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=-4.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED 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 168EFC35247 for ; Fri, 7 Feb 2020 00:30:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D341D217BA for ; Fri, 7 Feb 2020 00:30:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581035409; bh=nIr/9PKnEgrt2GxIVCRtoJWwTwGJ9J5EHRzdrefNNgc=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=Zet5ZBJG7e6BP9tbtgwfMdI34Tc9R8BmavMKjMhA7gXBRtCGbPdIFyHYVqhplhSTp lVc8FDb8Kfuq9ZZM2dz+0nGjj2YzvzQUrouENmP5jpWNgYsw0NQHgGNQFPpRyZl3+a DPFfqq4XoHfq86c/5inj3hxejnBwMUuMpUzzZnW0= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727446AbgBGAaJ (ORCPT ); Thu, 6 Feb 2020 19:30:09 -0500 Received: from mail.kernel.org ([198.145.29.99]:36652 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726509AbgBGAaI (ORCPT ); Thu, 6 Feb 2020 19:30:08 -0500 Received: from devnote2 (NE2965lan1.rev.em-net.ne.jp [210.141.244.193]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id A09302064C; Fri, 7 Feb 2020 00:30:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581035407; bh=nIr/9PKnEgrt2GxIVCRtoJWwTwGJ9J5EHRzdrefNNgc=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=M9HW/WBjhMDhYkqE8O7McctHiinjZc+KYs2P8Zvoof9LecSqM4aqWHrJ8iVoX+GBI unU9ZhJJzMY9Z3NwOLg//3OUucBpu7Yy0C5cIWehvlJwv1Cv7gPLQ9TbjF3FCD1sZ6 XokEYS9iPnPBCge+5/GUwZcyd1Rfh98IsUZAZIcE= Date: Fri, 7 Feb 2020 09:30:03 +0900 From: Masami Hiramatsu To: Geert Uytterhoeven Cc: Borislav Petkov , Steven Rostedt , Linux Kernel Mailing List , Ingo Molnar , Andrew Morton Subject: Re: [for-next][PATCH 04/26] bootconfig: Add Extra Boot Config support Message-Id: <20200207093003.93711310cfafae98bb2a62f6@kernel.org> In-Reply-To: References: <20200114210316.450821675@goodmis.org> <20200114210336.259202220@goodmis.org> <20200206115405.GA22608@zn.tnic> <20200206234100.953b48ecef04f97c112d2e8b@kernel.org> X-Mailer: Sylpheed 3.5.1 (GTK+ 2.24.32; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 6 Feb 2020 18:20:15 +0100 Geert Uytterhoeven wrote: > Hi Hiramatsu-san, > > On Thu, Feb 6, 2020 at 3:42 PM Masami Hiramatsu wrote: > > On Thu, 6 Feb 2020 12:54:05 +0100 > > Borislav Petkov wrote: > > > On Tue, Jan 14, 2020 at 04:03:20PM -0500, Steven Rostedt wrote: > > > > diff --git a/init/Kconfig b/init/Kconfig > > > > index a34064a031a5..63450d3bbf12 100644 > > > > --- a/init/Kconfig > > > > +++ b/init/Kconfig > > > > @@ -1215,6 +1215,17 @@ source "usr/Kconfig" > > > > > > > > endif > > > > > > > > +config BOOT_CONFIG > > > > + bool "Boot config support" > > > > + select LIBXBC > > > > + default y > > > > > > Any particular reason this is default y? Why should it be enabled by > > > default on all boxes? > > > > Oh, you are not the first person asked that :) > > > > https://lkml.org/lkml/2019/12/9/563 > > > > And yes, I think this is important that will useful for most developers > > and admins. Since the bootconfig already covers kernel and init options, > > this can be a new standard way to pass args to kernel boot. > > > > And as I reported above thread, the memory footpoint of view, most code > > and working memory are released after boot. Also, as Linus's suggested, > > now this feature is enabled only if user gives "bootconfig" on the kernel > > command line. So the side effect is minimized. > > With m68k/atari_defconfig, bloat-o-meter says: > > add/remove: 39/0 grow/shrink: 2/0 up/down: 13086/0 (13086) > > which is IMHO not that small for a "default y" option that may or may not > be used. > > Especially: > > Function old new delta > xbc_nodes - 8192 +8192 > > Any chance xbc_nodes can be allocated dynamically, and only when needed? Yes, I think we can use memblock to allocate it. However, this xbc_nodes is __init_data, which is released right after boot. So I think it should be OK except for your system doesn't have user space... > Yes, there are industrial products running Linux on a current ARM SoC > using the builtin 8 or 10 MiB of SRAM (+ XIP for the kernel), so these > definitely want to say CONFIG_BOOT_CONFIG=n. I think for such products the kernel must be tuned with custom config, and you can say CONFIG_BOOT_CONFIG=n. That is a configurable feature. Thank you, > > Thanks! > > add/remove: 39/0 grow/shrink: 2/0 up/down: 13086/0 (13086) > Function old new delta > xbc_nodes - 8192 +8192 > xbc_init - 854 +854 > start_kernel 1020 1580 +560 > copy_xbc_key_value_list - 362 +362 > __xbc_parse_value - 324 +324 > xbc_snprint_cmdline - 294 +294 > xbc_node_compose_key_after - 266 +266 > xbc_namebuf - 256 +256 > xbc_add_sibling - 254 +254 > xbc_node_find_next_leaf - 186 +186 > xbc_node_find_child - 176 +176 > __xbc_add_key - 162 +162 > proc_boot_config_init - 124 +124 > xbc_make_cmdline - 122 +122 > xbc_node_find_value - 104 +104 > xbc_node_find_next_key_value - 102 +102 > __xbc_close_brace - 92 +92 > find_match_node - 80 +80 > __xbc_parse_keys - 78 +78 > xbc_node_get_data - 64 +64 > xbc_parse_key - 60 +60 > skip_comment - 48 +48 > xbc_destroy_all - 42 +42 > xbc_node_get_parent - 38 +38 > xbc_parse_error - 36 +36 > xbc_node_get_child - 34 +34 > xbc_node_get_next - 32 +32 > boot_config_checksum - 30 +30 > boot_config_proc_show - 26 +26 > xbc_root_node - 20 +20 > kzalloc.constprop 810 830 +20 > xbc_node_index - 14 +14 > xbc_node_num - 4 +4 > xbc_data_size - 4 +4 > xbc_data - 4 +4 > saved_boot_config - 4 +4 > last_parent - 4 +4 > extra_init_args - 4 +4 > extra_command_line - 4 +4 > __initcall_proc_boot_config_init5 - 4 +4 > xbc_debug_dump - 2 +2 > Total: Before=3688860, After=3701946, chg +0.35% > > Gr{oetje,eeting}s, > > Geert > > -- > Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org > > In personal conversations with technical people, I call myself a hacker. But > when I'm talking to journalists I just say "programmer" or something like that. > -- Linus Torvalds -- Masami Hiramatsu