE)
        reqtsuprilim = tspp->ts_uprilim;
    else
        reqtsuprilim = tsparmsp->ts_uprilim;

    if (tsparmsp->ts_upri == TS_NOCHANGE)
        reqtsupri = tspp->ts_upri;
    else
        reqtsupri = tsparmsp->ts_upri;

    /*
     * Make sure the user priority doesn't exceed the upri limit.
     */
    if (reqtsupri > reqtsuprilim)
        reqtsupri = reqtsuprilim;

    /*
     * Basic permissions enforced by generic kernel code
     * for all classes require that a thread attempting
     * to change the scheduling parameters of a target
     * thread be privileged or have a real or effective
     * UID matching that of the target thread. We are not
     * called unless these basic permission checks have
     * already passed. The time-sharing class requires in
     * addition that the calling thread be privileged if it
     * is attempting to raise the upri limit above its current
     * value This may have been checked previously but if our
     * caller passed us a non-NULL credential pointer we assume
     * it hasn't and we check it here.
     */
    if (reqpcredp != NULL &&
        reqtsuprilim > tspp->ts_uprilim &&
        secpolicy_setpriority(reqpcredp) != 0)
        return (EPERM);

    /*
     * Set ts_nice to the nice value corresponding to the user
     * priority we are setting.  Note that setting the nice field
     * of the parameter struct won't affect upri or nice.
     */
    nice = NZERO - (reqtsupri * NZERO) / ts_maxupri;
    if (nice >= 2 * NZERO)
        nice = 2 * NZERO - 1;

    thread_lock(tx);

    tspp->ts_uprilim = reqtsuprilim;
    tspp->ts_upri = reqtsupri;
    TS_NEWUMDPRI(tspp);
    tspp->ts_nice = nice;

    if ((tspp->ts_flags & TSKPRI) != 0) {
        thread_unlock(tx);
        return (0);
    }

    tspp->ts_dispwait = 0;
    ts_change_priority(tx, tspp);
    thread_unlock(tx);
    return (0);
}


static int
ia_parmsset(kthread_t *tx, void *parmsp, id_t reqpcid, cred_t *reqpcredp)
{
    tsproc_t    *tspp = (tsproc_t *)tx->t_cldata;
    iaparms_t   *iaparmsp = (iaparms_t *)parmsp;
    proc_t      *p;
    pid_t       pid, pgid, sid;
    pid_t       on, off;
    struct stdata   *stp;
    int     sess_held;

    /*
     * Handle user priority changes
     */
    if (iaparmsp->ia_mode == IA_NOCHANGE)
        return (ts_parmsset(tx, parmsp, reqpcid, reqpcredp));

    /*
     * Check permissions for changing modes.
     */

    if (reqpcredp != NULL && !groupmember(IA_gid, reqpcredp) &&
        secpolicy_setpriority(reqpcredp) != 0) {
        /*
         * Silently fail in case this is just a priocntl
         * call with upri and uprilim set to IA_NOCHANGE.
         */
        return (0);
    }

    ASSERT(MUTEX_HELD(&pidlock));
    if ((p = ttoproc(tx)) == NULL) {
        return (0);
    }
    ASSERT(MUTEX_HELD(&p->p_lock));
    if (p->p_stat == SIDL) {
        return (0);
    }
    pid = p->p_pid;
    sid = p->p_sessp->s_sid;
    pgid = p->p_pgrp;
    if (iaparmsp->ia_mode == IA_SET_INTERACTIVE) {
        /*
         * session leaders must be turned on now so all processes
         * in the group controlling the tty will be turned on or off.
         * if the ia_mode is off for the session leader,
         * ia_set_process_group will return without setting the
         * processes in the group controlling the tty on.
         */
        thread_lock(tx);
        tspp->ts_flags |= TSIASET;
        thread_unlock(tx);
    }
    TTY_HOLD(p->p_sessp);
    sess_held = 1;
    if ((pid == sid) && (p->p_sessp->s_vp != NULL) &&
        ((stp = p->p_sessp->s_vp->v_stream) != NULL)) {
        if ((stp->sd_pgidp != NULL) && (stp->sd_sidp != NULL)) {
            pgid = stp->sd_pgidp->pid_id;
            sess_held = 0;
            TTY_RELE(p->p_sessp);
            if (iaparmsp->ia_mode ==
                IA_SET_INTERACTIVE) {
                off = 0;
                on = pgid;
            } else {
                off = pgid;
                on = 0;
            }
            TRACE_3(TR_FAC_IA, TR_ACTIVE_CHAIN,
                "active chain:pid %d gid %d %p",
                pid, pgid, p);
            ia_set_process_group(sid, off, on);
        }
    }
    if (sess_held)
        TTY_RELE(p->p_sessp);

    thread_lock(tx);

    if (iaparmsp->ia_mode == IA_SET_INTERACTIVE) {
        tspp->ts_flags |= TSIASET;
        tspp->ts_boost = ia_boost;
    } else {
        tspp->ts_flags &= ~TSIASET;
        tspp->ts_boost = -ia_boost;
    }
    thread_unlock(tx);

    return (ts_parmsset(tx, parmsp, reqpcid, reqpcredp));
}

/*
 * Return the global scheduling priority that would be assigned
 * to a thread entering the time-sharing class with the ts_upri.
 */
static pri_t
ts_globpri(kthread_t *t)
{
    tsproc_t *tspp;
    pri_t   tspri;

