From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.5 required=3.0 tests=MAILING_LIST_MULTI,SPF_PASS, USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2A5C0C43610 for ; Tue, 20 Nov 2018 07:45:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4F6A6208E3 for ; Tue, 20 Nov 2018 07:44:52 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4F6A6208E3 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725890AbeKTSMe (ORCPT ); Tue, 20 Nov 2018 13:12:34 -0500 Received: from mx2.suse.de ([195.135.220.15]:46536 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725770AbeKTSMe (ORCPT ); Tue, 20 Nov 2018 13:12:34 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 6D08EAC9F; Tue, 20 Nov 2018 07:44:49 +0000 (UTC) Date: Tue, 20 Nov 2018 08:44:47 +0100 From: Michal Hocko To: David Rientjes Cc: Greg Kroah-Hartman , linux-kernel@vger.kernel.org, stable@vger.kernel.org, Andrea Arcangeli , Stefan Priebe , Alex Williamson , Mel Gorman , Zi Yan , Vlastimil Babka , "Kirill A. Shutemov" , Andrew Morton , Linus Torvalds Subject: Re: [PATCH 4.4 131/160] mm: thp: relax __GFP_THISNODE for MADV_HUGEPAGE mappings Message-ID: <20181120074447.GZ22247@dhcp22.suse.cz> References: <20181119162630.031306128@linuxfoundation.org> <20181119162643.032920932@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon 19-11-18 14:16:24, David Rientjes wrote: > On Mon, 19 Nov 2018, Greg Kroah-Hartman wrote: > > > 4.4-stable review patch. If anyone has any objections, please let me know. > > > > As I noted when this patch was originally proposed and when I nacked it[*] > because it causes a 13.9% increase in remote memory access latency and up > to 40% increase in remote memory allocation latency on much of our > software stack that uses MADV_HUGEPAGE after mremapping the text segment > to memory backed by hugepages, I don't think this is stable material. There was a wider consensus that this is the most minimal fix for users who see a regression introduced by 5265047ac301 ("mm, thp: really limit transparent hugepage allocation to local node"). As it has been discussed extensively there is no universal win but we should always opt for the safer side which this patch is accomplishing. The changelog goes in length explaining them along with numbers. I am not happy that your particular workload is suffering but this area certainly requires much more changes to satisfy wider range of users. > The 4.4 kernel is almost three years old and this changes the NUMA > locality of any user of MADV_HUGEPAGE. Yes and we have seen bug reports as we adopted this older kernel only now. -- Michal Hocko SUSE Labs