/*
* 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/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/kernel.h>
#include <sys/resource.h>
#include <machine/cpu.h> /* For need_resched */
#include <posix4/posix4.h>
/* ksched: Real-time extension to support POSIX priority scheduling.
*/
struct ksched {
struct timespec rr_interval;
};
int ksched_attach(struct ksched **p)
{
struct ksched *ksched= p31b_malloc(sizeof(*ksched));
ksched->rr_interval.tv_sec = 0;
ksched->rr_interval.tv_nsec = 1000000000L / roundrobin_interval();
*p = ksched;
return 0;
}
int ksched_detach(struct ksched *p)
{
p31b_free(p);
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.
*
* I'm rejecting sched_setparam for SCHED_OTHER with EINVAL.
*/
/* 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))
/* 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(int *ret, struct ksched *ksched, struct proc *p)
{
int e = 0;
switch (p->p_rtprio.type)
{
case RTP_PRIO_FIFO:
*ret = SCHED_FIFO;
break;
case RTP_PRIO_REALTIME:
*ret = SCHED_RR;
break;
default:
*ret = SCHED_OTHER;
break;
}
return e;
}
int ksched_setparam(int *ret, struct ksched *ksched,
struct proc *p, const struct sched_param *param)
{
int e, policy;
e = getscheduler(&policy, ksched, p);
if (e == 0)
{
if (policy == SCHED_OTHER)
e = EINVAL;
else
e = ksched_setscheduler(ret, ksched, p, policy, param);
}
return e;
}
int ksched_getparam(int *ret, struct ksched *ksched,
struct proc *p, struct sched_param *param)
{
if (RTP_PRIO_IS_REALTIME(p->p_rtprio.type))
param->sched_priority = rtpprio_to_p4prio(p->p_rtprio.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(int *ret, struct ksched *ksched,
struct proc *p, int policy, const struct sched_param *param)
{
int e = 0;
struct rtprio rtp;
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;
p->p_rtprio = rtp;
need_resched();
}
else
e = EPERM;
break;
case SCHED_OTHER:
{
rtp.type = RTP_PRIO_NORMAL;
rtp.prio = p4prio_to_rtpprio(param->sched_priority);
p->p_rtprio = rtp;
/* XXX Simply revert to whatever we had for last
* normal scheduler priorities.
* This puts a requirement
* on the scheduling code: You must leave the
* scheduling info alone.
*/
need_resched();
}
break;
}
return e;
}
int ksched_getscheduler(int *ret, struct ksched *ksched, struct proc *p)
{
return getscheduler(ret, ksched, p);
}
/* ksched_yield: Yield the CPU.
*/
int ksched_yield(int *ret, struct ksched *ksched)
{
need_resched();
return 0;
}
int ksched_get_priority_max(int *ret, struct ksched *ksched, int policy)
{
int e = 0;
switch (policy)
{
case SCHED_FIFO:
case SCHED_RR:
*ret = RTP_PRIO_MAX;
break;
case SCHED_OTHER:
*ret = PRIO_MAX;
break;
default:
e = EINVAL;
}
return e;
}
int ksched_get_priority_min(int *ret, struct ksched *ksched, int policy)
{
int e = 0;
switch (policy)
{
case SCHED_FIFO:
case SCHED_RR:
*ret = P1B_PRIO_MIN;
break;
case SCHED_OTHER:
*ret = PRIO_MIN;
break;
default:
e = EINVAL;
}
return e;
}
int ksched_rr_get_interval(int *ret, struct ksched *ksched,
struct proc *p, struct timespec *timespec)
{
*timespec = ksched->rr_interval;
return 0;
}
