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

[Wei Yang]

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
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