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=-2.5 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 C9450C43381 for ; Mon, 25 Feb 2019 01:53:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9276620645 for ; Mon, 25 Feb 2019 01:53:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728319AbfBYBx6 (ORCPT ); Sun, 24 Feb 2019 20:53:58 -0500 Received: from mx1.redhat.com ([209.132.183.28]:55680 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725991AbfBYBx5 (ORCPT ); Sun, 24 Feb 2019 20:53:57 -0500 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 063183001952; Mon, 25 Feb 2019 01:53:57 +0000 (UTC) Received: from dhcp-128-65.nay.redhat.com (ovpn-12-131.pek2.redhat.com [10.72.12.131]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 1880560BE7; Mon, 25 Feb 2019 01:53:49 +0000 (UTC) Date: Mon, 25 Feb 2019 09:53:46 +0800 From: Dave Young To: Pingfan Liu Cc: Borislav Petkov , Joerg Roedel , Baoquan He , Jerry Hoemann , x86@kernel.org, Randy Dunlap , kexec@lists.infradead.org, LKML , Mike Rapoport , Andrew Morton , Yinghai Lu , vgoyal@redhat.com, iommu@lists.linux-foundation.org, konrad.wilk@oracle.com Subject: Re: [PATCHv7] x86/kdump: bugfix, make the behavior of crashkernel=X consistent with kaslr Message-ID: <20190225015346.GC1941@dhcp-128-65.nay.redhat.com> References: <20190211204816.GB21473@dhcp-128-65.nay.redhat.com> <20190215102458.GD10433@zn.tnic> <20190218014820.GA10711@dhcp-128-65.nay.redhat.com> <20190220083241.GA3447@zn.tnic> <20190220094146.GA8597@dhcp-128-65.nay.redhat.com> <20190221171321.GD12997@zn.tnic> <20190222021101.GA11654@dhcp-128-65.nay.redhat.com> <20190222084241.GC8380@suse.de> <20190222130026.GA30766@zn.tnic> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.5 (2018-04-13) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.40]); Mon, 25 Feb 2019 01:53:57 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/24/19 at 09:25pm, Pingfan Liu wrote: > On Fri, Feb 22, 2019 at 9:00 PM Borislav Petkov wrote: > > > > On Fri, Feb 22, 2019 at 09:42:41AM +0100, Joerg Roedel wrote: > > > The current default of 256MB was found by experiments on a bigger > > > number of machines, to create a reasonable default that is at least > > > likely to be sufficient of an average machine. > > > > Exactly, and this is what makes sense. > > > > The code should try the requested reservation and if it fails, it should > > try high allocation with default swiotlb size because we need to reserve > > *some* range. > > > > If that reservation succeeds, we should say something along the lines of > > > > "... requested range failed, reserved range instead." > > > Maybe I misunderstood you, but does "requested range failed" mean that > user specify the range? If yes, then it should be the duty of user as > you said later, not the duty of kernel" If you go with the changes in your current patch it is needed to say something like: "crashkernel: can not find free memory under 4G, reserve XM@.. instead" Also need to print the reserved low memory area in case ,high being used. But for 896M -> 4G, the 896M faulure is not necessary to show in dmesg, it is some in kernel logic. Thanks Dave