Re: [PATCH] Stop reloading kdump service on CPU hotplug event for FADump

[Baoquan He]

On 02/21/21 at 05:23pm, Sourabh Jain wrote:
>  As FADump does not require an explicit elfcorehdr update whenever
> there is CPU
>  hotplug event so let's stop kdump service reload for FADump when CPU hotplug
>  event is triggered.
>  
>  A new label is added to handle CPU and memory hotplug events separately. The
>  updated CPU hotplug event handler make sure that kdump service should not be
>  reloaded when FADump is configured.
>  
>  Signed-off-by: Sourabh Jain <sourabhjain(a)linux.ibm.com&gt;
>  ---
>   98-kexec.rules.ppc64 | 17 ++++++++++++-----
>   1 file changed, 12 insertions(+), 5 deletions(-)
>  
>  diff --git a/98-kexec.rules.ppc64 b/98-kexec.rules.ppc64
>  index 1a91220..a1c00a9 100644
>  --- a/98-kexec.rules.ppc64
>  +++ b/98-kexec.rules.ppc64
>  @@ -1,15 +1,22 @@
>  -SUBSYSTEM=="cpu", ACTION=="online", GOTO="kdump_reload"
>  -SUBSYSTEM=="memory", ACTION=="online",
> GOTO="kdump_reload"
>  -SUBSYSTEM=="memory", ACTION=="offline",
> GOTO="kdump_reload"
>  +SUBSYSTEM=="cpu", ACTION=="online",
> GOTO="kdump_reload_cpu"
>  +SUBSYSTEM=="memory", ACTION=="online",
> GOTO="kdump_reload_mem"
>  +SUBSYSTEM=="memory", ACTION=="offline",
> GOTO="kdump_reload_mem"
>   
>   GOTO="kdump_reload_end"
>   
>  -LABEL="kdump_reload"
>  -
>   # If kdump is not loaded, calling kdump-udev-throttle will end up
>   # doing nothing, but systemd-run will always generate extra logs for
>   # each call, so trigger the kdump-udev-throttler only if kdump
>   # service is active to avoid unnecessary logs
>  +
>  +LABEL="kdump_reload_mem"
>  +
>   RUN+="/bin/sh -c '/usr/bin/systemctl is-active kdump.service || exit 0;
> /usr/bin/systemd-run --quiet --no-block /usr/lib/udev/kdump-udev-throttler'"
>   
>  +GOTO="kdump_reload_end"
>  +
>  +LABEL="kdump_reload_cpu"
>  +
>  +RUN+="/bin/sh -c '/usr/bin/systemctl is-active kdump.service || exit 0; ! test
> -f /sys/kernel/fadump_enabled || cat /sys/kernel/fadump_enabled | grep 0  || exit 0;
> /usr/bin/systemd-run --quiet --no-block /usr/lib/udev/kdump-udev-throttler'"
>  +
>   LABEL="kdump_reload_end" 
This looks good to me. It splits the cpu/mem hotplug and checks FADump
separately for special handling, seems no harm.

Acked-by: Baoquan He <bhe(a)redhat.com&gt;

Thanks
Baoquan