On 4/21/22 06:34, Michael Ellerman wrote:
Sourabh Jain <sourabhjain@xxxxxxxxxxxxx> writes:
The option CRASH_HOTPLUG enables, in kernel update to kexec segments on
hotplug events.
All the updates needed on the capture kernel load path in the kernel for
both kexec_load and kexec_file_load system will be kept under this config.
Signed-off-by: Sourabh Jain <sourabhjain@xxxxxxxxxxxxx>
Reviewed-by: Eric DeVolder <eric.devolder@xxxxxxxxxx>
---
arch/powerpc/Kconfig | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index b779603978e1..777db33f75b5 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -623,6 +623,17 @@ config FA_DUMP
If unsure, say "y". Only special kernels like petitboot may
need to say "N" here.
+config CRASH_HOTPLUG
+ bool "kernel updates of crash kexec segments"
+ depends on CRASH_DUMP && (HOTPLUG_CPU) && KEXEC_FILE
+ help
+ An efficient way to keep the capture kernel up-to-date with CPU
+ hotplug events. On CPU hotplug event the kexec segments of capture
+ kernel becomes stale and need to be updated with latest CPU data.
+ In this method the kernel performs minimal update to only relevant
+ kexec segments on CPU hotplug event, instead of triggering full
+ capture kernel reload from userspace using udev rule.
Why would a user ever want to turn this off?
Seems to me we should just make it always behave this way, and not have
a CONFIG option at all.
Sourabh,
Borislav Petkov also requested I remove the config option, which will be the
case in upcoming v8.
Where I was using CONFIG_CRASH_HOTPLUG, I've replaced it with the
CONFIG_HOTPLUG_CPU || CONFIG_MEMORY_HOTPLUG.
Eric
cheers
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