test module to verify percpu allocator

[Tejun Heo]

Hello, again.

Attached is the test module to test percpu allocator.  Just build as
an external module and load/unload to perform the test.

Thanks.

-- 
tejun
#include <linux/module.h>
#include <linux/device.h>
#include <linux/sysfs.h>
#include <linux/percpu.h>

static inline void pcpu_dump_chunk_slots(void) {}

struct alloc_cmd {
	size_t size;
	int marker;
};

static const struct alloc_cmd cmds[] = {
	{  256, 0 }, {  256, 1 }, {  256, 0 }, {  256, 1 },
	{  256, 0 }, {  256, 1 }, {  256, 0 }, {  256, 1 },
	{  256, 0 }, {  256, 1 }, {  256, 0 }, {  256, 1 },
	{  256, 0 }, {  256, 1 }, {  256, 0 }, {  256, 1 },
	{  256, 0 }, {  256, 1 }, {  256, 0 }, {  256, 1 },
	{  256, 0 }, {  256, 1 }, {  256, 0 }, {  256, 1 },
	{  256, 0 }, {  256, 1 }, {  256, 0 }, {  256, 1 },
	{  256, 0 }, {  256, 1 }, {  256, 0 }, {  256, 1 },	/* 8k */

	{ 1024, 2 }, { 1024, 2 }, { 1024, 2 }, { 1024, 2 },
	{ 1024, 2 }, { 1024, 2 }, { 1024, 2 }, { 1024, 2 },
	{ 1024, 2 }, { 1024, 2 }, { 1024, 2 }, { 1024, 2 },
	{ 1024, 2 }, { 1024, 2 }, { 1024, 2 }, { 1024, 2 },
	{ 1024, 2 }, { 1024, 2 }, { 1024, 2 }, { 1024, 2 },
	{ 1024, 2 }, { 1024, 2 }, { 1024, 2 }, { 1024, 2 },
	{ 1024, 2 }, { 1024, 2 }, { 1024, 2 }, { 1024, 2 },
	{ 1024, 2 }, { 1024, 2 }, { 1024, 2 }, { 1024, 2 },	/* 32k */

	{ 8192, 3 }, { 8192, 3 }, { 8192, 3 }, { 8192, 3 },
	{ 8192, 3 }, { 8192, 3 }, { 8192, 3 }, { 8192, 3 },
	{ 8192, 3 }, { 8192, 3 }, { 8192, 3 }, { 8192, 3 },
	{ 8192, 3 }, { 8192, 3 }, { 8192, 3 }, { 8192, 3 },
	{ 8192, 3 }, { 8192, 3 }, { 8192, 3 }, { 8192, 3 },
	{ 8192, 3 }, { 8192, 3 }, { 8192, 3 }, { 8192, 3 },
	{ 8192, 3 }, { 8192, 3 }, { 8192, 3 }, { 8192, 3 },
	{ 8192, 3 }, { 8192, 3 }, { 8192, 3 }, { 8192, 3 },	/* 128k */

	{ 0, 0 },	/* free 0s */

	{  128, 4 }, {  128, 4 }, {  128, 4 }, {  128, 4 },
	{  128, 4 }, {  128, 4 }, {  128, 4 }, {  128, 4 },
	{  128, 4 }, {  128, 4 }, {  128, 4 }, {  128, 4 },
	{  128, 4 }, {  128, 4 }, {  128, 4 }, {  128, 4 },
	{  128, 4 }, {  128, 4 }, {  128, 4 }, {  128, 4 },
	{  128, 4 }, {  128, 4 }, {  128, 4 }, {  128, 4 },
	{  128, 4 }, {  128, 4 }, {  128, 4 }, {  128, 4 },
	{  128, 4 }, {  128, 4 }, {  128, 4 }, {  128, 4 },
	{  128, 4 }, {  128, 4 }, {  128, 4 }, {  128, 4 },	/* 4.5k */

	{ 0, 1 },	/* free 1s */

	{ 1024, 5 }, { 1024, 5 }, { 1024, 5 }, { 1024, 5 },	/* 4k */

	{ 0, 5 },	/* free 5s */
	{ 0, 4 },
	{ 0, 3 },
	{ 0, 2 },
};

