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 <hbath...@linux.vnet.ibm.com>
---
Changes from v5:
* Changed subject line to have 'fadump_extra_args='
Documentation/powerpc/firmware-assisted-dump.txt | 16 +++++++++++++++-
1 file changed, 15 insertions(+), 1 deletion(-)
diff --git a/Documentation/powerpc/firmware-assisted-dump.txt
b/Documentation/powerpc/firmware-assisted-dump.txt
index bdd344a..f2dd058 100644
--- a/Documentation/powerpc/firmware-assisted-dump.txt
+++ b/Documentation/powerpc/firmware-assisted-dump.txt
@@ -162,7 +162,18 @@ 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.
+4. Optionally, user can also set 'crashkernel=' kernel cmdline
to specify size of the memory to reserve for boot memory dump
preservation.
@@ -172,6 +183,9 @@ 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 '--' are also just replaced in-place.
+ So, the user is advised to consider this while specifying
+ such parameters.
Sysfs/debugfs files:
------------