    ASSERT(MUTEX_HELD(&ttoproc(t)->p_lock));
    tspp = (tsproc_t *)t->t_cldata;
    tspri = tsmedumdpri + tspp->ts_upri;
    if (tspri > ts_maxumdpri)
        tspri = ts_maxumdpri;
    else if (tspri < 0)
        tspri = 0;
    return (ts_dptbl[tspri].ts_globpri);
}

/*
 * Arrange for thread to be placed in appropriate location
 * on dispatcher queue.
 *
 * This is called with the current thread in TS_ONPROC and locked.
 */
static void
ts_preempt(kthread_t *t)
{
    tsproc_t    *tspp = (tsproc_t *)(t->t_cldata);
    klwp_t      *lwp;
#ifdef KSLICE
    extern int  kslice;
#endif
    pri_t       oldpri = t->t_pri;

    ASSERT(t == curthread);
    ASSERT(THREAD_LOCK_HELD(curthread));

    /*
     * If preempted in the kernel, make sure the thread has
     * a kernel priority if needed.
     */
    lwp = curthread->t_lwp;
    if (!(tspp->ts_flags & TSKPRI) && lwp != NULL && t->t_kpri_req) {
        tspp->ts_flags |= TSKPRI;
        THREAD_CHANGE_PRI(t, ts_kmdpris[0]);
        ASSERT(t->t_pri >= 0 && t->t_pri <= ts_maxglobpri);
        t->t_trapret = 1;       /* so ts_trapret will run */
        aston(t);
    }
    /*
     * If preempted in user-land mark the thread
     * as swappable because I know it isn't holding any locks.
     */
    ASSERT(t->t_schedflag & TS_DONT_SWAP);
    if (lwp != NULL && lwp->lwp_state == LWP_USER)
        t->t_schedflag &= ~TS_DONT_SWAP;

    /*
     * Check to see if we're doing "preemption control" here.  If
     * we are, and if the user has requested that this thread not
     * be preempted, and if preemptions haven't been put off for
     * too long, let the preemption happen here but try to make
     * sure the thread is rescheduled as soon as possible.  We do
     * this by putting it on the front of the highest priority run
     * queue in the TS class.  If the preemption has been put off
     * for too long, clear the "nopreempt" bit and let the thread
     * be preempted.
     */
    if (t->t_schedctl && schedctl_get_nopreempt(t)) {
        if (tspp->ts_timeleft > -SC_MAX_TICKS) {
            DTRACE_SCHED1(schedctl__nopreempt, kthread_t *, t);
            if (!(tspp->ts_flags & TSKPRI)) {
                /*
                 * If not already remembered, remember current
                 * priority for restoration in ts_yield().
                 */
                if (!(tspp->ts_flags & TSRESTORE)) {
                    tspp->ts_scpri = t->t_pri;
                    tspp->ts_flags |= TSRESTORE;
                }
                THREAD_CHANGE_PRI(t, ts_maxumdpri);
                t->t_schedflag |= TS_DONT_SWAP;
            }
            schedctl_set_yield(t, 1);
            setfrontdq(t);
            goto done;
        } else {
            if (tspp->ts_flags & TSRESTORE) {
                THREAD_CHANGE_PRI(t, tspp->ts_scpri);
                tspp->ts_flags &= ~TSRESTORE;
            }
            schedctl_set_nopreempt(t, 0);
            DTRACE_SCHED1(schedctl__preempt, kthread_t *, t);
            TNF_PROBE_2(schedctl_preempt, "schedctl TS ts_preempt",
                /* CSTYLED */, tnf_pid, pid, ttoproc(t)->p_pid,
                tnf_lwpid, lwpid, t->t_tid);
            /*
             * Fall through and be preempted below.
             */
        }
    }

    if ((tspp->ts_flags & (TSBACKQ|TSKPRI)) == TSBACKQ) {
        tspp->ts_timeleft = ts_dptbl[tspp->ts_cpupri].ts_quantum;
        tspp->ts_dispwait = 0;
        tspp->ts_flags &= ~TSBACKQ;
        setbackdq(t);
    } else if ((tspp->ts_flags & (TSBACKQ|TSKPRI)) == (TSBACKQ|TSKPRI)) {
        tspp->ts_flags &= ~TSBACKQ;
        setbackdq(t);
    } else {
#ifdef KSLICE
        if (kslice)
            setbackdq(t);
        else
#endif
            setfrontdq(t);
    }

done:
    TRACE_2(TR_FAC_DISP, TR_PREEMPT,
        "preempt:tid %p old pri %d", t, oldpri);
}

static void
ts_setrun(kthread_t *t)
{
    tsproc_t *tspp = (tsproc_t *)(t->t_cldata);