#define NR_CMDS		ARRAY_SIZE(cmds)

static void *ptrs[NR_CMDS];

static unsigned long seed_val(unsigned int cmdno, unsigned int cpu)
{
	return 0xdeadbeefbeefdeadULL
		+ cmdno + (cmdno << 16) + (cpu << 8) + (cpu << 24);
}

static void fill_area(void *p, size_t size, unsigned int cmdno)
{
	unsigned int cpu;

	for_each_possible_cpu(cpu) {
		unsigned long v = seed_val(cmdno, cpu);
		unsigned long *up = per_cpu_ptr(p, cpu);
		size_t left = size;

		while (left >= sizeof(unsigned long)) {
			*up++ = v++;
			left -= sizeof(unsigned long);
		}
	}
}

static void verify_area(void *p, size_t size, unsigned int cmdno)
{
	unsigned int warns = 5;
	unsigned int cpu;

	for_each_possible_cpu(cpu) {
		unsigned long v = seed_val(cmdno, cpu);
		unsigned long *up = per_cpu_ptr(p, cpu);
		size_t left = size;

		while (left >= sizeof(unsigned long)) {
			if (*up != v && warns-- > 0) {
				printk("MISMATCH: cmdno=%u size=%zu cpu=%u off=%zu p=%p\n",
				       cmdno, size, cpu, size - left, p);
				printk("          [%p]=%lx should be %lx\n",
				       up, *up, v);
			}
			up++; v++;
			left -= sizeof(unsigned long);
		}
	}
}

static void free_cmd(unsigned int cmdno)
{
	if (!ptrs[cmdno])
		return;

	verify_area(ptrs[cmdno], cmds[cmdno].size, cmdno);
	free_percpu(ptrs[cmdno]);
	ptrs[cmdno] = NULL;
}

static void run_test(void)
{
	unsigned int i, j;

	for (i = 0; i < NR_CMDS; i++) {
		const struct alloc_cmd *cmd = &cmds[i];

		if (cmd->size) {
			printk("ALLOC: %zu bytes marker=%d\n",
			       cmd->size, cmd->marker);
			ptrs[i] = __alloc_percpu(cmd->size,
					__alignof__(unsigned long long));
			if (ptrs[i])
				fill_area(ptrs[i], cmd->size, i);
			else
				printk("failed to allocate %zu bytes\n",
				       cmd->size);
			continue;
		}

		printk("FREE: marker=%d\n", cmd->marker);
		pcpu_dump_chunk_slots();
		for (j = 0; j < i; j++)
			if (cmds[j].marker == cmd->marker)
				free_cmd(j);
		printk("FREE: done\n");
		pcpu_dump_chunk_slots();
	}
}

struct stupid_large_alignment_struct {
	int a;
	int b;
	int c;
} __aligned(2048);

struct stupid_large_struct {
	char a[1024];
};

static DEFINE_PER_CPU(struct stupid_large_alignment_struct, blah_blah);
DEFINE_PER_CPU(struct stupid_large_struct, blah_blah2);
DEFINE_PER_CPU(struct stupid_large_struct, blah_blah3);
DEFINE_PER_CPU(struct stupid_large_struct, blah_blah4);
DEFINE_PER_CPU(struct stupid_large_struct, blah_blah5);
DEFINE_PER_CPU(struct stupid_large_struct, blah_blah6);

static int __init test_init(void)
{
	unsigned int cpu;

	printk("XXX test_pcpu:");
	for_each_possible_cpu(cpu)
		printk(" %p", &per_cpu(blah_blah, cpu));
	printk("\n");
	pcpu_dump_chunk_slots();

	run_test();
	return 0;
}

static void __exit test_exit(void)
{
	unsigned int i;

	printk("XXX cleaning up\n");
	pcpu_dump_chunk_slots();

	for (i = 0; i < NR_CMDS; i++)
		free_cmd(i);

	printk("XXX done\n");
	pcpu_dump_chunk_slots();
}

module_init(test_init);
module_exit(test_exit);
MODULE_LICENSE("GPL");