port/rt/sched.c

	sched.c revision 8cd45542f2a452ca0dab13d8b2d5cfa876ccbebc
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#pragma ident   "%Z%%M% %I% %E% SMI"

#include "synonyms.h"
#include "thr_uberdata.h"
#include <sched.h>
#include <sys/tspriocntl.h>
#include <sys/rtpriocntl.h>
#include <sys/fxpriocntl.h>

/*
 * The following array is used for caching information
 * for priocntl scheduling classes.
 */
static pcclass_t sched_class[] = {
    {0, SCHED_OTHER, 0, 0, {-1, "TS",  0}},
    {0, SCHED_FIFO,  0, 0, {-1, "RT",  0}},
    {0, SCHED_RR,    0, 0, {-1, "RT",  0}},
    {0, SCHED_SYS,   0, 0, {0,  "SYS", 0}},
    {0, SCHED_IA,    0, 0, {-1, "IA",  0}},
    {0, SCHED_FSS,   0, 0, {-1, "FSS", 0}},
    {0, SCHED_FX,    0, 0, {-1, "FX",  0}},
    /*
     * Allow unknown (to us) scheduling classes.
     * The kernel allows space for exactly 10 scheduling classes
     * (see the definitions of 'sclass' and 'nclass' in the kernel).
     * We need that number of available slots here.
     * If the kernel space is changed, this has to change too.
     */
    {0, -1,      0, 0, {-1, "",    0}},
    {0, -1,      0, 0, {-1, "",    0}},
    {0, -1,      0, 0, {-1, "",    0}},
    {0, -1,      0, 0, {-1, "",    0}},
    {0, -1,      0, 0, {-1, "",    0}},
    {0, -1,      0, 0, {-1, "",    0}},
    {0, -1,      0, 0, {-1, "",    0}},
    {0, -1,      0, 0, {-1, "",    0}},
    {0, -1,      0, 0, {-1, "",    0}},
    {0, -1,      0, 0, {-1, "",    0}},
};

#define NPOLICY (sizeof (sched_class) / sizeof (pcclass_t))

#if _SCHED_NEXT != SCHED_FX + 1
#error "fatal: _SCHED_NEXT != SCHED_FX + 1"
#endif

static mutex_t class_lock = DEFAULTMUTEX;   /* protects sched_class[] */

/*
 * Helper function for get_info_by_policy(), below.
 * Don't let a manufactured policy number duplicate
 * the class of one of our base policy numbers.
 */
static int
is_base_class(const char *clname)
{
    const pcclass_t *pccp;
    int     policy;

    for (policy = 0, pccp = sched_class;
        policy < _SCHED_NEXT;
        policy++, pccp++) {
        if (strcmp(clname, pccp->pcc_info.pc_clname) == 0)
            return (1);
    }
    return (0);
}

/*
 * Cache priocntl information on scheduling class by policy.
 */
const pcclass_t *
get_info_by_policy(int policy)
{
    pcclass_t *pccp = &sched_class[policy];
    pcpri_t pcpri;
    pri_t prio;
    int base = 0;

    if ((uint_t)policy >= NPOLICY || pccp->pcc_state < 0) {
        errno = EINVAL;
        return (NULL);
    }

    if (pccp->pcc_state > 0)
        return (pccp);

    lmutex_lock(&class_lock);

    /* get class info (the system class is known to have class-id == 0) */
    if (pccp->pcc_policy == -1) {
        /* policy number not defined in <sched.h> */
        ASSERT(policy >= _SCHED_NEXT);
        pccp->pcc_info.pc_cid = policy - _SCHED_NEXT;
        if (priocntl(0, 0, PC_GETCLINFO, &pccp->pcc_info) == -1 ||
            (base = is_base_class(pccp->pcc_info.pc_clname)) != 0) {
            pccp->pcc_info.pc_clname[0] = '\0';
            pccp->pcc_info.pc_cid = -1;
            /*
             * If we duplicated a base class, permanently
             * disable this policy entry.  Else allow for
             * dynamic loading of scheduling classes.
             */
            if (base) {
                _membar_producer();
                pccp->pcc_state = -1;
            }
            errno = EINVAL;
            lmutex_unlock(&class_lock);
            return (NULL);
        }
        pccp->pcc_policy = policy;
    } else if (policy != SCHED_SYS &&
        priocntl(0, 0, PC_GETCID, &pccp->pcc_info) == -1) {
        _membar_producer();
        pccp->pcc_state = -1;
        errno = EINVAL;
        lmutex_unlock(&class_lock);
        return (NULL);
    }

