sysfs-devices-memory 3.3 KB

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  1. What: /sys/devices/system/memory
  2. Date: June 2008
  3. Contact: Badari Pulavarty <pbadari@us.ibm.com>
  4. Description:
  5. The /sys/devices/system/memory contains a snapshot of the
  6. internal state of the kernel memory blocks. Files could be
  7. added or removed dynamically to represent hot-add/remove
  8. operations.
  9. Users: hotplug memory add/remove tools
  10. http://www.ibm.com/developerworks/wikis/display/LinuxP/powerpc-utils
  11. What: /sys/devices/system/memory/memoryX/removable
  12. Date: June 2008
  13. Contact: Badari Pulavarty <pbadari@us.ibm.com>
  14. Description:
  15. The file /sys/devices/system/memory/memoryX/removable
  16. indicates whether this memory block is removable or not.
  17. This is useful for a user-level agent to determine
  18. identify removable sections of the memory before attempting
  19. potentially expensive hot-remove memory operation
  20. Users: hotplug memory remove tools
  21. http://www.ibm.com/developerworks/wikis/display/LinuxP/powerpc-utils
  22. What: /sys/devices/system/memory/memoryX/phys_device
  23. Date: September 2008
  24. Contact: Badari Pulavarty <pbadari@us.ibm.com>
  25. Description:
  26. The file /sys/devices/system/memory/memoryX/phys_device
  27. is read-only and is designed to show the name of physical
  28. memory device. Implementation is currently incomplete.
  29. What: /sys/devices/system/memory/memoryX/phys_index
  30. Date: September 2008
  31. Contact: Badari Pulavarty <pbadari@us.ibm.com>
  32. Description:
  33. The file /sys/devices/system/memory/memoryX/phys_index
  34. is read-only and contains the section ID in hexadecimal
  35. which is equivalent to decimal X contained in the
  36. memory section directory name.
  37. What: /sys/devices/system/memory/memoryX/state
  38. Date: September 2008
  39. Contact: Badari Pulavarty <pbadari@us.ibm.com>
  40. Description:
  41. The file /sys/devices/system/memory/memoryX/state
  42. is read-write. When read, its contents show the
  43. online/offline state of the memory section. When written,
  44. root can toggle the the online/offline state of a removable
  45. memory section (see removable file description above)
  46. using the following commands.
  47. # echo online > /sys/devices/system/memory/memoryX/state
  48. # echo offline > /sys/devices/system/memory/memoryX/state
  49. For example, if /sys/devices/system/memory/memory22/removable
  50. contains a value of 1 and
  51. /sys/devices/system/memory/memory22/state contains the
  52. string "online" the following command can be executed by
  53. by root to offline that section.
  54. # echo offline > /sys/devices/system/memory/memory22/state
  55. Users: hotplug memory remove tools
  56. http://www.ibm.com/developerworks/wikis/display/LinuxP/powerpc-utils
  57. What: /sys/devices/system/memoryX/nodeY
  58. Date: October 2009
  59. Contact: Linux Memory Management list <linux-mm@kvack.org>
  60. Description:
  61. When CONFIG_NUMA is enabled, a symbolic link that
  62. points to the corresponding NUMA node directory.
  63. For example, the following symbolic link is created for
  64. memory section 9 on node0:
  65. /sys/devices/system/memory/memory9/node0 -> ../../node/node0
  66. What: /sys/devices/system/node/nodeX/memoryY
  67. Date: September 2008
  68. Contact: Gary Hade <garyhade@us.ibm.com>
  69. Description:
  70. When CONFIG_NUMA is enabled
  71. /sys/devices/system/node/nodeX/memoryY is a symbolic link that
  72. points to the corresponding /sys/devices/system/memory/memoryY
  73. memory section directory. For example, the following symbolic
  74. link is created for memory section 9 on node0.
  75. /sys/devices/system/node/node0/memory9 -> ../../memory/memory9