Re: [RFC Patch 2/2] selftests/mm: assert rmap behave as expected

[Wei Yang <richard.weiyang@gmail.com>]

On Wed, Jun 04, 2025 at 08:21:45AM +0000, Wei Yang wrote:
[...]
>+int try_to_move_page(char *region)
>+{
>+	int ret;
>+	int node;
>+	int status = 0;
>+
>+	ksft_print_msg("worker %d move_pages of content: %.15s\n", getpid(), region);

One thing confused me here.

If I don't access region here, the following move_pages() would report
-ENOENT occationally. The reason is do_pages_stat_array() ->
folio_walk_start() returns NULL.

Not sure which part I missed.

>+
>+	ret = move_pages(0, 1, (void **)&region, NULL, &status, MPOL_MF_MOVE_ALL);
>+	if (ret != 0)
>+		return FAIL_ON_WORK;
>+
>+	/* Pick up a different target node */
>+	for (node = 0; node <= numa_max_node(); node++) {
>+		if (numa_bitmask_isbitset(numa_all_nodes_ptr, node) && node != status)
>+			break;
>+	}
>+
>+	if (node > numa_max_node()) {
>+		ksft_print_msg("Couldn't find available numa node for testing\n");
>+		return FAIL_ON_WORK;
>+	}
>+
>+	ret = move_pages(0, 1, (void **)&region, &node, &status, MPOL_MF_MOVE_ALL);
>+	if (ret != 0)
>+		return FAIL_ON_WORK;
>+
>+	return 0;
>+}
>+

-- 
Wei Yang
Help you, Help me