From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754729AbdDJRjL (ORCPT ); Mon, 10 Apr 2017 13:39:11 -0400 Received: from outbound-smtp02.blacknight.com ([81.17.249.8]:56303 "EHLO outbound-smtp02.blacknight.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754540AbdDJRjB (ORCPT ); Mon, 10 Apr 2017 13:39:01 -0400 Date: Mon, 10 Apr 2017 18:38:49 +0100 From: Mel Gorman To: Michal Hocko Cc: Andrew Morton , Andrea Arcangeli , Rik van Riel , Vlastimil Babka , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm, numa: Fix bad pmd by atomically check for pmd_trans_huge when marking page tables prot_numa Message-ID: <20170410173849.ecy2ysm7twzgcm53@techsingularity.net> References: <20170410094825.2yfo5zehn7pchg6a@techsingularity.net> <20170410135342.GD4618@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <20170410135342.GD4618@dhcp22.suse.cz> User-Agent: Mutt/1.6.2 (2016-07-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Apr 10, 2017 at 03:53:42PM +0200, Michal Hocko wrote: > > While this could be fixed with heavy locking, it's only necessary to > > make a copy of the PMD on the stack during change_pmd_range and avoid > > races. A new helper is created for this as the check if quite subtle and the > > existing similar helpful is not suitable. This passed 154 hours of testing > > s@helpful@helper@ I suspect > Yes. I'll wait to see if there is more feedback and if not, resend unless Andrew decides to pick it up and correct the mistake directly. > > (usually triggers between 20 minutes and 24 hours) without detecting bad > > PMDs or corruption. A basic test of an autonuma-intensive workload showed > > no significant change in behaviour. > > > > Signed-off-by: Mel Gorman > > Cc: stable@vger.kernel.org > > Acked-by: Michal Hocko > Thanks. > you will probably win the_longest_function_name_contest but I do not > have much better suggestion. > I know, it's not a type of function that yields a snappy name. -- Mel Gorman SUSE Labs