aba7d989208c07cb8f3e8efe14fd9fc334ecafb4
[linux-2.6.git] / Documentation / ABI / testing / sysfs-devices-memory
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                 https://w3.opensource.ibm.com/projects/powerpc-utils/
11
12 What:           /sys/devices/system/memory/memoryX/removable
13 Date:           June 2008
14 Contact:        Badari Pulavarty <pbadari@us.ibm.com>
15 Description:
16                 The file /sys/devices/system/memory/memoryX/removable
17                 indicates whether this memory block is removable or not.
18                 This is useful for a user-level agent to determine
19                 identify removable sections of the memory before attempting
20                 potentially expensive hot-remove memory operation
21 Users:          hotplug memory remove tools
22                 https://w3.opensource.ibm.com/projects/powerpc-utils/
23
24 What:           /sys/devices/system/memory/memoryX/phys_device
25 Date:           September 2008
26 Contact:        Badari Pulavarty <pbadari@us.ibm.com>
27 Description:
28                 The file /sys/devices/system/memory/memoryX/phys_device
29                 is read-only and is designed to show the name of physical
30                 memory device.  Implementation is currently incomplete.
31
32 What:           /sys/devices/system/memory/memoryX/phys_index
33 Date:           September 2008
34 Contact:        Badari Pulavarty <pbadari@us.ibm.com>
35 Description:
36                 The file /sys/devices/system/memory/memoryX/phys_index
37                 is read-only and contains the section ID in hexadecimal
38                 which is equivalent to decimal X contained in the
39                 memory section directory name.
40
41 What:           /sys/devices/system/memory/memoryX/state
42 Date:           September 2008
43 Contact:        Badari Pulavarty <pbadari@us.ibm.com>
44 Description:
45                 The file /sys/devices/system/memory/memoryX/state
46                 is read-write.  When read, its contents show the
47                 online/offline state of the memory section.  When written,
48                 root can toggle the the online/offline state of a removable
49                 memory section (see removable file description above)
50                 using the following commands.
51                 # echo online > /sys/devices/system/memory/memoryX/state
52                 # echo offline > /sys/devices/system/memory/memoryX/state
53
54                 For example, if /sys/devices/system/memory/memory22/removable
55                 contains a value of 1 and
56                 /sys/devices/system/memory/memory22/state contains the
57                 string "online" the following command can be executed by
58                 by root to offline that section.
59                 # echo offline > /sys/devices/system/memory/memory22/state
60 Users:          hotplug memory remove tools
61                 https://w3.opensource.ibm.com/projects/powerpc-utils/
62
63
64 What:           /sys/devices/system/memoryX/nodeY
65 Date:           October 2009
66 Contact:        Linux Memory Management list <linux-mm@kvack.org>
67 Description:
68                 When CONFIG_NUMA is enabled, a symbolic link that
69                 points to the corresponding NUMA node directory.
70
71                 For example, the following symbolic link is created for
72                 memory section 9 on node0:
73                 /sys/devices/system/memory/memory9/node0 -> ../../node/node0
74
75
76 What:           /sys/devices/system/node/nodeX/memoryY
77 Date:           September 2008
78 Contact:        Gary Hade <garyhade@us.ibm.com>
79 Description:
80                 When CONFIG_NUMA is enabled
81                 /sys/devices/system/node/nodeX/memoryY is a symbolic link that
82                 points to the corresponding /sys/devices/system/memory/memoryY
83                 memory section directory.  For example, the following symbolic
84                 link is created for memory section 9 on node0.
85                 /sys/devices/system/node/node0/memory9 -> ../../memory/memory9