// SPDX-License-Identifier: GPL-2.0
  
  /*
   * Test module for stress and analyze performance of vmalloc allocator.
   * (C) 2018 Uladzislau Rezki (Sony) <urezki@gmail.com>
   */
  #include <linux/init.h>
  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <linux/vmalloc.h>
  #include <linux/random.h>
  #include <linux/kthread.h>
  #include <linux/moduleparam.h>
  #include <linux/completion.h>
  #include <linux/delay.h>
  #include <linux/rwsem.h>
  #include <linux/mm.h>

  #include <linux/rcupdate.h>
  #include <linux/slab.h>

  
  #define __param(type, name, init, msg)		\
  	static type name = init;				\
  	module_param(name, type, 0444);			\
  	MODULE_PARM_DESC(name, msg)				\

  __param(int, nr_threads, 0,
  	"Number of workers to perform tests(min: 1 max: USHRT_MAX)");

  
  __param(bool, sequential_test_order, false,
  	"Use sequential stress tests order");
  
  __param(int, test_repeat_count, 1,
  	"Set test repeat counter");
  
  __param(int, test_loop_count, 1000000,
  	"Set test loop counter");

  __param(int, nr_pages, 0,
  	"Set number of pages for fix_size_alloc_test(default: 1)");

  __param(int, run_test_mask, INT_MAX,
  	"Set tests specified in the mask.
  
  "

  		"\t\tid: 1,    name: fix_size_alloc_test
  "
  		"\t\tid: 2,    name: full_fit_alloc_test
  "
  		"\t\tid: 4,    name: long_busy_list_alloc_test
  "
  		"\t\tid: 8,    name: random_size_alloc_test
  "
  		"\t\tid: 16,   name: fix_align_alloc_test
  "
  		"\t\tid: 32,   name: random_size_align_alloc_test
  "
  		"\t\tid: 64,   name: align_shift_alloc_test
  "
  		"\t\tid: 128,  name: pcpu_alloc_test
  "
  		"\t\tid: 256,  name: kvfree_rcu_1_arg_vmalloc_test
  "
  		"\t\tid: 512,  name: kvfree_rcu_2_arg_vmalloc_test
  "

  		/* Add a new test case description here. */
  );
  
  /*

   * Read write semaphore for synchronization of setup
   * phase that is done in main thread and workers.
   */
  static DECLARE_RWSEM(prepare_for_test_rwsem);
  
  /*
   * Completion tracking for worker threads.
   */
  static DECLARE_COMPLETION(test_all_done_comp);
  static atomic_t test_n_undone = ATOMIC_INIT(0);
  
  static inline void
  test_report_one_done(void)
  {
  	if (atomic_dec_and_test(&test_n_undone))
  		complete(&test_all_done_comp);
  }
  
  static int random_size_align_alloc_test(void)
  {
  	unsigned long size, align, rnd;
  	void *ptr;
  	int i;
  
  	for (i = 0; i < test_loop_count; i++) {
  		get_random_bytes(&rnd, sizeof(rnd));
  
  		/*
  		 * Maximum 1024 pages, if PAGE_SIZE is 4096.
  		 */
  		align = 1 << (rnd % 23);
  
  		/*
  		 * Maximum 10 pages.
  		 */
  		size = ((rnd % 10) + 1) * PAGE_SIZE;

  		ptr = __vmalloc_node(size, align, GFP_KERNEL | __GFP_ZERO, 0,
  				__builtin_return_address(0));

  		if (!ptr)
  			return -1;
  
  		vfree(ptr);
  	}
  
  	return 0;
  }
  
  /*
   * This test case is supposed to be failed.
   */
  static int align_shift_alloc_test(void)
  {
  	unsigned long align;
  	void *ptr;
  	int i;
  
  	for (i = 0; i < BITS_PER_LONG; i++) {
  		align = ((unsigned long) 1) << i;

  		ptr = __vmalloc_node(PAGE_SIZE, align, GFP_KERNEL|__GFP_ZERO, 0,
  				__builtin_return_address(0));

  		if (!ptr)
  			return -1;
  
  		vfree(ptr);
  	}
  
  	return 0;
  }
  
  static int fix_align_alloc_test(void)
  {
  	void *ptr;
  	int i;
  
