Re: [PATCH 7.2 v2 12/12] selftests/mm: remove READ_ONLY_THP_FOR_FS from comments in guard-regions

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From: Matthew Wilcox

Date: Mon Apr 13 2026 - 16:48:10 EST

On Mon, Apr 13, 2026 at 03:20:30PM -0400, Zi Yan wrote:
> +++ b/tools/testing/selftests/mm/guard-regions.c
> @@ -2205,7 +2205,7 @@ TEST_F(guard_regions, collapse)
>
> /*
> * We must close and re-open local-file backed as read-only for
> - * CONFIG_READ_ONLY_THP_FOR_FS to work.
> + * MADV_COLLAPSE to work.

Is this true? Does MADV_COLLAPSE refuse to work on writable files?
Should we delete some code here as well as fix the comment? ;-)