From: Michal Suchanek <msuchanek@suse.de>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Michael Ellerman <mpe@ellerman.id.au>,
Jonathan Corbet <corbet@lwn.net>, Jessica Yu <jeyu@kernel.org>,
Rusty Russell <rusty@rustcorp.com.au>,
Jason Baron <jbaron@akamai.com>,
Hari Bathini <hbathini@linux.vnet.ibm.com>,
Mahesh J Salgaonkar <mahesh@linux.vnet.ibm.com>,
Daniel Axtens <dja@axtens.net>,
Andrew Morton <akpm@linux-foundation.org>,
Michal Suchanek <msuchanek@suse.de>,
Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com>,
Balbir Singh <bsingharora@gmail.com>,
Nicholas Piggin <npiggin@gmail.com>,
Michael Neuling <mikey@neuling.org>,
"Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>,
Christophe Leroy <christophe.leroy@c-s.fr>,
Scott Wood <oss@buserror.net>,
"Oliver O'Halloran" <oohall@gmail.com>,
David Howells <dhowells@redhat.com>,
"Sylvain 'ythier' Hitier" <sylvain.hitier@gmail.com>,
Ingo Molnar <mingo@kernel.org>, Kees Cook <keescook@chromium.org>,
Thomas Gleixner <tglx@linutronix.de>
Cc: "Steven Rostedt," <rostedt@goodmis.org>,
Viresh Kumar <viresh.kumar@linaro.org>, Tejun Heo <tj@kernel.org>,
Lokesh Vutla <lokeshvutla@ti.com>, Baoquan He <bhe@redhat.com>,
Ilya Matveychikov <matvejchikov@gmail.com>,
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 [thread overview]
Message-ID: <c4158a55f2db61bd4cee158edb03526800fd491b.1503000577.git.msuchanek@suse.de> (raw)
In-Reply-To: <78655b3689f6cd0c76b787b8ef2c824ef75a99a5.1503000577.git.msuchanek@suse.de>
In-Reply-To: <78655b3689f6cd0c76b787b8ef2c824ef75a99a5.1503000577.git.msuchanek@suse.de>
From: Hari Bathini <hbathini@linux.vnet.ibm.com>
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 <hbathini@linux.vnet.ibm.com>
Signed-off-by: Michal Suchanek <msuchanek@suse.de>
---
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
next prev parent reply other threads:[~2017-08-17 20:15 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-17 20:14 [PATCH v7 1/4] powerpc/fadump: reduce memory consumption for capture kernel Michal Suchanek
2017-08-17 20:14 ` Michal Suchanek [this message]
2017-08-17 20:14 ` [PATCH v7 3/4] lib/cmdline.c Remove quotes symmetrically Michal Suchanek
2017-08-17 21:27 ` msuchanek
2017-08-21 10:27 ` Baoquan He
2017-08-21 11:30 ` Michal Suchánek
2017-08-24 11:02 ` Michael Ellerman
2017-08-24 12:15 ` msuchanek
2017-08-17 20:14 ` [PATCH v7 4/4] boot/param: add pointer to next argument to unknown parameter callback Michal Suchanek
2017-08-24 11:04 ` Michael Ellerman
2017-08-24 12:17 ` msuchanek
2017-08-18 10:50 ` [PATCH v7 1/4] powerpc/fadump: reduce memory consumption for capture kernel Hari Bathini
2017-08-18 11:57 ` Michal Suchánek
2017-08-18 14:00 ` Hari Bathini
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