Re: [PATCH 1/3] mm: pgtable: correct the wrong comment about ptdesc->__page_flags

Vishal Moola
2024-03-26T19:12:48Z

On Mon, Mar 04, 2024 at 07:07:18PM +0800, Qi Zheng wrote:
> The commit 32cc0b7c9d50 ("powerpc: add pte_free_defer() for pgtables
> sharing page") introduced the use of PageActive flag to page table
> fragments tracking, so the ptdesc->__page_flags is not unused, so
> correct the wrong comment.

Thanks for catching this!

In regards to naming, we're trying to prefix unused variables with
__underscores so I'd prefer to see the __ eliminated from the
ptdesc->page_flags field here as well. This doesn't warrant a fix
as it is already in 6.9-rc1, but is something to keep in
mind for the future. Aside from that, LGTM.

Reviewed-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
> Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
> ---
> include/linux/mm_types.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
> index a7223ba3ea1e..5ea77969daae 100644
> --- a/include/linux/mm_types.h
> +++ b/include/linux/mm_types.h
> @@ -419,7 +419,7 @@ FOLIO_MATCH(compound_head, _head_2a);
>
> /**
> * struct ptdesc - Memory descriptor for page tables.
> - * @__page_flags: Same as page flags. Unused for page tables.
> + * @__page_flags: Same as page flags. Powerpc only.
> * @pt_rcu_head: For freeing page table pages.
> * @pt_list: List of used page tables. Used for s390 and x86.
> * @_pt_pad_1: Padding that aliases with page's compound head.
> --
> 2.30.2
>