Instead of declaring it volatile. Signed-off-by: Emilio G. Cota <cota@braap.org> Message-Id: <20180819091335.22863-6-cota@braap.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
312 lines
7.8 KiB
C
312 lines
7.8 KiB
C
/*
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* rcuq_test.c
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*
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* usage: rcuq_test <readers> <duration>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*
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* Copyright (c) 2013 Mike D. Day, IBM Corporation.
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*/
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#include "qemu/osdep.h"
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#include "qemu/atomic.h"
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#include "qemu/rcu.h"
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#include "qemu/thread.h"
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#include "qemu/rcu_queue.h"
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/*
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* Test variables.
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*/
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static QemuMutex counts_mutex;
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static long long n_reads = 0LL;
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static long long n_updates = 0LL;
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static long long n_reclaims = 0LL;
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static long long n_nodes_removed = 0LL;
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static long long n_nodes = 0LL;
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static int g_test_in_charge = 0;
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static int nthreadsrunning;
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#define GOFLAG_INIT 0
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#define GOFLAG_RUN 1
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#define GOFLAG_STOP 2
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static int goflag = GOFLAG_INIT;
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#define RCU_READ_RUN 1000
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#define RCU_UPDATE_RUN 10
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#define NR_THREADS 100
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#define RCU_Q_LEN 100
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static QemuThread threads[NR_THREADS];
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static struct rcu_reader_data *data[NR_THREADS];
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static int n_threads;
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static int select_random_el(int max)
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{
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return (rand() % max);
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}
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static void create_thread(void *(*func)(void *))
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{
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if (n_threads >= NR_THREADS) {
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fprintf(stderr, "Thread limit of %d exceeded!\n", NR_THREADS);
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exit(-1);
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}
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qemu_thread_create(&threads[n_threads], "test", func, &data[n_threads],
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QEMU_THREAD_JOINABLE);
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n_threads++;
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}
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static void wait_all_threads(void)
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{
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int i;
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for (i = 0; i < n_threads; i++) {
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qemu_thread_join(&threads[i]);
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}
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n_threads = 0;
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}
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struct list_element {
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QLIST_ENTRY(list_element) entry;
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struct rcu_head rcu;
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};
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static void reclaim_list_el(struct rcu_head *prcu)
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{
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struct list_element *el = container_of(prcu, struct list_element, rcu);
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g_free(el);
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/* Accessed only from call_rcu thread. */
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n_reclaims++;
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}
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static QLIST_HEAD(q_list_head, list_element) Q_list_head;
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static void *rcu_q_reader(void *arg)
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{
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long long n_reads_local = 0;
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struct list_element *el;
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rcu_register_thread();
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*(struct rcu_reader_data **)arg = &rcu_reader;
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atomic_inc(&nthreadsrunning);
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while (atomic_read(&goflag) == GOFLAG_INIT) {
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g_usleep(1000);
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}
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while (atomic_read(&goflag) == GOFLAG_RUN) {
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rcu_read_lock();
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QLIST_FOREACH_RCU(el, &Q_list_head, entry) {
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n_reads_local++;
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if (atomic_read(&goflag) == GOFLAG_STOP) {
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break;
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}
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}
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rcu_read_unlock();
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g_usleep(100);
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}
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qemu_mutex_lock(&counts_mutex);
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n_reads += n_reads_local;
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qemu_mutex_unlock(&counts_mutex);
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rcu_unregister_thread();
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return NULL;
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}
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static void *rcu_q_updater(void *arg)
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{
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int j, target_el;
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long long n_nodes_local = 0;
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long long n_updates_local = 0;
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long long n_removed_local = 0;
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struct list_element *el, *prev_el;
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*(struct rcu_reader_data **)arg = &rcu_reader;
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atomic_inc(&nthreadsrunning);
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while (atomic_read(&goflag) == GOFLAG_INIT) {
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g_usleep(1000);
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}
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while (atomic_read(&goflag) == GOFLAG_RUN) {
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target_el = select_random_el(RCU_Q_LEN);
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j = 0;
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/* FOREACH_RCU could work here but let's use both macros */
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QLIST_FOREACH_SAFE_RCU(prev_el, &Q_list_head, entry, el) {
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j++;
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if (target_el == j) {
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QLIST_REMOVE_RCU(prev_el, entry);
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/* may be more than one updater in the future */
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call_rcu1(&prev_el->rcu, reclaim_list_el);
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n_removed_local++;
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break;
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}
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}
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if (atomic_read(&goflag) == GOFLAG_STOP) {
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break;
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}
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target_el = select_random_el(RCU_Q_LEN);
