source: mainline/kernel/test/synch/semaphore2.c@ a000878c

/*
 * Copyright (c) 2001-2004 Jakub Jermar
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <test.h>
#include <arch.h>
#include <atomic.h>
#include <print.h>
#include <proc/thread.h>
#include <arch/types.h>
#include <arch/context.h>

#include <synch/waitq.h>
#include <synch/semaphore.h>
#include <synch/synch.h>
#include <synch/spinlock.h>

static semaphore_t sem;

SPINLOCK_INITIALIZE(sem_lock);

static waitq_t can_start;

static uint32_t seed = 0xdeadbeef;

static uint32_t random(uint32_t max)
{
        uint32_t rc;
        
        spinlock_lock(&sem_lock);
        rc = seed % max;
        seed = (((seed << 2) ^ (seed >> 2)) * 487) + rc;
        spinlock_unlock(&sem_lock);
        return rc;
}

static void consumer(void *arg)
{
        int rc, to;
        
        thread_detach(THREAD);
        
        waitq_sleep(&can_start);
        
        to = random(20000);
        TPRINTF("cpu%u, tid %" PRIu64 " down+ (%d)\n", CPU->id, THREAD->tid, to);
        rc = semaphore_down_timeout(&sem, to);
        if (SYNCH_FAILED(rc)) {
                TPRINTF("cpu%u, tid %" PRIu64 " down!\n", CPU->id, THREAD->tid);
                return;
        }
        
        TPRINTF("cpu%u, tid %" PRIu64 " down=\n", CPU->id, THREAD->tid);        
        thread_usleep(random(30000));
        
        semaphore_up(&sem);
        TPRINTF("cpu%u, tid %" PRIu64 " up\n", CPU->id, THREAD->tid);
}

const char *test_semaphore2(void)
{
        uint32_t i, k;
        
        waitq_initialize(&can_start);
        semaphore_initialize(&sem, 5);
        
        thread_t *thrd;
        
        k = random(7) + 1;
        TPRINTF("Creating %" PRIu32 " consumers\n", k);
        for (i = 0; i < k; i++) {
                thrd = thread_create(consumer, NULL, TASK, 0, "consumer", false);
                if (thrd)
                        thread_ready(thrd);
                else
                        TPRINTF("Error creating thread\n");
        }
        
        thread_usleep(20000);
        waitq_wakeup(&can_start, WAKEUP_ALL);
        
        return NULL;
}