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Diffstat (limited to 'Documentation/ABI/testing/sysfs-devices-memory')
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diff --git a/Documentation/ABI/testing/sysfs-devices-memory b/Documentation/ABI/testing/sysfs-devices-memory new file mode 100644 index 000000000..a95e0f17c --- /dev/null +++ b/Documentation/ABI/testing/sysfs-devices-memory @@ -0,0 +1,120 @@ +What: /sys/devices/system/memory +Date: June 2008 +Contact: Badari Pulavarty <pbadari@us.ibm.com> +Description: + The /sys/devices/system/memory contains a snapshot of the + internal state of the kernel memory blocks. Files could be + added or removed dynamically to represent hot-add/remove + operations. +Users: hotplug memory add/remove tools + http://www.ibm.com/developerworks/wikis/display/LinuxP/powerpc-utils + +What: /sys/devices/system/memory/memoryX/removable +Date: June 2008 +Contact: Badari Pulavarty <pbadari@us.ibm.com> +Description: + The file /sys/devices/system/memory/memoryX/removable is a + legacy interface used to indicated whether a memory block is + likely to be offlineable or not. Newer kernel versions return + "1" if and only if the kernel supports memory offlining. +Users: hotplug memory remove tools + http://www.ibm.com/developerworks/wikis/display/LinuxP/powerpc-utils + lsmem/chmem part of util-linux + +What: /sys/devices/system/memory/memoryX/phys_device +Date: September 2008 +Contact: Badari Pulavarty <pbadari@us.ibm.com> +Description: + The file /sys/devices/system/memory/memoryX/phys_device + is read-only; it is a legacy interface only ever used on s390x + to expose the covered storage increment. +Users: Legacy s390-tools lsmem/chmem + +What: /sys/devices/system/memory/memoryX/phys_index +Date: September 2008 +Contact: Badari Pulavarty <pbadari@us.ibm.com> +Description: + The file /sys/devices/system/memory/memoryX/phys_index + is read-only and contains the section ID in hexadecimal + which is equivalent to decimal X contained in the + memory section directory name. + +What: /sys/devices/system/memory/memoryX/state +Date: September 2008 +Contact: Badari Pulavarty <pbadari@us.ibm.com> +Description: + The file /sys/devices/system/memory/memoryX/state + is read-write. When read, it returns the online/offline + state of the memory block. When written, root can toggle + the online/offline state of a memory block using the following + commands:: + + # echo online > /sys/devices/system/memory/memoryX/state + # echo offline > /sys/devices/system/memory/memoryX/state + + On newer kernel versions, advanced states can be specified + when onlining to select a target zone: "online_movable" + selects the movable zone. "online_kernel" selects the + applicable kernel zone (DMA, DMA32, or Normal). However, + after successfully setting one of the advanced states, + reading the file will return "online"; the zone information + can be obtained via "valid_zones" instead. + + While onlining is unlikely to fail, there are no guarantees + that offlining will succeed. Offlining is more likely to + succeed if "valid_zones" indicates "Movable". +Users: hotplug memory remove tools + http://www.ibm.com/developerworks/wikis/display/LinuxP/powerpc-utils + + +What: /sys/devices/system/memory/memoryX/valid_zones +Date: July 2014 +Contact: Zhang Zhen <zhenzhang.zhang@huawei.com> +Description: + The file /sys/devices/system/memory/memoryX/valid_zones is + read-only. + + For online memory blocks, it returns in which zone memory + provided by a memory block is managed. If multiple zones + apply (not applicable for hotplugged memory), "None" is returned + and the memory block cannot be offlined. + + For offline memory blocks, it returns by which zone memory + provided by a memory block can be managed when onlining. + The first returned zone ("default") will be used when setting + the state of an offline memory block to "online". Only one of + the kernel zones (DMA, DMA32, Normal) is applicable for a single + memory block. + +What: /sys/devices/system/memoryX/nodeY +Date: October 2009 +Contact: Linux Memory Management list <linux-mm@kvack.org> +Description: + When CONFIG_NUMA is enabled, a symbolic link that + points to the corresponding NUMA node directory. + + For example, the following symbolic link is created for + memory section 9 on node0: + + /sys/devices/system/memory/memory9/node0 -> ../../node/node0 + + +What: /sys/devices/system/node/nodeX/memoryY +Date: September 2008 +Contact: Gary Hade <garyhade@us.ibm.com> +Description: + When CONFIG_NUMA is enabled + /sys/devices/system/node/nodeX/memoryY is a symbolic link that + points to the corresponding /sys/devices/system/memory/memoryY + memory section directory. For example, the following symbolic + 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. |