Messages in this thread | | | Date | Thu, 29 Jun 2023 17:31:33 -0500 | Subject | Re: [PATCH v25 06/10] crash: memory and CPU hotplug sysfs attributes | From | Eric DeVolder <> |
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Randy, Thanks for looking at this! Inline comments below. eric
On 6/29/23 15:59, Randy Dunlap wrote: > Hi-- > > On 6/29/23 12:21, Eric DeVolder wrote: >> >> Signed-off-by: Eric DeVolder <eric.devolder@oracle.com> >> Reviewed-by: Sourabh Jain <sourabhjain@linux.ibm.com> >> Acked-by: Hari Bathini <hbathini@linux.ibm.com> >> Acked-by: Baoquan He <bhe@redhat.com> >> --- >> Documentation/ABI/testing/sysfs-devices-memory | 8 ++++++++ >> .../ABI/testing/sysfs-devices-system-cpu | 8 ++++++++ >> .../admin-guide/mm/memory-hotplug.rst | 8 ++++++++ >> Documentation/core-api/cpu_hotplug.rst | 18 ++++++++++++++++++ >> drivers/base/cpu.c | 16 ++++++++++++++-- >> drivers/base/memory.c | 13 +++++++++++++ >> include/linux/kexec.h | 8 ++++++++ >> 7 files changed, 77 insertions(+), 2 deletions(-) >> > >> diff --git a/Documentation/admin-guide/mm/memory-hotplug.rst b/Documentation/admin-guide/mm/memory-hotplug.rst >> index 1b02fe5807cc..eb99d79223a3 100644 >> --- a/Documentation/admin-guide/mm/memory-hotplug.rst >> +++ b/Documentation/admin-guide/mm/memory-hotplug.rst >> @@ -291,6 +291,14 @@ The following files are currently defined: >> Availability depends on the CONFIG_ARCH_MEMORY_PROBE >> kernel configuration option. >> ``uevent`` read-write: generic udev file for device subsystems. >> +``crash_hotplug`` read-only: when changes to the system memory map >> + occur due to hot un/plug of memory, this file contains >> + '1' if the kernel updates the kdump capture kernel memory >> + map itself (via elfcorehdr), or '0' if userspace must update >> + the kdump capture kernel memory map. >> + >> + Availability depends on the CONFIG_MEMORY_HOTPLUG kernel >> + configuration option. >> ====================== ========================================================= > > Did you test build the documentation? > It looks to me like the end-of-table '=' signs line needs 3 more === to be long > enough for the text above it.
Hmm, the 'make htmldocs' renders and views ok. Is there perhaps another method I should use?
> >> >> .. note:: >> diff --git a/Documentation/core-api/cpu_hotplug.rst b/Documentation/core-api/cpu_hotplug.rst >> index e6f5bc39cf5c..54581c501562 100644 >> --- a/Documentation/core-api/cpu_hotplug.rst >> +++ b/Documentation/core-api/cpu_hotplug.rst >> @@ -741,6 +741,24 @@ will receive all events. A script like:: >> >> 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. >> + >> +The availability depends on the CONFIG_HOTPLUG_CPU kernel configuration >> +option. >> + >> +To skip userspace processing of CPU hot un/plug events for kdump >> +(ie the unload-then-reload to obtain a current list of CPUs), this sysfs > > i.e. > got it, thanks.
>> +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 > > CPU > for consistency > got it, thanks.
>> +of the elfcorehdr (which contains the list of CPUs), then the rule skips >> +the unload-then-reload of the kdump capture kernel. >> + >> Kernel Inline Documentations Reference >> ====================================== >> > > Thanks.
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