source: libcfa/src/concurrency/alarm.cfa@ 353aaba

//
// Cforall Version 1.0.0 Copyright (C) 2016 University of Waterloo
//
// The contents of this file are covered under the licence agreement in the
// file "LICENCE" distributed with Cforall.
//
// alarm.c --
//
// Author           : Thierry Delisle
// Created On       : Fri Jun 2 11:31:25 2017
// Last Modified By : Peter A. Buhr
// Last Modified On : Wed Jun 17 16:11:35 2020
// Update Count     : 75
//

#define __cforall_thread__
// #define __CFA_DEBUG_PRINT_PREEMPTION__

#include <errno.h>
#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <sys/time.h>

#include "alarm.hfa"
#include "kernel/fwd.hfa"
#include "preemption.hfa"

//=============================================================================================
// Clock logic
//=============================================================================================

Time __kernel_get_time() {
        timespec curr;
        clock_gettime( CLOCK_MONOTONIC_RAW, &curr );            // CLOCK_REALTIME
        return (Time){ curr };
}

void __kernel_set_timer( Duration alarm ) {
        alarm = max(alarm, 1`us);
        itimerval otv @= { 0 };
        getitimer( ITIMER_REAL, &otv );
        Duration od = { otv.it_value };
        if(od == 0 || od > alarm) {
                setitimer( ITIMER_REAL, &(itimerval){ alarm }, 0p );
        }
}

//=============================================================================================
// Alarm logic
//=============================================================================================

void ?{}( alarm_node_t & this, $thread * thrd, Duration alarm, Duration period) with( this ) {
        this.initial = alarm;
        this.period  = period;
        this.thrd = thrd;
        set = false;
        type = User;
}

void ?{}( alarm_node_t & this, processor * proc, Duration alarm, Duration period ) with( this ) {
        this.initial = alarm;
        this.period  = period;
        this.proc = proc;
        set = false;
        type = Kernel;
}
void ?{}( alarm_node_t & this, Alarm_Callback callback, Duration alarm, Duration period ) with( this ) {
        this.initial = alarm;
        this.period  = period;
        this.callback = callback;
        set = false;
        type = Callback;
}

void ^?{}( alarm_node_t & this ) {
        if( this.set ) {
                unregister_self( &this );
        }
}

void insert( alarm_list_t * this, alarm_node_t * n ) {
        alarm_node_t * it = & (*this)`first;
        while( it && (n->timeval > it->timeval) ) {
                it = & (*it)`next;
        }
        if ( it ) {
                insert_before( *it, *n );
        } else {
                insert_last(*this, *n);
        }

        verify( validate( *this ) );
}

alarm_node_t * pop( alarm_list_t * this ) {
        verify( validate( *this ) );
        alarm_node_t * head = & (*this)`first;
        if( head ) {
                remove(*head);
        }
        verify( validate( *this ) );
        return head;
}

void register_self( alarm_node_t * this ) {
        alarm_list_t & alarms = event_kernel->alarms;

        disable_interrupts();
        lock( event_kernel->lock __cfaabi_dbg_ctx2 );
        {
                Time curr = __kernel_get_time();
                this->timeval = curr + this->initial;

                /* paranoid */ verify( validate( alarms ) );

                __cfadbg_print_safe( preemption, " KERNEL: alarm inserting %p (%lu -> %lu).\n", this, curr.tn, this->timeval.tn );
                insert( &alarms, this );
                __kernel_set_timer( this->initial );
        }
        unlock( event_kernel->lock );
        this->set = true;
        enable_interrupts();
}

void unregister_self( alarm_node_t * this ) {
        disable_interrupts();
        lock( event_kernel->lock __cfaabi_dbg_ctx2 );
        {
                verify( validate( event_kernel->alarms ) );
                remove( *this );
        }
        unlock( event_kernel->lock );
        enable_interrupts();
        this->set = false;
}

//=============================================================================================
// Utilities
//=============================================================================================

void sleep( Duration duration ) {
        alarm_node_t node = { active_thread(), duration, 0`s };

        register_self( &node );
        park();

        /* paranoid */ verify( !node.set );
        /* paranoid */ verify( & node`next == 0p );
        /* paranoid */ verify( & node`prev == 0p );
}

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