From cfeed8ffe55b37fa10286aaaa1369da00cb88440 Mon Sep 17 00:00:00 2001 From: David Hildenbrand Date: Mon, 21 Aug 2023 18:08:46 +0200 Subject: mm/swap: stop using page->private on tail pages for THP_SWAP Patch series "mm/swap: stop using page->private on tail pages for THP_SWAP + cleanups". This series stops using page->private on tail pages for THP_SWAP, replaces folio->private by folio->swap for swapcache folios, and starts using "new_folio" for tail pages that we are splitting to remove the usage of page->private for swapcache handling completely. This patch (of 4): Let's stop using page->private on tail pages, making it possible to just unconditionally reuse that field in the tail pages of large folios. The remaining usage of the private field for THP_SWAP is in the THP splitting code (mm/huge_memory.c), that we'll handle separately later. Update the THP_SWAP documentation and sanity checks in mm_types.h and __split_huge_page_tail(). [david@redhat.com: stop using page->private on tail pages for THP_SWAP] Link: https://lkml.kernel.org/r/6f0a82a3-6948-20d9-580b-be1dbf415701@redhat.com Link: https://lkml.kernel.org/r/20230821160849.531668-1-david@redhat.com Link: https://lkml.kernel.org/r/20230821160849.531668-2-david@redhat.com Signed-off-by: David Hildenbrand Acked-by: Catalin Marinas [arm64] Reviewed-by: Yosry Ahmed Cc: Dan Streetman Cc: Hugh Dickins Cc: Matthew Wilcox (Oracle) Cc: Peter Xu Cc: Seth Jennings Cc: Vitaly Wool Cc: Will Deacon Signed-off-by: Andrew Morton --- include/linux/swap.h | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'include/linux/swap.h') diff --git a/include/linux/swap.h b/include/linux/swap.h index bb5adc604144..e5cf58a1cf9e 100644 --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -339,6 +339,15 @@ static inline swp_entry_t folio_swap_entry(struct folio *folio) return entry; } +static inline swp_entry_t page_swap_entry(struct page *page) +{ + struct folio *folio = page_folio(page); + swp_entry_t entry = folio_swap_entry(folio); + + entry.val += folio_page_idx(folio, page); + return entry; +} + static inline void folio_set_swap_entry(struct folio *folio, swp_entry_t entry) { folio->private = (void *)entry.val; -- cgit v1.2.3