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=-12.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 8B0C4C4741F for ; Sat, 31 Oct 2020 07:39:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 612DF22226 for ; Sat, 31 Oct 2020 07:39:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726473AbgJaHje (ORCPT ); Sat, 31 Oct 2020 03:39:34 -0400 Received: from szxga04-in.huawei.com ([45.249.212.190]:6684 "EHLO szxga04-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726392AbgJaHjR (ORCPT ); Sat, 31 Oct 2020 03:39:17 -0400 Received: from DGGEMS402-HUB.china.huawei.com (unknown [172.30.72.60]) by szxga04-in.huawei.com (SkyGuard) with ESMTP id 4CNWJz4PxRz15PPG; Sat, 31 Oct 2020 15:39:15 +0800 (CST) Received: from localhost.localdomain.localdomain (10.175.113.25) by DGGEMS402-HUB.china.huawei.com (10.3.19.202) with Microsoft SMTP Server id 14.3.487.0; Sat, 31 Oct 2020 15:39:07 +0800 From: Chen Zhou To: , , , , , , , , , CC: , , , , , , , , , , , , , , John Donnelly Subject: [PATCH v13 8/8] kdump: update Documentation about crashkernel Date: Sat, 31 Oct 2020 15:44:37 +0800 Message-ID: <20201031074437.168008-9-chenzhou10@huawei.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20201031074437.168008-1-chenzhou10@huawei.com> References: <20201031074437.168008-1-chenzhou10@huawei.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7BIT Content-Type: text/plain; charset=US-ASCII X-Originating-IP: [10.175.113.25] X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org For arm64, the behavior of crashkernel=X has been changed, which tries low allocation in DMA zone or DMA32 zone if CONFIG_ZONE_DMA is disabled, 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 (or the DMA32 zone if CONFIG_ZONE_DMA is disabled). "crashkernel=Y,low" can be used to allocate specified size low memory. So update the Documentation. Signed-off-by: Chen Zhou Tested-by: John Donnelly --- Documentation/admin-guide/kdump/kdump.rst | 23 ++++++++++++++++--- .../admin-guide/kernel-parameters.txt | 12 ++++++++-- 2 files changed, 30 insertions(+), 5 deletions(-) diff --git a/Documentation/admin-guide/kdump/kdump.rst b/Documentation/admin-guide/kdump/kdump.rst index 75a9dd98e76e..bde5f994d185 100644 --- a/Documentation/admin-guide/kdump/kdump.rst +++ b/Documentation/admin-guide/kdump/kdump.rst @@ -299,7 +299,16 @@ Boot into System Kernel "crashkernel=64M@16M" tells the system kernel to reserve 64 MB of memory starting at physical address 0x01000000 (16MB) for the dump-capture kernel. - On x86 and x86_64, use "crashkernel=64M@16M". + On x86 use "crashkernel=64M@16M". + + On x86_64, use "crashkernel=X" to select a region under 4G first, and + fall back to reserve region above 4G. And go for high allocation + directly if the required size is too large. + We can also use "crashkernel=X,high" to select a region above 4G, which + also tries to allocate at least 256M below 4G automatically and + "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. On ppc64, use "crashkernel=128M@32M". @@ -316,8 +325,16 @@ 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 (or + DMA32 zone if CONFIG_ZONE_DMA is disabled), 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 (or the DMA32 zone if CONFIG_ZONE_DMA is disabled). + "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). Load the Dump-capture Kernel ============================ diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 526d65d8573a..b2955d9379e8 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -738,6 +738,9 @@ [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 (or DMA32 zone + if CONFIG_ZONE_DMA is disabled), fall back to high allocation + if it fails when '@offset' hasn't been specified. See Documentation/admin-guide/kdump/kdump.rst for further details. crashkernel=range1:size1[,range2:size2,...][@offset] @@ -754,6 +757,8 @@ 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. crashkernel=size[KMG],low [KNL, X86-64] range under 4G. When crashkernel=X,high is passed, kernel could allocate physical memory region @@ -762,13 +767,16 @@ 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 (or the DMA32 zone if CONFIG_ZONE_DMA + is disabled). cryptomgr.notests [KNL] Disable crypto self-tests -- 2.20.1