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| author |  Sourabh Jain <sourabhjain@linux.ibm.com>
| 2024-04-23 01:29:31 +0530 |
|---|---|---|
| committer |  Michael Ellerman <mpe@ellerman.id.au>
| 2024-04-29 23:51:15 +1000 |
| commit | bc446c5acabadeb38b61b565535401c5dfdd1214 (patch) | |
| tree | b6d4fc00fab794e0132237ba35d8ba0f2944cfbe /Documentation/ABI | |
| parent | powerpc: make fadump resilient with memory add/remove events (diff) | |
| download | linux-bc446c5acabadeb38b61b565535401c5dfdd1214.tar.gz linux-bc446c5acabadeb38b61b565535401c5dfdd1214.tar.bz2 linux-bc446c5acabadeb38b61b565535401c5dfdd1214.zip | |
powerpc/fadump: add hotplug_ready sysfs interface
The elfcorehdr describes the CPUs and memory of the crashed kernel to
the kernel that captures the dump, known as the second or fadump kernel.
The elfcorehdr needs to be updated if the system's memory changes due to
memory hotplug or online/offline events.
Currently, memory hotplug events are monitored in userspace by udev
rules, and fadump is re-registered, which recreates the elfcorehdr with
the latest available memory in the system.
However, the previous patch ("powerpc: make fadump resilient with memory
add/remove events") moved the creation of elfcorehdr to the second or
fadump kernel. This eliminates the need to regenerate the elfcorehdr
during memory hotplug or online/offline events.
Create a sysfs entry at /sys/kernel/fadump/hotplug_ready to let
userspace know that fadump re-registration is not required for memory
add/remove events.
Signed-off-by: Sourabh Jain <sourabhjain@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20240422195932.1583833-3-sourabhjain@linux.ibm.com
Diffstat (limited to 'Documentation/ABI')
| -rw-r--r-- | Documentation/ABI/testing/sysfs-kernel-fadump | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-kernel-fadump b/Documentation/ABI/testing/sysfs-kernel-fadump index 8f7a64a81783..c586054657d6 100644 --- a/Documentation/ABI/testing/sysfs-kernel-fadump +++ b/Documentation/ABI/testing/sysfs-kernel-fadump @@ -38,3 +38,14 @@ Contact: linuxppc-dev@lists.ozlabs.org Description: read only Provide information about the amount of memory reserved by FADump to save the crash dump in bytes. + +What: /sys/kernel/fadump/hotplug_ready +Date: Apr 2024 +Contact: linuxppc-dev@lists.ozlabs.org +Description: read only + Kdump udev rule re-registers fadump on memory add/remove events, + primarily to update the elfcorehdr. This sysfs indicates the + kdump udev rule that fadump re-registration is not required on + memory add/remove events because elfcorehdr is now prepared in + the second/fadump kernel. +User: kexec-tools |