From 4101196b19d7f905dca5dcf46cd35eb758cf06c0 Mon Sep 17 00:00:00 2001 From: "Matthew Wilcox (Oracle)" Date: Mon, 23 Sep 2019 15:34:52 -0700 Subject: mm: page cache: store only head pages in i_pages Transparent Huge Pages are currently stored in i_pages as pointers to consecutive subpages. This patch changes that to storing consecutive pointers to the head page in preparation for storing huge pages more efficiently in i_pages. Large parts of this are "inspired" by Kirill's patch https://lore.kernel.org/lkml/20170126115819.58875-2-kirill.shutemov@linux.intel.com/ Kirill and Huang Ying contributed several fixes. [willy@infradead.org: use compound_nr, squish uninit-var warning] Link: http://lkml.kernel.org/r/20190731210400.7419-1-willy@infradead.org Signed-off-by: Matthew Wilcox Acked-by: Jan Kara Reviewed-by: Kirill Shutemov Reviewed-by: Song Liu Tested-by: Song Liu Tested-by: William Kucharski Reviewed-by: William Kucharski Tested-by: Qian Cai Tested-by: Mikhail Gavrilov Cc: Hugh Dickins Cc: Chris Wilson Cc: Song Liu Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/pagemap.h | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'include/linux') diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h index c7552459a15f..37a4d9e32cd3 100644 --- a/include/linux/pagemap.h +++ b/include/linux/pagemap.h @@ -333,6 +333,16 @@ static inline struct page *grab_cache_page_nowait(struct address_space *mapping, mapping_gfp_mask(mapping)); } +static inline struct page *find_subpage(struct page *page, pgoff_t offset) +{ + if (PageHuge(page)) + return page; + + VM_BUG_ON_PAGE(PageTail(page), page); + + return page + (offset & (compound_nr(page) - 1)); +} + struct page *find_get_entry(struct address_space *mapping, pgoff_t offset); struct page *find_lock_entry(struct address_space *mapping, pgoff_t offset); unsigned find_get_entries(struct address_space *mapping, pgoff_t start, -- cgit v1.2.3