Commit 433abed6 authored Sep 10, 2010 by Naoya Horiguchi Committed by Linus Torvalds Sep 23, 2010

hugetlb, rmap: always use anon_vma root pointer



This patch applies Andrea's fix given by the following patch into hugepage
rmapping code:

  commit 288468c3
  Author: Andrea Arcangeli <aarcange@redhat.com>
  Date:   Mon Aug 9 17:19:09 2010 -0700

This patch uses anon_vma->root and avoids unnecessary overwriting when
anon_vma is already set up.

Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Andrea Arcangeli <aarcange@redhat.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent bcf835e5

mm/rmap.c

+7 −6

Original line number	Diff line number	Diff line
		@@ -1564,13 +1564,14 @@ static void __hugepage_set_anon_rmap(struct page *page,
		struct vm_area_struct *vma, unsigned long address, int exclusive)
		{
		struct anon_vma *anon_vma = vma->anon_vma;

		BUG_ON(!anon_vma);
		if (!exclusive) {
		struct anon_vma_chain *avc;
		avc = list_entry(vma->anon_vma_chain.prev,
		struct anon_vma_chain, same_vma);
		anon_vma = avc->anon_vma;
		}

		if (PageAnon(page))
		return;
		if (!exclusive)
		anon_vma = anon_vma->root;

		anon_vma = (void *) anon_vma + PAGE_MAPPING_ANON;
		page->mapping = (struct address_space *) anon_vma;
		page->index = linear_page_index(vma, address);