From patchwork Sat Oct 31 07:44:37 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: chenzhou X-Patchwork-Id: 11871141 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,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,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 CF6C8C388F7 for ; Sat, 31 Oct 2020 07:40:51 +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 6BB9D22247 for ; Sat, 31 Oct 2020 07:40:51 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="u1mWj04h" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6BB9D22247 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=huawei.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:MIME-Version:References:In-Reply-To:Message-ID:Date: Subject:To:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=m29z3ozIR6YTzAi6kJcycUqLEf0n+OvtqOEtrVEilXk=; b=u1mWj04hOX21fWuTKwksqiKiI o4SyiBXyRFc1bBwwl9jBgGmFlmtNtomq+GSF0XYQw+WT+fbyjMhK+OO1yu/pSe5yW/YqrsFoPgUoI jbcOze86mzi1vtq/V/FyoMMoUdod4f3PqxCBgtFiZKY9iAsuc+hy2oAhdqIvBx1lCgvJbq/8MnRBx sDnKxxiaxd5MNmuWgJogLAyCXSUmEHi8GPxv11k15qtMIgOUN7f3PD/jWZbn/o+WGfUEs5D0MkxeV Of9y/NG4Bda7CAstbEg19mHQVFAYtEXjaPMQcGOHoAKjNwapekmYrYrUIjTzo0gF/2QhErJnCs/Zs mUnGA1+aA==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kYlUa-0004yi-E5; Sat, 31 Oct 2020 07:40:04 +0000 Received: from szxga04-in.huawei.com ([45.249.212.190]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kYlTs-0004js-9l; Sat, 31 Oct 2020 07:39:24 +0000 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: , , , , , , , , , 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 X-Originating-IP: [10.175.113.25] X-CFilter-Loop: Reflected X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201031_033920_843944_13AD6654 X-CRM114-Status: GOOD ( 13.69 ) 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: John Donnelly , wangkefeng.wang@huawei.com, arnd@arndb.de, linux-doc@vger.kernel.org, chenzhou10@huawei.com, xiexiuqi@huawei.com, kexec@lists.infradead.org, linux-kernel@vger.kernel.org, robh+dt@kernel.org, horms@verge.net.au, james.morse@arm.com, linux-arm-kernel@lists.infradead.org, huawei.libin@huawei.com, guohanjun@huawei.com, nsaenzjulienne@suse.de Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.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