    ASSERT(THREAD_LOCK_HELD(t));    /* t should be in transition */

    if (tspp->ts_dispwait > ts_dptbl[tspp->ts_umdpri].ts_maxwait) {
        tspp->ts_cpupri = ts_dptbl[tspp->ts_cpupri].ts_slpret;
        TS_NEWUMDPRI(tspp);
        tspp->ts_timeleft = ts_dptbl[tspp->ts_cpupri].ts_quantum;
        tspp->ts_dispwait = 0;
        if ((tspp->ts_flags & TSKPRI) == 0) {
            THREAD_CHANGE_PRI(t,
                ts_dptbl[tspp->ts_umdpri].ts_globpri);
            ASSERT(t->t_pri >= 0 && t->t_pri <= ts_maxglobpri);
        }
    }

    tspp->ts_flags &= ~TSBACKQ;

    if (tspp->ts_flags & TSIA) {
        if (tspp->ts_flags & TSIASET)
            setfrontdq(t);
        else
            setbackdq(t);
    } else {
        if (t->t_disp_time != lbolt)
            setbackdq(t);
        else
            setfrontdq(t);
    }
}


/*
 * Prepare thread for sleep. We reset the thread priority so it will
 * run at the kernel priority level when it wakes up.
 */
static void
ts_sleep(kthread_t *t)
{
    tsproc_t    *tspp = (tsproc_t *)(t->t_cldata);
    int     flags;
    pri_t       old_pri = t->t_pri;

    ASSERT(t == curthread);
    ASSERT(THREAD_LOCK_HELD(t));

    flags = tspp->ts_flags;
    if (t->t_kpri_req) {
        tspp->ts_flags = flags | TSKPRI;
        THREAD_CHANGE_PRI(t, ts_kmdpris[0]);
        ASSERT(t->t_pri >= 0 && t->t_pri <= ts_maxglobpri);
        t->t_trapret = 1;       /* so ts_trapret will run */
        aston(t);
    } else if (tspp->ts_dispwait > ts_dptbl[tspp->ts_umdpri].ts_maxwait) {
        /*
         * If thread has blocked in the kernel (as opposed to
         * being merely preempted), recompute the user mode priority.
         */
        tspp->ts_cpupri = ts_dptbl[tspp->ts_cpupri].ts_slpret;
        TS_NEWUMDPRI(tspp);
        tspp->ts_timeleft = ts_dptbl[tspp->ts_cpupri].ts_quantum;
        tspp->ts_dispwait = 0;

        THREAD_CHANGE_PRI(curthread,
            ts_dptbl[tspp->ts_umdpri].ts_globpri);
        ASSERT(curthread->t_pri >= 0 &&
            curthread->t_pri <= ts_maxglobpri);
        tspp->ts_flags = flags & ~TSKPRI;

        if (DISP_MUST_SURRENDER(curthread))
            cpu_surrender(curthread);
    } else if (flags & TSKPRI) {
        THREAD_CHANGE_PRI(curthread,
            ts_dptbl[tspp->ts_umdpri].ts_globpri);
        ASSERT(curthread->t_pri >= 0 &&
            curthread->t_pri <= ts_maxglobpri);
        tspp->ts_flags = flags & ~TSKPRI;

        if (DISP_MUST_SURRENDER(curthread))
            cpu_surrender(curthread);
    }
    t->t_stime = lbolt;     /* time stamp for the swapper */
    TRACE_2(TR_FAC_DISP, TR_SLEEP,
        "sleep:tid %p old pri %d", t, old_pri);
}


/*
 * Return Values:
 *
 *  -1 if the thread is loaded or is not eligible to be swapped in.
 *
 *  effective priority of the specified thread based on swapout time
 *      and size of process (epri >= 0 , epri <= SHRT_MAX).
 */
/* ARGSUSED */
static pri_t
ts_swapin(kthread_t *t, int flags)
{
    tsproc_t    *tspp = (tsproc_t *)(t->t_cldata);
    long        epri = -1;
    proc_t      *pp = ttoproc(t);

    ASSERT(THREAD_LOCK_HELD(t));

    /*
     * We know that pri_t is a short.
     * Be sure not to overrun its range.
     */
    if (t->t_state == TS_RUN && (t->t_schedflag & TS_LOAD) == 0) {
        time_t swapout_time;

        swapout_time = (lbolt - t->t_stime) / hz;
        if (INHERITED(t) || (tspp->ts_flags & (TSKPRI | TSIASET)))
            epri = (long)DISP_PRIO(t) + swapout_time;
        else {
            /*
             * Threads which have been out for a long time,
             * have high user mode priority and are associated
             * with a small address space are more deserving
             */
            epri = ts_dptbl[tspp->ts_umdpri].ts_globpri;
            ASSERT(epri >= 0 && epri <= ts_maxumdpri);
            epri += swapout_time - pp->p_swrss / nz(maxpgio)/2;
        }
        /*
         * Scale epri so SHRT_MAX/2 represents zero priority.
         */
        epri += SHRT_MAX/2;
        if (epri < 0)
            epri = 0;
        else if (epri > SHRT_MAX)
            epri = SHRT_MAX;
    }
    return ((pri_t)epri);
}