  	for (i = 0; i < test_loop_count; i++) {

  		ptr = __vmalloc_node(5 * PAGE_SIZE, THREAD_ALIGN << 1,
  				GFP_KERNEL | __GFP_ZERO, 0,
  				__builtin_return_address(0));

  		if (!ptr)
  			return -1;
  
  		vfree(ptr);
  	}
  
  	return 0;
  }
  
  static int random_size_alloc_test(void)
  {
  	unsigned int n;
  	void *p;
  	int i;
  
  	for (i = 0; i < test_loop_count; i++) {
  		get_random_bytes(&n, sizeof(i));
  		n = (n % 100) + 1;
  
  		p = vmalloc(n * PAGE_SIZE);
  
  		if (!p)
  			return -1;
  
  		*((__u8 *)p) = 1;
  		vfree(p);
  	}
  
  	return 0;
  }
  
  static int long_busy_list_alloc_test(void)
  {
  	void *ptr_1, *ptr_2;
  	void **ptr;
  	int rv = -1;
  	int i;
  
  	ptr = vmalloc(sizeof(void *) * 15000);
  	if (!ptr)
  		return rv;
  
  	for (i = 0; i < 15000; i++)
  		ptr[i] = vmalloc(1 * PAGE_SIZE);
  
  	for (i = 0; i < test_loop_count; i++) {
  		ptr_1 = vmalloc(100 * PAGE_SIZE);
  		if (!ptr_1)
  			goto leave;
  
  		ptr_2 = vmalloc(1 * PAGE_SIZE);
  		if (!ptr_2) {
  			vfree(ptr_1);
  			goto leave;
  		}
  
  		*((__u8 *)ptr_1) = 0;
  		*((__u8 *)ptr_2) = 1;
  
  		vfree(ptr_1);
  		vfree(ptr_2);
  	}
  
  	/*  Success */
  	rv = 0;
  
  leave:
  	for (i = 0; i < 15000; i++)
  		vfree(ptr[i]);
  
  	vfree(ptr);
  	return rv;
  }
  
  static int full_fit_alloc_test(void)
  {
  	void **ptr, **junk_ptr, *tmp;
  	int junk_length;
  	int rv = -1;
  	int i;
  
  	junk_length = fls(num_online_cpus());
  	junk_length *= (32 * 1024 * 1024 / PAGE_SIZE);
  
  	ptr = vmalloc(sizeof(void *) * junk_length);
  	if (!ptr)
  		return rv;
  
  	junk_ptr = vmalloc(sizeof(void *) * junk_length);
  	if (!junk_ptr) {
  		vfree(ptr);
  		return rv;
  	}
  
  	for (i = 0; i < junk_length; i++) {
  		ptr[i] = vmalloc(1 * PAGE_SIZE);
  		junk_ptr[i] = vmalloc(1 * PAGE_SIZE);
  	}
  
  	for (i = 0; i < junk_length; i++)
  		vfree(junk_ptr[i]);
  
  	for (i = 0; i < test_loop_count; i++) {
  		tmp = vmalloc(1 * PAGE_SIZE);
  
  		if (!tmp)
  			goto error;
  
  		*((__u8 *)tmp) = 1;
  		vfree(tmp);
  	}
  
  	/* Success */
  	rv = 0;
  
  error:
  	for (i = 0; i < junk_length; i++)
  		vfree(ptr[i]);
  
  	vfree(ptr);
  	vfree(junk_ptr);
  
  	return rv;
  }
  
  static int fix_size_alloc_test(void)
  {
  	void *ptr;
  	int i;
  
  	for (i = 0; i < test_loop_count; i++) {

  		ptr = vmalloc((nr_pages > 0 ? nr_pages:1) * PAGE_SIZE);

  
  		if (!ptr)
  			return -1;
  
  		*((__u8 *)ptr) = 0;
  
  		vfree(ptr);
  	}
  
  	return 0;
  }
  
  static int
  pcpu_alloc_test(void)
  {
  	int rv = 0;
  #ifndef CONFIG_NEED_PER_CPU_KM
  	void __percpu **pcpu;
  	size_t size, align;
  	int i;
  
  	pcpu = vmalloc(sizeof(void __percpu *) * 35000);
  	if (!pcpu)
  		return -1;
  
  	for (i = 0; i < 35000; i++) {
  		unsigned int r;
  
  		get_random_bytes(&r, sizeof(i));
  		size = (r % (PAGE_SIZE / 4)) + 1;
  
