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

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;

+}