/*
 * Return Values
 *  -1 if the thread isn't loaded or is not eligible to be swapped out.
 *
 *  effective priority of the specified thread based on if the swapper
 *      is in softswap or hardswap mode.
 *
 *      Softswap:  Return a low effective priority for threads
 *             sleeping for more than maxslp secs.
 *
 *      Hardswap:  Return an effective priority such that threads
 *             which have been in memory for a while and are
 *             associated with a small address space are swapped
 *             in before others.
 *
 *      (epri >= 0 , epri <= SHRT_MAX).
 */
time_t  ts_minrun = 2;      /* XXX - t_pri becomes 59 within 2 secs */
time_t  ts_minslp = 2;      /* min time on sleep queue for hardswap */

static pri_t
ts_swapout(kthread_t *t, int flags)
{
    tsproc_t    *tspp = (tsproc_t *)(t->t_cldata);
    long        epri = -1;
    proc_t      *pp = ttoproc(t);
    time_t      swapin_time;

    ASSERT(THREAD_LOCK_HELD(t));

    if (INHERITED(t) || (tspp->ts_flags & (TSKPRI | TSIASET)) ||
        (t->t_proc_flag & TP_LWPEXIT) ||
        (t->t_state & (TS_ZOMB | TS_FREE | TS_STOPPED | TS_ONPROC)) ||
        !(t->t_schedflag & TS_LOAD) || !SWAP_OK(t))
        return (-1);

    ASSERT(t->t_state & (TS_SLEEP | TS_RUN));

    /*
     * We know that pri_t is a short.
     * Be sure not to overrun its range.
     */
    swapin_time = (lbolt - t->t_stime) / hz;
    if (flags == SOFTSWAP) {
        if (t->t_state == TS_SLEEP && swapin_time > maxslp) {
            epri = 0;
        } else {
            return ((pri_t)epri);
        }
    } else {
        pri_t pri;

        if ((t->t_state == TS_SLEEP && swapin_time > ts_minslp) ||
            (t->t_state == TS_RUN && swapin_time > ts_minrun)) {
            pri = ts_dptbl[tspp->ts_umdpri].ts_globpri;
            ASSERT(pri >= 0 && pri <= ts_maxumdpri);
            epri = swapin_time -
                (rm_asrss(pp->p_as) / nz(maxpgio)/2) - (long)pri;
        } else {
            return ((pri_t)epri);
        }
    }

    /*
     * Scale epri so SHRT_MAX/2 represents zero priority.
     */
    epri += SHRT_MAX/2;
    if (epri < 0)
        epri = 0;
    else if (epri > SHRT_MAX)
        epri = SHRT_MAX;

    return ((pri_t)epri);
}

/*
 * Check for time slice expiration.  If time slice has expired
 * move thread to priority specified in tsdptbl for time slice expiration
 * and set runrun to cause preemption.
 */

static void
ts_tick(kthread_t *t)
{
    tsproc_t *tspp = (tsproc_t *)(t->t_cldata);
    klwp_t *lwp;
    pri_t   oldpri = t->t_pri;

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

    thread_lock(t);
    if ((tspp->ts_flags & TSKPRI) == 0) {
        if (--tspp->ts_timeleft <= 0) {
            pri_t   new_pri;

            /*
             * If we're doing preemption control and trying to
             * avoid preempting this thread, just note that
             * the thread should yield soon and let it keep
             * running (unless it's been a while).
             */
            if (t->t_schedctl && schedctl_get_nopreempt(t)) {
                if (tspp->ts_timeleft > -SC_MAX_TICKS) {
                    DTRACE_SCHED1(schedctl__nopreempt,
                        kthread_t *, t);
                    schedctl_set_yield(t, 1);
                    thread_unlock_nopreempt(t);
                    return;
                }

                TNF_PROBE_2(schedctl_failsafe,
                    "schedctl TS ts_tick", /* CSTYLED */,
                    tnf_pid, pid, ttoproc(t)->p_pid,
                    tnf_lwpid, lwpid, t->t_tid);
            }
            tspp->ts_flags &= ~TSRESTORE;
            tspp->ts_cpupri = ts_dptbl[tspp->ts_cpupri].ts_tqexp;
            TS_NEWUMDPRI(tspp);
            tspp->ts_dispwait = 0;
            new_pri = ts_dptbl[tspp->ts_umdpri].ts_globpri;
            ASSERT(new_pri >= 0 && new_pri <= ts_maxglobpri);
            /*
             * When the priority of a thread is changed,
             * it may be necessary to adjust its position
             * on a sleep queue or dispatch queue.
             * The function thread_change_pri accomplishes
             * this.
             */
            if (thread_change_pri(t, new_pri, 0)) {
                if ((t->t_schedflag & TS_LOAD) &&
                    (lwp = t->t_lwp) &&
                    lwp->lwp_state == LWP_USER)
                    t->t_schedflag &= ~TS_DONT_SWAP;
                tspp->ts_timeleft =
                    ts_dptbl[tspp->ts_cpupri].ts_quantum;
            } else {
                tspp->ts_flags |= TSBACKQ;
                cpu_surrender(t);
            }
            TRACE_2(TR_FAC_DISP, TR_TICK,
                "tick:tid %p old pri %d", t, oldpri);
        } else if (t->t_state == TS_ONPROC &&
                t->t_pri < t->t_disp_queue->disp_maxrunpri) {
            tspp->ts_flags |= TSBACKQ;
            cpu_surrender(t);
        }
    }
    thread_unlock_nopreempt(t); /* clock thread can't be preempted */
}


