selftests: add a selftest to verify hugetlb usage in memcg (c0dddb7a) · Commits · git / linux-net

MAINTAINERS

+2 −0

Original line number	Diff line number	Diff line
		@@ -5269,6 +5269,7 @@ S: Maintained
		F: mm/memcontrol.c
		F: mm/swap_cgroup.c
		F: tools/testing/selftests/cgroup/memcg_protection.m
		F: tools/testing/selftests/cgroup/test_hugetlb_memcg.c
		F: tools/testing/selftests/cgroup/test_kmem.c
		F: tools/testing/selftests/cgroup/test_memcontrol.c

		@@ -9652,6 +9653,7 @@ F: include/linux/hugetlb.h
		F: mm/hugetlb.c
		F: mm/hugetlb_vmemmap.c
		F: mm/hugetlb_vmemmap.h
		F: tools/testing/selftests/cgroup/test_hugetlb_memcg.c

		HVA ST MEDIA DRIVER
		M: Jean-Christophe Trotin <jean-christophe.trotin@foss.st.com>

tools/testing/selftests/cgroup/.gitignore

+1 −0

Original line number	Diff line number	Diff line
		@@ -7,4 +7,5 @@ test_kill
		test_cpu
		test_cpuset
		test_zswap
		test_hugetlb_memcg
		wait_inotify

tools/testing/selftests/cgroup/Makefile

+2 −0

Original line number	Diff line number	Diff line
		@@ -14,6 +14,7 @@ TEST_GEN_PROGS += test_kill
		TEST_GEN_PROGS += test_cpu
		TEST_GEN_PROGS += test_cpuset
		TEST_GEN_PROGS += test_zswap
		TEST_GEN_PROGS += test_hugetlb_memcg

		LOCAL_HDRS += $(selfdir)/clone3/clone3_selftests.h $(selfdir)/pidfd/pidfd.h

		@@ -27,3 +28,4 @@ $(OUTPUT)/test_kill: cgroup_util.c
		$(OUTPUT)/test_cpu: cgroup_util.c
		$(OUTPUT)/test_cpuset: cgroup_util.c
		$(OUTPUT)/test_zswap: cgroup_util.c
		$(OUTPUT)/test_hugetlb_memcg: cgroup_util.c

tools/testing/selftests/cgroup/test_hugetlb_memcg.c

0 → 100644

+234 −0

Original line number	Diff line number	Diff line
		// SPDX-License-Identifier: GPL-2.0
		#define _GNU_SOURCE

		#include <linux/limits.h>
		#include <sys/mman.h>
		#include <stdio.h>
		#include <stdlib.h>
		#include <string.h>
		#include <fcntl.h>
		#include "../kselftest.h"
		#include "cgroup_util.h"

		#define ADDR ((void *)(0x0UL))
		#define FLAGS (MAP_PRIVATE \| MAP_ANONYMOUS \| MAP_HUGETLB)
		/* mapping 8 MBs == 4 hugepages */
		#define LENGTH (8UL10241024)
		#define PROTECTION (PROT_READ \| PROT_WRITE)

		/* borrowed from mm/hmm-tests.c */
		static long get_hugepage_size(void)
		{
		int fd;
		char buf[2048];
		int len;
		char p, q, path = "/proc/meminfo", tag = "Hugepagesize:";
		long val;

		fd = open(path, O_RDONLY);
		if (fd < 0) {
		/* Error opening the file */
		return -1;
		}

		len = read(fd, buf, sizeof(buf));
		close(fd);
		if (len < 0) {
		/* Error in reading the file */
		return -1;
		}
		if (len == sizeof(buf)) {
		/* Error file is too large */
		return -1;
		}
		buf[len] = '\0';

		/* Search for a tag if provided */
		if (tag) {
		p = strstr(buf, tag);
		if (!p)
		return -1; /* looks like the line we want isn't there */
		p += strlen(tag);
		} else
		p = buf;

		val = strtol(p, &q, 0);
		if (*q != ' ') {
		/* Error parsing the file */
		return -1;
		}

		return val;
		}

		static int set_file(const char *path, long value)
		{
		FILE *file;
		int ret;

		file = fopen(path, "w");
		if (!file)
		return -1;
		ret = fprintf(file, "%ld\n", value);
		fclose(file);
		return ret;
		}

		static int set_nr_hugepages(long value)
		{
		return set_file("/proc/sys/vm/nr_hugepages", value);
		}

		static unsigned int check_first(char *addr)
		{
		return (unsigned int )addr;
		}

		static void write_data(char *addr)
		{
		unsigned long i;

