Commit a0650604 authored by Matthew Wilcox (Oracle)'s avatar Matthew Wilcox (Oracle) Committed by Linus Torvalds

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: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Acked-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Link: http://lkml.kernel.org/r/20200318140253.6141-5-willy@infradead.orgSigned-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 85b9f46e
...@@ -341,9 +341,7 @@ static inline struct page *find_subpage(struct page *head, pgoff_t index) ...@@ -341,9 +341,7 @@ static inline struct page *find_subpage(struct page *head, pgoff_t index)
if (PageHuge(head)) if (PageHuge(head))
return head; return head;
VM_BUG_ON_PAGE(PageTail(head), head); return head + (index & (hpage_nr_pages(head) - 1));
return head + (index & (compound_nr(head) - 1));
} }
struct page *find_get_entry(struct address_space *mapping, pgoff_t offset); struct page *find_get_entry(struct address_space *mapping, pgoff_t offset);
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment