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Diffstat (limited to '')
| -rw-r--r-- | Documentation/ABI/testing/sysfs-devices-memory | 67 |
1 files changed, 43 insertions, 24 deletions
diff --git a/Documentation/ABI/testing/sysfs-devices-memory b/Documentation/ABI/testing/sysfs-devices-memory index deef3b5723cf..d8b0f80b9e33 100644 --- a/Documentation/ABI/testing/sysfs-devices-memory +++ b/Documentation/ABI/testing/sysfs-devices-memory @@ -13,21 +13,22 @@ 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 - indicates whether this memory block is removable or not. - This is useful for a user-level agent to determine - identify removable sections of the memory before attempting - potentially expensive hot-remove memory operation + 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 + 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 and is designed to show the name of physical - memory device. Implementation is currently incomplete. + 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 @@ -43,20 +44,25 @@ Date: September 2008 Contact: Badari Pulavarty <pbadari@us.ibm.com> Description: The file /sys/devices/system/memory/memoryX/state - is read-write. When read, its contents show the - online/offline state of the memory section. When written, - root can toggle the the online/offline state of a removable - memory section (see removable file description above) - using the following commands. - # echo online > /sys/devices/system/memory/memoryX/state - # echo offline > /sys/devices/system/memory/memoryX/state - - For example, if /sys/devices/system/memory/memory22/removable - contains a value of 1 and - /sys/devices/system/memory/memory22/state contains the - string "online" the following command can be executed by - by root to offline that section. - # echo offline > /sys/devices/system/memory/memory22/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 @@ -66,8 +72,19 @@ Date: July 2014 Contact: Zhang Zhen <zhenzhang.zhang@huawei.com> Description: The file /sys/devices/system/memory/memoryX/valid_zones is - read-only and is designed to show which zone this memory - block can be onlined to. + 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 @@ -78,6 +95,7 @@ Description: For example, the following symbolic link is created for memory section 9 on node0: + /sys/devices/system/memory/memory9/node0 -> ../../node/node0 @@ -90,4 +108,5 @@ Description: 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 |