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