Blame |
Last modification |
View Log
| RSS feed
/*
* Project: S.Ha.R.K.
*
* Coordinators:
* Giorgio Buttazzo <giorgio@sssup.it>
* Paolo Gai <pj@gandalf.sssup.it>
*
* Authors :
* Trimarchi Michael <trimarchi@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: posixstar.c,v 1.1 2004-06-01 11:42:44 giacomo Exp $
File: $File$
Revision: $Revision: 1.1 $
Last update: $Date: 2004-06-01 11:42:44 $
------------
This file contains the scheduling module compatible with POSIX
specifications
Read posixstar.h for further details.
RR tasks have the CONTROL_CAP bit set
**/
/*
* 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 WARR2ANTY; without even the implied waRR2anty 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 <ll/stdio.h>
#include <ll/string.h>
#include <kernel/model.h>
#include <kernel/descr.h>
#include <kernel/var.h>
#include <kernel/func.h>
#include "posixstar.h"
#include "cbsstar.h"
//#define POSIXSTAR_DEBUG
/*+ Status used in the level +*/
#define POSIXSTAR_READY MODULE_STATUS_BASE
/*+ the level redefinition for the Round Robin level +*/
typedef struct {
level_des l; /*+ the standard level descriptor +*/
int nact[MAX_PROC]; /*+ number of pending activations +*/
int priority[MAX_PROC]; /*+ priority of each task +*/
IQUEUE *ready; /*+ the ready queue array +*/
int slice; /*+ the level's time slice +*/
// the multiboot is not usefull for this module
// struct multiboot_info *multiboot; /*+ used if the level have to insert
// the main task +*/
int maxpriority; /*+ the priority are from 0 to maxpriority
(i.e 0 to 31) +*/
int yielding; /*+ equal to 1 when a sched_yield is called +*/
int budget;
PID activated;
int scheduling_level;
} POSIXSTAR_level_des;
/* the private scheduler choice a task and insert in cbsstar module */
/* 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 void POSIXSTAR_private_scheduler(POSIXSTAR_level_des * lev)
{
/* the old posix scheduler select the private job for CBS */
PID p=NIL;
int prio;
prio = lev->maxpriority;
for (;;) {
p = iq_query_first(&lev->ready[prio]);
if (p == NIL) {
if (prio) {
prio--;
continue;
}
else {
p=NIL;
break;
}
}
//if (p != NIL && (proc_table[p].control & CONTROL_CAP))
// kern_printf("CC SET %d",p);
//kern_printf("task %d", p);
if ((proc_table[p].control & CONTROL_CAP) &&
(proc_table[p].avail_time <= 0)) {
if (proc_table[p].avail_time<=0)
proc_table[p].avail_time += proc_table[p].wcet;
//kern_printf("RR policy");
iq_extract(p,&lev->ready[prio]);
iq_insertlast(p,&lev->ready[prio]);
}
else {
break;
}
}
if (p!=lev->activated) {
if (lev->activated != NIL ) {
level_table[ lev->scheduling_level ]->
private_extract(lev->scheduling_level, lev->activated);
//kern_printf("CBS ext %d",p);
}
lev->activated = p;
if (p != NIL) {
BUDGET_TASK_MODEL b;
budget_task_default_model(b, lev->budget);
//kern_printf("(Act %d",p);
level_table[ lev->scheduling_level ]->
private_insert(lev->scheduling_level, p, (TASK_MODEL *)&b);
}
}
}
static int POSIXSTAR_public_eligible(LEVEL l, PID p)
{
POSIXSTAR_level_des *lev = (POSIXSTAR_level_des *)(level_table[l]);
