Messages in this thread | | | Date | Fri, 1 Apr 2022 13:31:54 -0500 | Subject | Re: [PATCH v5 2/8] x86/crash hp: Introduce CRASH_HOTPLUG configuration options | From | Eric DeVolder <> |
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On 3/21/22 06:59, Baoquan He wrote: > On 03/03/22 at 11:27am, Eric DeVolder wrote: >> Support for CPU and memory hotplug for crash is controlled by the >> CRASH_HOTPLUG configuration option, introduced by this patch. >> >> The CRASH_HOTPLUG_ELFCOREHDR_SZ related configuration option is >> also introduced with this patch. > > Maybe can rephrase it as: > > x86/crash: Introduce new options to support cpu and memory hotplug of crash > > CRASH_HOTPLUG is to enable cpu and memory hotplug of crash. > > CRASH_HOTPLUG_ELFCOREHDR_SZ is used to Specify the maximum size of > the elfcorehdr buffer/segment. > > This is a preparation for later usage. > > Otherwise, this looks good to me. Commit message updated. eric
> > >> >> Signed-off-by: Eric DeVolder <eric.devolder@oracle.com> >> --- >> arch/x86/Kconfig | 26 ++++++++++++++++++++++++++ >> 1 file changed, 26 insertions(+) >> >> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig >> index 9f5bd41bf660..37eb26563f07 100644 >> --- a/arch/x86/Kconfig >> +++ b/arch/x86/Kconfig >> @@ -2061,6 +2061,32 @@ config CRASH_DUMP >> (CONFIG_RELOCATABLE=y). >> For more details see Documentation/admin-guide/kdump/kdump.rst >> >> +config CRASH_HOTPLUG >> + bool "kernel updates of crash elfcorehdr" >> + depends on CRASH_DUMP && (HOTPLUG_CPU || MEMORY_HOTPLUG) && KEXEC_FILE >> + help >> + Enable the kernel to update the crash elfcorehdr (which contains >> + the list of CPUs and memory regions) directly when hot plug/unplug >> + of CPUs or memory. Otherwise userspace must monitor these hot >> + plug/unplug change notifications via udev in order to >> + unload-then-reload the crash kernel so that the list of CPUs and >> + memory regions is kept up-to-date. Note that the udev CPU and >> + memory change notifications still occur (however, userspace is not >> + required to monitor for crash dump purposes). >> + >> +config CRASH_HOTPLUG_ELFCOREHDR_SZ >> + depends on CRASH_HOTPLUG >> + int >> + default 131072 >> + help >> + Specify the maximum size of the elfcorehdr buffer/segment. >> + The 128KiB default is sized so that it can accommodate 2048 >> + Elf64_Phdr, where each Phdr represents either a CPU or a >> + region of memory. >> + For example, this size can accommodate a machine with up to 1024 >> + CPUs and up to 1024 memory regions, eg. as represented by the >> + 'System RAM' entries in /proc/iomem. >> + >> config KEXEC_JUMP >> bool "kexec jump" >> depends on KEXEC && HIBERNATION >> -- >> 2.27.0 >> >
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