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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: rr2.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 RR2 (Round Robin) version 2

 Read rr2.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 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 <modules/rr2.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>

/*+ Status used in the level +*/

#define RR2_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       +*/

  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 +*/

} RR2_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 RR2_public_scheduler(LEVEL l)

{

  RR2_level_des *lev = (RR2_level_des *)(level_table[l]);

  PID p;

  for (;;) {

    p = iq_query_first(&lev->ready);

    if (p == -1)

      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

      return p;

  }

}

static int RR2_public_create(LEVEL l, PID p, TASK_MODEL *m)

{

  RR2_level_des *lev = (RR2_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

     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;

  if (nrt->arrivals == SAVE_ARRIVALS)

    lev->nact[p] = 0;

  else

    lev->nact[p] = -1;

  return 0; /* OK */

}

static void RR2_public_dispatch(LEVEL l, PID p, int nostop)

{

  RR2_level_des *lev = (RR2_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);

}

static void RR2_public_epilogue(LEVEL l, PID p)

{

  RR2_level_des *lev = (RR2_level_des *)(level_table[l]);

  /* check if the slice is finished and insert the task in the coRR2ect

     qqueue position */

  if (proc_table[p].avail_time <= 0) {

    proc_table[p].avail_time += proc_table[p].wcet;

    iq_insertlast(p,&lev->ready);

  }

  else

    /* cuRR2 is >0, so the running task have to run for another cuRR2 usec */

    iq_insertfirst(p,&lev->ready);

  proc_table[p].status = RR2_READY;

}

static void RR2_public_activate(LEVEL l, PID p)

{

  RR2_level_des *lev = (RR2_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;

  }

  /* Insert task in the coRR2ect position */

  proc_table[p].status = RR2_READY;

  iq_insertlast(p,&lev->ready);

}

static void RR2_public_unblock(LEVEL l, PID p)

{

  RR2_level_des *lev = (RR2_level_des *)(level_table[l]);

  /* Similar to RR2_task_activate,

     but we don't check in what state the task is */

  /* Insert task in the coRR2ect position */

  proc_table[p].status = RR2_READY;

  iq_insertlast(p,&lev->ready);

}

static void RR2_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!!!

  */

}

static int RR2_public_message(LEVEL l, PID p, void *m)

{

  RR2_level_des *lev = (RR2_level_des *)(level_table[l]);

  if (lev->nact[p] > 0) {

    /* continue!!!! */

    lev->nact[p]--;

    iq_insertfirst(p,&lev->ready);

    proc_table[p].status = RR2_READY;

  }

  else

    proc_table[p].status = SLEEP;

  jet_update_endcycle(); /* Update the Jet data... */

  trc_logevent(TRC_ENDCYCLE,&exec_shadow); /* tracer stuff */

  return 0;

}

static void RR2_public_end(LEVEL l, PID p)

{

  RR2_level_des *lev = (RR2_level_des *)(level_table[l]);

  lev->nact[p] = -1;

  /* then, we insert the task in the free queue */

  proc_table[p].status = FREE;

  iq_insertlast(p,&freedesc);

}

/* Registration functions */

/*+ This init function install the "main" task +*/

static void RR2_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 aRR2ives

                                to the coRR2ect level */

  mb = ((RR2_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("\nPanic!!! can't create main task...\n");

  RR2_public_activate(lev,p);

}

/*+ 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 RR2_register_level(TIME slice,

                       int createmain,

                       struct multiboot_info *mb)

{

  LEVEL l;             /* the level that we register */

  RR2_level_des *lev;  /* for readableness only */

  PID i;

  printk("RR2_register_level\n");

  /* request an entry in the level_table */

  l = level_alloc_descriptor(sizeof(RR2_level_des));

  lev = (RR2_level_des *)level_table[l];

  printk("    lev=%d\n",(int)lev);

  /* fill the standard descriptor */

  lev->l.public_scheduler = RR2_public_scheduler;

  lev->l.public_create    = RR2_public_create;

  lev->l.public_end       = RR2_public_end;

  lev->l.public_dispatch  = RR2_public_dispatch;

  lev->l.public_epilogue  = RR2_public_epilogue;

  lev->l.public_activate  = RR2_public_activate;

  lev->l.public_unblock   = RR2_public_unblock;

  lev->l.public_block     = RR2_public_block;

  lev->l.public_message   = RR2_public_message;

  /* fill the RR2 descriptor part */

  for (i = 0; i < MAX_PROC; i++)

    lev->nact[i] = -1;

  iq_init(&lev->ready, &freedesc, 0);

  if (slice < RR2_MINIMUM_SLICE) slice = RR2_MINIMUM_SLICE;

  if (slice > RR2_MAXIMUM_SLICE) slice = RR2_MAXIMUM_SLICE;

  lev->slice      = slice;

  lev->multiboot  = mb;

  if (createmain)

    sys_atrunlevel(RR2_call_main,(void *) l, RUNLEVEL_INIT);

  return l;

}