diff --git a/lib/test_vmalloc.c b/lib/test_vmalloc.c
new file mode 100644
index 0000000..8bbefca
--- /dev/null
+++ b/lib/test_vmalloc.c
@@ -0,0 +1,549 @@
+// 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.\n\n"
+		"\t\tid: 1,   name: fix_size_alloc_test\n"
+		"\t\tid: 2,   name: full_fit_alloc_test\n"
+		"\t\tid: 4,   name: long_busy_list_alloc_test\n"
+		"\t\tid: 8,   name: random_size_alloc_test\n"
+		"\t\tid: 16,  name: fix_align_alloc_test\n"
+		"\t\tid: 32,  name: random_size_align_alloc_test\n"
+		"\t\tid: 64,  name: align_shift_alloc_test\n"
+		"\t\tid: 128, name: pcpu_alloc_test\n"
+		/* 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\n", 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\n", 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\n",
+				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\n",
+			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");