/*
 * If thread is currently at a kernel mode priority (has slept)
 * we assign it the appropriate user mode priority and time quantum
 * here.  If we are lowering the thread's priority below that of
 * other runnable threads we will normally set runrun via cpu_surrender() to
 * cause preemption.
 */
static void
ts_trapret(kthread_t *t)
{
    tsproc_t    *tspp = (tsproc_t *)t->t_cldata;
    cpu_t       *cp = CPU;
    pri_t       old_pri = curthread->t_pri;

    ASSERT(THREAD_LOCK_HELD(t));
    ASSERT(t == curthread);
    ASSERT(cp->cpu_dispthread == t);
    ASSERT(t->t_state == TS_ONPROC);

    t->t_kpri_req = 0;
    if (tspp->ts_dispwait > ts_dptbl[tspp->ts_umdpri].ts_maxwait) {
        tspp->ts_cpupri = ts_dptbl[tspp->ts_cpupri].ts_slpret;
        TS_NEWUMDPRI(tspp);
        tspp->ts_timeleft = ts_dptbl[tspp->ts_cpupri].ts_quantum;
        tspp->ts_dispwait = 0;

        /*
         * If thread has blocked in the kernel (as opposed to
         * being merely preempted), recompute the user mode priority.
         */
        THREAD_CHANGE_PRI(t, ts_dptbl[tspp->ts_umdpri].ts_globpri);
        cp->cpu_dispatch_pri = DISP_PRIO(t);
        ASSERT(t->t_pri >= 0 && t->t_pri <= ts_maxglobpri);
        tspp->ts_flags &= ~TSKPRI;

        if (DISP_MUST_SURRENDER(t))
            cpu_surrender(t);
    } else if (tspp->ts_flags & TSKPRI) {
        /*
         * If thread has blocked in the kernel (as opposed to
         * being merely preempted), recompute the user mode priority.
         */
        THREAD_CHANGE_PRI(t, ts_dptbl[tspp->ts_umdpri].ts_globpri);
        cp->cpu_dispatch_pri = DISP_PRIO(t);
        ASSERT(t->t_pri >= 0 && t->t_pri <= ts_maxglobpri);
        tspp->ts_flags &= ~TSKPRI;

        if (DISP_MUST_SURRENDER(t))
            cpu_surrender(t);
    }

    /*
     * Swapout lwp if the swapper is waiting for this thread to
     * reach a safe point.
     */
    if ((t->t_schedflag & TS_SWAPENQ) && !(tspp->ts_flags & TSIASET)) {
        thread_unlock(t);
        swapout_lwp(ttolwp(t));
        thread_lock(t);
    }

    TRACE_2(TR_FAC_DISP, TR_TRAPRET,
        "trapret:tid %p old pri %d", t, old_pri);
}


/*
 * Update the ts_dispwait values of all time sharing threads that
 * are currently runnable at a user mode priority and bump the priority
 * if ts_dispwait exceeds ts_maxwait.  Called once per second via
 * timeout which we reset here.
 *
 * There are several lists of time sharing threads broken up by a hash on
 * the thread pointer.  Each list has its own lock.  This avoids blocking
 * all ts_enterclass, ts_fork, and ts_exitclass operations while ts_update
 * runs.  ts_update traverses each list in turn.
 *
 * If multiple threads have their priorities updated to the same value,
 * the system implicitly favors the one that is updated first (since it
 * winds up first on the run queue).  To avoid this unfairness, the
 * traversal of threads starts at the list indicated by a marker.  When
 * threads in more than one list have their priorities updated, the marker
 * is moved.  This changes the order the threads will be placed on the run
 * queue the next time ts_update is called and preserves fairness over the
 * long run.  The marker doesn't need to be protected by a lock since it's
 * only accessed by ts_update, which is inherently single-threaded (only
 * one instance can be running at a time).
 */
static void
ts_update(void *arg)
{
    int     i;
    int     new_marker = -1;
    static int  ts_update_marker;

    /*
     * Start with the ts_update_marker list, then do the rest.
     */
    i = ts_update_marker;
    do {
        /*
         * If this is the first list after the current marker to
         * have threads with priorities updated, advance the marker
         * to this list for the next time ts_update runs.
         */
        if (ts_update_list(i) && new_marker == -1 &&
            i != ts_update_marker) {
            new_marker = i;
        }
    } while ((i = TS_LIST_NEXT(i)) != ts_update_marker);

    /* advance marker for next ts_update call */
    if (new_marker != -1)
        ts_update_marker = new_marker;