    switch (policy) {
    case SCHED_OTHER:
        prio = ((tsinfo_t *)pccp->pcc_info.pc_clinfo)->ts_maxupri;
        pccp->pcc_primin = -prio;
        pccp->pcc_primax = prio;
        break;
    case SCHED_FIFO:
    case SCHED_RR:
        prio = ((rtinfo_t *)pccp->pcc_info.pc_clinfo)->rt_maxpri;
        pccp->pcc_primin = 0;
        pccp->pcc_primax = prio;
        break;
    default:
        /*
         * All other policy numbers, including policy numbers
         * not defined in <sched.h>.
         */
        pcpri.pc_cid = pccp->pcc_info.pc_cid;
        if (priocntl(0, 0, PC_GETPRIRANGE, &pcpri) == 0) {
            pccp->pcc_primin = pcpri.pc_clpmin;
            pccp->pcc_primax = pcpri.pc_clpmax;
        }
        break;
    }

    _membar_producer();
    pccp->pcc_state = 1;
    lmutex_unlock(&class_lock);
    return (pccp);
}

const pcclass_t *
get_info_by_class(id_t classid)
{
    pcinfo_t    pcinfo;
    pcclass_t   *pccp;
    int     policy;

    if (classid < 0) {
        errno = EINVAL;
        return (NULL);
    }

    /* determine if we already know this classid */
    for (policy = 0, pccp = sched_class;
        policy < NPOLICY;
        policy++, pccp++) {
        if (pccp->pcc_state > 0 && pccp->pcc_info.pc_cid == classid)
            return (pccp);
    }

    pcinfo.pc_cid = classid;
    if (priocntl(0, 0, PC_GETCLINFO, &pcinfo) == -1) {
        if (classid == 0)   /* no kernel info for sys class */
            return (get_info_by_policy(SCHED_SYS));
        return (NULL);
    }

    for (policy = 0, pccp = sched_class;
        policy < NPOLICY;
        policy++, pccp++) {
        if (pccp->pcc_state == 0 &&
            strcmp(pcinfo.pc_clname, pccp->pcc_info.pc_clname) == 0)
            return (get_info_by_policy(pccp->pcc_policy));
    }

    /*
     * We have encountered an unknown (to us) scheduling class.
     * Manufacture a policy number for it.  Hopefully we still
     * have room in the sched_class[] table.
     */
    policy = _SCHED_NEXT + classid;
    if (policy >= NPOLICY) {
        errno = EINVAL;
        return (NULL);
    }
    lmutex_lock(&class_lock);
    pccp = &sched_class[policy];
    pccp->pcc_policy = policy;
    (void) strlcpy(pccp->pcc_info.pc_clname, pcinfo.pc_clname, PC_CLNMSZ);
    lmutex_unlock(&class_lock);
    return (get_info_by_policy(pccp->pcc_policy));
}

/*
 * Helper function: get process or lwp current scheduling policy.
 */
static const pcclass_t *
get_parms(idtype_t idtype, id_t id, pcparms_t *pcparmp)
{
    pcparmp->pc_cid = PC_CLNULL;
    if (priocntl(idtype, id, PC_GETPARMS, pcparmp) == -1)
        return (NULL);
    return (get_info_by_class(pcparmp->pc_cid));
}

/*
 * Helper function for setprio() and setparam(), below.
 */
static int
set_priority(idtype_t idtype, id_t id, int policy, int prio,
    pcparms_t *pcparmp, int settq)
{
    int rv;

    switch (policy) {
    case SCHED_OTHER:
    {
        tsparms_t *tsp = (tsparms_t *)pcparmp->pc_clparms;
        tsp->ts_uprilim = prio;
        tsp->ts_upri = prio;
        break;
    }
    case SCHED_FIFO:
    case SCHED_RR:
    {
        rtparms_t *rtp = (rtparms_t *)pcparmp->pc_clparms;
        rtp->rt_tqnsecs = settq?
            (policy == SCHED_FIFO? RT_TQINF : RT_TQDEF) :
            RT_NOCHANGE;
        rtp->rt_pri = prio;
        break;
    }
    default:
    {
        /*
         * Class-independent method for setting the priority.
         */
        pcprio_t pcprio;

        pcprio.pc_op = PC_SETPRIO;
        pcprio.pc_cid = pcparmp->pc_cid;
        pcprio.pc_val = prio;
        do {
            rv = priocntl(idtype, id, PC_DOPRIO, &pcprio);
        } while (rv == -1 && errno == ENOMEM);
        return (rv);
    }
    }

    do {
        rv = priocntl(idtype, id, PC_SETPARMS, pcparmp);
    } while (rv == -1 && errno == ENOMEM);
    return (rv);
}

