xref: /linux/Documentation/ABI/testing/sysfs-devices-memory (revision 4949009eb8d40a441dcddcd96e101e77d31cf1b2)
1What:		/sys/devices/system/memory
2Date:		June 2008
3Contact:	Badari Pulavarty <pbadari@us.ibm.com>
4Description:
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.
9Users:		hotplug memory add/remove tools
10		http://www.ibm.com/developerworks/wikis/display/LinuxP/powerpc-utils
11
12What:		/sys/devices/system/memory/memoryX/removable
13Date:		June 2008
14Contact:	Badari Pulavarty <pbadari@us.ibm.com>
15Description:
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
21Users:		hotplug memory remove tools
22		http://www.ibm.com/developerworks/wikis/display/LinuxP/powerpc-utils
23
24What:		/sys/devices/system/memory/memoryX/phys_device
25Date:		September 2008
26Contact:	Badari Pulavarty <pbadari@us.ibm.com>
27Description:
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
32What:		/sys/devices/system/memory/memoryX/phys_index
33Date:		September 2008
34Contact:	Badari Pulavarty <pbadari@us.ibm.com>
35Description:
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
41What:		/sys/devices/system/memory/memoryX/state
42Date:		September 2008
43Contact:	Badari Pulavarty <pbadari@us.ibm.com>
44Description:
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
60Users:		hotplug memory remove tools
61		http://www.ibm.com/developerworks/wikis/display/LinuxP/powerpc-utils
62
63
64What:           /sys/devices/system/memory/memoryX/valid_zones
65Date:           July 2014
66Contact:	Zhang Zhen <zhenzhang.zhang@huawei.com>
67Description:
68		The file /sys/devices/system/memory/memoryX/valid_zones	is
69		read-only and is designed to show which zone this memory
70		block can be onlined to.
71
72What:		/sys/devices/system/memoryX/nodeY
73Date:		October 2009
74Contact:	Linux Memory Management list <linux-mm@kvack.org>
75Description:
76		When CONFIG_NUMA is enabled, a symbolic link that
77		points to the corresponding NUMA node directory.
78
79		For example, the following symbolic link is created for
80		memory section 9 on node0:
81		/sys/devices/system/memory/memory9/node0 -> ../../node/node0
82
83
84What:		/sys/devices/system/node/nodeX/memoryY
85Date:		September 2008
86Contact:	Gary Hade <garyhade@us.ibm.com>
87Description:
88		When CONFIG_NUMA is enabled
89		/sys/devices/system/node/nodeX/memoryY is a symbolic link that
90		points to the corresponding /sys/devices/system/memory/memoryY
91		memory section directory.  For example, the following symbolic
92		link is created for memory section 9 on node0.
93		/sys/devices/system/node/node0/memory9 -> ../../memory/memory9
94