From a0650604a707b1926cbc32feb2f006ebb74ef47b Mon Sep 17 00:00:00 2001 From: "Matthew Wilcox (Oracle)" Date: Mon, 6 Apr 2020 20:04:31 -0700 Subject: include/linux/pagemap.h: optimise find_subpage for !THP If THP is disabled, find_subpage() can become a no-op by using hpage_nr_pages() instead of compound_nr(). hpage_nr_pages() embeds a check for PageTail, so we can drop the check here. Signed-off-by: Matthew Wilcox (Oracle) Signed-off-by: Andrew Morton Reviewed-by: Christoph Hellwig Acked-by: Kirill A. Shutemov Cc: Aneesh Kumar K.V Cc: Pankaj Gupta Link: http://lkml.kernel.org/r/20200318140253.6141-5-willy@infradead.org Signed-off-by: Linus Torvalds --- include/linux/pagemap.h | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) (limited to 'include') diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h index f56282491a48..a8f7bd8ea1c6 100644 --- a/include/linux/pagemap.h +++ b/include/linux/pagemap.h @@ -341,9 +341,7 @@ static inline struct page *find_subpage(struct page *head, pgoff_t index) if (PageHuge(head)) return head; - VM_BUG_ON_PAGE(PageTail(head), head); - - return head + (index & (compound_nr(head) - 1)); + return head + (index & (hpage_nr_pages(head) - 1)); } struct page *find_get_entry(struct address_space *mapping, pgoff_t offset); -- cgit 1.4.1