source: mainline/kernel/test/synch/rwlock4.c@ dff0a94

/*
 * 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 <context.h>
#include <panic.h>

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

#define READERS         50
#define WRITERS         50

static rwlock_t rwlock;

SPINLOCK_INITIALIZE(rw_lock);

static waitq_t can_start;

static uint32_t seed = 0xdeadbeef;

static uint32_t random(uint32_t max);

static void writer(void *arg);
static void reader(void *arg);
static void failed(void);

static uint32_t random(uint32_t max)
{
        uint32_t rc;

        spinlock_lock(&rw_lock);        
        rc = seed % max;
        seed = (((seed<<2) ^ (seed>>2)) * 487) + rc;
        spinlock_unlock(&rw_lock);
        return rc;
}


static void writer(void *arg)
{
        int rc, to;
        thread_detach(THREAD);
        waitq_sleep(&can_start);

        to = random(40000);
        printf("cpu%d, tid %d w+ (%d)\n", CPU->id, THREAD->tid, to);
        rc = rwlock_write_lock_timeout(&rwlock, to);
        if (SYNCH_FAILED(rc)) {
                printf("cpu%d, tid %d w!\n", CPU->id, THREAD->tid);
                return;
        };
        printf("cpu%d, tid %d w=\n", CPU->id, THREAD->tid);

        if (rwlock.readers_in) panic("Oops.");
        thread_usleep(random(1000000));
        if (rwlock.readers_in) panic("Oops.");  

        rwlock_write_unlock(&rwlock);
        printf("cpu%d, tid %d w-\n", CPU->id, THREAD->tid);     
}

static void reader(void *arg)
{
        int rc, to;
        thread_detach(THREAD);
        waitq_sleep(&can_start);
        
        to = random(2000);
        printf("cpu%d, tid %d r+ (%d)\n", CPU->id, THREAD->tid, to);
        rc = rwlock_read_lock_timeout(&rwlock, to);
        if (SYNCH_FAILED(rc)) {
                printf("cpu%d, tid %d r!\n", CPU->id, THREAD->tid);
                return;
        }
        printf("cpu%d, tid %d r=\n", CPU->id, THREAD->tid);
        thread_usleep(30000);
        rwlock_read_unlock(&rwlock);
        printf("cpu%d, tid %d r-\n", CPU->id, THREAD->tid);             
}

static void failed(void)
{
        printf("Test failed prematurely.\n");
        thread_exit();
}

void test_rwlock4(void)
{
        context_t ctx;
        uint32_t i, k;
        
        printf("Read/write locks test #4\n");
    
        waitq_initialize(&can_start);
        rwlock_initialize(&rwlock);
        
        for (;;) {
                thread_t *thrd;
                
                context_save(&ctx);
                printf("sp=%#x, readers_in=%d\n", ctx.sp, rwlock.readers_in);
                
                k = random(7) + 1;
                printf("Creating %d readers\n", k);
                for (i=0; i<k; i++) {
                        thrd = thread_create(reader, NULL, TASK, 0, "reader");
                        if (thrd)
                                thread_ready(thrd);
                        else
                                failed();
                }

                k = random(5) + 1;
                printf("Creating %d writers\n", k);
                for (i=0; i<k; i++) {
                        thrd = thread_create(writer, NULL, TASK, 0, "writer");
                        if (thrd)
                                thread_ready(thrd);
                        else
                                failed();
                }
                
                thread_usleep(20000);
                waitq_wakeup(&can_start, WAKEUP_ALL);
        }               

}