if (p==lev->activated) {
//kern_printf("eli %d", p);
return level_table[ lev->scheduling_level ]->
private_eligible(lev->scheduling_level,p);
}
return 0;
}
static int POSIXSTAR_public_create(LEVEL l, PID p, TASK_MODEL *m)
{
POSIXSTAR_level_des *lev = (POSIXSTAR_level_des *)(level_table[l]);
NRT_TASK_MODEL *nrt;
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 */
/* I used the wcet field because using wcet can account if a task
consume more than the timeslice... */
if (nrt->inherit == NRT_INHERIT_SCHED &&
proc_table[exec_shadow].task_level == l) {
/* We inherit the scheduling properties if the scheduling level
*is* the same */
lev->priority[p] = lev->priority[exec_shadow];
proc_table[p].avail_time = proc_table[exec_shadow].avail_time;
proc_table[p].wcet = proc_table[exec_shadow].wcet;
proc_table[p].control = (proc_table[p].control & ~CONTROL_CAP) |
(proc_table[exec_shadow].control & CONTROL_CAP);
lev->nact[p] = (lev->nact[exec_shadow] == -1) ? -1 : 0;
}
else {
if (nrt->weight<=lev->maxpriority)
lev->priority[p] = nrt->weight;
else lev->priority[p]=lev->maxpriority;
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;
}
if (nrt->policy == NRT_RR_POLICY) {
proc_table[p].control |= CONTROL_CAP;
//kern_printf("CCAP set:%d",p);
}
if (nrt->arrivals == SAVE_ARRIVALS)
lev->nact[p] = 0;
else
lev->nact[p] = -1;
}
return 0; /* OK */
}
static void POSIXSTAR_public_dispatch(LEVEL l, PID p, int nostop)
{
POSIXSTAR_level_des *lev = (POSIXSTAR_level_des *)(level_table[l]);
//#ifdef POSIXSTAR_DEBUG
//#endif
/* 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[lev->priority[p]]);
//if (!nostop) {
//kern_printf("PDisp:%d(%d)",p, lev->activated);
if (p==lev->activated)
level_table[lev->scheduling_level]->private_dispatch(lev->scheduling_level, p, nostop);
//} else
// kern_printf("PDisp:%d(%d)",p, lev->activated);
}
static void POSIXSTAR_public_epilogue(LEVEL l, PID p)
{
POSIXSTAR_level_des *lev = (POSIXSTAR_level_des *)(level_table[l]);
//#ifdef POSIXSTAR_DEBUG
//kern_printf("PEpic:%d",p);
//#endif
if (p==lev->activated) {
if (lev->yielding) {
lev->yielding = 0;
iq_extract(p,&lev->ready[lev->priority[p]]);
iq_insertlast(p,&lev->ready[lev->priority[p]]);
}
/* check if the slice is finished and insert the task in the coPOSIXect
qqueue position */
else if (proc_table[p].control & CONTROL_CAP &&
proc_table[p].avail_time <= 0) {
//proc_table[p].avail_time += proc_table[p].wcet;
//kern_printf("avail_time %d", proc_table[p].avail_time);
iq_extract(p,&lev->ready[lev->priority[p]]);
iq_insertlast(p,&lev->ready[lev->priority[p]]);
//level_table[lev->scheduling_level]->private_extract(lev->scheduling_level,p);
//lev->activated=NIL;
POSIXSTAR_private_scheduler(lev);
if (p==lev->activated)
level_table[lev->scheduling_level]->private_epilogue(lev->scheduling_level,p);
}
else {
//iq_insertfirst(p,&lev->ready[lev->priority[p]]);
level_table[lev->scheduling_level]->private_epilogue(lev->scheduling_level,p);
}
proc_table[p].status = POSIXSTAR_READY;
}
}
static void POSIXSTAR_internal_activate(POSIXSTAR_level_des *lev, PID p)