    (void) timeout(ts_update, arg, hz);
}

/*
 * Updates priority for a list of threads.  Returns 1 if the priority of
 * one of the threads was actually updated, 0 if none were for various
 * reasons (thread is no longer in the TS or IA class, isn't runnable,
 * hasn't waited long enough, has the preemption control no-preempt bit
 * set, etc.)
 */
static int
ts_update_list(int i)
{
    tsproc_t *tspp;
    kthread_t *tx;
    int updated = 0;

    mutex_enter(&ts_list_lock[i]);
    for (tspp = ts_plisthead[i].ts_next; tspp != &ts_plisthead[i];
        tspp = tspp->ts_next) {
        tx = tspp->ts_tp;
        /*
         * Lock the thread and verify state.
         */
        thread_lock(tx);
        /*
         * Skip the thread if it is no longer in the TS (or IA) class.
         */
        if (tx->t_clfuncs != &ts_classfuncs.thread &&
            tx->t_clfuncs != &ia_classfuncs.thread)
            goto next;
        tspp->ts_dispwait++;
        if ((tspp->ts_flags & TSKPRI) != 0)
            goto next;
        if (tspp->ts_dispwait <= ts_dptbl[tspp->ts_umdpri].ts_maxwait)
            goto next;
        if (tx->t_schedctl && schedctl_get_nopreempt(tx))
            goto next;
        if (tx->t_state != TS_RUN && (tx->t_state != TS_SLEEP ||
            !ts_sleep_promote)) {
            /* make next syscall/trap do CL_TRAPRET */
            tx->t_trapret = 1;
            aston(tx);
            goto next;
        }
        tspp->ts_cpupri = ts_dptbl[tspp->ts_cpupri].ts_lwait;
        TS_NEWUMDPRI(tspp);
        tspp->ts_dispwait = 0;
        updated = 1;

        /*
         * Only dequeue it if needs to move; otherwise it should
         * just round-robin here.
         */
        if (tx->t_pri != ts_dptbl[tspp->ts_umdpri].ts_globpri) {
            pri_t oldpri = tx->t_pri;
            ts_change_priority(tx, tspp);
            TRACE_2(TR_FAC_DISP, TR_UPDATE,
                "update:tid %p old pri %d", tx, oldpri);
        }
next:
        thread_unlock(tx);
    }
    mutex_exit(&ts_list_lock[i]);

    return (updated);
}


/*
 * Processes waking up go to the back of their queue.  We don't
 * need to assign a time quantum here because thread is still
 * at a kernel mode priority and the time slicing is not done
 * for threads running in the kernel after sleeping.  The proper
 * time quantum will be assigned by ts_trapret before the thread
 * returns to user mode.
 */
static void
ts_wakeup(kthread_t *t)
{
    tsproc_t    *tspp = (tsproc_t *)(t->t_cldata);

    ASSERT(THREAD_LOCK_HELD(t));

    t->t_stime = lbolt;     /* time stamp for the swapper */

    if (tspp->ts_flags & TSKPRI) {
        tspp->ts_flags &= ~TSBACKQ;
        if (tspp->ts_flags & TSIASET)
            setfrontdq(t);
        else
            setbackdq(t);
    } else if (t->t_kpri_req) {
        /*
         * Give thread a priority boost if we were asked.
         */
        tspp->ts_flags |= TSKPRI;
        THREAD_CHANGE_PRI(t, ts_kmdpris[0]);
        setbackdq(t);
        t->t_trapret = 1;   /* so that ts_trapret will run */
        aston(t);
    } else {
        if (tspp->ts_dispwait > ts_dptbl[tspp->ts_umdpri].ts_maxwait) {
            tspp->ts_cpupri = ts_dptbl[tspp->ts_cpupri].ts_slpret;
            TS_NEWUMDPRI(tspp);
            tspp->ts_timeleft =
                ts_dptbl[tspp->ts_cpupri].ts_quantum;
            tspp->ts_dispwait = 0;
            THREAD_CHANGE_PRI(t,
                ts_dptbl[tspp->ts_umdpri].ts_globpri);
            ASSERT(t->t_pri >= 0 && t->t_pri <= ts_maxglobpri);
        }

        tspp->ts_flags &= ~TSBACKQ;

        if (tspp->ts_flags & TSIA) {
            if (tspp->ts_flags & TSIASET)
                setfrontdq(t);
            else
                setbackdq(t);
        } else {
            if (t->t_disp_time != lbolt)
                setbackdq(t);
            else
                setfrontdq(t);
        }
    }
}


/*
 * When a thread yields, put it on the back of the run queue.
 */
static void
ts_yield(kthread_t *t)
{
    tsproc_t    *tspp = (tsproc_t *)(t->t_cldata);

    ASSERT(t == curthread);
    ASSERT(THREAD_LOCK_HELD(t));

