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 AA9DBC77B6F for ; Tue, 11 Apr 2023 07:36:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229962AbjDKHgJ (ORCPT ); Tue, 11 Apr 2023 03:36:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55248 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229957AbjDKHgH (ORCPT ); Tue, 11 Apr 2023 03:36:07 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EC4291734; Tue, 11 Apr 2023 00:36:01 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 8810960AAE; Tue, 11 Apr 2023 07:36:01 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1DE4DC433EF; Tue, 11 Apr 2023 07:35:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1681198561; bh=9ighdUcP/UTYLMiyXaga2dDu7U1Ozp7TXI7PHr3dDYU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=pc3B3hgSIKCjI2c/0a4HjZdd2ehgt6z2AB/2lkt3ZD6vimWx/pG5aGfdOrQOKPqBx gjPeI3PzxplsapH8uFKl4f+UNMeQlirH6NJ6KQEL4JYpMdrlAhgc1e/+qQSLPnJ6Jt Z1r3Ty3+mnw9Oj7MUoOrTlHiUY2ndF8deB2I3KnvL3FWE7fXSuDRq+RSoWwlPp3c6D qv/asV3Ccah13L3j+wQu/EayolE5EbXi4uitIEu42TucY1rgfDOee6evA4HatXTpwF 6dJhup7XFRTiwuy8FxHXbRACloOKnZ5kfXVq4yfp6LSnzMlnfs/3XmYg/cP3gsVGh1 8lMMn383lj2Lw== Date: Tue, 11 Apr 2023 09:35:55 +0200 From: Simon Horman To: Chen Jiahao Cc: linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, kexec@lists.infradead.org, linux-doc@vger.kernel.org, paul.walmsley@sifive.com, palmer@dabbelt.com, conor.dooley@microchip.com, guoren@kernel.org, heiko@sntech.de, bjorn@rivosinc.com, alex@ghiti.fr, akpm@linux-foundation.org, atishp@rivosinc.com, bhe@redhat.com, thunder.leizhen@huawei.com Subject: Re: [PATCH -next v4 1/2] riscv: kdump: Implement crashkernel=X,[high,low] Message-ID: References: <20230410130553.3226347-1-chenjiahao16@huawei.com> <20230410130553.3226347-2-chenjiahao16@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230410130553.3226347-2-chenjiahao16@huawei.com> Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org On Mon, Apr 10, 2023 at 09:05:52PM +0800, Chen Jiahao wrote: > On riscv, the current crash kernel allocation logic is trying to > allocate within 32bit addressible memory region by default, if > failed, try to allocate without 4G restriction. > > In need of saving DMA zone memory while allocating a relatively large > crash kernel region, allocating the reserved memory top down in > high memory, without overlapping the DMA zone, is a mature solution. > Here introduce the parameter option crashkernel=X,[high,low]. > > One can reserve the crash kernel from high memory above DMA zone range > by explicitly passing "crashkernel=X,high"; or reserve a memory range > below 4G with "crashkernel=X,low". > > Signed-off-by: Chen Jiahao > Acked-by: Guo Ren > Reviewed-by: Zhen Lei Reviewed-by: Simon Horman