source: mainline/kernel/test/synch/rwlock4.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 <context.h>

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

#define READERS  50
#define WRITERS  50

static atomic_t thread_count;
static rwlock_t rwlock;
static atomic_t threads_fault;

SPINLOCK_INITIALIZE(rw_lock);

static waitq_t can_start;

static uint32_t seed = 0xdeadbeef;

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);
        
        TPRINTF("cpu%u, tid %" PRIu64 " w+ (%d)\n", CPU->id, THREAD->tid, to);
        
        rc = rwlock_write_lock_timeout(&rwlock, to);
        if (SYNCH_FAILED(rc)) {
                TPRINTF("cpu%u, tid %" PRIu64 " w!\n", CPU->id, THREAD->tid);
                atomic_dec(&thread_count);
                return;
        }
        
        TPRINTF("cpu%u, tid %" PRIu64 " w=\n", CPU->id, THREAD->tid);
        
        if (rwlock.readers_in) {
                TPRINTF("Oops.\n");
                atomic_inc(&threads_fault);
                atomic_dec(&thread_count);
                return;
        }
        
        thread_usleep(random(1000000));
        
        if (rwlock.readers_in) {
                TPRINTF("Oops.\n");
                atomic_inc(&threads_fault);
                atomic_dec(&thread_count);
                return;
        }
        
        rwlock_write_unlock(&rwlock);
        
        TPRINTF("cpu%u, tid %" PRIu64 " w-\n", CPU->id, THREAD->tid);
        atomic_dec(&thread_count);
}

static void reader(void *arg)
{
        int rc, to;
        thread_detach(THREAD);
        waitq_sleep(&can_start);
        
        to = random(2000);
        
        TPRINTF("cpu%u, tid %" PRIu64 " r+ (%d)\n", CPU->id, THREAD->tid, to);
        
        rc = rwlock_read_lock_timeout(&rwlock, to);
        if (SYNCH_FAILED(rc)) {
                TPRINTF("cpu%u, tid %" PRIu64 " r!\n", CPU->id, THREAD->tid);
                atomic_dec(&thread_count);
                return;
        }
        
        TPRINTF("cpu%u, tid %" PRIu64 " r=\n", CPU->id, THREAD->tid);
        
        thread_usleep(30000);
        rwlock_read_unlock(&rwlock);
        
        TPRINTF("cpu%u, tid %" PRIu64 " r-\n", CPU->id, THREAD->tid);
        atomic_dec(&thread_count);
}

const char *test_rwlock4(void)
{
        context_t ctx;
        uint32_t i;
        
        waitq_initialize(&can_start);
        rwlock_initialize(&rwlock);
        atomic_set(&threads_fault, 0);
        
        uint32_t rd = random(7) + 1;
        uint32_t wr = random(5) + 1;
        
        atomic_set(&thread_count, rd + wr);
        
        thread_t *thrd;
        
        context_save(&ctx);
        TPRINTF("sp=%#x, readers_in=%" PRIs "\n", ctx.sp, rwlock.readers_in);
        TPRINTF("Creating %" PRIu32 " readers\n", rd);
        
        for (i = 0; i < rd; i++) {
                thrd = thread_create(reader, NULL, TASK, 0, "reader", false);
                if (thrd)
                        thread_ready(thrd);
                else
                        TPRINTF("Could not create reader %" PRIu32 "\n", i);
        }
        
        TPRINTF("Creating %" PRIu32 " writers\n", wr);
        
        for (i = 0; i < wr; i++) {
                thrd = thread_create(writer, NULL, TASK, 0, "writer", false);
                if (thrd)
                        thread_ready(thrd);
                else
                        TPRINTF("Could not create writer %" PRIu32 "\n", i);
        }
        
        thread_usleep(20000);
        waitq_wakeup(&can_start, WAKEUP_ALL);
        
        while (atomic_get(&thread_count) > 0) {
                TPRINTF("Threads left: %ld\n", atomic_get(&thread_count));
                thread_sleep(1);
        }
        
        if (atomic_get(&threads_fault) == 0)
                return NULL;
        
        return "Test failed";
}