/*-
* SPDX-License-Identifier: BSD-4-Clause
*
* Copyright (c) 1996, 1997
* HD Associates, Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by HD Associates, Inc
* 4. Neither the name of the author nor the names of any co-contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY HD ASSOCIATES AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL HD ASSOCIATES OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
/* ksched: Soft real time scheduling based on "rtprio". */
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_posix.h"
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/lock.h>
#include <sys/sysctl.h>
#include <sys/kernel.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/posix4.h>
#include <sys/resource.h>
#include <sys/sched.h>
FEATURE(kposix_priority_scheduling, "POSIX P1003.1B realtime extensions");
/* ksched: Real-time extension to support POSIX priority scheduling. */
struct ksched {
struct timespec rr_interval;
};
int
ksched_attach(struct ksched **p)
{
struct ksched *ksched;
ksched = malloc(sizeof(*ksched), M_P31B, M_WAITOK);
ksched->rr_interval.tv_sec = 0;
ksched->rr_interval.tv_nsec = 1000000000L / hz * sched_rr_interval();
*p = ksched;
return (0);
}
int
ksched_detach(struct ksched *ks)
{
free(ks, M_P31B);
return (0);
}
/*
* XXX About priorities
*
* POSIX 1003.1b requires that numerically higher priorities be of
* higher priority. It also permits sched_setparam to be
* implementation defined for SCHED_OTHER. I don't like
* the notion of inverted priorites for normal processes when
* you can use "setpriority" for that.
*
*/
/* Macros to convert between the unix (lower numerically is higher priority)
* and POSIX 1003.1b (higher numerically is higher priority)
*/
#define p4prio_to_rtpprio(P) (RTP_PRIO_MAX - (P))
#define rtpprio_to_p4prio(P) (RTP_PRIO_MAX - (P))
#define p4prio_to_tsprio(P) ((PRI_MAX_TIMESHARE - PRI_MIN_TIMESHARE) - (P))
#define tsprio_to_p4prio(P) ((PRI_MAX_TIMESHARE - PRI_MIN_TIMESHARE) - (P))
/* These improve readability a bit for me:
*/
#define P1B_PRIO_MIN rtpprio_to_p4prio(RTP_PRIO_MAX)
#define P1B_PRIO_MAX rtpprio_to_p4prio(RTP_PRIO_MIN)
static __inline int
getscheduler(struct ksched *ksched, struct thread *td, int *policy)
{
struct rtprio rtp;
int e;
e = 0;
pri_to_rtp(td, &rtp);
switch (rtp.type) {
case RTP_PRIO_FIFO:
*policy = SCHED_FIFO;
break;
case RTP_PRIO_REALTIME:
*policy = SCHED_RR;
break;
default:
*policy = SCHED_OTHER;
break;
}
return (e);
}
int
ksched_setparam(struct ksched *ksched,
struct thread *td, const struct sched_param *param)
{
int e, policy;
e = getscheduler(ksched, td, &policy);
if (e == 0)
e = ksched_setscheduler(ksched, td, policy, param);
return (e);
}
int
ksched_getparam(struct ksched *ksched, struct thread *td,
struct sched_param *param)
{
struct rtprio rtp;
pri_to_rtp(td, &rtp);
if (RTP_PRIO_IS_REALTIME(rtp.type))
param->sched_priority = rtpprio_to_p4prio(rtp.prio);
else {
if (PRI_MIN_TIMESHARE < rtp.prio)
/*
* The interactive score has it to min realtime
* so we must show max (64 most likely).
*/
param->sched_priority = PRI_MAX_TIMESHARE -
PRI_MIN_TIMESHARE;
else
param->sched_priority = tsprio_to_p4prio(rtp.prio);
}
return (0);
}
/*
* XXX The priority and scheduler modifications should
* be moved into published interfaces in kern/kern_sync.
*
* The permissions to modify process p were checked in "p31b_proc()".
*
*/
int
ksched_setscheduler(struct ksched *ksched, struct thread *td, int policy,
const struct sched_param *param)
{
struct rtprio rtp;
int e;
e = 0;
switch(policy) {
case SCHED_RR:
case SCHED_FIFO:
if (param->sched_priority >= P1B_PRIO_MIN &&
param->sched_priority <= P1B_PRIO_MAX) {
rtp.prio = p4prio_to_rtpprio(param->sched_priority);
rtp.type = (policy == SCHED_FIFO) ? RTP_PRIO_FIFO :
RTP_PRIO_REALTIME;
rtp_to_pri(&rtp, td);
} else {
e = EPERM;
}
break;
case SCHED_OTHER:
if (param->sched_priority >= 0 && param->sched_priority <=
(PRI_MAX_TIMESHARE - PRI_MIN_TIMESHARE)) {
rtp.type = RTP_PRIO_NORMAL;
rtp.prio = p4prio_to_tsprio(param->sched_priority);
rtp_to_pri(&rtp, td);
} else {
e = EINVAL;
}
break;
default:
e = EINVAL;
break;
}
return (e);
}
int
ksched_getscheduler(struct ksched *ksched, struct thread *td, int *policy)
{
return (getscheduler(ksched, td, policy));
}
/* ksched_yield: Yield the CPU. */
int
ksched_yield(struct ksched *ksched)
{
sched_relinquish(curthread);
return (0);
}
int
ksched_get_priority_max(struct ksched *ksched, int policy, int *prio)
{
int e;
e = 0;
switch (policy) {
case SCHED_FIFO:
case SCHED_RR:
*prio = P1B_PRIO_MAX;
break;
case SCHED_OTHER:
*prio = PRI_MAX_TIMESHARE - PRI_MIN_TIMESHARE;
break;
default:
e = EINVAL;
break;
}
return (e);
}
int
ksched_get_priority_min(struct ksched *ksched, int policy, int *prio)
{
int e;
e = 0;
switch (policy) {
case SCHED_FIFO:
case SCHED_RR:
*prio = P1B_PRIO_MIN;
break;
case SCHED_OTHER:
*prio = 0;
break;
default:
e = EINVAL;
break;
}
return (e);
}
int
ksched_rr_get_interval(struct ksched *ksched, struct thread *td,
struct timespec *timespec)
{
*timespec = ksched->rr_interval;
return (0);
}
