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/*
* Project: S.Ha.R.K.
*
* Coordinators:
* Giorgio Buttazzo <giorgio@sssup.it>
* Paolo Gai <pj@gandalf.sssup.it>
*
* Authors :
* Paolo Gai <pj@gandalf.sssup.it>
* Massimiliano Giorgi <massy@gandalf.sssup.it>
* Luca Abeni <luca@gandalf.sssup.it>
* (see the web pages for full authors list)
*
* ReTiS Lab (Scuola Superiore S.Anna - Pisa - Italy)
*
* http://www.sssup.it
* http://retis.sssup.it
* http://shark.sssup.it
*/
/**
------------
CVS : $Id: rr.c,v 1.4 2003-01-07 17:07:50 pj Exp $
File: $File$
Revision: $Revision: 1.4 $
Last update: $Date: 2003-01-07 17:07:50 $
------------
This file contains the scheduling module RR (Round Robin)
Read rr.h for further details.
**/
/*
* Copyright (C) 2000 Paolo Gai
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
#include <modules/rr.h>
#include <ll/stdio.h>
#include <ll/string.h>
#include <kernel/model.h>
#include <kernel/descr.h>
#include <kernel/var.h>
#include <kernel/func.h>
#include <kernel/trace.h>
//#define RRDEBUG
#define rr_printf kern_printf
/*+ Status used in the level +*/
#define RR_READY MODULE_STATUS_BASE
/*+ the level redefinition for the Round Robin level +*/
typedef struct {
level_des l; /*+ the standard level descriptor +*/
IQUEUE ready; /*+ the ready queue +*/
int slice; /*+ the level's time slice +*/
struct multiboot_info *multiboot; /*+ used if the level have to insert
the main task +*/
} RR_level_des;
/* This is not efficient but very fair :-)
The need of all this stuff is because if a task execute a long time
due to (shadow!) priority inheritance, then the task shall go to the
tail of the queue many times... */
static PID RR_public_scheduler(LEVEL l)
{
RR_level_des *lev = (RR_level_des *)(level_table[l]);
PID p;
#ifdef RRDEBUG
rr_printf("(RRs",p);
#endif
for (;;) {
p = iq_query_first(&lev->ready);
if (p == -1) {
#ifdef RRDEBUG
rr_printf(" %d)",p);
#endif
return p;
}
if (proc_table[p].avail_time <= 0) {
proc_table[p].avail_time += proc_table[p].wcet;
iq_extract(p,&lev->ready);
iq_insertlast(p,&lev->ready);
}
else {
#ifdef RRDEBUG
rr_printf(" %d)",p);
#endif
return p;
}
}
}
static int RR_public_create(LEVEL l, PID p, TASK_MODEL *m)
{
RR_level_des *lev = (RR_level_des *)(level_table[l]);
NRT_TASK_MODEL *nrt;
#ifdef RRDEBUG
rr_printf("(create %d!!!!)",p);
#endif
if (m->pclass != NRT_PCLASS) return -1;
if (m->level != 0 && m->level != l) return -1;
nrt = (NRT_TASK_MODEL *)m;
/* the task state is set at SLEEP by the general task_create
the only thing to set remains the capacity stuffs that are set
to the values passed in the model... */
/* I used the wcet field because using wcet can account if a task
consume more than the timeslice... */
if (nrt->slice) {
proc_table[p].avail_time = nrt->slice;
proc_table[p].wcet = nrt->slice;
}
else {
proc_table[p].avail_time = lev->slice;
proc_table[p].wcet = lev->slice;
}
proc_table[p].control |= CONTROL_CAP;
#ifdef RRDEBUG
rr_printf("(c%d av%d w%d )",p,proc_table[p].avail_time,proc_table[p].wcet);
#endif
return 0; /* OK */
}
static void RR_public_dispatch(LEVEL l, PID p, int nostop)
{
RR_level_des *lev = (RR_level_des *)(level_table[l]);
/* the task state is set EXE by the scheduler()
we extract the task from the ready queue
NB: we can't assume that p is the first task in the queue!!! */
iq_extract(p, &lev->ready);
#ifdef RRDEBUG
rr_printf("(dis%d)",p);
#endif
}
static void RR_public_epilogue(LEVEL l, PID p)
{
RR_level_des *lev = (RR_level_des *)(level_table[l]);
/* check if the slice is finished and insert the task in the correct
qqueue position */
if (proc_table[p].avail_time <= 0) {
proc_table[p].avail_time += proc_table[p].wcet;
iq_insertlast(p,&lev->ready);
}
else
/* curr is >0, so the running task have to run for another curr usec */
iq_insertfirst(p,&lev->ready);
proc_table[p].status = RR_READY;
#ifdef RRDEBUG
rr_printf("(epi%d)",p);
#endif
}
static void RR_public_activate(LEVEL l, PID p)
{
RR_level_des *lev = (RR_level_des *)(level_table[l]);
/* Test if we are trying to activate a non sleeping task */
/* Ignore this; the task is already active */
if (proc_table[p].status != SLEEP)
return;
/* Insert task in the correct position */
proc_table[p].status = RR_READY;
iq_insertlast(p,&lev->ready);
#ifdef RRDEBUG
rr_printf("(act%d)",p);
#endif
}
static void RR_public_unblock(LEVEL l, PID p)
{
RR_level_des *lev = (RR_level_des *)(level_table[l]);
/* Similar to RR_task_activate,
but we don't check in what state the task is */
/* Insert task in the correct position */
proc_table[p].status = RR_READY;
iq_insertlast(p,&lev->ready);
#ifdef RRDEBUG
rr_printf("(ubl%d)",p);
#endif
}
static void RR_public_block(LEVEL l, PID p)
{
/* Extract the running task from the level
. we have already extract it from the ready queue at the dispatch time.
