From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751468Ab3LKNVO (ORCPT ); Wed, 11 Dec 2013 08:21:14 -0500 Received: from cantor2.suse.de ([195.135.220.15]:49300 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751345Ab3LKNVN (ORCPT ); Wed, 11 Dec 2013 08:21:13 -0500 Date: Wed, 11 Dec 2013 13:21:09 +0000 From: Mel Gorman To: Andrew Morton Cc: "Paul E. McKenney" , Peter Zijlstra , Alex Thorlton , Rik van Riel , Linux-MM , LKML Subject: [PATCH] mm: numa: Guarantee that tlb_flush_pending updates are visible before page table updates Message-ID: <20131211132109.GB24125@suse.de> References: <1386690695-27380-1-git-send-email-mgorman@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <1386690695-27380-1-git-send-email-mgorman@suse.de> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org According to documentation on barriers, stores issued before a LOCK can complete after the lock implying that it's possible tlb_flush_pending can be visible after a page table update. As per revised documentation, this patch adds a smp_mb__before_spinlock to guarantee the correct ordering. Cc: stable@vger.kernel.org Signed-off-by: Mel Gorman --- include/linux/mm_types.h | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index c122bb1..a12f2ab 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -482,7 +482,12 @@ static inline bool tlb_flush_pending(struct mm_struct *mm) static inline void set_tlb_flush_pending(struct mm_struct *mm) { mm->tlb_flush_pending = true; - barrier(); + + /* + * Guarantee that the tlb_flush_pending store does not leak into the + * critical section updating the page tables + */ + smp_mb__before_spinlock(); } /* Clearing is done after a TLB flush, which also provides a barrier. */ static inline void clear_tlb_flush_pending(struct mm_struct *mm)