From ab95d23bab220ef845c0d422f49452a475330eaf Mon Sep 17 00:00:00 2001 From: Pankaj Raghav Date: Thu, 22 Aug 2024 15:50:10 +0200 Subject: filemap: allocate mapping_min_order folios in the page cache filemap_create_folio() and do_read_cache_folio() were always allocating folio of order 0. __filemap_get_folio was trying to allocate higher order folios when fgp_flags had higher order hint set but it will default to order 0 folio if higher order memory allocation fails. Supporting mapping_min_order implies that we guarantee each folio in the page cache has at least an order of mapping_min_order. When adding new folios to the page cache we must also ensure the index used is aligned to the mapping_min_order as the page cache requires the index to be aligned to the order of the folio. Co-developed-by: Luis Chamberlain Signed-off-by: Luis Chamberlain Signed-off-by: Pankaj Raghav Link: https://lore.kernel.org/r/20240822135018.1931258-3-kernel@pankajraghav.com Tested-by: David Howells Reviewed-by: Hannes Reinecke Reviewed-by: Darrick J. Wong Reviewed-by: Matthew Wilcox (Oracle) Reviewed-by: Daniel Gomez Reviewed-by: Dave Chinner Signed-off-by: Christian Brauner --- include/linux/pagemap.h | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) (limited to 'include/linux') diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h index c60025bb584c..4cc170949e9c 100644 --- a/include/linux/pagemap.h +++ b/include/linux/pagemap.h @@ -448,6 +448,26 @@ mapping_min_folio_order(const struct address_space *mapping) return (mapping->flags & AS_FOLIO_ORDER_MIN_MASK) >> AS_FOLIO_ORDER_MIN; } +static inline unsigned long +mapping_min_folio_nrpages(struct address_space *mapping) +{ + return 1UL << mapping_min_folio_order(mapping); +} + +/** + * mapping_align_index() - Align index for this mapping. + * @mapping: The address_space. + * + * The index of a folio must be naturally aligned. If you are adding a + * new folio to the page cache and need to know what index to give it, + * call this function. + */ +static inline pgoff_t mapping_align_index(struct address_space *mapping, + pgoff_t index) +{ + return round_down(index, mapping_min_folio_nrpages(mapping)); +} + /* * Large folio support currently depends on THP. These dependencies are * being worked on but are not yet fixed. -- cgit v1.2.3