locktorture: Add infrastructure for torturing read locks (4f6332c1) · Commits · 戴 / test

Documentation/locking/locktorture.txt

+12 −4

Original line number	Diff line number	Diff line
		@@ -29,6 +29,11 @@ nwriters_stress Number of kernel threads that will stress exclusive lock
		ownership (writers). The default value is twice the number
		of online CPUs.

		nreaders_stress Number of kernel threads that will stress shared lock
		ownership (readers). The default is the same amount of writer
		locks. If the user did not specify nwriters_stress, then
		both readers and writers be the amount of online CPUs.

		torture_type Type of lock to torture. By default, only spinlocks will
		be tortured. This module can torture the following locks,
		with string values as follows:
		@@ -97,15 +102,18 @@ STATISTICS
		Statistics are printed in the following format:

		spin_lock-torture: Writes: Total: 93746064 Max/Min: 0/0 Fail: 0
		(A) (B) (C) (D)
		(A) (B) (C) (D) (E)

		(A): Lock type that is being tortured -- torture_type parameter.

		(B): Number of times the lock was acquired.
		(B): Number of writer lock acquisitions. If dealing with a read/write primitive
		a second "Reads" statistics line is printed.

		(C): Number of times the lock was acquired.

		(C): Min and max number of times threads failed to acquire the lock.
		(D): Min and max number of times threads failed to acquire the lock.

		(D): true/false values if there were errors acquiring the lock. This should
		(E): true/false values if there were errors acquiring the lock. This should
		-only- be positive if there is a bug in the locking primitive's
		implementation. Otherwise a lock should never fail (i.e., spin_lock()).
		Of course, the same applies for (C), above. A dummy example of this is

kernel/locking/locktorture.c

+156 −20

Original line number	Diff line number	Diff line
		@@ -52,6 +52,8 @@ MODULE_AUTHOR("Paul E. McKenney <paulmck@us.ibm.com>");

		torture_param(int, nwriters_stress, -1,
		"Number of write-locking stress-test threads");
		torture_param(int, nreaders_stress, -1,
		"Number of read-locking stress-test threads");
		torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)");
		torture_param(int, onoff_interval, 0,
		"Time between CPU hotplugs (s), 0=disable");
		@@ -74,15 +76,19 @@ static atomic_t n_lock_torture_errors;

		static struct task_struct *stats_task;
		static struct task_struct **writer_tasks;
		static struct task_struct **reader_tasks;

		static int nrealwriters_stress;
		static bool lock_is_write_held;
		static int nrealreaders_stress;
		static bool lock_is_read_held;

		struct lock_stress_stats {
		long n_lock_fail;
		long n_lock_acquired;
		};
		static struct lock_stress_stats lwsa; / writer statistics */
		static struct lock_stress_stats lrsa; / reader statistics */

		#if defined(MODULE)
		#define LOCKTORTURE_RUNNABLE_INIT 1
		@@ -104,6 +110,9 @@ struct lock_torture_ops {
		int (*writelock)(void);
		void (write_delay)(struct torture_random_state trsp);
		void (*writeunlock)(void);
		int (*readlock)(void);
		void (read_delay)(struct torture_random_state trsp);
		void (*readunlock)(void);
		unsigned long flags;
		const char *name;
		};
		@@ -142,6 +151,9 @@ static struct lock_torture_ops lock_busted_ops = {
		.writelock = torture_lock_busted_write_lock,
		.write_delay = torture_lock_busted_write_delay,
		.writeunlock = torture_lock_busted_write_unlock,
		.readlock = NULL,
		.read_delay = NULL,
		.readunlock = NULL,
		.name = "lock_busted"
		};

		@@ -182,6 +194,9 @@ static struct lock_torture_ops spin_lock_ops = {
		.writelock = torture_spin_lock_write_lock,
		.write_delay = torture_spin_lock_write_delay,
		.writeunlock = torture_spin_lock_write_unlock,
		.readlock = NULL,
		.read_delay = NULL,
		.readunlock = NULL,
		.name = "spin_lock"
		};

		@@ -205,6 +220,9 @@ static struct lock_torture_ops spin_lock_irq_ops = {
		.writelock = torture_spin_lock_write_lock_irq,
		.write_delay = torture_spin_lock_write_delay,
		.writeunlock = torture_lock_spin_write_unlock_irq,
		.readlock = NULL,
		.read_delay = NULL,
		.readunlock = NULL,
		.name = "spin_lock_irq"
		};

