From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752221AbaJBS6t (ORCPT ); Thu, 2 Oct 2014 14:58:49 -0400 Received: from userp1040.oracle.com ([156.151.31.81]:50978 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751983AbaJBS6r (ORCPT ); Thu, 2 Oct 2014 14:58:47 -0400 Message-ID: <542DA038.9000908@oracle.com> Date: Thu, 02 Oct 2014 14:58:00 -0400 From: Sasha Levin User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.0 MIME-Version: 1.0 To: Linus Torvalds , Mel Gorman CC: Dave Jones , Hugh Dickins , Al Viro , Rik van Riel , Ingo Molnar , Peter Zijlstra , Aneesh Kumar , Michel Lespinasse , Kirill A Shutemov , Linux Kernel Subject: Re: [PATCH 4/4] mm: numa: Do not mark PTEs pte_numa when splitting huge pages References: <1412256558-9995-1-git-send-email-mgorman@suse.de> <1412256558-9995-5-git-send-email-mgorman@suse.de> In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-Source-IP: ucsinet21.oracle.com [156.151.31.93] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/02/2014 12:36 PM, Linus Torvalds wrote: > On Thu, Oct 2, 2014 at 6:29 AM, Mel Gorman wrote: >> > This patch reverts 1ba6e0b50b ("mm: numa: split_huge_page: transfer the >> > NUMA type from the pmd to the pte"). If a huge page is being split due >> > a protection change and the tail will be in a PROT_NONE vma then NUMA >> > hinting PTEs are temporarily created in the protected VMA. > So this is the particular bug I was worried about when tracing through the code. > > Should I just apply this as-is? And mark it for stable, since this has > been around since 3.8 or so. It would seem to be a very safe change to > do, regardless of whether this is actually the issue that Dave and > maybe Sasha are seeing. > > Sasha, I notice that you weren't on the cc for Mel's patches (probably > because you got added later to the other thread), but they were all > cc'd to lkml so you should see them there. Or I can forward them > separately. I grabbed them and will keep them in my tree for now instead of your NUMA-chainsaw-massacre patch. You've also mentioned that while I can tell you if nothing dies, I can't really tell you if everything is working well. Is there a reasonable way to easily say if NUMA is working properly? Even something that would just tell me "your NUMA balancing seems to be sane" would be good. Thanks, Sasha