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=-1.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 A7C00C35DFE for ; Tue, 25 Feb 2020 10:02:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7BC5E218AC for ; Tue, 25 Feb 2020 10:02:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582624951; bh=L9wVFDiG7i2e2QopiyF9lYRVNbRhhGOMTb9xiWy1gzw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=0soKilroePdfNUtyTJMVXpbx4QHNbqO0S6FTQY69RsxC8oWuJUzDHSOpINWOEEXEW hRF3Sxo+v84lf4JSulmkkUyJxPXQTPkIcr5LA8BZPsOO8Gdc4kNITVx26zNSr1hNlc k+Cwo43X7zLWD1Y4L27qqHRc4Tdu3Zd1shkUmR98= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729834AbgBYKCa (ORCPT ); Tue, 25 Feb 2020 05:02:30 -0500 Received: from mail-wm1-f67.google.com ([209.85.128.67]:51944 "EHLO mail-wm1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727016AbgBYKC3 (ORCPT ); Tue, 25 Feb 2020 05:02:29 -0500 Received: by mail-wm1-f67.google.com with SMTP id t23so2330624wmi.1 for ; Tue, 25 Feb 2020 02:02:28 -0800 (PST) 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; bh=lnOg0BFJC0Xq2X5KIoU2QBkyMNBMepmyg8YCqkA6k7U=; b=W5pkAJ7vs+/eKUiyjkKoAdyaEr6gD+WDTwNHpqLhMbMG24m5oWZknwhCKJeRVzD6aQ XDbwYe3WQxHFS6SvwJYwsZxvjDyEfDpAzb5Yq80FmYrBqG80MncXLUH+Cjw2CBHmZ7rr WbjZY0/SSLqp/W1IW5MyDjQJUv0z6q4Z6h1+vne8dFmKabEUampqJvBm9V47r7OUEfIL vYGem9IGfyxigxShdBffLqOg8fsR7ImcX1wMhluRCMEREpivWH9oo0PnPM8kksmhjQDA IaMHk2F6gMUSUYqx60n7M70CroNivXMRmAcoLOTLd0mht9G0GckD8nB5FlRRnza4iC3C 5f6A== X-Gm-Message-State: APjAAAUyOwvIhwxmtA5P2nZttksbCAHlEV6KOuZZ7wDxQsqeD70x005q Z36O58vt611l9aXYwYJnkNM= X-Google-Smtp-Source: APXvYqxzKot3XeUYUWdPD1zoO4zHgH+OtF66V+GASD3x4k3iPE0BSwi344jjt8FwnvA1YSzHJ7GvTQ== X-Received: by 2002:a7b:c08d:: with SMTP id r13mr4418391wmh.84.1582624947879; Tue, 25 Feb 2020 02:02:27 -0800 (PST) Received: from localhost (prg-ext-pat.suse.com. [213.151.95.130]) by smtp.gmail.com with ESMTPSA id a13sm5808318wrt.55.2020.02.25.02.02.26 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 25 Feb 2020 02:02:26 -0800 (PST) Date: Tue, 25 Feb 2020 11:02:26 +0100 From: Michal Hocko To: David Hildenbrand Cc: Baoquan He , linux-kernel@vger.kernel.org, linux-mm@kvack.org, akpm@linux-foundation.org, richardw.yang@linux.intel.com, osalvador@suse.de, dan.j.williams@intel.com, rppt@linux.ibm.com, robin.murphy@arm.com Subject: Re: [PATCH v2 0/7] mm/hotplug: Only use subsection map in VMEMMAP case Message-ID: <20200225100226.GM22443@dhcp22.suse.cz> References: <20200220043316.19668-1-bhe@redhat.com> <20200220103849.GG20509@dhcp22.suse.cz> <20200221142847.GG4937@MiWiFi-R3L-srv> <75b4f840-7454-d6d0-5453-f0a045c852fa@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <75b4f840-7454-d6d0-5453-f0a045c852fa@redhat.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue 25-02-20 10:10:45, David Hildenbrand wrote: > >>> include/linux/mmzone.h | 2 + > >>> mm/sparse.c | 178 +++++++++++++++++++++++++++++------------ > >>> 2 files changed, 127 insertions(+), 53 deletions(-) > >> > >> Why do we need to add so much code to remove a functionality from one > >> memory model? > > > > Hmm, Dan also asked this before. > > > > The adding mainly happens in patch 2, 3, 4, including the two newly > > added function defitions, the code comments above them, and those added > > dummy functions for !VMEMMAP. > > AFAIKS, it's mostly a bunch of newly added comments on top of functions. > E.g., the comment for fill_subsection_map() alone spans 12 LOC in total. > I do wonder if we have to be that verbose. We are barely that verbose on > MM code (and usually I don't see much benefit unless it's a function > with many users from many different places). I would tend to agree here. Not that I am against kernel doc documentation but these are internal functions and the comment doesn't really give any better insight IMHO. I would be much more inclined if this was the general pattern in the respective file but it just stands out. -- Michal Hocko SUSE Labs