{
/* Insert task in the correct position */
proc_table[p].status = POSIXSTAR_READY;
iq_insertlast(p,&lev->ready[lev->priority[p]]);
}
static void POSIXSTAR_public_activate(LEVEL l, PID p)
{
POSIXSTAR_level_des *lev = (POSIXSTAR_level_des *)(level_table[l]);
/* Test if we are trying to activate a non sleeping task */
/* save activation (only if needed...) */
if (proc_table[p].status != SLEEP) {
if (lev->nact[p] != -1)
lev->nact[p]++;
return;
}
#ifdef POSIXSTAR_DEBUG
kern_printf("PA:%d",p);
#endif
POSIXSTAR_internal_activate(lev, p);
POSIXSTAR_private_scheduler(lev);
}
static void POSIXSTAR_public_unblock(LEVEL l, PID p)
{
POSIXSTAR_level_des *lev = (POSIXSTAR_level_des *)(level_table[l]);
/* Similar to POSIX_task_activate, but we don't check in what state
the task is */
/* Insert task in the coPOSIXect position */
//kern_printf("PU:%d", p);
proc_table[p].status = POSIXSTAR_READY;
iq_insertlast(p,&lev->ready[lev->priority[p]]);
POSIXSTAR_private_scheduler(lev);
}
static void POSIXSTAR_public_block(LEVEL l, PID p)
{
POSIXSTAR_level_des *lev = (POSIXSTAR_level_des *)(level_table[l]);
/* 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 POSIXSTAR_DEBUG
//kern_printf("PB:%d", p);
//#endif
iq_extract(p,&lev->ready[lev->priority[p]]);
POSIXSTAR_private_scheduler(lev);
}
static int POSIXSTAR_public_message(LEVEL l, PID p, void *m)
{
POSIXSTAR_level_des *lev = (POSIXSTAR_level_des *)(level_table[l]);
if (lev->nact[p] > 0) {
/* continue!!!! */
lev->nact[p]--;
iq_extract(p,&lev->ready[lev->priority[p]]);
iq_insertfirst(p,&lev->ready[lev->priority[p]]);
proc_table[p].status = POSIXSTAR_READY;
}
else {
proc_table[p].status = SLEEP;
}
//#ifdef POSIXSTAR_DEBUG
kern_printf("PM:%d",p);
//#endif
POSIXSTAR_private_scheduler(lev);
return 0;
}
static void POSIXSTAR_public_end(LEVEL l, PID p)
{
POSIXSTAR_level_des *lev = (POSIXSTAR_level_des *)(level_table[l]);
#ifdef POSIXSTAR_DEBUG
kern_printf("PEnd:%d", p);
#endif
lev->nact[p] = -1;
/* then, we insert the task in the free queue */
proc_table[p].status = FREE;
iq_priority_insert(p,NULL);
POSIXSTAR_private_scheduler(lev);
}
/* Registration functions */
/*+ Registration function:
TIME slice the slice for the Round Robin queue
struct multiboot_info *mb used if createmain specified +*/
LEVEL POSIXSTAR_register_level(int budget, int master, TIME slice,
int prioritylevels)
{
LEVEL l; /* the level that we register */
POSIXSTAR_level_des *lev; /* for readableness only */
PID i; /* a counter */
int x; /* a counter */
printk("POSIXSTAR_register_level\n");
l = level_alloc_descriptor(sizeof(POSIXSTAR_level_des));
lev = (POSIXSTAR_level_des *)level_table[l];
printk(" lev=%d\n",(int)lev);
/* fill the standard descriptor */
/*
lev->l.private_insert = NULL;
lev->l.private_extract = NULL;
lev->l.private_dispatch = NULL;
lev->l.private_epilogue = NULL;
*/
//lev->l.public_scheduler = NULL;
lev->l.public_create = POSIXSTAR_public_create;
lev->l.public_end = POSIXSTAR_public_end;
lev->l.public_dispatch = POSIXSTAR_public_dispatch;
