| Message ID | 20220411084357.157308-3-sourabhjain@linux.ibm.com (mailing list archive) |
|---|---|
| State | RFC |
| Headers | show |
| Series | [RFC,v4,1/5] powerpc/kexec: make update_cpus_node non-static | expand |
On 11/04/2022, 10:43:54, Sourabh Jain wrote: > 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@linux.ibm.com> > Reviewed-by: Eric DeVolder <eric.devolder@oracle.com> Reviewed-by: Laurent Dufour <ldufour@linux.ibm.com> > --- > 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. > + > config PRESERVE_FA_DUMP > bool "Preserve Firmware-assisted dump" > depends on PPC64 && PPC_POWERNV && !FA_DUMP
On 14/04/22 22:10, Laurent Dufour wrote: > On 11/04/2022, 10:43:54, Sourabh Jain wrote: >> 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@linux.ibm.com> >> Reviewed-by: Eric DeVolder <eric.devolder@oracle.com> > Reviewed-by: Laurent Dufour <ldufour@linux.ibm.com> Thanks for the review. - Sourabh Jain > >> --- >> 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. >> + >> config PRESERVE_FA_DUMP >> bool "Preserve Firmware-assisted dump" >> depends on PPC64 && PPC_POWERNV && !FA_DUMP
Sourabh Jain <sourabhjain@linux.ibm.com> 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@linux.ibm.com> > Reviewed-by: Eric DeVolder <eric.devolder@oracle.com> > --- > 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
On 4/21/22 06:34, Michael Ellerman wrote: > Sourabh Jain <sourabhjain@linux.ibm.com> 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@linux.ibm.com> >> Reviewed-by: Eric DeVolder <eric.devolder@oracle.com> >> --- >> 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 >
Eric DeVolder <eric.devolder@oracle.com> writes: > On 4/21/22 06:34, Michael Ellerman wrote: >> Sourabh Jain <sourabhjain@linux.ibm.com> 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@linux.ibm.com> >>> Reviewed-by: Eric DeVolder <eric.devolder@oracle.com> >>> --- >>> 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. If you're having to spell "CONFIG_HOTPLUG_CPU || CONFIG_MEMORY_HOTPLUG" in many places then you can still add CONFIG_CRASH_HOTPLUG to represent the sum of all the dependencies, just don't make it user-selectable. cheers
On 21/04/22 17:04, Michael Ellerman wrote: > Sourabh Jain <sourabhjain@linux.ibm.com> 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@linux.ibm.com> >> Reviewed-by: Eric DeVolder <eric.devolder@oracle.com> >> --- >> 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. Yes, we don't need a new CONFIG option. Thanks for the suggestion. Thanks, Sourabh Jain
On 21/04/22 20:59, Eric DeVolder wrote: > > > On 4/21/22 06:34, Michael Ellerman wrote: >> Sourabh Jain <sourabhjain@linux.ibm.com> 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@linux.ibm.com> >>> Reviewed-by: Eric DeVolder <eric.devolder@oracle.com> >>> --- >>> 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. Yes good idea. Even Michael suggested there is no need for new CONFIG option. I will also remove CRASH_HOTPLUG config in the next version. Thanks, Sourabh Jain
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. + config PRESERVE_FA_DUMP bool "Preserve Firmware-assisted dump" depends on PPC64 && PPC_POWERNV && !FA_DUMP