diff options
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/ABI/testing/sysfs-devices-memory | 8 | ||||
| -rw-r--r-- | Documentation/ABI/testing/sysfs-devices-system-cpu | 8 | ||||
| -rw-r--r-- | Documentation/admin-guide/mm/memory-hotplug.rst | 8 | ||||
| -rw-r--r-- | Documentation/core-api/cpu_hotplug.rst | 18 |
4 files changed, 42 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-devices-memory b/Documentation/ABI/testing/sysfs-devices-memory index d8b0f80b9e33..a95e0f17c35a 100644 --- a/Documentation/ABI/testing/sysfs-devices-memory +++ b/Documentation/ABI/testing/sysfs-devices-memory @@ -110,3 +110,11 @@ Description: link is created for memory section 9 on node0. /sys/devices/system/node/node0/memory9 -> ../../memory/memory9 + +What: /sys/devices/system/memory/crash_hotplug +Date: Aug 2023 +Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org> +Description: + (RO) indicates whether or not the kernel directly supports + modifying the crash elfcorehdr for memory hot un/plug and/or + on/offline changes. diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu index 183a07c4f191..7ecd5c8161a6 100644 --- a/Documentation/ABI/testing/sysfs-devices-system-cpu +++ b/Documentation/ABI/testing/sysfs-devices-system-cpu @@ -688,3 +688,11 @@ Description: (RO) the list of CPUs that are isolated and don't participate in load balancing. These CPUs are set by boot parameter "isolcpus=". + +What: /sys/devices/system/cpu/crash_hotplug +Date: Aug 2023 +Contact: Linux kernel mailing list <linux-kernel@vger.kernel.org> +Description: + (RO) indicates whether or not the kernel directly supports + modifying the crash elfcorehdr for CPU hot un/plug and/or + on/offline changes. diff --git a/Documentation/admin-guide/mm/memory-hotplug.rst b/Documentation/admin-guide/mm/memory-hotplug.rst index 2994958c7ce8..cfe034cf1e87 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. ====================== ========================================================= .. note:: diff --git a/Documentation/core-api/cpu_hotplug.rst b/Documentation/core-api/cpu_hotplug.rst index b9ae591d0b18..9511e405aabd 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 +(i.e. the unload-then-reload to obtain a current list of CPUs), this sysfs +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. + Kernel Inline Documentations Reference ====================================== |