From 0a2e280b6d8ea4afef07c749070705d6af403b7f Mon Sep 17 00:00:00 2001 From: "Kirill A. Shutemov" Date: Wed, 9 Mar 2016 14:08:30 -0800 Subject: [PATCH] mm, thp: fix migration of PTE-mapped transparent huge pages We don't have native support of THP migration, so we have to split huge page into small pages in order to migrate it to different node. This includes PTE-mapped huge pages. I made mistake in refcounting patchset: we don't actually split PTE-mapped huge page in queue_pages_pte_range(), if we step on head page. The result is that the head page is queued for migration, but none of tail pages: putting head page on queue takes pin on the page and any subsequent attempts of split_huge_pages() would fail and we skip queuing tail pages. unmap_and_move_huge_page() will eventually split the huge pages, but only one of 512 pages would get migrated. Let's fix the situation. Fixes: 248db92da13f2507 ("migrate_pages: try to split pages on queuing") Signed-off-by: Kirill A. Shutemov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/mempolicy.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/mempolicy.c b/mm/mempolicy.c index 4c4187c0e1de..9a3f6b90e628 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -532,7 +532,7 @@ retry: nid = page_to_nid(page); if (node_isset(nid, *qp->nmask) == !!(flags & MPOL_MF_INVERT)) continue; - if (PageTail(page) && PageAnon(page)) { + if (PageTransCompound(page) && PageAnon(page)) { get_page(page); pte_unmap_unlock(pte, ptl); lock_page(page);