lev->l.public_epilogue = POSIXSTAR_public_epilogue;
lev->l.public_activate = POSIXSTAR_public_activate;
lev->l.public_unblock = POSIXSTAR_public_unblock;
lev->l.public_block = POSIXSTAR_public_block;
lev->l.public_message = POSIXSTAR_public_message;
lev->l.public_eligible = POSIXSTAR_public_eligible;
/* fill the POSIX descriptor part */
for (i = 0; i < MAX_PROC; i++)
lev->nact[i] = -1;
lev->maxpriority = prioritylevels -1;
lev->ready = (IQUEUE *)kern_alloc(sizeof(IQUEUE) * prioritylevels);
for (x = 0; x < prioritylevels; x++)
iq_init(&lev->ready[x], NULL, 0);
if (slice < POSIXSTAR_MINIMUM_SLICE) slice = POSIXSTAR_MINIMUM_SLICE;
if (slice > POSIXSTAR_MAXIMUM_SLICE) slice = POSIXSTAR_MAXIMUM_SLICE;
lev->slice = slice;
lev->activated=NIL;
lev->budget = budget;
lev->scheduling_level = master;
//lev->multiboot = mb;
//if (createmain)
// sys_atrunlevel(POSIXSTAR_call_main,(void *) l, RUNLEVEL_INIT);
return l;
}
/*+ this function forces the running task to go to his queue tail;
(it works only on the POSIX level) +*/
int POSIXSTAR_sched_yield(LEVEL l)
{
POSIXSTAR_level_des *lev = (POSIXSTAR_level_des *)(level_table[l]);
if (proc_table[exec_shadow].task_level != l)
return -1;
proc_table[exec_shadow].context = kern_context_save();
lev->yielding = 1;
scheduler();
kern_context_load(proc_table[exec_shadow].context);
return 0;
}
/*+ this function returns the maximum level allowed for the POSIX level +*/
int POSIXSTAR_get_priority_max(LEVEL l)
{
POSIXSTAR_level_des *lev = (POSIXSTAR_level_des *)(level_table[l]);
return lev->maxpriority;
}
/*+ this function returns the default timeslice for the POSIX level +*/
int POSIXSTAR_rr_get_interval(LEVEL l)
{
POSIXSTAR_level_des *lev = (POSIXSTAR_level_des *)(level_table[l]);
return lev->slice;
}
/*+ this functions returns some paramaters of a task;
policy must be NRT_RR_POLICY or NRT_FIFO_POLICY;
priority must be in the range [0..prioritylevels]
returns ENOSYS or ESRCH if there are problems +*/
int POSIXSTAR_getschedparam(LEVEL l, PID p, int *policy, int *priority)
{
if (p<0 || p>= MAX_PROC || proc_table[p].status == FREE)
return ESRCH;
if (proc_table[p].task_level != l)
return ENOSYS;
if (proc_table[p].control & CONTROL_CAP)
*policy = NRT_RR_POLICY;
else
*policy = NRT_FIFO_POLICY;
*priority = ((POSIXSTAR_level_des *)(level_table[l]))->priority[p];
return 0;
}
/*+ this functions sets paramaters of a task +*/
int POSIXSTAR_setschedparam(LEVEL l, PID p, int policy, int priority)
{
POSIXSTAR_level_des *lev = (POSIXSTAR_level_des *)(level_table[l]);
if (p<0 || p>= MAX_PROC || proc_table[p].status == FREE)
return ESRCH;
if (proc_table[p].task_level != l)
return ENOSYS;
if (policy == SCHED_RR)
proc_table[p].control |= CONTROL_CAP;
else if (policy == SCHED_FIFO)
proc_table[p].control &= ~CONTROL_CAP;
else
return EINVAL;
if (lev->priority[p] != priority) {
if (proc_table[p].status == POSIXSTAR_READY) {
iq_extract(p,&lev->ready[lev->priority[p]]);
lev->priority[p] = priority;
iq_insertlast(p,&lev->ready[priority]);
}
else
lev->priority[p] = priority;
}
return 0;
}