Re: [PATCH 6/8] filemap: Convert __readahead_batch() to use a folio

[David Hildenbrand <david@redhat.com>]

On 02.04.25 23:06, Matthew Wilcox (Oracle) wrote:
> Extract folios from i_mapping, not pages.  Removes a hidden call to
> compound_head(), a use of thp_nr_pages() and an unnecessary assertion
> that we didn't find a tail page in the page cache.
> 
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> ---
>   include/linux/pagemap.h | 13 ++++++-------
>   1 file changed, 6 insertions(+), 7 deletions(-)
> 
> diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
> index 0ddd4bd8cdf8..c5c9b3770d75 100644
> --- a/include/linux/pagemap.h
> +++ b/include/linux/pagemap.h
> @@ -1424,7 +1424,7 @@ static inline unsigned int __readahead_batch(struct readahead_control *rac,
>   {
>   	unsigned int i = 0;
>   	XA_STATE(xas, &rac->mapping->i_pages, 0);
> -	struct page *page;
> +	struct folio *folio;
>   
>   	BUG_ON(rac->_batch_count > rac->_nr_pages);
>   	rac->_nr_pages -= rac->_batch_count;
> @@ -1433,13 +1433,12 @@ static inline unsigned int __readahead_batch(struct readahead_control *rac,
>   
>   	xas_set(&xas, rac->_index);
>   	rcu_read_lock();
> -	xas_for_each(&xas, page, rac->_index + rac->_nr_pages - 1) {
> -		if (xas_retry(&xas, page))
> +	xas_for_each(&xas, folio, rac->_index + rac->_nr_pages - 1) {
> +		if (xas_retry(&xas, folio))
>   			continue;
> -		VM_BUG_ON_PAGE(!PageLocked(page), page);
> -		VM_BUG_ON_PAGE(PageTail(page), page);
> -		array[i++] = page;
> -		rac->_batch_count += thp_nr_pages(page);
> +		VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio);
> +		array[i++] = folio_page(folio, 0);
> +		rac->_batch_count += folio_nr_pages(folio);
>   		if (i == array_sz)
>   			break;
>   	}

Reviewed-by: David Hildenbrand <david@redhat.com>

-- 
Cheers,

David / dhildenb