hugetlb, rmap: always use anon_vma root pointer

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

  commit 288468c334
  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>
This commit is contained in:
Naoya Horiguchi 2010-09-10 13:23:03 +09:00 committed by Linus Torvalds
parent bcf835e52e
commit 433abed6c6

View File

@ -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);