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authorChris Wilson <chris@chris-wilson.co.uk>2016-12-01 11:47:10 +0000
committerIngo Molnar <mingo@kernel.org>2017-01-14 11:37:17 +0100
commit2a0c11282881875dc44f166a20eedf0d866dd0ef (patch)
tree9a353f126e29fd7680db5bbf6e0422576ec2faf2 /kernel/locking
parentd1b42b800e5d09dcee52812b4396aca3a3696ba9 (diff)
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>
Diffstat (limited to 'kernel/locking')
-rw-r--r--kernel/locking/test-ww_mutex.c254
1 files changed, 254 insertions, 0 deletions
diff --git a/kernel/locking/test-ww_mutex.c b/kernel/locking/test-ww_mutex.c
index 84da738e57d1..da6c9a34f62f 100644
--- a/kernel/locking/test-ww_mutex.c
+++ b/kernel/locking/test-ww_mutex.c
@@ -19,8 +19,10 @@
#include <linux/kernel.h>
#include <linux/completion.h>
+#include <linux/delay.h>
#include <linux/kthread.h>
#include <linux/module.h>
+#include <linux/random.h>
#include <linux/slab.h>
#include <linux/ww_mutex.h>
@@ -348,6 +350,246 @@ static int test_cycle(unsigned int ncpus)
return 0;
}
+struct stress {
+ struct work_struct work;
+ struct ww_mutex *locks;
+ int nlocks;
+ int nloops;
+};
+
+static int *get_random_order(int count)
+{
+ int *order;
+ int n, r, tmp;
+
+ order = kmalloc_array(count, sizeof(*order), GFP_TEMPORARY);
+ if (!order)
+ return order;
+
+ for (n = 0; n < count; n++)
+ order[n] = n;
+
+ for (n = count - 1; n > 1; n--) {
+ r = get_random_int() % (n + 1);
+ if (r != n) {
+ tmp = order[n];
+ order[n] = order[r];
+ order[r] = tmp;
+ }
+ }
+
+ return order;
+}
+
+static void dummy_load(struct stress *stress)
+{
+ usleep_range(1000, 2000);
+}
+
+static void stress_inorder_work(struct work_struct *work)
+{
+ struct stress *stress = container_of(work, typeof(*stress), work);
+ const int nlocks = stress->nlocks;
+ struct ww_mutex *locks = stress->locks;
+ struct ww_acquire_ctx ctx;
+ int *order;
+
+ order = get_random_order(nlocks);
+ if (!order)
+ return;
+
+ ww_acquire_init(&ctx, &ww_class);
+
+ do {
+ int contended = -1;
+ int n, err;
+
+retry:
+ err = 0;
+ for (n = 0; n < nlocks; n++) {
+ if (n == contended)
+ continue;
+
+ err = ww_mutex_lock(&locks[order[n]], &ctx);
+ if (err < 0)
+ break;
+ }
+ if (!err)
+ dummy_load(stress);
+
+ if (contended > n)
+ ww_mutex_unlock(&locks[order[contended]]);
+ contended = n;
+ while (n--)
+ ww_mutex_unlock(&locks[order[n]]);
+
+ if (err == -EDEADLK) {
+ ww_mutex_lock_slow(&locks[order[contended]], &ctx);
+ goto retry;
+ }
+
+ if (err) {
+ pr_err_once("stress (%s) failed with %d\n",
+ __func__, err);
+ break;
+ }
+ } while (--stress->nloops);
+
+ ww_acquire_fini(&ctx);
+
+ kfree(order);
+ kfree(stress);
+}
+
+struct reorder_lock {
+ struct list_head link;
+ struct ww_mutex *lock;
+};
+
+static void stress_reorder_work(struct work_struct *work)
+{
+ struct stress *stress = container_of(work, typeof(*stress), work);
+ LIST_HEAD(locks);
+ struct ww_acquire_ctx ctx;
+ struct reorder_lock *ll, *ln;
+ int *order;
+ int n, err;
+
+ order = get_random_order(stress->nlocks);
+ if (!order)
+ return;
+
