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=HEADER_FROM_DIFFERENT_DOMAINS, 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 A18D6C282DA for ; Fri, 19 Apr 2019 19:15:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 69DAE204FD for ; Fri, 19 Apr 2019 19:15:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729325AbfDSTP1 (ORCPT ); Fri, 19 Apr 2019 15:15:27 -0400 Received: from outbound-smtp18.blacknight.com ([46.22.139.245]:53891 "EHLO outbound-smtp18.blacknight.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728924AbfDSTP0 (ORCPT ); Fri, 19 Apr 2019 15:15:26 -0400 Received: from mail.blacknight.com (pemlinmail04.blacknight.ie [81.17.254.17]) by outbound-smtp18.blacknight.com (Postfix) with ESMTPS id 77B301C2B5B for ; Fri, 19 Apr 2019 15:28:37 +0100 (IST) Received: (qmail 11311 invoked from network); 19 Apr 2019 14:28:37 -0000 Received: from unknown (HELO techsingularity.net) (mgorman@techsingularity.net@[37.228.225.79]) by 81.17.254.9 with ESMTPSA (AES256-SHA encrypted, authenticated); 19 Apr 2019 14:28:37 -0000 Date: Fri, 19 Apr 2019 15:28:35 +0100 From: Mel Gorman To: Matthew Wilcox Cc: Andrew Morton , Mikulas Patocka , James Bottomley , linux-parisc@vger.kernel.org, linux-mm@kvack.org, Vlastimil Babka , LKML , linux-arch@vger.kernel.org Subject: Re: DISCONTIGMEM is deprecated Message-ID: <20190419142835.GM18914@techsingularity.net> References: <20190419094335.GJ18914@techsingularity.net> <20190419140521.GI7751@bombadil.infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <20190419140521.GI7751@bombadil.infradead.org> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-parisc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-parisc@vger.kernel.org On Fri, Apr 19, 2019 at 07:05:21AM -0700, Matthew Wilcox wrote: > On Fri, Apr 19, 2019 at 10:43:35AM +0100, Mel Gorman wrote: > > DISCONTIG is essentially deprecated and even parisc plans to move to > > SPARSEMEM so there is no need to be fancy, this patch simply disables > > watermark boosting by default on DISCONTIGMEM. > > I don't think parisc is the only arch which uses DISCONTIGMEM for !NUMA > scenarios. Grepping the arch/ directories shows: > > alpha (does support NUMA, but also non-NUMA DISCONTIGMEM) > arc (for supporting more than 1GB of memory) > ia64 (looks complicated ...) > m68k (for multiple chunks of memory) > mips (does support NUMA but also non-NUMA) > parisc (both NUMA and non-NUMA) > > I'm not sure that these architecture maintainers even know that DISCONTIGMEM > is deprecated. Adding linux-arch to the cc. Poor wording then -- yes, DISCONTIGMEM is still used but look where it's used. I find it impossible to believe that any new arch would support DISCONTIGMEM or that DISCONTIGMEM would be selected when SPARSEMEM is available.`It's even more insane when you consider that SPARSEMEM can be extended to support VMEMMAP so that it has similar overhead to FLATMEM when mapping pfns to struct pages and vice-versa. -- Mel Gorman SUSE Labs