Commit 8dd60a3a authored Jan 13, 2011 by Andrea Arcangeli Committed by Linus Torvalds Jan 13, 2011

thp: clear compound mapping



Clear compound mapping for anonymous compound pages like it already
happens for regular anonymous pages.  But crash if mapping is set for any
tail page, also the PageAnon check is meaningless for tail pages.  This
check only makes sense for the head page, for tail page it can only hide
bugs and we definitely don't want to hide bugs.

Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent a5b338f2

mm/page_alloc.c

+4 −7

Original line number	Diff line number	Diff line
		@@ -651,13 +651,10 @@ static bool free_pages_prepare(struct page *page, unsigned int order)
		trace_mm_page_free_direct(page, order);
		kmemcheck_free_shadow(page, order);

		for (i = 0; i < (1 << order); i++) {
		struct page *pg = page + i;

		if (PageAnon(pg))
		pg->mapping = NULL;
		bad += free_pages_check(pg);
		}
		if (PageAnon(page))
		page->mapping = NULL;
		for (i = 0; i < (1 << order); i++)
		bad += free_pages_check(page + i);
		if (bad)
		return false;

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