		@@ -241,6 +259,9 @@ static struct lock_torture_ops mutex_lock_ops = {
		.writelock = torture_mutex_lock,
		.write_delay = torture_mutex_delay,
		.writeunlock = torture_mutex_unlock,
		.readlock = NULL,
		.read_delay = NULL,
		.readunlock = NULL,
		.name = "mutex_lock"
		};

		@@ -273,29 +294,58 @@ static int lock_torture_writer(void *arg)
		return 0;
		}

		/*
		* Lock torture reader kthread. Repeatedly acquires and releases
		* the reader lock.
		*/
		static int lock_torture_reader(void *arg)
		{
		struct lock_stress_stats *lrsp = arg;
		static DEFINE_TORTURE_RANDOM(rand);

		VERBOSE_TOROUT_STRING("lock_torture_reader task started");
		set_user_nice(current, MAX_NICE);

		do {
		if ((torture_random(&rand) & 0xfffff) == 0)
		schedule_timeout_uninterruptible(1);
		cur_ops->readlock();
		lock_is_read_held = 1;
		lrsp->n_lock_acquired++;
		cur_ops->read_delay(&rand);
		lock_is_read_held = 0;
		cur_ops->readunlock();
		stutter_wait("lock_torture_reader");
		} while (!torture_must_stop());
		torture_kthread_stopping("lock_torture_reader");
		return 0;
		}

		/*
		* Create an lock-torture-statistics message in the specified buffer.
		*/
		static void lock_torture_printk(char *page)
		static void __torture_print_stats(char *page,
		struct lock_stress_stats *statp, bool write)
		{
		bool fail = 0;
		int i;
		int i, n_stress;
		long max = 0;
		long min = lwsa[0].n_lock_acquired;
		long min = statp[0].n_lock_acquired;
		long long sum = 0;

		for (i = 0; i < nrealwriters_stress; i++) {
		if (lwsa[i].n_lock_fail)
		n_stress = write ? nrealwriters_stress : nrealreaders_stress;
		for (i = 0; i < n_stress; i++) {
		if (statp[i].n_lock_fail)
		fail = true;
		sum += lwsa[i].n_lock_acquired;
		if (max < lwsa[i].n_lock_fail)
		max = lwsa[i].n_lock_fail;
		if (min > lwsa[i].n_lock_fail)
		min = lwsa[i].n_lock_fail;
		sum += statp[i].n_lock_acquired;
		if (max < statp[i].n_lock_fail)
		max = statp[i].n_lock_fail;
		if (min > statp[i].n_lock_fail)
		min = statp[i].n_lock_fail;
		}
		page += sprintf(page, "%s%s ", torture_type, TORTURE_FLAG);
		page += sprintf(page,
		"Writes: Total: %lld Max/Min: %ld/%ld %s Fail: %d %s\n",
		"%s: Total: %lld Max/Min: %ld/%ld %s Fail: %d %s\n",
		write ? "Writes" : "Reads ",
		sum, max, min, max / 2 > min ? "???" : "",
		fail, fail ? "!!!" : "");
		if (fail)
		@@ -315,15 +365,32 @@ static void lock_torture_stats_print(void)
		int size = nrealwriters_stress * 200 + 8192;
		char *buf;

		if (cur_ops->readlock)
		size += nrealreaders_stress * 200 + 8192;

		buf = kmalloc(size, GFP_KERNEL);
		if (!buf) {
		pr_err("lock_torture_stats_print: Out of memory, need: %d",
		size);
		return;
		}
		lock_torture_printk(buf);

		__torture_print_stats(buf, lwsa, true);
		pr_alert("%s", buf);
		kfree(buf);

		if (cur_ops->readlock) {
		buf = kmalloc(size, GFP_KERNEL);
		if (!buf) {
		pr_err("lock_torture_stats_print: Out of memory, need: %d",
		size);
		return;
		}

		__torture_print_stats(buf, lrsa, false);
		pr_alert("%s", buf);
		kfree(buf);
		}
		}

		/*
		@@ -350,10 +417,10 @@ lock_torture_print_module_parms(struct lock_torture_ops *cur_ops,
		const char *tag)
		{
		pr_alert("%s" TORTURE_FLAG
		"--- %s%s: nwriters_stress=%d stat_interval=%d verbose=%d shuffle_interval=%d stutter=%d shutdown_secs=%d onoff_interval=%d onoff_holdoff=%d\n",
		"--- %s%s: nwriters_stress=%d nreaders_stress=%d stat_interval=%d verbose=%d shuffle_interval=%d stutter=%d shutdown_secs=%d onoff_interval=%d onoff_holdoff=%d\n",
		torture_type, tag, debug_lock ? " [debug]": "",
		nrealwriters_stress, stat_interval, verbose,
		shuffle_interval, stutter, shutdown_secs,
		nrealwriters_stress, nrealreaders_stress, stat_interval,
		verbose, shuffle_interval, stutter, shutdown_secs,
		onoff_interval, onoff_holdoff);
		}

