From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ee0-f46.google.com (mail-ee0-f46.google.com [74.125.83.46]) by kanga.kvack.org (Postfix) with ESMTP id 17DEF6B003C for ; Tue, 10 Dec 2013 10:51:41 -0500 (EST) Received: by mail-ee0-f46.google.com with SMTP id d49so2312117eek.19 for ; Tue, 10 Dec 2013 07:51:41 -0800 (PST) Received: from mx2.suse.de (cantor2.suse.de. [195.135.220.15]) by mx.google.com with ESMTP id a9si14897424eew.54.2013.12.10.07.51.41 for ; Tue, 10 Dec 2013 07:51:41 -0800 (PST) From: Mel Gorman Subject: [PATCH 06/18] mm: numa: Ensure anon_vma is locked to prevent parallel THP splits Date: Tue, 10 Dec 2013 15:51:24 +0000 Message-Id: <1386690695-27380-7-git-send-email-mgorman@suse.de> In-Reply-To: <1386690695-27380-1-git-send-email-mgorman@suse.de> References: <1386690695-27380-1-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 Reviewed-by: Rik van Riel --- 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