--- /dev/null
+// 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 (8UL*1024*1024)
+#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;
+}
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