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

[Hari Bathini]

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):

[piliu]

On 11/25/2020 01:55 PM, Hari Bathini wrote:
>  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):
>  
>   
Acked-by: Pingfan Liu <piliu(a)redhat.com&gt;