    /*
     * Clear the preemption control "yield" bit since the user is
     * doing a yield.
     */
    if (t->t_schedctl)
        schedctl_set_yield(t, 0);
    /*
     * If ts_preempt() artifically increased the thread's priority
     * to avoid preemption, restore the original priority now.
     */
    if (tspp->ts_flags & TSRESTORE) {
        THREAD_CHANGE_PRI(t, tspp->ts_scpri);
        tspp->ts_flags &= ~TSRESTORE;
    }
    if (tspp->ts_timeleft <= 0) {
        /*
         * Time slice was artificially extended to avoid
         * preemption, so pretend we're preempting it now.
         */
        DTRACE_SCHED1(schedctl__yield, int, -tspp->ts_timeleft);
        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;
        THREAD_CHANGE_PRI(t, ts_dptbl[tspp->ts_umdpri].ts_globpri);
        ASSERT(t->t_pri >= 0 && t->t_pri <= ts_maxglobpri);
    }
    tspp->ts_flags &= ~TSBACKQ;
    setbackdq(t);
}


/*
 * Increment the nice value of the specified thread by incr and
 * return the new value in *retvalp.
 */
static int
ts_donice(kthread_t *t, cred_t *cr, int incr, int *retvalp)
{
    int     newnice;
    tsproc_t    *tspp = (tsproc_t *)(t->t_cldata);
    tsparms_t   tsparms;

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

    /* If there's no change to priority, just return current setting */
    if (incr == 0) {
        if (retvalp) {
            *retvalp = tspp->ts_nice - NZERO;
        }
        return (0);
    }

    if ((incr < 0 || incr > 2 * NZERO) &&
        secpolicy_setpriority(cr) != 0)
        return (EPERM);

    /*
     * Specifying a nice increment greater than the upper limit of
     * 2 * NZERO - 1 will result in the thread's nice value being
     * set to the upper limit.  We check for this before computing
     * the new value because otherwise we could get overflow
     * if a privileged process specified some ridiculous increment.
     */
    if (incr > 2 * NZERO - 1)
        incr = 2 * NZERO - 1;

    newnice = tspp->ts_nice + incr;
    if (newnice >= 2 * NZERO)
        newnice = 2 * NZERO - 1;
    else if (newnice < 0)
        newnice = 0;

    tsparms.ts_uprilim = tsparms.ts_upri =
        -((newnice - NZERO) * ts_maxupri) / NZERO;
    /*
     * Reset the uprilim and upri values of the thread.
     * Call ts_parmsset even if thread is interactive since we're
     * not changing mode.
     */
    (void) ts_parmsset(t, (void *)&tsparms, (id_t)0, (cred_t *)NULL);

    /*
     * Although ts_parmsset already reset ts_nice it may
     * not have been set to precisely the value calculated above
     * because ts_parmsset determines the nice value from the
     * user priority and we may have truncated during the integer
     * conversion from nice value to user priority and back.
     * We reset ts_nice to the value we calculated above.
     */
    tspp->ts_nice = (char)newnice;

    if (retvalp)
        *retvalp = newnice - NZERO;
    return (0);
}


/*
 * ia_set_process_group marks foreground processes as interactive
 * and background processes as non-interactive iff the session
 * leader is interactive.  This routine is called from two places:
 *  strioctl:SPGRP when a new process group gets
 *      control of the tty.
 *  ia_parmsset-when the process in question is a session leader.
 * ia_set_process_group assumes that pidlock is held by the caller,
 * either strioctl or priocntlsys.  If the caller is priocntlsys
 * (via ia_parmsset) then the p_lock of the session leader is held
 * and the code needs to be careful about acquiring other p_locks.
 */
static void
ia_set_process_group(pid_t sid, pid_t bg_pgid, pid_t fg_pgid)
{
    proc_t      *leader, *fg, *bg;
    tsproc_t    *tspp;
    kthread_t   *tx;
    int     plocked = 0;

    ASSERT(MUTEX_HELD(&pidlock));

    /*
     * see if the session leader is interactive AND
     * if it is currently "on" AND controlling a tty
     * iff it is then make the processes in the foreground
     * group interactive and the processes in the background
     * group non-interactive.
     */
    if ((leader = (proc_t *)prfind(sid)) == NULL) {
        return;
    }
    if (leader->p_stat == SIDL) {
        return;
    }
    if ((tx = proctot(leader)) == NULL) {
        return;
    }
    /*
     * XXX do all the threads in the leader
     */
    if (tx->t_cid != ia_cid) {
        return;
    }
    tspp = tx->t_cldata;
    /*
     * session leaders that are not interactive need not have
     * any processing done for them.  They are typically shells
     * that do not have focus and are changing the process group
     * attatched to the tty, e.g. a process that is exiting
     */
    TTY_HOLD(leader->p_sessp);
    if (!(tspp->ts_flags & TSIASET) ||
        (leader->p_sessp->s_vp == NULL) ||
        (leader->p_sessp->s_vp->v_stream == NULL)) {
        TTY_RELE(leader->p_sessp);
        return;
    }
    TTY_RELE(leader->p_sessp);

    /*
     * If we're already holding the leader's p_lock, we should use
     * mutex_tryenter instead of mutex_enter to avoid deadlocks from
     * lock ordering violations.
     */
    if (mutex_owned(&leader->p_lock))
        plocked = 1;

    if (fg_pgid == 0)
        goto skip;
    /*
     * now look for all processes in the foreground group and
     * make them interactive
     */
    for (fg = (proc_t *)pgfind(fg_pgid); fg != NULL; fg = fg->p_pglink) {
        /*
         * if the process is SIDL it's begin forked, ignore it
         */
        if (fg->p_stat == SIDL) {
            continue;
        }
        /*
         * sesssion leaders must be turned on/off explicitly
         * not implicitly as happens to other members of
         * the process group.
         */
        if (fg->p_pid  == fg->p_sessp->s_sid) {
            continue;
        }