		@@ -372,6 +439,14 @@ static void lock_torture_cleanup(void)
		writer_tasks = NULL;
		}

		if (reader_tasks) {
		for (i = 0; i < nrealreaders_stress; i++)
		torture_stop_kthread(lock_torture_reader,
		reader_tasks[i]);
		kfree(reader_tasks);
		reader_tasks = NULL;
		}

		torture_stop_kthread(lock_torture_stats, stats_task);
		lock_torture_stats_print(); /* -After- the stats thread is stopped! */

		@@ -389,7 +464,7 @@ static void lock_torture_cleanup(void)

		static int __init lock_torture_init(void)
		{
		int i;
		int i, j;
		int firsterr = 0;
		static struct lock_torture_ops *torture_ops[] = {
		&lock_busted_ops, &spin_lock_ops, &spin_lock_irq_ops, &mutex_lock_ops,
		@@ -430,7 +505,6 @@ static int __init lock_torture_init(void)
		if (strncmp(torture_type, "spin", 4) == 0)
		debug_lock = true;
		#endif
		lock_torture_print_module_parms(cur_ops, "Start of test");

		/* Initialize the statistics so that each run gets its own numbers. */

		@@ -446,8 +520,37 @@ static int __init lock_torture_init(void)
		lwsa[i].n_lock_acquired = 0;
		}

		/* Start up the kthreads. */
		if (cur_ops->readlock) {
		if (nreaders_stress >= 0)
		nrealreaders_stress = nreaders_stress;
		else {
		/*
		* By default distribute evenly the number of
		* readers and writers. We still run the same number
		* of threads as the writer-only locks default.
		*/
		if (nwriters_stress < 0) /* user doesn't care */
		nrealwriters_stress = num_online_cpus();
		nrealreaders_stress = nrealwriters_stress;
		}

		lock_is_read_held = 0;
		lrsa = kmalloc(sizeof(lrsa) nrealreaders_stress, GFP_KERNEL);
		if (lrsa == NULL) {
		VERBOSE_TOROUT_STRING("lrsa: Out of memory");
		firsterr = -ENOMEM;
		kfree(lwsa);
		goto unwind;
		}

		for (i = 0; i < nrealreaders_stress; i++) {
		lrsa[i].n_lock_fail = 0;
		lrsa[i].n_lock_acquired = 0;
		}
		}
		lock_torture_print_module_parms(cur_ops, "Start of test");

		/* Prepare torture context. */
		if (onoff_interval > 0) {
		firsterr = torture_onoff_init(onoff_holdoff * HZ,
		onoff_interval * HZ);
		@@ -478,11 +581,44 @@ static int __init lock_torture_init(void)
		firsterr = -ENOMEM;
		goto unwind;
		}
		for (i = 0; i < nrealwriters_stress; i++) {

		if (cur_ops->readlock) {
		reader_tasks = kzalloc(nrealreaders_stress * sizeof(reader_tasks[0]),
		GFP_KERNEL);
		if (reader_tasks == NULL) {
		VERBOSE_TOROUT_ERRSTRING("reader_tasks: Out of memory");
		firsterr = -ENOMEM;
		goto unwind;
		}
		}

		/*
		* Create the kthreads and start torturing (oh, those poor little locks).
		*
		* TODO: Note that we interleave writers with readers, giving writers a
		* slight advantage, by creating its kthread first. This can be modified
		* for very specific needs, or even let the user choose the policy, if
		* ever wanted.
		*/
		for (i = 0, j = 0; i < nrealwriters_stress \|\|
		j < nrealreaders_stress; i++, j++) {
		if (i >= nrealwriters_stress)
		goto create_reader;

		/* Create writer. */
		firsterr = torture_create_kthread(lock_torture_writer, &lwsa[i],
		writer_tasks[i]);
		if (firsterr)
		goto unwind;

		create_reader:
		if (cur_ops->readlock == NULL \|\| (j >= nrealreaders_stress))
		continue;
		/* Create reader. */
		firsterr = torture_create_kthread(lock_torture_reader, &lrsa[j],
		reader_tasks[j]);
		if (firsterr)
		goto unwind;
		}
		if (stat_interval > 0) {
		firsterr = torture_create_kthread(lock_torture_stats, NULL,

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