From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michael Ellerman Date: Thu, 21 Apr 2022 21:34:22 +1000 Subject: [RFC v4 PATCH 2/5] powerpc/crash hp: introduce a new config option CRASH_HOTPLUG In-Reply-To: <20220411084357.157308-3-sourabhjain@linux.ibm.com> References: <20220411084357.157308-1-sourabhjain@linux.ibm.com> <20220411084357.157308-3-sourabhjain@linux.ibm.com> Message-ID: <874k2mfz5t.fsf@mpe.ellerman.id.au> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: kexec@lists.infradead.org Sourabh Jain 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 > Reviewed-by: Eric DeVolder > --- > 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. cheers