  		/*
  		 * Maximum PAGE_SIZE
  		 */
  		get_random_bytes(&r, sizeof(i));
  		align = 1 << ((i % 11) + 1);
  
  		pcpu[i] = __alloc_percpu(size, align);
  		if (!pcpu[i])
  			rv = -1;
  	}
  
  	for (i = 0; i < 35000; i++)
  		free_percpu(pcpu[i]);
  
  	vfree(pcpu);
  #endif
  	return rv;
  }

  struct test_kvfree_rcu {
  	struct rcu_head rcu;
  	unsigned char array[20];
  };
  
  static int
  kvfree_rcu_1_arg_vmalloc_test(void)
  {
  	struct test_kvfree_rcu *p;
  	int i;
  
  	for (i = 0; i < test_loop_count; i++) {
  		p = vmalloc(1 * PAGE_SIZE);
  		if (!p)
  			return -1;
  
  		p->array[0] = 'a';
  		kvfree_rcu(p);
  	}
  
  	return 0;
  }
  
  static int
  kvfree_rcu_2_arg_vmalloc_test(void)
  {
  	struct test_kvfree_rcu *p;
  	int i;
  
  	for (i = 0; i < test_loop_count; i++) {
  		p = vmalloc(1 * PAGE_SIZE);
  		if (!p)
  			return -1;
  
  		p->array[0] = 'a';
  		kvfree_rcu(p, rcu);
  	}
  
  	return 0;
  }

  struct test_case_desc {
  	const char *test_name;
  	int (*test_func)(void);
  };
  
  static struct test_case_desc test_case_array[] = {
  	{ "fix_size_alloc_test", fix_size_alloc_test },
  	{ "full_fit_alloc_test", full_fit_alloc_test },
  	{ "long_busy_list_alloc_test", long_busy_list_alloc_test },
  	{ "random_size_alloc_test", random_size_alloc_test },
  	{ "fix_align_alloc_test", fix_align_alloc_test },
  	{ "random_size_align_alloc_test", random_size_align_alloc_test },
  	{ "align_shift_alloc_test", align_shift_alloc_test },
  	{ "pcpu_alloc_test", pcpu_alloc_test },

  	{ "kvfree_rcu_1_arg_vmalloc_test", kvfree_rcu_1_arg_vmalloc_test },
  	{ "kvfree_rcu_2_arg_vmalloc_test", kvfree_rcu_2_arg_vmalloc_test },

  	/* Add a new test case here. */
  };
  
  struct test_case_data {
  	int test_failed;
  	int test_passed;
  	u64 time;
  };

  static struct test_driver {
  	struct task_struct *task;

  	struct test_case_data data[ARRAY_SIZE(test_case_array)];

  	unsigned long start;
  	unsigned long stop;

  } *tdriver;

  
  static void shuffle_array(int *arr, int n)
  {
  	unsigned int rnd;
  	int i, j, x;
  
  	for (i = n - 1; i > 0; i--)  {
  		get_random_bytes(&rnd, sizeof(rnd));
  
  		/* Cut the range. */
  		j = rnd % i;
  
  		/* Swap indexes. */
  		x = arr[i];
  		arr[i] = arr[j];
  		arr[j] = x;
  	}
  }
  
  static int test_func(void *private)
  {
  	struct test_driver *t = private;

  	int random_array[ARRAY_SIZE(test_case_array)];

  	int index, i, j;

  	ktime_t kt;
  	u64 delta;

  	for (i = 0; i < ARRAY_SIZE(test_case_array); i++)
  		random_array[i] = i;
  
  	if (!sequential_test_order)
  		shuffle_array(random_array, ARRAY_SIZE(test_case_array));
  
  	/*
  	 * Block until initialization is done.
  	 */
  	down_read(&prepare_for_test_rwsem);
  
  	t->start = get_cycles();
  	for (i = 0; i < ARRAY_SIZE(test_case_array); i++) {
  		index = random_array[i];
  
