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-rw-r--r--tools/testing/selftests/vm/userfaultfd.c46
1 files changed, 28 insertions, 18 deletions
diff --git a/tools/testing/selftests/vm/userfaultfd.c b/tools/testing/selftests/vm/userfaultfd.c
index 7b8171e3128a..5ff3a4f9173e 100644
--- a/tools/testing/selftests/vm/userfaultfd.c
+++ b/tools/testing/selftests/vm/userfaultfd.c
@@ -34,18 +34,6 @@
* per-CPU threads 1 by triggering userfaults inside
* pthread_mutex_lock will also verify the atomicity of the memory
* transfer (UFFDIO_COPY).
- *
- * The program takes two parameters: the amounts of physical memory in
- * megabytes (MiB) of the area and the number of bounces to execute.
- *
- * # 100MiB 99999 bounces
- * ./userfaultfd 100 99999
- *
- * # 1GiB 99 bounces
- * ./userfaultfd 1000 99
- *
- * # 10MiB-~6GiB 999 bounces, continue forever unless an error triggers
- * while ./userfaultfd $[RANDOM % 6000 + 10] 999; do true; done
*/
#define _GNU_SOURCE
@@ -115,6 +103,30 @@ pthread_attr_t attr;
~(unsigned long)(sizeof(unsigned long long) \
- 1)))
+const char *examples =
+ "# Run anonymous memory test on 100MiB region with 99999 bounces:\n"
+ "./userfaultfd anon 100 99999\n\n"
+ "# Run share memory test on 1GiB region with 99 bounces:\n"
+ "./userfaultfd shmem 1000 99\n\n"
+ "# Run hugetlb memory test on 256MiB region with 50 bounces (using /dev/hugepages/hugefile):\n"
+ "./userfaultfd hugetlb 256 50 /dev/hugepages/hugefile\n\n"
+ "# Run the same hugetlb test but using shmem:\n"
+ "./userfaultfd hugetlb_shared 256 50 /dev/hugepages/hugefile\n\n"
+ "# 10MiB-~6GiB 999 bounces anonymous test, "
+ "continue forever unless an error triggers\n"
+ "while ./userfaultfd anon $[RANDOM % 6000 + 10] 999; do true; done\n\n";
+
+static void usage(void)
+{
+ fprintf(stderr, "\nUsage: ./userfaultfd <test type> <MiB> <bounces> "
+ "[hugetlbfs_file]\n\n");
+ fprintf(stderr, "Supported <test type>: anon, hugetlb, "
+ "hugetlb_shared, shmem\n\n");
+ fprintf(stderr, "Examples:\n\n");
+ fprintf(stderr, examples);
+ exit(1);
+}
+
static int anon_release_pages(char *rel_area)
{
int ret = 0;
@@ -1272,8 +1284,7 @@ static void sigalrm(int sig)
int main(int argc, char **argv)
{
if (argc < 4)
- fprintf(stderr, "Usage: <test type> <MiB> <bounces> [hugetlbfs_file]\n"),
- exit(1);
+ usage();
if (signal(SIGALRM, sigalrm) == SIG_ERR)
fprintf(stderr, "failed to arm SIGALRM"), exit(1);
@@ -1286,20 +1297,19 @@ int main(int argc, char **argv)
nr_cpus;
if (!nr_pages_per_cpu) {
fprintf(stderr, "invalid MiB\n");
- fprintf(stderr, "Usage: <MiB> <bounces>\n"), exit(1);
+ usage();
}
bounces = atoi(argv[3]);
if (bounces <= 0) {
fprintf(stderr, "invalid bounces\n");
- fprintf(stderr, "Usage: <MiB> <bounces>\n"), exit(1);
+ usage();
}
nr_pages = nr_pages_per_cpu * nr_cpus;
if (test_type == TEST_HUGETLB) {
if (argc < 5)
- fprintf(stderr, "Usage: hugetlb <MiB> <bounces> <hugetlbfs_file>\n"),
- exit(1);
+ usage();
huge_fd = open(argv[4], O_CREAT | O_RDWR, 0755);
if (huge_fd < 0) {
fprintf(stderr, "Open of %s failed", argv[3]);