The current test_memcontrol test fault in memory by write a value
to the start of a page based on the default value of 4k page size.
Micro-optimize it by using the actual system page size to do the
iteration.

Reviewed-by: Li Wang <liwang@redhat.com>
Signed-off-by: Waiman Long <longman@redhat.com>
---
 tools/testing/selftests/cgroup/test_memcontrol.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/tools/testing/selftests/cgroup/test_memcontrol.c b/tools/testing/selftests/cgroup/test_memcontrol.c
index a25eb097b31c..babbfad10aaf 100644
--- a/tools/testing/selftests/cgroup/test_memcontrol.c
+++ b/tools/testing/selftests/cgroup/test_memcontrol.c
@@ -25,6 +25,7 @@

 static bool has_localevents;
 static bool has_recursiveprot;
+static int page_size;

 int get_temp_fd(void)
 {
@@ -60,7 +61,7 @@ int alloc_anon(const char *cgroup, void *arg)
        char *buf, *ptr;

        buf = malloc(size);
-       for (ptr = buf; ptr < buf + size; ptr += PAGE_SIZE)
+       for (ptr = buf; ptr < buf + size; ptr += page_size)
                *ptr = 0;

        free(buf);
@@ -183,7 +184,7 @@ static int alloc_anon_50M_check(const char *cgroup, void *arg)
                return -1;
        }

-       for (ptr = buf; ptr < buf + size; ptr += PAGE_SIZE)
+       for (ptr = buf; ptr < buf + size; ptr += page_size)
                *ptr = 0;

        current = cg_read_long(cgroup, "memory.current");
@@ -413,7 +414,7 @@ static int alloc_anon_noexit(const char *cgroup, void *arg)
                return -1;
        }

-       for (ptr = buf; ptr < buf + size; ptr += PAGE_SIZE)
+       for (ptr = buf; ptr < buf + size; ptr += page_size)
                *ptr = 0;

        while (getppid() == ppid)
@@ -999,7 +1000,7 @@ static int alloc_anon_50M_check_swap(const char *cgroup, void *arg)
                return -1;
        }

-       for (ptr = buf; ptr < buf + size; ptr += PAGE_SIZE)
+       for (ptr = buf; ptr < buf + size; ptr += page_size)
                *ptr = 0;

        mem_current = cg_read_long(cgroup, "memory.current");
@@ -1679,6 +1680,10 @@ int main(int argc, char **argv)
        char root[PATH_MAX];
        int i, proc_status;

+       page_size = sysconf(_SC_PAGE_SIZE);
+       if (page_size <= 0)
+               page_size = PAGE_SIZE;
+
        ksft_print_header();
        ksft_set_plan(ARRAY_SIZE(tests));
        if (cg_find_unified_root(root, sizeof(root), NULL))
--
2.53.0