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=-2.3 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 6F0A2C433F5 for ; Wed, 29 Aug 2018 20:34:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2F13620658 for ; Wed, 29 Aug 2018 20:34:38 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2F13620658 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=techadventures.net 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 S1728684AbeH3AdI (ORCPT ); Wed, 29 Aug 2018 20:33:08 -0400 Received: from mail-wr1-f66.google.com ([209.85.221.66]:33044 "EHLO mail-wr1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727392AbeH3AdI (ORCPT ); Wed, 29 Aug 2018 20:33:08 -0400 Received: by mail-wr1-f66.google.com with SMTP id v90-v6so6029946wrc.0 for ; Wed, 29 Aug 2018 13:34:34 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=5KdLqEy/lMlUJABiqnnQ+7Qa0Gbn0qySS//fRdbw8zM=; b=j7OQ/n7mvBK8I3jpZr9PX4Y1G+fyc9Z39ufKrxnZRf5JrOAdu96VnuJurklD5KCaaN j5qk2VbBJMxunOuQa70Jcd46o3/290AcD8Rb0QGoO1bA+XBxoGI7hGDKjXQwvpGQNdJq mer39MQO+7lHQVuFvBM+TytYSJAhWpWwcnZkLzxsurVbaLXMB2RkAclzYHv/kLAlTju5 bUXDF3AlJE8nKRXpdyPybFp+liRkYAGMwImrLplRFGp0Hv0sUo+42klRls3vrehn8TJu DGuu1wOwvgMwRLi4o9+99qW8sPutAJ9BNhjdVBoM1/NboB89ZmUoEtFgpOfLzxr33EKg t2uA== X-Gm-Message-State: APzg51AJqDa2gIv09XezY7yyRLF3HC8dI3Uuuw//POO4c8aa5FRRi6zG kMu/RJv13io0NShpcPqxnOo= X-Google-Smtp-Source: ANB0VdYNDX/C18GKNqwuNCSthsd1ubReGIhx+FbzpINurJPZ0uVoQVUoLshe4l0ydRCyCL23/eTGwQ== X-Received: by 2002:adf:e1c5:: with SMTP id l5-v6mr5448698wri.36.1535574873993; Wed, 29 Aug 2018 13:34:33 -0700 (PDT) Received: from techadventures.net (techadventures.net. [62.201.165.239]) by smtp.gmail.com with ESMTPSA id j16-v6sm3439345wmc.25.2018.08.29.13.34.33 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 29 Aug 2018 13:34:33 -0700 (PDT) Received: by techadventures.net (Postfix, from userid 1000) id 6E908124C52; Wed, 29 Aug 2018 22:34:32 +0200 (CEST) Date: Wed, 29 Aug 2018 22:34:32 +0200 From: Oscar Salvador To: Andrew Morton Cc: mhocko@suse.com, vbabka@suse.cz, Pavel.Tatashin@microsoft.com, sfr@canb.auug.org.au, iamjoonsoo.kim@lge.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Oscar Salvador , Lai Jiangshan Subject: Re: [PATCH] mm/page_alloc: Clean up check_for_memory Message-ID: <20180829203432.GA24978@techadventures.net> References: <20180828210158.4617-1-osalvador@techadventures.net> <20180828143530.4b681bf9e0b3c03519fbe943@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180828143530.4b681bf9e0b3c03519fbe943@linux-foundation.org> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Aug 28, 2018 at 02:35:30PM -0700, Andrew Morton wrote: > > First, we should only set N_HIGH_MEMORY in case we have > > CONFIG_HIGHMEM. > > Why? Just a teeny optimization? Hi Andrew, Optimization was not really my point here, my point was to make the code less subtle and more clear. One may wonder why we set N_HIGH_MEMORY unconditionally when __only__ CONFIG_HIGHMEM matters for this case, and why we set N_NORMAL_MEMORY __only__ for CONFIG_HIGHMEM when we should not care about that at all. I do not really expect a big impact here, mainly because check_for_memory is only being used during boot. -- Oscar Salvador SUSE L3