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=-9.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 A70F4C41604 for ; Wed, 7 Oct 2020 16:26:29 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 17FDE2064E for ; Wed, 7 Oct 2020 16:26:29 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="K157hmUA" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 17FDE2064E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=imCsOAY76bj25VwSqNI2xhbQtFltE09qekJcaZlxEFU=; b=K157hmUAjEH9lmVnCYHy9F4Xh 8V/bGVeOFGEY4MNYRyZStiChENc60/tN2Fn64LsALHg/hQrw7CMI9BhW7YGz0osk02JU8eeuPWEil rPBpsh/Yr4Q/5Ok1hQQm+upJmtTIgCP85xK+FCtcbFyPGBWBdM7zyIvF6NCz2qUYN4F2Y6/USknRK HI6g26jmiRrcHq+AW/DY77HX8/zCO9AtFR3tc/Icg7v5SRdKuLP8RfE6+toNGCkcfF8TqwGN4620N NLJkVQyPfGQM4gWR9+ZCFz1KD13MrMpPhS3A3AW+lGKhDD71JSZgaPoBuHtwvx21Jlf3s3UqTF9NA pleIrJCSQ==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kQCFW-0006ix-Fh; Wed, 07 Oct 2020 16:25:06 +0000 Received: from mail.kernel.org ([198.145.29.99]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kQCFR-0006hy-9h; Wed, 07 Oct 2020 16:25:03 +0000 Received: from gaia (unknown [95.149.105.49]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 3B21E216C4; Wed, 7 Oct 2020 16:24:56 +0000 (UTC) Date: Wed, 7 Oct 2020 17:24:53 +0100 From: Catalin Marinas To: chenzhou Subject: Re: [PATCH v12 9/9] kdump: update Documentation about crashkernel Message-ID: <20201007162453.GR3462@gaia> References: <20200907134745.25732-1-chenzhou10@huawei.com> <20200907134745.25732-10-chenzhou10@huawei.com> <20201005171936.GD14576@gaia> <8644712d-1331-1efc-1cd2-6da8640145b7@huawei.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <8644712d-1331-1efc-1cd2-6da8640145b7@huawei.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201007_122501_694486_8B710FD6 X-CRM114-Status: GOOD ( 22.08 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: wangkefeng.wang@huawei.com, linux-doc@vger.kernel.org, bhsharma@redhat.com, huawei.libin@huawei.com, guohanjun@huawei.com, will@kernel.org, bhe@redhat.com, corbet@lwn.net, mingo@redhat.com, dyoung@redhat.com, John.P.donnelly@oracle.com, arnd@arndb.de, xiexiuqi@huawei.com, horms@verge.net.au, tglx@linutronix.de, linux-arm-kernel@lists.infradead.org, kexec@lists.infradead.org, linux-kernel@vger.kernel.org, robh+dt@kernel.org, james.morse@arm.com, prabhakar.pkin@gmail.com, nsaenzjulienne@suse.de Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, Oct 06, 2020 at 10:10:54AM +0800, chenzhou wrote: > On 2020/10/6 1:19, Catalin Marinas wrote: > > On Mon, Sep 07, 2020 at 09:47:45PM +0800, Chen Zhou wrote: > >> diff --git a/Documentation/admin-guide/kdump/kdump.rst b/Documentation/admin-guide/kdump/kdump.rst > >> index 2da65fef2a1c..549611abc581 100644 > >> --- a/Documentation/admin-guide/kdump/kdump.rst > >> +++ b/Documentation/admin-guide/kdump/kdump.rst > > [...] > >> @@ -316,8 +325,18 @@ 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. And go for high allocation > >> + directly if the required size is too large. > >> + 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 > >> + in DMA zone. > >> + For non-RPi4 platforms, change DMA zone memtioned above to DMA32 zone. > > I don't think we should mention non-RPi4 explicitly here. I don't even > > understand what the suggestion is since the only way is to disable > > ZONE_DMA in the kernel config. I'd just stick to ZONE_DMA description > > here. > How about like this: > If the kernel config ZONE_DMA is disabled, just try low allocation in DMA32 zone > and high allocation above DMA32 zone. Something like: "allocate 256M low memory in the DMA zone automatically (or the DMA32 zone if CONFIG_ZONE_DMA is disabled)". I'd keep it short. -- Catalin _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel