mm/filemap.c: add comment for confusing logic in page_cache_tree_insert()
Unlike THP, hugetlb pages are represented by one entry in the
radix-tree.
[akpm@linux-foundation.org: tweak comment]
Link: http://lkml.kernel.org/r/20161110163640.126124-1-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/filemap.c b/mm/filemap.c
index 50b52fe..caa779f 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -169,7 +169,10 @@
static void page_cache_tree_delete(struct address_space *mapping,
struct page *page, void *shadow)
{
- int i, nr = PageHuge(page) ? 1 : hpage_nr_pages(page);
+ int i, nr;
+
+ /* hugetlb pages are represented by one entry in the radix tree */
+ nr = PageHuge(page) ? 1 : hpage_nr_pages(page);
VM_BUG_ON_PAGE(!PageLocked(page), page);
VM_BUG_ON_PAGE(PageTail(page), page);