+ for (n = 0; n < stress->nlocks; n++) {
+ ll = kmalloc(sizeof(*ll), GFP_KERNEL);
+ if (!ll)
+ goto out;
+
+ ll->lock = &stress->locks[order[n]];
+ list_add(&ll->link, &locks);
+ }
+ kfree(order);
+ order = NULL;
+
+ ww_acquire_init(&ctx, &ww_class);
+
+ do {
+ list_for_each_entry(ll, &locks, link) {
+ err = ww_mutex_lock(ll->lock, &ctx);
+ if (!err)
+ continue;
+
+ ln = ll;
+ list_for_each_entry_continue_reverse(ln, &locks, link)
+ ww_mutex_unlock(ln->lock);
+
+ if (err != -EDEADLK) {
+ pr_err_once("stress (%s) failed with %d\n",
+ __func__, err);
+ break;
+ }
+
+ ww_mutex_lock_slow(ll->lock, &ctx);
+ list_move(&ll->link, &locks); /* restarts iteration */
+ }
+
+ dummy_load(stress);
+ list_for_each_entry(ll, &locks, link)
+ ww_mutex_unlock(ll->lock);
+ } while (--stress->nloops);
+
+ ww_acquire_fini(&ctx);
+
+out:
+ list_for_each_entry_safe(ll, ln, &locks, link)
+ kfree(ll);
+ kfree(order);
+ kfree(stress);
+}
+
+static void stress_one_work(struct work_struct *work)
+{
+ struct stress *stress = container_of(work, typeof(*stress), work);
+ const int nlocks = stress->nlocks;
+ struct ww_mutex *lock = stress->locks + (get_random_int() % nlocks);
+ int err;
+
+ do {
+ err = ww_mutex_lock(lock, NULL);
+ if (!err) {
+ dummy_load(stress);
+ ww_mutex_unlock(lock);
+ } else {
+ pr_err_once("stress (%s) failed with %d\n",
+ __func__, err);
+ break;
+ }
+ } while (--stress->nloops);
+
+ kfree(stress);
+}
+
+#define STRESS_INORDER BIT(0)
+#define STRESS_REORDER BIT(1)
+#define STRESS_ONE BIT(2)
+#define STRESS_ALL (STRESS_INORDER | STRESS_REORDER | STRESS_ONE)
+
+static int stress(int nlocks, int nthreads, int nloops, unsigned int flags)
+{
+ struct ww_mutex *locks;
+ int n;
+
+ locks = kmalloc_array(nlocks, sizeof(*locks), GFP_KERNEL);
+ if (!locks)
+ return -ENOMEM;
+
+ for (n = 0; n < nlocks; n++)
+ ww_mutex_init(&locks[n], &ww_class);
+
+ for (n = 0; nthreads; n++) {
+ struct stress *stress;
+ void (*fn)(struct work_struct *work);
+
+ fn = NULL;
+ switch (n & 3) {
+ case 0:
+ if (flags & STRESS_INORDER)
+ fn = stress_inorder_work;
+ break;
+ case 1:
+ if (flags & STRESS_REORDER)
+ fn = stress_reorder_work;
+ break;
+ case 2:
+ if (flags & STRESS_ONE)
+ fn = stress_one_work;
+ break;
+ }
+
+ if (!fn)
+ continue;
+
+ stress = kmalloc(sizeof(*stress), GFP_KERNEL);
+ if (!stress)
+ break;
+
+ INIT_WORK(&stress->work, fn);
+ stress->locks = locks;
+ stress->nlocks = nlocks;
+ stress->nloops = nloops;
+
+ queue_work(wq, &stress->work);
+ nthreads--;
+ }
+
+ flush_workqueue(wq);
+
+ for (n = 0; n < nlocks; n++)
+ ww_mutex_destroy(&locks[n]);
+ kfree(locks);
+
+ return 0;
+}
+
static int __init test_ww_mutex_init(void)
{
int ncpus = num_online_cpus();
@@ -377,6 +619,18 @@ static int __init test_ww_mutex_init(void)
if (ret)
return ret;
+ ret = stress(16, 2*ncpus, 1<<10, STRESS_INORDER);
+ if (ret)
+ return ret;
+
+ ret = stress(16, 2*ncpus, 1<<10, STRESS_REORDER);
+ if (ret)
+ return ret;
+
+ ret = stress(4096, hweight32(STRESS_ALL)*ncpus, 1<<12, STRESS_ALL);
+ if (ret)
+ return ret;
+
return 0;
}