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/*
* Copyright (c) 2014-2018 Richard Braun.
*
* This program 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
* (at your option) any later version.
*
* This program 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 this program. If not, see <http://www.gnu.org/licenses/>.
*
*
* This test module is a stress test, expected to never terminate, of the
* work deferring functionality of the rcu module. It creates three
* threads, a producer, a consumer, and a reader. The producer allocates
* a page and writes it. It then transfers the page to the consumer, using
* the rcu interface to update the global page pointer. Once at the
* consumer, the rcu interface is used to defer the release of the page.
* Concurrently, the reader accesses the page and checks its content when
* available. These accesses are performed inside a read-side critical
* section and should therefore never fail.
*
* Each thread regularly prints a string to report that it's making progress.
*/
#include <stddef.h>
#include <stdio.h>
#include <string.h>
#include <kern/condition.h>
#include <kern/error.h>
#include <kern/kmem.h>
#include <kern/macros.h>
#include <kern/mutex.h>
#include <kern/panic.h>
#include <kern/rcu.h>
#include <kern/thread.h>
#include <kern/work.h>
#include <machine/page.h>
#include <test/test.h>
#include <vm/vm_kmem.h>
#define TEST_LOOPS_PER_PRINT 100000
struct test_pdsc {
struct work work;
void *addr;
};
#define TEST_VALIDATION_BYTE 0xab
static struct mutex test_lock;
static struct condition test_condition;
static struct test_pdsc *test_pdsc;
static struct kmem_cache test_pdsc_cache;
static void
test_alloc(void *arg)
{
struct test_pdsc *pdsc;
unsigned long nr_loops;
(void)arg;
nr_loops = 0;
mutex_lock(&test_lock);
for (;;) {
while (test_pdsc != NULL) {
condition_wait(&test_condition, &test_lock);
}
pdsc = kmem_cache_alloc(&test_pdsc_cache);
if (pdsc != NULL) {
pdsc->addr = vm_kmem_alloc(PAGE_SIZE);
if (pdsc->addr != NULL) {
memset(pdsc->addr, TEST_VALIDATION_BYTE, PAGE_SIZE);
}
}
rcu_store_ptr(test_pdsc, pdsc);
condition_signal(&test_condition);
if ((nr_loops % TEST_LOOPS_PER_PRINT) == 0) {
printf("alloc ");
}
nr_loops++;
}
}
static void
test_deferred_free(struct work *work)
{
struct test_pdsc *pdsc;
pdsc = structof(work, struct test_pdsc, work);
if (pdsc->addr != NULL) {
vm_kmem_free(pdsc->addr, PAGE_SIZE);
}
kmem_cache_free(&test_pdsc_cache, pdsc);
}
static void
test_free(void *arg)
{
struct test_pdsc *pdsc;
unsigned long nr_loops;
(void)arg;
nr_loops = 0;
mutex_lock(&test_lock);
for (;;) {
while (test_pdsc == NULL) {
condition_wait(&test_condition, &test_lock);
}
pdsc = test_pdsc;
rcu_store_ptr(test_pdsc, NULL);
if (pdsc != NULL) {
work_init(&pdsc->work, test_deferred_free);
rcu_defer(&pdsc->work);
}
condition_signal(&test_condition);
if ((nr_loops % TEST_LOOPS_PER_PRINT) == 0) {
printf("free ");
}
nr_loops++;
}
}
static void
test_read(void *arg)
{
const struct test_pdsc *pdsc;
const unsigned char *s;
unsigned long nr_loops;
(void)arg;
nr_loops = 0;
for (;;) {
rcu_read_enter();
pdsc = rcu_load_ptr(test_pdsc);
if (pdsc != NULL) {
s = (const unsigned char *)pdsc->addr;
if (s != NULL) {
for (unsigned int i = 0; i < PAGE_SIZE; i++) {
if (s[i] != TEST_VALIDATION_BYTE) {
panic("invalid content");
}
}
if ((nr_loops % TEST_LOOPS_PER_PRINT) == 0) {
printf("read ");
}
nr_loops++;
}
}
rcu_read_leave();
}
}
void
test_setup(void)
{
struct thread_attr attr;
struct thread *thread;
int error;
condition_init(&test_condition);
mutex_init(&test_lock);
kmem_cache_init(&test_pdsc_cache, "test_pdsc",
sizeof(struct test_pdsc), 0, NULL, 0);
thread_attr_init(&attr, THREAD_KERNEL_PREFIX "test_alloc");
thread_attr_set_detached(&attr);
error = thread_create(&thread, &attr, test_alloc, NULL);
error_check(error, "thread_create");
thread_attr_init(&attr, THREAD_KERNEL_PREFIX "test_free");
thread_attr_set_detached(&attr);
error = thread_create(&thread, &attr, test_free, NULL);
error_check(error, "thread_create");
thread_attr_init(&attr, THREAD_KERNEL_PREFIX "test_read");
thread_attr_set_detached(&attr);
error = thread_create(&thread, &attr, test_read, NULL);
error_check(error, "thread_create");
}
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