Commit 0bb2c763 authored Dec 18, 2012 by Gavin Shan Committed by Linus Torvalds Dec 18, 2012

mm/page_alloc.c: remove duplicate check



While allocating pages using buddy allocator, the compound page is
probably split up to free pages.  Under these circumstances, the compound
page should be destroyed by destroy_compound_page().  However, there is a
duplicate check to judge if the page is compound.

Remove the duplicate check since the compound_order() returns 0 when the
page doesn't have PG_head set in destroy_compound_page().  That is to say,
destroy_compound_page() needn't check PageHead().

Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 3012d60b

mm/page_alloc.c

+1 −2

Original line number	Diff line number	Diff line
		@@ -371,8 +371,7 @@ static int destroy_compound_page(struct page *page, unsigned long order)
		int nr_pages = 1 << order;
		int bad = 0;

		if (unlikely(compound_order(page) != order) \|\|
		unlikely(!PageHead(page))) {
		if (unlikely(compound_order(page) != order)) {
		bad_page(page);
		bad++;
		}