/*
 * 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 (c) 1994, 2010, Oracle and/or its affiliates. All rights reserved.
 * Copyright 2019 Joyent, Inc.
 */

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

#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/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 *);

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 && atomic_cas_32(&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 & ~(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);
        continuelwps(cp);
        mutex_exit(&cp->p_lock);

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

        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);
        THREAD_TRANSITION(t);
        ts_setrun(t);
        thread_unlock(t);
        /*
         * Safe to drop p_lock now since since it is safe to change
         * the scheduling class after this point.
         */
        mutex_exit(&pp->p_lock);

        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(&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_raisepriority(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;

        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_raisepriority(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);
        }
        mutex_enter(&p->p_sessp->s_lock);
        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;
                        mutex_exit(&p->p_sessp->s_lock);
                        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)
                mutex_exit(&p->p_sessp->s_lock);

        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));
}

static void
ts_exit(kthread_t *t)
{
        tsproc_t *tspp;

        if (CPUCAPS_ON()) {
                /*
                 * A thread could be exiting in between clock ticks,
                 * so we need to calculate how much CPU time it used
                 * since it was charged last time.
                 *
                 * CPU caps are not enforced on exiting processes - it is
                 * usually desirable to exit as soon as possible to free
                 * resources.
                 */
                thread_lock(t);
                tspp = (tsproc_t *)t->t_cldata;
                (void) cpucaps_charge(t, &tspp->ts_caps, CPUCAPS_CHARGE_ONLY);
                thread_unlock(t);
        }
}

/*
 * 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 = ttolwp(t);
        pri_t           oldpri = t->t_pri;

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

        /*
         * This thread may be placed on wait queue by CPU Caps. In this case we
         * do not need to do anything until it is removed from the wait queue.
         */
        if (CPUCAPS_ON()) {
                (void) cpucaps_charge(t, &tspp->ts_caps,
                    CPUCAPS_CHARGE_ENFORCE);
                if (CPUCAPS_ENFORCE(t))
                        return;
        }

        /*
         * If thread got preempted in the user-land then we know
         * it isn't holding any locks.  Mark it as swappable.
         */
        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 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);
                        /*
                         * Fall through and be preempted below.
                         */
                }
        }

        if ((tspp->ts_flags & TSBACKQ) != 0) {
                tspp->ts_timeleft = ts_dptbl[tspp->ts_cpupri].ts_quantum;
                tspp->ts_dispwait = 0;
                tspp->ts_flags &= ~TSBACKQ;
                setbackdq(t);
        } else {
                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;
                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 != ddi_get_lbolt())
                        setbackdq(t);
                else
                        setfrontdq(t);
        }
}


/*
 * Prepare thread for sleep.
 */
static void
ts_sleep(kthread_t *t)
{
        tsproc_t        *tspp = (tsproc_t *)(t->t_cldata);
        pri_t           old_pri = t->t_pri;

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

        /*
         * Account for time spent on CPU before going to sleep.
         */
        (void) CPUCAPS_CHARGE(t, &tspp->ts_caps, CPUCAPS_CHARGE_ENFORCE);

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

                if (DISP_MUST_SURRENDER(curthread))
                        cpu_surrender(curthread);
        }
        t->t_stime = ddi_get_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 = (ddi_get_lbolt() - t->t_stime) / hz;
                if (INHERITED(t) || (tspp->ts_flags & 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 & TSIASET) ||
            (t->t_proc_flag & TP_LWPEXIT) ||
            (t->t_state & (TS_ZOMB | TS_FREE | TS_STOPPED |
            TS_ONPROC | TS_WAIT)) ||
            !(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 = (ddi_get_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;
        boolean_t call_cpu_surrender = B_FALSE;
        pri_t   oldpri = t->t_pri;

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

        thread_lock(t);

        /*
         * Keep track of thread's project CPU usage.  Note that projects
         * get charged even when threads are running in the kernel.
         */
        if (CPUCAPS_ON()) {
                call_cpu_surrender = cpucaps_charge(t, &tspp->ts_caps,
                    CPUCAPS_CHARGE_ENFORCE);
        }

        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;
                        }

                        DTRACE_SCHED1(schedctl__failsafe,
                            kthread_t *, t);
                }
                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 {
                        call_cpu_surrender = B_TRUE;
                }
                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) {
                call_cpu_surrender = B_TRUE;
        }

        if (call_cpu_surrender) {
                tspp->ts_flags |= TSBACKQ;
                cpu_surrender(t);
        }

        thread_unlock_nopreempt(t);     /* clock thread can't be preempted */
}


/*
 * 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);

        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);

                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_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_WAIT &&
                    (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.
 */
static void
ts_wakeup(kthread_t *t)
{
        tsproc_t        *tspp = (tsproc_t *)(t->t_cldata);

        ASSERT(THREAD_LOCK_HELD(t));

        t->t_stime = ddi_get_lbolt();           /* time stamp for the swapper */

        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 != ddi_get_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));

        /*
         * Collect CPU usage spent before yielding
         */
        (void) CPUCAPS_CHARGE(t, &tspp->ts_caps, CPUCAPS_CHARGE_ENFORCE);

        /*
         * 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_raisepriority(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);
}

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

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

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

        newpri = tspp->ts_upri + incr;
        if (newpri > ts_maxupri || newpri < -ts_maxupri)
                return (EINVAL);

        *retvalp = newpri;
        tsparms.ts_uprilim = tsparms.ts_upri = newpri;
        /*
         * Reset the uprilim and upri values of the thread.
         * Call ts_parmsset even if thread is interactive since we're
         * not changing mode.
         */
        return (ts_parmsset(t, &tsparms, 0, cr));
}

/*
 * 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
         */
        mutex_enter(&leader->p_sessp->s_lock);
        if (!(tspp->ts_flags & TSIASET) ||
            (leader->p_sessp->s_vp == NULL) ||
            (leader->p_sessp->s_vp->v_stream == NULL)) {
                mutex_exit(&leader->p_sessp->s_lock);
                return;
        }
        mutex_exit(&leader->p_sessp->s_lock);

        /*
         * 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);
                        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);

                        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;
        t->t_cpri = tspp->ts_upri;
        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));
}