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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 71EADC433F5 for ; Mon, 21 Feb 2022 03:49:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245333AbiBUDt1 (ORCPT ); Sun, 20 Feb 2022 22:49:27 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:60506 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240546AbiBUDt0 (ORCPT ); Sun, 20 Feb 2022 22:49:26 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 5BB651C13F for ; Sun, 20 Feb 2022 19:49:04 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1645415343; 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: in-reply-to:in-reply-to:references:references; bh=Hb0dx0H8touNMHxGlfdIWo0CdWNEhRBt6iaUhiuotgs=; b=J9FUb60W9nybdBb+XuqVf8tia5a3Eq5UC8TClfE8oxkCnXSg8Lhw2Ku2ZsvD3i3BMi4Pga jofbcxXIuzpN9ZMxy5ANjX769WDCtM0rgpXjmyhZGZVBnb5Ibb5YmrQZ1fORf4RcGIVta8 eR4nWuUBf0tsi+AMal9g02f5Zhcl7w4= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-389-ulf2aE0VPKO2tiC1rn67Tw-1; Sun, 20 Feb 2022 22:49:00 -0500 X-MC-Unique: ulf2aE0VPKO2tiC1rn67Tw-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 4F221814243; Mon, 21 Feb 2022 03:48:56 +0000 (UTC) Received: from localhost (ovpn-12-166.pek2.redhat.com [10.72.12.166]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 09DF0E71E; Mon, 21 Feb 2022 03:48:51 +0000 (UTC) Date: Mon, 21 Feb 2022 11:48:49 +0800 From: Baoquan He To: Zhen Lei Cc: Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org, "H . Peter Anvin" , linux-kernel@vger.kernel.org, Dave Young , Vivek Goyal , Eric Biederman , kexec@lists.infradead.org, Catalin Marinas , Will Deacon , linux-arm-kernel@lists.infradead.org, Rob Herring , Frank Rowand , devicetree@vger.kernel.org, Jonathan Corbet , linux-doc@vger.kernel.org, Randy Dunlap , Feng Zhou , Kefeng Wang , Chen Zhou , John Donnelly , Dave Kleikamp Subject: Re: [PATCH v20 5/5] kdump: update Documentation about crashkernel Message-ID: References: <20220124084708.683-1-thunder.leizhen@huawei.com> <20220124084708.683-6-thunder.leizhen@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220124084708.683-6-thunder.leizhen@huawei.com> X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On 01/24/22 at 04:47pm, Zhen Lei wrote: > From: Chen Zhou > > For arm64, the behavior of crashkernel=X has been changed, which > tries low allocation in DMA zone and fall back to high allocation > if it fails. > > We can also use "crashkernel=X,high" to select a high region above > DMA zone, which also tries to allocate at least 256M low memory in > DMA zone automatically and "crashkernel=Y,low" can be used to allocate > specified size low memory. > > So update the Documentation. > > Signed-off-by: Chen Zhou > Signed-off-by: Zhen Lei > --- > Documentation/admin-guide/kdump/kdump.rst | 11 +++++++++-- > Documentation/admin-guide/kernel-parameters.txt | 11 +++++++++-- > 2 files changed, 18 insertions(+), 4 deletions(-) > > diff --git a/Documentation/admin-guide/kdump/kdump.rst b/Documentation/admin-guide/kdump/kdump.rst > index cb30ca3df27c9b2..d4c287044be0c70 100644 > --- a/Documentation/admin-guide/kdump/kdump.rst > +++ b/Documentation/admin-guide/kdump/kdump.rst > @@ -361,8 +361,15 @@ Boot into System Kernel > kernel will automatically locate the crash kernel image within the > first 512MB of RAM if X is not given. > > - On arm64, use "crashkernel=Y[@X]". Note that the start address of > - the kernel, X if explicitly specified, must be aligned to 2MiB (0x200000). > + On arm64, use "crashkernel=X" to try low allocation in DMA zone and > + fall back to high allocation if it fails. > + We can also use "crashkernel=X,high" to select a high region above > + DMA zone, which also tries to allocate at least 256M low memory in > + DMA zone automatically. > + "crashkernel=Y,low" can be used to allocate specified size low memory. > + Use "crashkernel=Y@X" if you really have to reserve memory from > + specified start address X. Note that the start address of the kernel, > + X if explicitly specified, must be aligned to 2MiB (0x200000). Hmm, we may not need the details related to crashkernel,high|low in this section. This just gives examples of basic configation for each ARCH. The detailed configuration of all crashkernel setting can be found in "crashkernel syntax" section, I don't think arm64 is so special to need a specific one. > > Load the Dump-capture Kernel > ============================ > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > index f5a27f067db9ed9..65780c2ca830be0 100644 > --- a/Documentation/admin-guide/kernel-parameters.txt > +++ b/Documentation/admin-guide/kernel-parameters.txt > @@ -792,6 +792,9 @@ > [KNL, X86-64] Select a region under 4G first, and > fall back to reserve region above 4G when '@offset' > hasn't been specified. > + [KNL, ARM64] Try low allocation in DMA zone and fall back > + to high allocation if it fails when '@offset' hasn't been > + specified. > See Documentation/admin-guide/kdump/kdump.rst for further details. How about add ARM64 like below to avoid redundant words? [KNL, X86-64, ARM64] Select a region under 4G first, and fall back to reserve region above 4G when '@offset' hasn't been specified. > > crashkernel=range1:size1[,range2:size2,...][@offset] > @@ -808,6 +811,8 @@ > Otherwise memory region will be allocated below 4G, if > available. > It will be ignored if crashkernel=X is specified. > + [KNL, ARM64] range in high memory. > + Allow kernel to allocate physical memory region from top. Ditto, please don't add redundent words if it's similar to x86_64 handling. > crashkernel=size[KMG],low > [KNL, X86-64] range under 4G. When crashkernel=X,high > is passed, kernel could allocate physical memory region > @@ -816,13 +821,15 @@ > requires at least 64M+32K low memory, also enough extra > low memory is needed to make sure DMA buffers for 32-bit > devices won't run out. Kernel would try to allocate at > - at least 256M below 4G automatically. > + least 256M below 4G automatically. > This one let user to specify own low range under 4G > for second kernel instead. > 0: to disable low allocation. > It will be ignored when crashkernel=X,high is not used > or memory reserved is below 4G. > - > + [KNL, ARM64] range in low memory. > + This one let user to specify a low range in DMA zone for > + crash dump kernel. Ditto. > cryptomgr.notests > [KNL] Disable crypto self-tests > > -- > 2.25.1 >