/*
 * Utility function, private to libc, used by sched_setparam()
 * and posix_spawn().  Because it is called by the vfork() child of
 * posix_spawn(), we must not call any functions exported from libc.
 */
id_t
setprio(idtype_t idtype, id_t id, int prio, int *policyp)
{
    pcparms_t   pcparm;
    int     policy;
    const pcclass_t *pccp;

    if ((pccp = get_parms(idtype, id, &pcparm)) == NULL)
        return (-1);
    if (prio < pccp->pcc_primin || prio > pccp->pcc_primax) {
        errno = EINVAL;
        return (-1);
    }

    policy = pccp->pcc_policy;
    if (policyp != NULL &&
        (policy == SCHED_FIFO || policy == SCHED_RR)) {
        rtparms_t *rtp = (rtparms_t *)pcparm.pc_clparms;
        policy = (rtp->rt_tqnsecs == RT_TQINF? SCHED_FIFO : SCHED_RR);
    }

    if (set_priority(idtype, id, policy, prio, &pcparm, 0) == -1)
        return (-1);
    if (policyp != NULL)
        *policyp = policy;
    return (pccp->pcc_info.pc_cid);
}

int
sched_setparam(pid_t pid, const struct sched_param *param)
{
    if (pid < 0) {
        errno = ESRCH;
        return (-1);
    }
    if (pid == 0)
        pid = P_MYID;

    if (setprio(P_PID, pid, param->sched_priority, NULL) == -1)
        return (-1);
    return (0);
}

id_t
getparam(idtype_t idtype, id_t id, int *policyp, struct sched_param *param)
{
    pcparms_t pcparm;
    const pcclass_t *pccp;
    int policy;
    int priority;

    if ((pccp = get_parms(idtype, id, &pcparm)) == NULL)
        return (-1);

    switch (policy = pccp->pcc_policy) {
    case SCHED_OTHER:
    {
        tsparms_t *tsp = (tsparms_t *)pcparm.pc_clparms;
        priority = tsp->ts_upri;
        break;
    }
    case SCHED_FIFO:
    case SCHED_RR:
    {
        rtparms_t *rtp = (rtparms_t *)pcparm.pc_clparms;
        priority = rtp->rt_pri;
        policy = (rtp->rt_tqnsecs == RT_TQINF? SCHED_FIFO : SCHED_RR);
        break;
    }
    default:
    {
        /*
         * Class-independent method for getting the priority.
         */
        pcprio_t pcprio;

        pcprio.pc_op = PC_GETPRIO;
        pcprio.pc_cid = 0;
        pcprio.pc_val = 0;
        if (priocntl(idtype, id, PC_DOPRIO, &pcprio) == 0)
            priority = pcprio.pc_val;
        else
            priority = 0;
        break;
    }
    }

    *policyp = policy;
    (void) memset(param, 0, sizeof (*param));
    param->sched_priority = priority;

    return (pcparm.pc_cid);
}

int
sched_getparam(pid_t pid, struct sched_param *param)
{
    int policy;

    if (pid < 0) {
        errno = ESRCH;
        return (-1);
    }
    if (pid == 0)
        pid = P_MYID;

    if (getparam(P_PID, pid, &policy, param) == -1)
        return (-1);
    return (0);
}

/*
 * Utility function, private to libc, used by sched_setscheduler()
 * and posix_spawn().  Because it is called by the vfork() child of
 * posix_spawn(), we must not call any functions exported from libc.
 */
id_t
setparam(idtype_t idtype, id_t id, int policy, int prio)
{
    pcparms_t   pcparm;
    const pcclass_t *pccp;

    if (policy == SCHED_SYS ||
        (pccp = get_info_by_policy(policy)) == NULL ||
        prio < pccp->pcc_primin || prio > pccp->pcc_primax) {
        errno = EINVAL;
        return (-1);
    }

    pcparm.pc_cid = pccp->pcc_info.pc_cid;
    if (set_priority(idtype, id, policy, prio, &pcparm, 1) == -1)
        return (-1);
    return (pccp->pcc_info.pc_cid);
}

int
sched_setscheduler(pid_t pid, int policy, const struct sched_param *param)
{
    pri_t       prio = param->sched_priority;
    int     oldpolicy;

    if ((oldpolicy = sched_getscheduler(pid)) < 0)
        return (-1);

    if (pid == 0)
        pid = P_MYID;

    if (setparam(P_PID, pid, policy, prio) == -1)
        return (-1);

    return (oldpolicy);
}

int
sched_getscheduler(pid_t pid)
{
    pcparms_t   pcparm;
    const pcclass_t *pccp;
    int     policy;

    if (pid < 0) {
        errno = ESRCH;
        return (-1);
    }
    if (pid == 0)
        pid = P_MYID;

    if ((pccp = get_parms(P_PID, pid, &pcparm)) == NULL)
        return (-1);

