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@xxxxxxxxxx>
---
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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