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j = 0;
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QLIST_FOREACH_RCU(el, &Q_list_head, entry) {
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j++;
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if (target_el == j) {
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prev_el = g_new(struct list_element, 1);
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n_nodes += n_nodes_local;
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QLIST_INSERT_BEFORE_RCU(el, prev_el, entry);
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break;
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}
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}
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n_updates_local += 2;
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synchronize_rcu();
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}
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synchronize_rcu();
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qemu_mutex_lock(&counts_mutex);
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n_nodes += n_nodes_local;
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n_updates += n_updates_local;
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n_nodes_removed += n_removed_local;
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qemu_mutex_unlock(&counts_mutex);
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return NULL;
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}
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static void rcu_qtest_init(void)
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{
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struct list_element *new_el;
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int i;
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nthreadsrunning = 0;
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srand(time(0));
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for (i = 0; i < RCU_Q_LEN; i++) {
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new_el = g_new(struct list_element, 1);
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QLIST_INSERT_HEAD_RCU(&Q_list_head, new_el, entry);
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}
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qemu_mutex_lock(&counts_mutex);
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n_nodes += RCU_Q_LEN;
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qemu_mutex_unlock(&counts_mutex);
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}
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static void rcu_qtest_run(int duration, int nreaders)
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{
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int nthreads = nreaders + 1;
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while (atomic_read(&nthreadsrunning) < nthreads) {
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g_usleep(1000);
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}
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atomic_set(&goflag, GOFLAG_RUN);
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sleep(duration);
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atomic_set(&goflag, GOFLAG_STOP);
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wait_all_threads();
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}
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static void rcu_qtest(const char *test, int duration, int nreaders)
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{
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int i;
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long long n_removed_local = 0;
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struct list_element *el, *prev_el;
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rcu_qtest_init();
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for (i = 0; i < nreaders; i++) {
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create_thread(rcu_q_reader);
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}
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create_thread(rcu_q_updater);
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rcu_qtest_run(duration, nreaders);
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QLIST_FOREACH_SAFE_RCU(prev_el, &Q_list_head, entry, el) {
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QLIST_REMOVE_RCU(prev_el, entry);
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call_rcu1(&prev_el->rcu, reclaim_list_el);
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n_removed_local++;
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}
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qemu_mutex_lock(&counts_mutex);
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n_nodes_removed += n_removed_local;
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qemu_mutex_unlock(&counts_mutex);
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synchronize_rcu();
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while (n_nodes_removed > n_reclaims) {
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g_usleep(100);
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synchronize_rcu();
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}
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if (g_test_in_charge) {
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g_assert_cmpint(n_nodes_removed, ==, n_reclaims);
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} else {
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printf("%s: %d readers; 1 updater; nodes read: " \
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"%lld, nodes removed: %lld; nodes reclaimed: %lld\n",
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test, nthreadsrunning - 1, n_reads, n_nodes_removed, n_reclaims);
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exit(0);
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}
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}
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static void usage(int argc, char *argv[])
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{
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fprintf(stderr, "Usage: %s duration nreaders\n", argv[0]);
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exit(-1);
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}
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static int gtest_seconds;
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static void gtest_rcuq_one(void)
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{
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rcu_qtest("rcuqtest", gtest_seconds / 4, 1);
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}
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static void gtest_rcuq_few(void)
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{
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rcu_qtest("rcuqtest", gtest_seconds / 4, 5);
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}
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static void gtest_rcuq_many(void)
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{
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rcu_qtest("rcuqtest", gtest_seconds / 2, 20);
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}
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int main(int argc, char *argv[])
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{
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int duration = 0, readers = 0;
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qemu_mutex_init(&counts_mutex);
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if (argc >= 2) {
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if (argv[1][0] == '-') {
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g_test_init(&argc, &argv, NULL);
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if (g_test_quick()) {
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gtest_seconds = 4;
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} else {
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gtest_seconds = 20;
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}
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g_test_add_func("/rcu/qlist/single-threaded", gtest_rcuq_one);
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g_test_add_func("/rcu/qlist/short-few", gtest_rcuq_few);
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g_test_add_func("/rcu/qlist/long-many", gtest_rcuq_many);
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g_test_in_charge = 1;
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return g_test_run();
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}
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duration = strtoul(argv[1], NULL, 0);
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}
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if (argc >= 3) {
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readers = strtoul(argv[2], NULL, 0);
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}
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if (duration && readers) {
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rcu_qtest(argv[0], duration, readers);
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return 0;
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}
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usage(argc, argv);
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return -1;
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}
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