Test compaction of mlocked memory

# Makefile for vm selftests

CFLAGS = -Wall

BINARIES = hugepage-mmap hugepage-shm map_hugetlb thuge-gen hugetlbfstest

BINARIES = compaction_test

BINARIES += hugepage-mmap

BINARIES += hugepage-shm

BINARIES += hugetlbfstest

BINARIES += map_hugetlb

BINARIES += thuge-gen

BINARIES += transhuge-stress

all: $(BINARIES)

/*

 *

 * A test for the patch "Allow compaction of unevictable pages".

 * With this patch we should be able to allocate at least 1/4

 * of RAM in huge pages. Without the patch much less is

 * allocated.

 */

#include <stdio.h>

#include <stdlib.h>

#include <sys/mman.h>

#include <sys/resource.h>

#include <fcntl.h>

#include <errno.h>

#include <unistd.h>

#include <string.h>

#define MAP_SIZE 1048576

struct map_list {

	void *map;

	struct map_list *next;

};

int read_memory_info(unsigned long *memfree, unsigned long *hugepagesize)

{

	char  buffer[256] = {0};

	char *cmd = "cat /proc/meminfo | grep -i memfree | grep -o '[0-9]*'";

	FILE *cmdfile = popen(cmd, "r");

	if (!(fgets(buffer, sizeof(buffer), cmdfile))) {

		perror("Failed to read meminfo\n");

		return -1;

	}

	pclose(cmdfile);

	*memfree = atoll(buffer);

	cmd = "cat /proc/meminfo | grep -i hugepagesize | grep -o '[0-9]*'";

	cmdfile = popen(cmd, "r");

	if (!(fgets(buffer, sizeof(buffer), cmdfile))) {

		perror("Failed to read meminfo\n");

		return -1;

	}

	pclose(cmdfile);

	*hugepagesize = atoll(buffer);

	return 0;

}

int prereq(void)

{

	char allowed;

	int fd;

	fd = open("/proc/sys/vm/compact_unevictable_allowed",

		  O_RDONLY | O_NONBLOCK);

	if (fd < 0) {

		perror("Failed to open\n"

		       "/proc/sys/vm/compact_unevictable_allowed\n");

		return -1;

	}

	if (read(fd, &allowed, sizeof(char)) != sizeof(char)) {

		perror("Failed to read from\n"

		       "/proc/sys/vm/compact_unevictable_allowed\n");

		close(fd);

		return -1;

	}

	close(fd);

	if (allowed == '1')

		return 0;

	return -1;

}

int check_compaction(unsigned long mem_free, unsigned int hugepage_size)

{

	int fd;

	int compaction_index = 0;

	char initial_nr_hugepages[10] = {0};

	char nr_hugepages[10] = {0};

	/* We want to test with 80% of available memory. Else, OOM killer comes

	   in to play */

	mem_free = mem_free * 0.8;

	fd = open("/proc/sys/vm/nr_hugepages", O_RDWR | O_NONBLOCK);

	if (fd < 0) {

		perror("Failed to open /proc/sys/vm/nr_hugepages");

		return -1;

	}

	if (read(fd, initial_nr_hugepages, sizeof(initial_nr_hugepages)) <= 0) {

		perror("Failed to read from /proc/sys/vm/nr_hugepages");

		goto close_fd;

	}

	/* Start with the initial condition of 0 huge pages*/

	if (write(fd, "0", sizeof(char)) != sizeof(char)) {

		perror("Failed to write to /proc/sys/vm/nr_hugepages\n");

		goto close_fd;

	}

	lseek(fd, 0, SEEK_SET);

	/* Request a large number of huge pages. The Kernel will allocate

	   as much as it can */

	if (write(fd, "100000", (6*sizeof(char))) != (6*sizeof(char))) {

		perror("Failed to write to /proc/sys/vm/nr_hugepages\n");

		goto close_fd;

	}

	lseek(fd, 0, SEEK_SET);

	if (read(fd, nr_hugepages, sizeof(nr_hugepages)) <= 0) {

		perror("Failed to read from /proc/sys/vm/nr_hugepages\n");

		goto close_fd;

	}

	/* We should have been able to request at least 1/3 rd of the memory in

	   huge pages */

	compaction_index = mem_free/(atoi(nr_hugepages) * hugepage_size);

	if (compaction_index > 3) {

		printf("No of huge pages allocated = %d\n",

		       (atoi(nr_hugepages)));

		fprintf(stderr, "ERROR: Less that 1/%d of memory is available\n"

			"as huge pages\n", compaction_index);

		goto close_fd;

	}

	printf("No of huge pages allocated = %d\n",

	       (atoi(nr_hugepages)));

	if (write(fd, initial_nr_hugepages, sizeof(initial_nr_hugepages))

	    != strlen(initial_nr_hugepages)) {

		perror("Failed to write to /proc/sys/vm/nr_hugepages\n");

		goto close_fd;

	}

	close(fd);

	return 0;

 close_fd:

	close(fd);

	printf("Not OK. Compaction test failed.");

	return -1;

}

int main(int argc, char **argv)

{

	struct rlimit lim;

	struct map_list *list, *entry;

	size_t page_size, i;

	void *map = NULL;

	unsigned long mem_free = 0;

	unsigned long hugepage_size = 0;

	unsigned long mem_fragmentable = 0;

	if (prereq() != 0) {

		printf("Either the sysctl compact_unevictable_allowed is not\n"

		       "set to 1 or couldn't read the proc file.\n"

		       "Skipping the test\n");

		return 0;

	}

	lim.rlim_cur = RLIM_INFINITY;

	lim.rlim_max = RLIM_INFINITY;

	if (setrlimit(RLIMIT_MEMLOCK, &lim)) {

		perror("Failed to set rlimit:\n");

		return -1;

	}

	page_size = getpagesize();

	list = NULL;

	if (read_memory_info(&mem_free, &hugepage_size) != 0) {

		printf("ERROR: Cannot read meminfo\n");

		return -1;

	}

	mem_fragmentable = mem_free * 0.8 / 1024;

	while (mem_fragmentable > 0) {

		map = mmap(NULL, MAP_SIZE, PROT_READ | PROT_WRITE,

			   MAP_ANONYMOUS | MAP_PRIVATE | MAP_LOCKED, -1, 0);

		if (map == MAP_FAILED)

			break;

		entry = malloc(sizeof(struct map_list));

		if (!entry) {

			munmap(map, MAP_SIZE);

			break;

		}

		entry->map = map;

		entry->next = list;

		list = entry;

		/* Write something (in this case the address of the map) to

		 * ensure that KSM can't merge the mapped pages

		 */

		for (i = 0; i < MAP_SIZE; i += page_size)

			*(unsigned long *)(map + i) = (unsigned long)map + i;

		mem_fragmentable--;

	}

	for (entry = list; entry != NULL; entry = entry->next) {

		munmap(entry->map, MAP_SIZE);

		if (!entry->next)

			break;

		entry = entry->next;

	}

	if (check_compaction(mem_free, hugepage_size) == 0)

		return 0;

	return -1;

}

umount $mnt

rm -rf $mnt

echo $nr_hugepgs > /proc/sys/vm/nr_hugepages

echo "-----------------------"

echo "running compaction_test"

echo "-----------------------"

./compaction_test

if [ $? -ne 0 ]; then

	echo "[FAIL]"

	exitcode=1

else

	echo "[PASS]"

fi

exit $exitcode