From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753445Ab3LCIyc (ORCPT ); Tue, 3 Dec 2013 03:54:32 -0500 Received: from cantor2.suse.de ([195.135.220.15]:49436 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752007Ab3LCIwL (ORCPT ); Tue, 3 Dec 2013 03:52:11 -0500 From: Mel Gorman To: Alex Thorlton Cc: Rik van Riel , Linux-MM , LKML , Mel Gorman Subject: [PATCH 09/15] mm: numa: Ensure anon_vma is locked to prevent parallel THP splits Date: Tue, 3 Dec 2013 08:51:56 +0000 Message-Id: <1386060721-3794-10-git-send-email-mgorman@suse.de> X-Mailer: git-send-email 1.8.4 In-Reply-To: <1386060721-3794-1-git-send-email-mgorman@suse.de> References: <1386060721-3794-1-git-send-email-mgorman@suse.de> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 --- mm/huge_memory.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index d6c3bf4..98b6a79 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1342,6 +1342,13 @@ 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. -- 1.8.4