locking/ww_mutex: Add kselftests for ww_mutex stress (2a0c1128) · Commits · e / devices / android_kernel_teracube_mt6765

kernel/locking/test-ww_mutex.c

+254 −0

Original line number	Original line	Diff line number	Diff line
	@@ -19,8 +19,10 @@
	#include <linux/kernel.h>		#include <linux/kernel.h>

	#include <linux/completion.h>		#include <linux/completion.h>
			#include <linux/delay.h>
	#include <linux/kthread.h>		#include <linux/kthread.h>
	#include <linux/module.h>		#include <linux/module.h>
			#include <linux/random.h>
	#include <linux/slab.h>		#include <linux/slab.h>
	#include <linux/ww_mutex.h>		#include <linux/ww_mutex.h>

	@@ -348,6 +350,246 @@ static int test_cycle(unsigned int ncpus)
	return 0;		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)		static int __init test_ww_mutex_init(void)
	{		{
	int ncpus = num_online_cpus();		int ncpus = num_online_cpus();
	@@ -377,6 +619,18 @@ static int __init test_ww_mutex_init(void)
	if (ret)		if (ret)
	return 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;		return 0;
	}		}