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=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no 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 F31AFC10F14 for ; Tue, 8 Oct 2019 19:21:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CDD75206C0 for ; Tue, 8 Oct 2019 19:21:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1570562488; bh=LTCPkj87u5QMn1xLjpxVY89MdkjCHaieTcAOR7aS66c=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=uHL23TTymwu2f1uEUQfknOGOQpRJvAW3VeN5X4pWlkKwDwNZEEOzO6maNUrtyix7W QWLH665bNpngyLTk2AlkoVZowMJbA98awoWJ0ZDMOpIftxjyQ3s40dD2TB7zlPXY/g k1VQlzxP9Nftb4NQSBM+jyeThvJ7wzYHSVh5YoE8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730393AbfJHTV1 (ORCPT ); Tue, 8 Oct 2019 15:21:27 -0400 Received: from mx2.suse.de ([195.135.220.15]:34880 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726439AbfJHTV1 (ORCPT ); Tue, 8 Oct 2019 15:21:27 -0400 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 9689BB147; Tue, 8 Oct 2019 19:21:25 +0000 (UTC) Date: Tue, 8 Oct 2019 21:21:24 +0200 From: Michal Hocko To: Christopher Lameter Cc: Kaitao Cheng , akpm@linux-foundation.org, sashal@kernel.org, osalvador@suse.de, mgorman@techsingularity.net, rppt@linux.ibm.com, dan.j.williams@intel.com, alexander.h.duyck@linux.intel.com, pavel.tatashin@microsoft.com, glider@google.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Muchun Song Subject: Re: [PATCH] mm, page_alloc: drop pointless static qualifier in build_zonelists() Message-ID: <20191008192124.GT6681@dhcp22.suse.cz> References: <20190927161416.62293-1-pilgrimtao@gmail.com> 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 Tue 08-10-19 19:06:57, Cristopher Lameter wrote: > On Sat, 28 Sep 2019, Kaitao Cheng wrote: > > > There is no need to make the 'node_order' variable static > > since new value always be assigned before use it. > > In the past MAX_NUMMNODES could become quite large like 512 or 1k. Large > array allocations on the stack are problematic. > > Maybe that is no longer the case? CONFIG_NODES_SHIFT=10 is nothing really unusual in distribution kernels. Likely wasteful for most HW available but a proper way to address it in this particular case is to use a different data structure than drop the static modifier which seems to be more of an misunderstanding than an intention. -- Michal Hocko SUSE Labs