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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS 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 B70F4C6786F for ; Sat, 3 Nov 2018 09:10:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5DC112081F for ; Sat, 3 Nov 2018 09:10:14 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5DC112081F Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=nod.at 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 S1727719AbeKCSUv (ORCPT ); Sat, 3 Nov 2018 14:20:51 -0400 Received: from lithops.sigma-star.at ([195.201.40.130]:53002 "EHLO lithops.sigma-star.at" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726539AbeKCSUv (ORCPT ); Sat, 3 Nov 2018 14:20:51 -0400 Received: from localhost (localhost [127.0.0.1]) by lithops.sigma-star.at (Postfix) with ESMTP id E22A960A04B3; Sat, 3 Nov 2018 10:10:09 +0100 (CET) Received: from lithops.sigma-star.at ([127.0.0.1]) by localhost (lithops.sigma-star.at [127.0.0.1]) (amavisd-new, port 10032) with ESMTP id WBwD1CdxLQlt; Sat, 3 Nov 2018 10:10:09 +0100 (CET) Received: from localhost (localhost [127.0.0.1]) by lithops.sigma-star.at (Postfix) with ESMTP id A56FD609F82F; Sat, 3 Nov 2018 10:10:09 +0100 (CET) Received: from lithops.sigma-star.at ([127.0.0.1]) by localhost (lithops.sigma-star.at [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id tx5Gpe2Aac2O; Sat, 3 Nov 2018 10:10:09 +0100 (CET) Received: from blindfold.localnet (213-47-184-186.cable.dynamic.surfer.at [213.47.184.186]) by lithops.sigma-star.at (Postfix) with ESMTPSA id 2B103606C48C; Sat, 3 Nov 2018 10:10:09 +0100 (CET) From: Richard Weinberger To: Helen Koike , keescook@chromium.org Cc: dm-devel@redhat.com, agk@redhat.com, snitzer@redhat.com, linux-kernel@vger.kernel.org, enric.balletbo@collabora.com, wad@chromium.org, linux-doc@vger.kernel.org, linux-lvm@redhat.com, kernel@collabora.com Subject: Re: [PATCH v10 0/2] dm: boot a mapped device without an initramfs Date: Sat, 03 Nov 2018 10:10:08 +0100 Message-ID: <3624012.MiIzIq7dko@blindfold> In-Reply-To: <20181103035341.16893-1-helen.koike@collabora.com> References: <20181103035341.16893-1-helen.koike@collabora.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Helen, Am Samstag, 3. November 2018, 04:53:39 CET schrieb Helen Koike: > As mentioned in the discussion from the previous version of this patch, Android > and Chrome OS do not use initramfs mostly due to boot time and size liability. Do you have numbers on that? I understand that using something like dracut with systemd inside is not what you want from a boot time point of view. But having an initramfs embedded into the kernel image which contains only a single static linked binary can be *very* small and fast. If you invest a little more time, you don't even need a libc, just fire up some syscalls to setup your dm. I use this technique regularly on deeply embedded systems to setup non-trivial UBIFS/crypto stuff. Want I'm trying to say, before adding ad-hoc a feature to the kernel, we should be very sure that there is no other way to solve this in a sane manner. We have initramfs support for reasons. Thanks, //richard