From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ee0-f43.google.com (mail-ee0-f43.google.com [74.125.83.43]) by kanga.kvack.org (Postfix) with ESMTP id 20B5F6B003D for ; Mon, 9 Dec 2013 02:09:21 -0500 (EST) Received: by mail-ee0-f43.google.com with SMTP id c13so1332979eek.30 for ; Sun, 08 Dec 2013 23:09:20 -0800 (PST) Received: from mx2.suse.de (cantor2.suse.de. [195.135.220.15]) by mx.google.com with ESMTP id e2si8238838eeg.72.2013.12.08.23.09.19 for ; Sun, 08 Dec 2013 23:09:19 -0800 (PST) From: Mel Gorman Subject: [PATCH 06/18] mm: numa: Ensure anon_vma is locked to prevent parallel THP splits Date: Mon, 9 Dec 2013 07:09:00 +0000 Message-Id: <1386572952-1191-7-git-send-email-mgorman@suse.de> In-Reply-To: <1386572952-1191-1-git-send-email-mgorman@suse.de> References: <1386572952-1191-1-git-send-email-mgorman@suse.de> Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: Alex Thorlton , Rik van Riel , Linux-MM , LKML , Mel Gorman 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. Cc: stable@vger.kernel.org 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 5a5da50..0f00b96 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1359,6 +1359,13 @@ 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 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org