		for (i = 0; i < LENGTH; i++)
		*(addr + i) = (char)i;
		}

		static int hugetlb_test_program(const char cgroup, void arg)
		{
		char test_group = (char )arg;
		void *addr;
		long old_current, expected_current, current;
		int ret = EXIT_FAILURE;

		old_current = cg_read_long(test_group, "memory.current");
		set_nr_hugepages(20);
		current = cg_read_long(test_group, "memory.current");
		if (current - old_current >= MB(2)) {
		ksft_print_msg(
		"setting nr_hugepages should not increase hugepage usage.\n");
		ksft_print_msg("before: %ld, after: %ld\n", old_current, current);
		return EXIT_FAILURE;
		}

		addr = mmap(ADDR, LENGTH, PROTECTION, FLAGS, 0, 0);
		if (addr == MAP_FAILED) {
		ksft_print_msg("fail to mmap.\n");
		return EXIT_FAILURE;
		}
		current = cg_read_long(test_group, "memory.current");
		if (current - old_current >= MB(2)) {
		ksft_print_msg("mmap should not increase hugepage usage.\n");
		ksft_print_msg("before: %ld, after: %ld\n", old_current, current);
		goto out_failed_munmap;
		}
		old_current = current;

		/* read the first page */
		check_first(addr);
		expected_current = old_current + MB(2);
		current = cg_read_long(test_group, "memory.current");
		if (!values_close(expected_current, current, 5)) {
		ksft_print_msg("memory usage should increase by around 2MB.\n");
		ksft_print_msg(
		"expected memory: %ld, actual memory: %ld\n",
		expected_current, current);
		goto out_failed_munmap;
		}

		/* write to the whole range */
		write_data(addr);
		current = cg_read_long(test_group, "memory.current");
		expected_current = old_current + MB(8);
		if (!values_close(expected_current, current, 5)) {
		ksft_print_msg("memory usage should increase by around 8MB.\n");
		ksft_print_msg(
		"expected memory: %ld, actual memory: %ld\n",
		expected_current, current);
		goto out_failed_munmap;
		}

		/* unmap the whole range */
		munmap(addr, LENGTH);
		current = cg_read_long(test_group, "memory.current");
		expected_current = old_current;
		if (!values_close(expected_current, current, 5)) {
		ksft_print_msg("memory usage should go back down.\n");
		ksft_print_msg(
		"expected memory: %ld, actual memory: %ld\n",
		expected_current, current);
		return ret;
		}

		ret = EXIT_SUCCESS;
		return ret;

		out_failed_munmap:
		munmap(addr, LENGTH);
		return ret;
		}

		static int test_hugetlb_memcg(char *root)
		{
		int ret = KSFT_FAIL;
		char *test_group;

		test_group = cg_name(root, "hugetlb_memcg_test");
		if (!test_group \|\| cg_create(test_group)) {
		ksft_print_msg("fail to create cgroup.\n");
		goto out;
		}

		if (cg_write(test_group, "memory.max", "100M")) {
		ksft_print_msg("fail to set cgroup memory limit.\n");
		goto out;
		}

		/* disable swap */
		if (cg_write(test_group, "memory.swap.max", "0")) {
		ksft_print_msg("fail to disable swap.\n");
		goto out;
		}

		if (!cg_run(test_group, hugetlb_test_program, (void *)test_group))
		ret = KSFT_PASS;
		out:
		cg_destroy(test_group);
		free(test_group);
		return ret;
		}

		int main(int argc, char **argv)
		{
		char root[PATH_MAX];
		int ret = EXIT_SUCCESS, has_memory_hugetlb_acc;

		has_memory_hugetlb_acc = proc_mount_contains("memory_hugetlb_accounting");
		if (has_memory_hugetlb_acc < 0)
		ksft_exit_skip("Failed to query cgroup mount option\n");
		else if (!has_memory_hugetlb_acc)
		ksft_exit_skip("memory hugetlb accounting is disabled\n");

		/* Unit is kB! */
		if (get_hugepage_size() != 2048) {
		ksft_print_msg("test_hugetlb_memcg requires 2MB hugepages\n");
		ksft_test_result_skip("test_hugetlb_memcg\n");
		return ret;
		}

		if (cg_find_unified_root(root, sizeof(root)))
		ksft_exit_skip("cgroup v2 isn't mounted\n");

		switch (test_hugetlb_memcg(root)) {
		case KSFT_PASS:
		ksft_test_result_pass("test_hugetlb_memcg\n");
		break;
		case KSFT_SKIP:
		ksft_test_result_skip("test_hugetlb_memcg\n");
		break;
		default:
		ret = EXIT_FAILURE;
		ksft_test_result_fail("test_hugetlb_memcg\n");
		break;
		}

		return ret;
		}