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fadump: pass additional parameters for capture kernel

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Resolves: https://issues.redhat.com/browse/RHEL-52925
Upstream: kdump-utils
Confilict: apply the changes in kdump.sysconfig.ppc64le by manual

commit 77b80ce5e369c7b5cf8321e4cdc20c139910f92c
Author: Hari Bathini <hbathini@linux.ibm.com>
Date:   Sat Oct 19 00:28:34 2024 +0530

    fadump: pass additional parameters for capture kernel

    Since kernel commit 3416c9daa6b13 ("powerpc/fadump: pass additional
    parameters when fadump is active"), fadump supports passing additional
    parameters to dump capture kernel. Leverage that support here to pass
    additional parameters to dump capture kernel.

    Also, update fadump-howto.txt to make clear on the options that are
    not relevant for fadump in /etc/sysconfig/kdump

    The default bootargs to append for fadump capture kernel boot are
    chosen with the intent to optimize resources and reduce memory
    footprint in dump capture environment.

    Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>

Signed-off-by: Pingfan Liu <piliu@redhat.com>
This commit is contained in:
Pingfan Liu 2024-12-09 21:40:28 +08:00
parent 869a920881
commit 340188939b
4 changed files with 36 additions and 6 deletions
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28
fadump-howto.txt
View File

@ -319,7 +319,27 @@ Advanced Setups & Failure action:
Kdump and fadump exhibit similar behavior in terms of setup & failure action.
For fadump advanced setup related information see section "Advanced Setups" in
"kexec-kdump-howto.txt" document. Refer to "Failure action" section in "kexec-
kdump-howto.txt" document for fadump failure action related information.
kdump-howto.txt" document for fadump failure action related information. Note
that the below options from /etc/sysconfig/kdump have no relevance to fadump
owing to the way it operates:
-KDUMP_BOOTDIR
-KDUMP_IMG
-KDUMP_IMG_EXT
-KEXEC_ARGS
-KDUMP_KERNELVER
-KDUMP_COMMANDLINE
-KDUMP_COMMANDLINE_REMOVE
-KDUMP_COMMANDLINE_APPEND
Passing additional parameters to fadump capture kerenl
-FADUMP_COMMANDLINE_APPEND
If a powerpc system supports passing additional parameters, it would have the
sysfs node '/sys/kernel/fadump/bootargs_append'. FADUMP_COMMANDLINE_APPEND
allows us to append arguments to fadump capture kernel, further to parameters
passed via the bootloader.
Compression and filtering
@ -331,11 +351,7 @@ Notes on rootfs mount:
Dracut is designed to mount rootfs by default. If rootfs mounting fails it
will refuse to go on. So fadump leaves rootfs mounting to dracut currently.
We make the assumtion that proper root= cmdline is being passed to dracut
initramfs for the time being. If you need modify "KDUMP_COMMANDLINE=" in
/etc/sysconfig/kdump, you will need to make sure that appropriate root=
options are copied from /proc/cmdline. In general it is best to append
command line options using "KDUMP_COMMANDLINE_APPEND=" instead of replacing
the original command line completely.
initramfs for the time being.
How to disable FADump:

1
kdump-lib.sh
View File

@ -7,6 +7,7 @@
FADUMP_ENABLED_SYS_NODE="/sys/kernel/fadump/enabled"
FADUMP_REGISTER_SYS_NODE="/sys/kernel/fadump/registered"
FADUMP_APPEND_ARGS_SYS_NODE="/sys/kernel/fadump/bootargs_append"
is_uki()
{

4
kdump.sysconfig.ppc64le
View File

@ -23,6 +23,10 @@ KDUMP_COMMANDLINE_REMOVE="hugepages hugepagesz slub_debug quiet log_buf_len swio
# after processed by KDUMP_COMMANDLINE_REMOVE
KDUMP_COMMANDLINE_APPEND="irqpoll nr_cpus=1 noirqdistrib reset_devices cgroup_disable=memory numa=off udev.children-max=2 ehea.use_mcs=0 panic=10 kvm_cma_resv_ratio=0 transparent_hugepage=never novmcoredd hugetlb_cma=0"
# This variable lets us append arguments to fadump (powerpc) capture kernel,
# further to the parameters passed via the bootloader.
FADUMP_COMMANDLINE_APPEND="nr_cpus=16 numa=off cgroup_disable=memory cma=0 kvm_cma_resv_ratio=0 hugetlb_cma=0 transparent_hugepage=never novmcoredd udev.children-max=2"
# Any additional kexec arguments required. In most situations, this should
# be left empty
#

9
kdumpctl
View File

@ -1130,6 +1130,15 @@ stop_kdump()
reload_fadump()
{
if "$FADUMP_APPEND_ARGS_SYS_NODE"; then
output=$(echo "${FADUMP_COMMANDLINE_APPEND}" > "$FADUMP_APPEND_ARGS_SYS_NODE")
if [ $? -eq 0 ]; then
output=$(cat "$FADUMP_APPEND_ARGS_SYS_NODE")
dinfo "fadump: additional parameters '$output' for capture kernel"
else
dwarn "WARNING: failed to setup additional parameters for fadump capture kernel ($output)"
fi
fi
if echo 1 > "$FADUMP_REGISTER_SYS_NODE"; then
dinfo "fadump: re-registered successfully"
return 0