    if ((policy = pccp->pcc_policy) == SCHED_FIFO || policy == SCHED_RR) {
        policy =
            (((rtparms_t *)pcparm.pc_clparms)->rt_tqnsecs == RT_TQINF?
            SCHED_FIFO : SCHED_RR);
    }

    return (policy);
}

int
sched_yield(void)
{
    yield();
    return (0);
}

int
sched_get_priority_max(int policy)
{
    const pcclass_t *pccp;

    if ((pccp = get_info_by_policy(policy)) != NULL)
        return (pccp->pcc_primax);
    errno = EINVAL;
    return (-1);
}

int
sched_get_priority_min(int policy)
{
    const pcclass_t *pccp;

    if ((pccp = get_info_by_policy(policy)) != NULL)
        return (pccp->pcc_primin);
    errno = EINVAL;
    return (-1);
}

int
sched_rr_get_interval(pid_t pid, timespec_t *interval)
{
    pcparms_t pcparm;
    const pcclass_t *pccp;

    if (pid < 0) {
        errno = ESRCH;
        return (-1);
    }
    if (pid == 0)
        pid = P_MYID;

    if ((pccp = get_parms(P_PID, pid, &pcparm)) == NULL)
        return (-1);

    /*
     * At the moment, we have no class-independent method to fetch
     * the process/lwp time quantum.  Since SUSv3 does not restrict
     * this operation to the real-time class, we return an indefinite
     * quantum (tv_sec == 0 and tv_nsec == 0) for scheduling policies
     * for which this information isn't available.
     */
    interval->tv_sec = 0;
    interval->tv_nsec = 0;

    switch (pccp->pcc_policy) {
    case SCHED_FIFO:
    case SCHED_RR:
        {
            rtparms_t *rtp = (rtparms_t *)pcparm.pc_clparms;
            if (rtp->rt_tqnsecs != RT_TQINF) {
                interval->tv_sec = rtp->rt_tqsecs;
                interval->tv_nsec = rtp->rt_tqnsecs;
            }
        }
        break;
    case SCHED_FX:
        {
            fxparms_t *fxp = (fxparms_t *)pcparm.pc_clparms;
            if (fxp->fx_tqnsecs != FX_TQINF) {
                interval->tv_sec = fxp->fx_tqsecs;
                interval->tv_nsec = fxp->fx_tqnsecs;
            }
        }
        break;
    }

    return (0);
}

/*
 * Initialize or update ul_policy, ul_cid, and ul_pri.
 */
void
update_sched(ulwp_t *self)
{
    volatile sc_shared_t *scp;
    pcparms_t pcparm;
    pcprio_t pcprio;
    const pcclass_t *pccp;
    int priority;
    int policy;

    ASSERT(self == curthread);

    enter_critical(self);

    if ((scp = self->ul_schedctl) == NULL &&
        (scp = setup_schedctl()) == NULL) {     /* can't happen? */
        if (self->ul_policy < 0) {
            self->ul_cid = 0;
            self->ul_pri = 0;
            _membar_producer();
            self->ul_policy = SCHED_OTHER;
        }
        exit_critical(self);
        return;
    }

    if (self->ul_policy >= 0 &&
        self->ul_cid == scp->sc_cid &&
        (self->ul_pri == scp->sc_cpri ||
        (self->ul_epri > 0 && self->ul_epri == scp->sc_cpri))) {
        exit_critical(self);
        return;
    }

    pccp = get_parms(P_LWPID, P_MYID, &pcparm);
    if (pccp == NULL) {     /* can't happen? */
        self->ul_cid = scp->sc_cid;
        self->ul_pri = scp->sc_cpri;
        _membar_producer();
        self->ul_policy = SCHED_OTHER;
        exit_critical(self);
        return;
    }

    switch (policy = pccp->pcc_policy) {
    case SCHED_OTHER:
        priority = ((tsparms_t *)pcparm.pc_clparms)->ts_upri;
        break;
    case SCHED_FIFO:
    case SCHED_RR:
        self->ul_rtclassid = pccp->pcc_info.pc_cid;
        priority = ((rtparms_t *)pcparm.pc_clparms)->rt_pri;
        policy =
            ((rtparms_t *)pcparm.pc_clparms)->rt_tqnsecs == RT_TQINF?
            SCHED_FIFO : SCHED_RR;
        break;
    default:
        /*
         * Class-independent method for getting the priority.
         */
        pcprio.pc_op = PC_GETPRIO;
        pcprio.pc_cid = 0;
        pcprio.pc_val = 0;
        if (priocntl(P_LWPID, P_MYID, PC_DOPRIO, &pcprio) == 0)
            priority = pcprio.pc_val;
        else
            priority = 0;
    }

    self->ul_cid = pcparm.pc_cid;
    self->ul_pri = priority;
    _membar_producer();
    self->ul_policy = policy;

    exit_critical(self);
}