os-k/include/ke/sched.h

//----------------------------------------------------------------------------//
//                           GNU GPL OS/K                                     //
//                                                                            //
//  Desc:       Scheduler-related functions                                   //
//                                                                            //
//                                                                            //
//  Copyright © 2018-2019 The OS/K Team                                       //
//                                                                            //
//  This file is part of OS/K.                                                //
//                                                                            //
//  OS/K 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 3 of the License, or         //
//  any later version.                                                        //
//                                                                            //
//  OS/K 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 OS/K.  If not, see <https://www.gnu.org/licenses/>.            //
//----------------------------------------------------------------------------//

#ifndef _KERNEL_H
#include <kernel.h>
#endif

#ifndef _KALKERN_SCHED_H
#define _KALKERN_SCHED_H

//----------------------------------------------------------------------------//

//
// Value of the preemption count indicating that preemption is activated
//
enum { PREEMPT_ON = 0 };

// Time in ticks a process should be run
enum
{
    DEF_PROC_TSLICE = 3,       // 20 ticks
    TCR_PROC_TSLICE = 20000    // 20000 ticks (time critical)
};

// Priority classes
enum
{
    TIME_CRIT_PROC = 0,
    SERV_PRIO_PROC = 1,
    REGL_PRIO_PROC = 2,
    IDLE_PRIO_PROC = 3,
};

// Names of the priority classes
extern const char *PsPrioClassesNames[];

//----------------------------------------------------------------------------//

//
// Re-scheduling and preemption
// XXX atomic operations
//
#define PsRequestReSched()     do { ++KeCurCPU->needReSched; } while (0)
#define PsDisablePreemption()  do { ++KeCurCPU->preemptCount; } while (0)
#define PsEnablePreemption()   do { assert(KeCurCPU->preemptCount > 0); \
                                    --KeCurCPU->preemptCount; } while(0)

//----------------------------------------------------------------------------//

void PsInitSched(void);
void PsFiniSched(void);

void PsSchedThisProc(Process_t *);
void PsSchedOnTick(void);

//----------------------------------------------------------------------------//

#endif