From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Luis Henriques To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Mel Gorman , Alex Thorlton , Andrew Morton , Linus Torvalds , Luis Henriques Subject: [PATCH 3.11 148/208] mm: numa: ensure anon_vma is locked to prevent parallel THP splits Date: Mon, 13 Jan 2014 15:59:49 +0000 Message-Id: <1389628849-1614-149-git-send-email-luis.henriques@canonical.com> In-Reply-To: <1389628849-1614-1-git-send-email-luis.henriques@canonical.com> References: <1389628849-1614-1-git-send-email-luis.henriques@canonical.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.11.10.3 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Mel Gorman commit c3a489cac38d43ea6dc4ac240473b44b46deecf7 upstream. The anon_vma lock prevents parallel THP splits and any associated complexity that arises when handling splits during THP migration. This patch checks if the lock was successfully acquired and bails from THP migration if it failed for any reason. Signed-off-by: Mel Gorman Reviewed-by: Rik van Riel Cc: Alex Thorlton Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Luis Henriques --- mm/huge_memory.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index ac2546c..0db1517 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1354,6 +1354,13 @@ int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma, goto out_unlock; } + /* Bail if we fail to protect against THP splits for any reason */ + if (unlikely(!anon_vma)) { + put_page(page); + page_nid = -1; + goto clear_pmdnuma; + } + /* * Migrate the THP to the requested node, returns with page unlocked * and pmd_numa cleared. -- 1.8.3.2