. the capacity event have to be removed by the generic kernel
. the wcet don't need modification...
. the state of the task is set by the calling function
So, we do nothing!!!
*/
#ifdef RRDEBUG
rr_printf("(bl%d)",p);
#endif
}
static int RR_public_message(LEVEL l, PID p, void *m)
{
proc_table[p].status = SLEEP;
jet_update_endcycle(); /* Update the Jet data... */
trc_logevent(TRC_ENDCYCLE,&exec_shadow); /* tracer stuff */
#ifdef RRDEBUG
rr_printf("(msg%d)",p);
#endif
return 0;
}
static void RR_public_end(LEVEL l, PID p)
{
/* we insert the task in the free queue */
proc_table[p].status = FREE;
iq_insertlast(p,&freedesc);
#ifdef RRDEBUG
rr_printf("(end%d)",p);
#endif
}
/* Registration functions */
/*+ This init function install the "main" task +*/
static void RR_call_main(void *l)
{
LEVEL lev;
PID p;
NRT_TASK_MODEL m;
void *mb;
lev = (LEVEL)l;
nrt_task_default_model(m);
nrt_task_def_level(m,lev); /* with this we are sure that the task arrives
to the correct level */
mb = ((RR_level_des *)level_table[lev])->multiboot;
nrt_task_def_arg(m,mb);
nrt_task_def_usemath(m);
nrt_task_def_nokill(m);
nrt_task_def_ctrl_jet(m);
p = task_create("Main", __init__, (TASK_MODEL *)&m, NULL);
if (p == NIL)
printk(KERN_EMERG "Panic!!! can't create main task... errno =%d\n",errno);
RR_public_activate(lev,p);
#ifdef RRDEBUG
rr_printf("(main created %d)",p);
#endif
}
/*+ Registration function:
TIME slice the slice for the Round Robin queue
int createmain 1 if the level creates the main task 0 otherwise
struct multiboot_info *mb used if createmain specified +*/
LEVEL RR_register_level(TIME slice,
int createmain,
struct multiboot_info *mb)
{
LEVEL l; /* the level that we register */
RR_level_des *lev; /* for readableness only */
printk("RR_register_level\n");
/* request an entry in the level_table */
l = level_alloc_descriptor(sizeof(RR_level_des));
lev = (RR_level_des *)level_table[l];
printk(" lev=%d\n",(int)lev);
/* fill the standard descriptor */
lev->l.public_scheduler = RR_public_scheduler;
lev->l.public_create = RR_public_create;
lev->l.public_end = RR_public_end;
lev->l.public_dispatch = RR_public_dispatch;
lev->l.public_epilogue = RR_public_epilogue;
lev->l.public_activate = RR_public_activate;
lev->l.public_unblock = RR_public_unblock;
lev->l.public_block = RR_public_block;
lev->l.public_message = RR_public_message;
/* fill the RR descriptor part */
iq_init(&lev->ready, &freedesc, 0);
if (slice < RR_MINIMUM_SLICE) slice = RR_MINIMUM_SLICE;
if (slice > RR_MAXIMUM_SLICE) slice = RR_MAXIMUM_SLICE;
lev->slice = slice;
lev->multiboot = mb;
if (createmain)
sys_atrunlevel(RR_call_main,(void *) l, RUNLEVEL_INIT);
return l;
}