Re: [PATCH 4/6] mm: don't remap unused subpages when splitting isolated thp

Rik van Riel
2024-07-30T18:08:36Z

On Tue, 2024-07-30 at 13:46 +0100, Usama Arif wrote:
>
> + /*
> + * The pmd entry mapping the old thp was flushed and the pte
> mapping
> + * this subpage has been non present. Therefore, this
> subpage is
> + * inaccessible. We don't need to remap it if it contains
> only zeros.
> + */
> + addr = kmap_local_page(page);
> + dirty = memchr_inv(addr, 0, PAGE_SIZE);
> + kunmap_local(addr);
> +
> + if (dirty)
> + return false;
>

A minor nitpick here. The word dirty has a few different meanings
in memory management already.

Could it be clearer to use something like "contains_data" ?

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