Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753883AbdHQUPN (ORCPT ); Thu, 17 Aug 2017 16:15:13 -0400 Received: from mx2.suse.de ([195.135.220.15]:44033 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753829AbdHQUPK (ORCPT ); Thu, 17 Aug 2017 16:15:10 -0400 X-Amavis-Alert: BAD HEADER SECTION, Duplicate header field: "References" From: Michal Suchanek To: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Jonathan Corbet , Jessica Yu , Rusty Russell , Jason Baron , Hari Bathini , Mahesh J Salgaonkar , Daniel Axtens , Andrew Morton , Michal Suchanek , Thiago Jung Bauermann , Balbir Singh , Nicholas Piggin , Michael Neuling , "Aneesh Kumar K.V" , Christophe Leroy , Scott Wood , "Oliver O'Halloran" , David Howells , "Sylvain 'ythier' Hitier" , Ingo Molnar , Kees Cook , Thomas Gleixner Cc: "Steven Rostedt," , Viresh Kumar , Tejun Heo , Lokesh Vutla , Baoquan He , Ilya Matveychikov , linuxppc-dev@lists.ozlabs.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v7 2/4] powerpc/fadump: update documentation about 'fadump_extra_args=' parameter Date: Thu, 17 Aug 2017 22:14:29 +0200 Message-Id: X-Mailer: git-send-email 2.10.2 In-Reply-To: <78655b3689f6cd0c76b787b8ef2c824ef75a99a5.1503000577.git.msuchanek@suse.de> References: <78655b3689f6cd0c76b787b8ef2c824ef75a99a5.1503000577.git.msuchanek@suse.de> In-Reply-To: <78655b3689f6cd0c76b787b8ef2c824ef75a99a5.1503000577.git.msuchanek@suse.de> References: <78655b3689f6cd0c76b787b8ef2c824ef75a99a5.1503000577.git.msuchanek@suse.de> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2615 Lines: 51 From: Hari Bathini With the introduction of 'fadump_extra_args=' parameter to pass additional parameters to fadump (capture) kernel, update documentation about it. Signed-off-by: Hari Bathini Signed-off-by: Michal Suchanek --- Documentation/powerpc/firmware-assisted-dump.txt | 20 +++++++++++++++++++- 1 file changed, 19 insertions(+), 1 deletion(-) diff --git a/Documentation/powerpc/firmware-assisted-dump.txt b/Documentation/powerpc/firmware-assisted-dump.txt index bdd344aa18d9..2df88524d2c7 100644 --- a/Documentation/powerpc/firmware-assisted-dump.txt +++ b/Documentation/powerpc/firmware-assisted-dump.txt @@ -162,7 +162,19 @@ How to enable firmware-assisted dump (fadump): 1. Set config option CONFIG_FA_DUMP=y and build kernel. 2. Boot into linux kernel with 'fadump=on' kernel cmdline option. -3. Optionally, user can also set 'crashkernel=' kernel cmdline +3. A user can pass additional command line parameters as a space + separated quoted list through 'fadump_extra_args=' parameter, + to be enforced when fadump is active. For example, parameter + 'fadump_extra_args="nr_cpus=1 numa=off udev.children-max=2"' + will be changed to 'fadump_extra_args nr_cpus=1 numa=off + udev.children-max=2' in-place when fadump is active. This + parameter has no affect when fadump is not active. Multiple + instances of 'fadump_extra_args=' can be passed. This provision + can be used to reduce memory consumption during dump capture by + disabling unwarranted resources/subsystems like CPUs, NUMA + and such. Value with spaces can be passed as + 'fadump_extra_args=""parameter="value with spaces"""' +4. Optionally, user can also set 'crashkernel=' kernel cmdline to specify size of the memory to reserve for boot memory dump preservation. @@ -172,6 +184,12 @@ NOTE: 1. 'fadump_reserve_mem=' parameter has been deprecated. Instead 2. If firmware-assisted dump fails to reserve memory then it will fallback to existing kdump mechanism if 'crashkernel=' option is set at kernel cmdline. + 3. Special parameters like '--' passed inside fadump_extra_args are also + just left in-place. So, the user is advised to consider this while + specifying such parameters. It may be required to quote the argument + to fadump_extra_args when the bootloader uses double-quotes as + argument delimiter as well. eg + append = " fadump_extra_args=\"nr_cpus=1 numa=off udev.children-max=2\"" Sysfs/debugfs files: ------------ -- 2.10.2