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(a)linux.ibm.com&gt; --- fadump-howto.txt | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/fadump-howto.txt b/fadump-howto.txt index c891e37..5360f3d 100644 --- a/fadump-howto.txt +++ b/fadump-howto.txt @@ -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):