From 695e5b8676ecbdf999ed535eae4074db8c3ef7aa Mon Sep 17 00:00:00 2001 From: Coiby Xu Date: Tue, 1 Mar 2022 17:30:30 +0800 Subject: [PATCH] update fadump-howto 1. yum is deprecated so use dnf instead 2. use the "kdumpctl reset-crashkernel --fadump=on" API Reviewed-by: Philipp Rudo Signed-off-by: Coiby Xu --- fadump-howto.txt | 24 ++++++++++++++---------- 1 file changed, 14 insertions(+), 10 deletions(-) diff --git a/fadump-howto.txt b/fadump-howto.txt index bc87644..9773f78 100644 --- a/fadump-howto.txt +++ b/fadump-howto.txt @@ -39,7 +39,7 @@ kernel are one and the same on ppc64. If you're reading this document, you should already have kexec-tools installed. If not, you install it via the following command: - # yum install kexec-tools + # dnf install kexec-tools Fadump Operational Flow: @@ -82,7 +82,7 @@ How to configure fadump: Again, we assume if you're reading this document, you should already have kexec-tools installed. If not, you install it via the following command: - # yum install kexec-tools + # dnf install kexec-tools Make the kernel to be configured with FADump as the default boot entry, if it isn't already: @@ -94,20 +94,24 @@ anything interesting in the way of debug analysis, you'll also need to install the kernel-debuginfo package, of the same arch as your running kernel, and the crash utility: - # yum --enablerepo=\*debuginfo install kernel-debuginfo.$(uname -m) crash + # dnf --enablerepo=\*debuginfo install kernel-debuginfo.$(uname -m) crash -Next up, we need to modify some boot parameters to enable firmware assisted -dump. With the help of grubby, it's very easy to append "fadump=on" to the end -of your kernel boot parameters. To reserve the appropriate amount of memory -for boot memory preservation, pass 'crashkernel=X' kernel cmdline parameter. -For the recommended value of X, see 'FADump Memory Requirements' section. +Next up, we can enable firmware assisted dump and reserve the memory for boot +memory preservation as specified in in the table of 'FADump Memory Requirements' +section: + + # kdumpctl reset-crashkernel --fadump=on + +Alternatively, you can use grubby to reserve custom amount of memory: # 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'. +linux kernel with 'fadump=nocma' instead of 'fadump=on': + + # kdumpctl reset-crashkernel --fadump=nocma 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, @@ -350,6 +354,6 @@ Remove "crashkernel=" from kernel cmdline parameters: If KDump is to be used as the dump capturing mechanism, reset the crashkernel parameter: - # kdumpctl reset-crashkernel `uname -r` + # kdumpctl reset-crashkernel --fadump=off Reboot the system for the settings to take effect.