  		/*
  		 * Skip tests if run_test_mask has been specified.
  		 */
  		if (!((run_test_mask & (1 << index)) >> index))
  			continue;
  
  		kt = ktime_get();
  		for (j = 0; j < test_repeat_count; j++) {

  			if (!test_case_array[index].test_func())

  				t->data[index].test_passed++;

  			else

  				t->data[index].test_failed++;

  		}
  
  		/*
  		 * Take an average time that test took.
  		 */
  		delta = (u64) ktime_us_delta(ktime_get(), kt);
  		do_div(delta, (u32) test_repeat_count);

  		t->data[index].time = delta;

  	}
  	t->stop = get_cycles();
  
  	up_read(&prepare_for_test_rwsem);
  	test_report_one_done();
  
  	/*
  	 * Wait for the kthread_stop() call.
  	 */
  	while (!kthread_should_stop())
  		msleep(10);
  
  	return 0;
  }

  static int

  init_test_configurtion(void)
  {
  	/*

  	 * A maximum number of workers is defined as hard-coded
  	 * value and set to USHRT_MAX. We add such gap just in
  	 * case and for potential heavy stressing.

  	 */

  	nr_threads = clamp(nr_threads, 1, (int) USHRT_MAX);

  	/* Allocate the space for test instances. */
  	tdriver = kvcalloc(nr_threads, sizeof(*tdriver), GFP_KERNEL);
  	if (tdriver == NULL)
  		return -1;

  
  	if (test_repeat_count <= 0)
  		test_repeat_count = 1;
  
  	if (test_loop_count <= 0)
  		test_loop_count = 1;

  
  	return 0;

  }
  
  static void do_concurrent_test(void)
  {

  	int i, ret;

  
  	/*
  	 * Set some basic configurations plus sanity check.
  	 */

  	ret = init_test_configurtion();
  	if (ret < 0)
  		return;

  
  	/*
  	 * Put on hold all workers.
  	 */
  	down_write(&prepare_for_test_rwsem);

  	for (i = 0; i < nr_threads; i++) {
  		struct test_driver *t = &tdriver[i];

  		t->task = kthread_run(test_func, t, "vmalloc_test/%d", i);

  
  		if (!IS_ERR(t->task))
  			/* Success. */
  			atomic_inc(&test_n_undone);
  		else

  			pr_err("Failed to start %d kthread
  ", i);

  	}
  
  	/*
  	 * Now let the workers do their job.
  	 */
  	up_write(&prepare_for_test_rwsem);
  
  	/*
  	 * Sleep quiet until all workers are done with 1 second
  	 * interval. Since the test can take a lot of time we
  	 * can run into a stack trace of the hung task. That is
  	 * why we go with completion_timeout and HZ value.
  	 */
  	do {
  		ret = wait_for_completion_timeout(&test_all_done_comp, HZ);
  	} while (!ret);

  	for (i = 0; i < nr_threads; i++) {
  		struct test_driver *t = &tdriver[i];
  		int j;

  
  		if (!IS_ERR(t->task))
  			kthread_stop(t->task);

  		for (j = 0; j < ARRAY_SIZE(test_case_array); j++) {
  			if (!((run_test_mask & (1 << j)) >> j))

  				continue;
  
  			pr_info(
  				"Summary: %s passed: %d failed: %d repeat: %d loops: %d avg: %llu usec
  ",

  				test_case_array[j].test_name,
  				t->data[j].test_passed,
  				t->data[j].test_failed,

  				test_repeat_count, test_loop_count,

  				t->data[j].time);

  		}

  		pr_info("All test took worker%d=%lu cycles
  ",
  			i, t->stop - t->start);

  	}

  
  	kvfree(tdriver);

  }
  
  static int vmalloc_test_init(void)
  {
  	do_concurrent_test();
  	return -EAGAIN; /* Fail will directly unload the module */
  }
  
  static void vmalloc_test_exit(void)
  {
  }
  
  module_init(vmalloc_test_init)
  module_exit(vmalloc_test_exit)
  
  MODULE_LICENSE("GPL");
  MODULE_AUTHOR("Uladzislau Rezki");
  MODULE_DESCRIPTION("vmalloc test module");