From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755601Ab3LCXHs (ORCPT ); Tue, 3 Dec 2013 18:07:48 -0500 Received: from mx1.redhat.com ([209.132.183.28]:54351 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755218Ab3LCXHM (ORCPT ); Tue, 3 Dec 2013 18:07:12 -0500 Message-ID: <529E641A.7040804@redhat.com> Date: Tue, 03 Dec 2013 18:07:06 -0500 From: Rik van Riel User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130625 Thunderbird/17.0.7 MIME-Version: 1.0 To: Mel Gorman CC: Alex Thorlton , Linux-MM , LKML Subject: Re: [PATCH 14/15] mm: numa: Flush TLB if NUMA hinting faults race with PTE scan update References: <1386060721-3794-1-git-send-email-mgorman@suse.de> <1386060721-3794-15-git-send-email-mgorman@suse.de> In-Reply-To: <1386060721-3794-15-git-send-email-mgorman@suse.de> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/03/2013 03:52 AM, Mel Gorman wrote: > NUMA PTE updates and NUMA PTE hinting faults can race against each other. The > setting of the NUMA bit defers the TLB flush to reduce overhead. NUMA > hinting faults do not flush the TLB as X86 at least does not cache TLB > entries for !present PTEs. However, in the event that the two race a NUMA > hinting fault may return with the TLB in an inconsistent state between > different processors. This patch detects potential for races between the > NUMA PTE scanner and fault handler and will flush the TLB for the affected > range if there is a race. > > Signed-off-by: Mel Gorman > diff --git a/mm/migrate.c b/mm/migrate.c > index 5dfd552..ccc814b 100644 > --- a/mm/migrate.c > +++ b/mm/migrate.c > @@ -1662,6 +1662,39 @@ void wait_migrate_huge_page(struct anon_vma *anon_vma, pmd_t *pmd) > smp_rmb(); > } > > +unsigned long numa_fault_prepare(struct mm_struct *mm) > +{ > + /* Paired with task_numa_work */ > + smp_rmb(); > + return mm->numa_next_reset; > +} The patch that introduces mm->numa_next_reset, and the patch that increments it, seem to be missing from your series... -- All rights reversed