locking/ww_mutex: Add kselftests for ww_mutex stress
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Maarten Lankhorst <dev@mblankhorst.nl> Cc: Nicolai Hähnle <nhaehnle@gmail.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20161201114711.28697-8-chris@chris-wilson.co.uk Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Chris Wilson
Ingo Molnar
parent
d1b42b800e
commit
2a0c112828
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@ -19,8 +19,10 @@
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#include <linux/kernel.h>
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#include <linux/completion.h>
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#include <linux/delay.h>
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#include <linux/kthread.h>
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#include <linux/module.h>
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#include <linux/random.h>
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#include <linux/slab.h>
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#include <linux/ww_mutex.h>
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@ -348,6 +350,246 @@ static int test_cycle(unsigned int ncpus)
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return 0;
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}
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struct stress {
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struct work_struct work;
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struct ww_mutex *locks;
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int nlocks;
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int nloops;
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};
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static int *get_random_order(int count)
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{
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int *order;
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int n, r, tmp;
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order = kmalloc_array(count, sizeof(*order), GFP_TEMPORARY);
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if (!order)
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return order;
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for (n = 0; n < count; n++)
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order[n] = n;
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for (n = count - 1; n > 1; n--) {
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r = get_random_int() % (n + 1);
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if (r != n) {
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tmp = order[n];
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order[n] = order[r];
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order[r] = tmp;
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}
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}
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return order;
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}
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static void dummy_load(struct stress *stress)
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{
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usleep_range(1000, 2000);
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}
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static void stress_inorder_work(struct work_struct *work)
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{
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struct stress *stress = container_of(work, typeof(*stress), work);
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const int nlocks = stress->nlocks;
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struct ww_mutex *locks = stress->locks;
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struct ww_acquire_ctx ctx;
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int *order;
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order = get_random_order(nlocks);
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if (!order)
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return;
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ww_acquire_init(&ctx, &ww_class);
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do {
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int contended = -1;
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int n, err;
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retry:
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err = 0;
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for (n = 0; n < nlocks; n++) {
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if (n == contended)
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continue;
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err = ww_mutex_lock(&locks[order[n]], &ctx);
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if (err < 0)
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break;
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}
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if (!err)
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dummy_load(stress);
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if (contended > n)
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ww_mutex_unlock(&locks[order[contended]]);
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contended = n;
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while (n--)
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ww_mutex_unlock(&locks[order[n]]);
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if (err == -EDEADLK) {
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ww_mutex_lock_slow(&locks[order[contended]], &ctx);
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goto retry;
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}
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if (err) {
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pr_err_once("stress (%s) failed with %d\n",
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__func__, err);
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break;
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}
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} while (--stress->nloops);
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ww_acquire_fini(&ctx);
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kfree(order);
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kfree(stress);
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}
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struct reorder_lock {
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struct list_head link;
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struct ww_mutex *lock;
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};
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static void stress_reorder_work(struct work_struct *work)
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{
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struct stress *stress = container_of(work, typeof(*stress), work);
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LIST_HEAD(locks);
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struct ww_acquire_ctx ctx;
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struct reorder_lock *ll, *ln;
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int *order;
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int n, err;
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order = get_random_order(stress->nlocks);
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if (!order)
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return;
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for (n = 0; n < stress->nlocks; n++) {
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ll = kmalloc(sizeof(*ll), GFP_KERNEL);
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if (!ll)
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goto out;
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ll->lock = &stress->locks[order[n]];
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list_add(&ll->link, &locks);
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}
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kfree(order);
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order = NULL;
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ww_acquire_init(&ctx, &ww_class);
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do {
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list_for_each_entry(ll, &locks, link) {
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err = ww_mutex_lock(ll->lock, &ctx);
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if (!err)
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continue;
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ln = ll;
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list_for_each_entry_continue_reverse(ln, &locks, link)
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ww_mutex_unlock(ln->lock);
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if (err != -EDEADLK) {
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pr_err_once("stress (%s) failed with %d\n",
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__func__, err);
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break;
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}
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ww_mutex_lock_slow(ll->lock, &ctx);
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list_move(&ll->link, &locks); /* restarts iteration */
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}
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dummy_load(stress);
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list_for_each_entry(ll, &locks, link)
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ww_mutex_unlock(ll->lock);
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} while (--stress->nloops);
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ww_acquire_fini(&ctx);
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out:
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list_for_each_entry_safe(ll, ln, &locks, link)
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kfree(ll);
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kfree(order);
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kfree(stress);
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}
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static void stress_one_work(struct work_struct *work)
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{
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struct stress *stress = container_of(work, typeof(*stress), work);
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const int nlocks = stress->nlocks;
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struct ww_mutex *lock = stress->locks + (get_random_int() % nlocks);
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int err;
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do {
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err = ww_mutex_lock(lock, NULL);
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if (!err) {
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dummy_load(stress);
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ww_mutex_unlock(lock);
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} else {
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pr_err_once("stress (%s) failed with %d\n",
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__func__, err);
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break;
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}
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} while (--stress->nloops);
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kfree(stress);
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}
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#define STRESS_INORDER BIT(0)
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#define STRESS_REORDER BIT(1)
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#define STRESS_ONE BIT(2)
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#define STRESS_ALL (STRESS_INORDER | STRESS_REORDER | STRESS_ONE)
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static int stress(int nlocks, int nthreads, int nloops, unsigned int flags)
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{
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struct ww_mutex *locks;
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int n;
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locks = kmalloc_array(nlocks, sizeof(*locks), GFP_KERNEL);
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if (!locks)
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return -ENOMEM;
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for (n = 0; n < nlocks; n++)
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ww_mutex_init(&locks[n], &ww_class);
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for (n = 0; nthreads; n++) {
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struct stress *stress;
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void (*fn)(struct work_struct *work);
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fn = NULL;
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switch (n & 3) {
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case 0:
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if (flags & STRESS_INORDER)
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fn = stress_inorder_work;
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break;
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case 1:
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if (flags & STRESS_REORDER)
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fn = stress_reorder_work;
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break;
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case 2:
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if (flags & STRESS_ONE)
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fn = stress_one_work;
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break;
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}
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if (!fn)
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continue;
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stress = kmalloc(sizeof(*stress), GFP_KERNEL);
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if (!stress)
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break;
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INIT_WORK(&stress->work, fn);
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stress->locks = locks;
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stress->nlocks = nlocks;
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stress->nloops = nloops;
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queue_work(wq, &stress->work);
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nthreads--;
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}
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flush_workqueue(wq);
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for (n = 0; n < nlocks; n++)
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ww_mutex_destroy(&locks[n]);
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kfree(locks);
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return 0;
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}
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static int __init test_ww_mutex_init(void)
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{
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int ncpus = num_online_cpus();
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@ -377,6 +619,18 @@ static int __init test_ww_mutex_init(void)
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if (ret)
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return ret;
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ret = stress(16, 2*ncpus, 1<<10, STRESS_INORDER);
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if (ret)
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return ret;
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ret = stress(16, 2*ncpus, 1<<10, STRESS_REORDER);
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if (ret)
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return ret;
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ret = stress(4096, hweight32(STRESS_ALL)*ncpus, 1<<12, STRESS_ALL);
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if (ret)
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return ret;
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return 0;
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}
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