// 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>
  
  #define __param(type, name, init, msg)		\
  	static type name = init;				\
  	module_param(name, type, 0444);			\
  	MODULE_PARM_DESC(name, msg)				\
  
  __param(bool, single_cpu_test, false,
  	"Use single first online CPU to run tests");
  
  __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, 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
  "
  		/* Add a new test case description here. */
  );
  
  /*
   * Depends on single_cpu_test parameter. If it is true, then
   * use first online CPU to trigger a test on, otherwise go with
   * all online CPUs.
   */
  static cpumask_t cpus_run_test_mask = CPU_MASK_NONE;
  
  /*
   * 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_range(size, align,
  		   VMALLOC_START, VMALLOC_END,
  		   GFP_KERNEL | __GFP_ZERO,
  		   PAGE_KERNEL,
  		   0, 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_range(PAGE_SIZE, align,
  			VMALLOC_START, VMALLOC_END,
  			GFP_KERNEL | __GFP_ZERO,
  			PAGE_KERNEL,
  			0, 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_range(5 * PAGE_SIZE,
  			THREAD_ALIGN << 1,
  			VMALLOC_START, VMALLOC_END,
  			GFP_KERNEL | __GFP_ZERO,
  			PAGE_KERNEL,
  			0, 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(3 * 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_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 },
  	/* Add a new test case here. */
  };
  
  struct test_case_data {
  	int test_failed;
  	int test_passed;
  	u64 time;
  };
  
  /* Split it to get rid of: WARNING: line over 80 characters */
  static struct test_case_data
  	per_cpu_test_data[NR_CPUS][ARRAY_SIZE(test_case_array)];
  
  static struct test_driver {
  	struct task_struct *task;
  	unsigned long start;
  	unsigned long stop;
  	int cpu;
  } per_cpu_test_driver[NR_CPUS];
  
  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;

  	if (set_cpus_allowed_ptr(current, cpumask_of(t->cpu)) < 0)

  		pr_err("Failed to set affinity to %d CPU
  ", t->cpu);

  
  	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())

  				per_cpu_test_data[t->cpu][index].test_passed++;
  			else
  				per_cpu_test_data[t->cpu][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);
  
  		per_cpu_test_data[t->cpu][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 void
  init_test_configurtion(void)
  {
  	/*
  	 * Reset all data of all CPUs.
  	 */
  	memset(per_cpu_test_data, 0, sizeof(per_cpu_test_data));
  
  	if (single_cpu_test)
  		cpumask_set_cpu(cpumask_first(cpu_online_mask),
  			&cpus_run_test_mask);
  	else
  		cpumask_and(&cpus_run_test_mask, cpu_online_mask,
  			cpu_online_mask);
  
  	if (test_repeat_count <= 0)
  		test_repeat_count = 1;
  
  	if (test_loop_count <= 0)
  		test_loop_count = 1;
  }
  
  static void do_concurrent_test(void)
  {
  	int cpu, ret;
  
  	/*
  	 * Set some basic configurations plus sanity check.
  	 */
  	init_test_configurtion();
  
  	/*
  	 * Put on hold all workers.
  	 */
  	down_write(&prepare_for_test_rwsem);
  
  	for_each_cpu(cpu, &cpus_run_test_mask) {
  		struct test_driver *t = &per_cpu_test_driver[cpu];
  
  		t->cpu = cpu;
  		t->task = kthread_run(test_func, t, "vmalloc_test/%d", cpu);
  
  		if (!IS_ERR(t->task))
  			/* Success. */
  			atomic_inc(&test_n_undone);
  		else
  			pr_err("Failed to start kthread for %d CPU
  ", cpu);
  	}
  
  	/*
  	 * 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_each_cpu(cpu, &cpus_run_test_mask) {
  		struct test_driver *t = &per_cpu_test_driver[cpu];
  		int i;
  
  		if (!IS_ERR(t->task))
  			kthread_stop(t->task);
  
  		for (i = 0; i < ARRAY_SIZE(test_case_array); i++) {
  			if (!((run_test_mask & (1 << i)) >> i))
  				continue;
  
  			pr_info(
  				"Summary: %s passed: %d failed: %d repeat: %d loops: %d avg: %llu usec
  ",
  				test_case_array[i].test_name,
  				per_cpu_test_data[cpu][i].test_passed,
  				per_cpu_test_data[cpu][i].test_failed,
  				test_repeat_count, test_loop_count,
  				per_cpu_test_data[cpu][i].time);
  		}
  
  		pr_info("All test took CPU%d=%lu cycles
  ",
  			cpu, t->stop - t->start);
  	}
  }
  
  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");