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=-2.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,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 F4147C2D0BF for ; Tue, 10 Dec 2019 14:05:45 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id B92C820652 for ; Tue, 10 Dec 2019 14:05:45 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="iLjkWXF2" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B92C820652 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 4EAB96B2C96; Tue, 10 Dec 2019 09:05:45 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 49B666B2C97; Tue, 10 Dec 2019 09:05:45 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 3B0A66B2CAE; Tue, 10 Dec 2019 09:05:45 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0160.hostedemail.com [216.40.44.160]) by kanga.kvack.org (Postfix) with ESMTP id 292A66B2C96 for ; Tue, 10 Dec 2019 09:05:45 -0500 (EST) Received: from smtpin11.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with SMTP id BBC878249980 for ; Tue, 10 Dec 2019 14:05:44 +0000 (UTC) X-FDA: 76249405008.11.part20_6c3d5a9696f46 X-HE-Tag: part20_6c3d5a9696f46 X-Filterd-Recvd-Size: 4338 Received: from us-smtp-delivery-1.mimecast.com (us-smtp-1.mimecast.com [207.211.31.81]) by imf15.hostedemail.com (Postfix) with ESMTP for ; Tue, 10 Dec 2019 14:05:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1575986743; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=SOYnZuCbc+qSbe4PVmdcAeY7lsD1liv9hGkxVuOBR+k=; b=iLjkWXF2tkSUuTegqgPuvaIsHgJI9qYuoPoRv5i0tBXbe8upa8IreRscCcLzRj85oCSiwm S/0OzqHFfs/Urpw9McIsprRxUA1mCZRe7DLyRE2pXFkEPP2bhes6/UFzExfsuMn0rFqo6N exaeHRu412IQP5hP+y+LcnbKXCRBZtA= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-159-BlQbeN4EOXuXUKazet-nYw-1; Tue, 10 Dec 2019 09:05:39 -0500 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 13ACC1800D45; Tue, 10 Dec 2019 14:05:38 +0000 (UTC) Received: from localhost (ovpn-12-38.pek2.redhat.com [10.72.12.38]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 5F2D3605C9; Tue, 10 Dec 2019 14:05:37 +0000 (UTC) Date: Tue, 10 Dec 2019 22:05:34 +0800 From: Baoquan He To: Michal Hocko Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, jgross@suse.com, william.kucharski@oracle.com, mingo@kernel.org, akpm@linux-foundation.org Subject: Re: [PATCH] mm/hotplug: Only respect mem= parameter during boot stage Message-ID: <20191210140534.GB28917@MiWiFi-R3L-srv> References: <20191206150524.14687-1-bhe@redhat.com> <20191209100717.GC6156@dhcp22.suse.cz> <20191210072453.GI2984@MiWiFi-R3L-srv> <20191210102834.GE10404@dhcp22.suse.cz> <20191210104303.GN2984@MiWiFi-R3L-srv> <20191210113341.GG10404@dhcp22.suse.cz> <20191210125557.GA28917@MiWiFi-R3L-srv> <20191210133202.GJ10404@dhcp22.suse.cz> MIME-Version: 1.0 In-Reply-To: <20191210133202.GJ10404@dhcp22.suse.cz> User-Agent: Mutt/1.10.1 (2018-07-13) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-MC-Unique: BlQbeN4EOXuXUKazet-nYw-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable Content-Disposition: inline X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 12/10/19 at 02:32pm, Michal Hocko wrote: > On Tue 10-12-19 20:55:57, Baoquan He wrote: > [...] > > Btw, as you said at above, I am confused by the '[KNL,BOOT]', what does > > the 'BOOT' mean in the documentation of 'mem=3D'? I checked all paramet= ers > > with 'BOOT', still don't get it clearly. >=20 > This is a good question indeed. I have checked closer and this is what > documentation says > Documentation/admin-guide/kernel-parameters.rst > " > BOOT Is a boot loader parameter. >=20 > Parameters denoted with BOOT are actually interpreted by the boot > loader, and have no meaning to the kernel directly. > " >=20 > and that really doesn't fit, right? So I went to check the full history > git tree just to get to 2.4.0-test5 and no explanation whatsoever. > Fun, isn't it? ;) Yeah, very interesting. Finally I got their original purpose from Documentation/x86/boot.rst. Special Command Line Options =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D If the command line provided by the boot loader is entered by the user, the user may expect the following command line options to work. They should normally not be deleted from the kernel command line even though not all of them are actually meaningful to the kernel. Boot loader authors who need additional command line options for the boot loader itself should get them registered in Documentation/admin-guide/kernel-parameters.rst to make sure they will not conflict with actual kernel options now or in the future. ... So here, [KNL,BOOT], KNL means it's used for kernel, BOOT means it's needed by boot loader. I think we should at least add a note in kernel-parameters.txt to explain this. Will add it. Thanks Baoquan