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authorMatthew Wilcox (Oracle)2020-04-06 20:04:31 -0700
committerLinus Torvalds2020-04-07 10:43:38 -0700
commita0650604a707b1926cbc32feb2f006ebb74ef47b (patch)
tree9ccf2f46cb62ab402dd3d028f0b984ae97d40a1f /include
parent85b9f46e8ea451633ccd60a7d8cacbfff9f34047 (diff)
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) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Acked-by: Kirill 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.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/pagemap.h4
1 files changed, 1 insertions, 3 deletions
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);