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fadump-howto: update about 'nocma' and 'off' options for 'fadump=' parameter

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Along with 'on' option, 'fadump=' kernel parameter also supports
'nocma' & 'off' options. Update about these missing options in the
fadump-howto.txt document.

Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>
Acked-by: Pingfan Liu <piliu@redhat.com>
This commit is contained in:
Hari Bathini 2020-11-25 11:25:18 +05:30 committed by Kairui Song
parent 6f9235887f
commit 7a77d5a267
1 changed files with 11 additions and 1 deletions
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fadump-howto.txt
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@ -104,6 +104,11 @@ For the recommended value of X, see 'FADump Memory Requirements' section.
# grubby --args="fadump=on crashkernel=6G" --update-kernel=/boot/vmlinuz-`uname -r`
By default, FADump reserved memory will be initialized as CMA area to make the
memory available through CMA allocator on the production kernel. We can opt out
of this, making reserved memory unavailable to production kernel, by booting the
linux kernel with 'fadump=nocma' instead of 'fadump=on'.
The term 'boot memory' means size of the low memory chunk that is required for
a kernel to boot successfully when booted with restricted memory. By default,
the boot memory size will be the larger of 5% of system RAM or 256MB.
@ -326,9 +331,14 @@ the original command line completely.
How to disable FADump:
Remove "fadump=on" from kernel cmdline parameters:
Remove "fadump=on"/"fadump=nocma" from kernel cmdline parameters OR replace
it with "fadump=off" kernel cmdline parameter:
# grubby --update-kernel=/boot/vmlinuz-`uname -r` --remove-args="fadump=on"
or
# grubby --update-kernel=/boot/vmlinuz-`uname -r` --remove-args="fadump=nocma"
OR
# grubby --update-kernel=/boot/vmlinuz-`uname -r` --args="fadump=off"
If KDump is to be used as the dump capturing mechanism, update the crashkernel
parameter (Else, remove "crashkernel=" parameter too, using grubby):