        TRACE_1(TR_FAC_IA, TR_GROUP_ON,
            "group on:proc %p", fg);

        if (plocked) {
            if (mutex_tryenter(&fg->p_lock) == 0)
                continue;
        } else {
            mutex_enter(&fg->p_lock);
        }

        if ((tx = proctot(fg)) == NULL) {
            mutex_exit(&fg->p_lock);
            continue;
        }
        do {
            thread_lock(tx);
            /*
             * if this thread is not interactive continue
             */
            if (tx->t_cid != ia_cid) {
                thread_unlock(tx);
                continue;
            }
            tspp = tx->t_cldata;
            tspp->ts_flags |= TSIASET;
            tspp->ts_boost = ia_boost;
            TS_NEWUMDPRI(tspp);
            if ((tspp->ts_flags & TSKPRI) != 0) {
                thread_unlock(tx);
                continue;
            }
            tspp->ts_dispwait = 0;
            ts_change_priority(tx, tspp);
            thread_unlock(tx);
        } while ((tx = tx->t_forw) != fg->p_tlist);
        mutex_exit(&fg->p_lock);
    }
skip:
    if (bg_pgid == 0)
        return;
    for (bg = (proc_t *)pgfind(bg_pgid); bg != NULL; bg = bg->p_pglink) {
        if (bg->p_stat == SIDL) {
            continue;
        }
        /*
         * sesssion leaders must be turned off explicitly
         * not implicitly as happens to other members of
         * the process group.
         */
        if (bg->p_pid == bg->p_sessp->s_sid) {
            continue;
        }

        TRACE_1(TR_FAC_IA, TR_GROUP_OFF,
            "group off:proc %p", bg);

        if (plocked) {
            if (mutex_tryenter(&bg->p_lock) == 0)
                continue;
        } else {
            mutex_enter(&bg->p_lock);
        }

        if ((tx = proctot(bg)) == NULL) {
            mutex_exit(&bg->p_lock);
            continue;
        }
        do {
            thread_lock(tx);
            /*
             * if this thread is not interactive continue
             */
            if (tx->t_cid != ia_cid) {
                thread_unlock(tx);
                continue;
            }
            tspp = tx->t_cldata;
            tspp->ts_flags &= ~TSIASET;
            tspp->ts_boost = -ia_boost;
            TS_NEWUMDPRI(tspp);
            if ((tspp->ts_flags & TSKPRI) != 0) {
                thread_unlock(tx);
                continue;
            }

            tspp->ts_dispwait = 0;
            ts_change_priority(tx, tspp);
            thread_unlock(tx);
        } while ((tx = tx->t_forw) != bg->p_tlist);
        mutex_exit(&bg->p_lock);
    }
}


static void
ts_change_priority(kthread_t *t, tsproc_t *tspp)
{
    pri_t   new_pri;

    ASSERT(THREAD_LOCK_HELD(t));
    new_pri = ts_dptbl[tspp->ts_umdpri].ts_globpri;
    ASSERT(new_pri >= 0 && new_pri <= ts_maxglobpri);
    tspp->ts_flags &= ~TSRESTORE;
    if (t == curthread || t->t_state == TS_ONPROC) {
        /* curthread is always onproc */
        cpu_t   *cp = t->t_disp_queue->disp_cpu;
        THREAD_CHANGE_PRI(t, new_pri);
        if (t == cp->cpu_dispthread)
            cp->cpu_dispatch_pri = DISP_PRIO(t);
        if (DISP_MUST_SURRENDER(t)) {
            tspp->ts_flags |= TSBACKQ;
            cpu_surrender(t);
        } else {
            tspp->ts_timeleft =
                ts_dptbl[tspp->ts_cpupri].ts_quantum;
        }
    } else {
        int frontq;

        frontq = (tspp->ts_flags & TSIASET) != 0;
        /*
         * When the priority of a thread is changed,
         * it may be necessary to adjust its position
         * on a sleep queue or dispatch queue.
         * The function thread_change_pri accomplishes
         * this.
         */
        if (thread_change_pri(t, new_pri, frontq)) {
            /*
             * The thread was on a run queue. Reset
             * its CPU timeleft from the quantum
             * associated with the new priority.
             */
            tspp->ts_timeleft =
                ts_dptbl[tspp->ts_cpupri].ts_quantum;
        } else {
            tspp->ts_flags |= TSBACKQ;
        }
    }
}

static int
ts_alloc(void **p, int flag)
{
    void *bufp;
    bufp = kmem_alloc(sizeof (tsproc_t), flag);
    if (bufp == NULL) {
        return (ENOMEM);
    } else {
        *p = bufp;
        return (0);
    }
}

static void
ts_free(void *bufp)
{
    if (bufp)
        kmem_free(bufp, sizeof (tsproc_t));
}