Re: [PATCH v5 11/12] mm: drop page_index and simplify folio_index

Huang, Ying
2024-05-11T05:41:46Z

Kairui Song <ryncsn@gmail.com> writes:

> From: Kairui Song <kasong@tencent.com>
>
> There are two helpers for retrieving the index within address space
> for mixed usage of swap cache and page cache:
>
> - page_index
> - folio_index
>
> This commit drops page_index, as we have eliminated all users, and
> converts folio_index's helper __page_file_index to use folio to avoid
> the page convertion.
>
> Signed-off-by: Kairui Song <kasong@tencent.com>

LGTM, Thanks!

Reviewed-by: "Huang, Ying" <ying.huang@intel.com>

> ---
> include/linux/mm.h | 13 -------------
> include/linux/pagemap.h | 8 ++++----
> mm/swapfile.c | 7 +++----
> 3 files changed, 7 insertions(+), 21 deletions(-)
>
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index 9849dfda44d4..e2718cac0fda 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -2290,19 +2290,6 @@ static inline void *folio_address(const struct folio *folio)
> return page_address(&folio->page);
> }
>
> -extern pgoff_t __page_file_index(struct page *page);
> -
> -/*
> - * Return the pagecache index of the passed page. Regular pagecache pages
> - * use ->index whereas swapcache pages use swp_offset(->private)
> - */
> -static inline pgoff_t page_index(struct page *page)
> -{
> - if (unlikely(PageSwapCache(page)))
> - return __page_file_index(page);
> - return page->index;
> -}
> -
> /*
> * Return true only if the page has been allocated with
> * ALLOC_NO_WATERMARKS and the low watermark was not
> diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
> index a324582ea702..0cfa5810cde3 100644
> --- a/include/linux/pagemap.h
> +++ b/include/linux/pagemap.h
> @@ -778,7 +778,7 @@ static inline struct page *grab_cache_page_nowait(struct address_space *mapping,
> mapping_gfp_mask(mapping));
> }
>
> -#define swapcache_index(folio) __page_file_index(&(folio)->page)
> +extern pgoff_t __folio_swap_cache_index(struct folio *folio);
>
> /**
> * folio_index - File index of a folio.
> @@ -793,9 +793,9 @@ static inline struct page *grab_cache_page_nowait(struct address_space *mapping,
> */
> static inline pgoff_t folio_index(struct folio *folio)
> {
> - if (unlikely(folio_test_swapcache(folio)))
> - return swapcache_index(folio);
> - return folio->index;
> + if (unlikely(folio_test_swapcache(folio)))
> + return __folio_swap_cache_index(folio);
> + return folio->index;
> }
>
> /**
> diff --git a/mm/swapfile.c b/mm/swapfile.c
> index f6ca215fb92f..0b0ae6e8c764 100644
> --- a/mm/swapfile.c
> +++ b/mm/swapfile.c
> @@ -3474,12 +3474,11 @@ struct address_space *swapcache_mapping(struct folio *folio)
> }
> EXPORT_SYMBOL_GPL(swapcache_mapping);
>
> -pgoff_t __page_file_index(struct page *page)
> +pgoff_t __folio_swap_cache_index(struct folio *folio)
> {
> - swp_entry_t swap = page_swap_entry(page);
> - return swp_offset(swap);
> + return swp_offset(folio->swap);
> }
> -EXPORT_SYMBOL_GPL(__page_file_index);
> +EXPORT_SYMBOL_GPL(__folio_swap_cache_index);
>
> /*
> * add_swap_count_continuation - called when a swap count is duplicated