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Document/kexec: generalize crash hotplug description

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Commit 79365026f8 ("crash: add a new kexec flag for hotplug support")
generalizes the crash hotplug support to allow architectures to update
multiple kexec segments on CPU/Memory hotplug and not just elfcorehdr. 
Therefore, update the relevant kernel documentation to reflect the same.

No functional change.

Link: https://lkml.kernel.org/r/20240812041651.703156-1-sourabhjain@linux.ibm.com
Signed-off-by: Sourabh Jain <sourabhjain@linux.ibm.com>
Reviewed-by: Petr Tesarik <ptesarik@suse.com>
Acked-by: Baoquan He <bhe@redhat.com>
Cc: Hari Bathini <hbathini@linux.ibm.com>
Cc: Petr Tesarik <petr@tesarici.cz>
Cc: Sourabh Jain <sourabhjain@linux.ibm.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Sourabh Jain
2024-08-12 09:46:51 +05:30
committed by Andrew Morton
parent caaab56609
commit c91c6062d6
5 changed files with 35 additions and 25 deletions
Download Patch File Download Diff File Expand all files Collapse all files
Documentation/core-api/cpu_hotplug.rst
+6 -4
View File
@@ -737,8 +737,9 @@ can process the event further.
When changes to the CPUs in the system occur, the sysfs file
/sys/devices/system/cpu/crash_hotplug contains '1' if the kernel
updates the kdump capture kernel list of CPUs itself (via elfcorehdr),
or '0' if userspace must update the kdump capture kernel list of CPUs.
updates the kdump capture kernel list of CPUs itself (via elfcorehdr and
other relevant kexec segment), or '0' if userspace must update the kdump
capture kernel list of CPUs.
The availability depends on the CONFIG_HOTPLUG_CPU kernel configuration
option.
@@ -750,8 +751,9 @@ file can be used in a udev rule as follows:
SUBSYSTEM=="cpu", ATTRS{crash_hotplug}=="1", GOTO="kdump_reload_end"
For a CPU hot un/plug event, if the architecture supports kernel updates
of the elfcorehdr (which contains the list of CPUs), then the rule skips
the unload-then-reload of the kdump capture kernel.
of the elfcorehdr (which contains the list of CPUs) and other relevant
kexec segments, then the rule skips the unload-then-reload of the kdump
capture kernel.
Kernel Inline Documentations Reference
======================================