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-rw-r--r--Documentation/ABI/testing/sysfs-devices-memory51
-rw-r--r--Documentation/memory-hotplug.txt16
2 files changed, 63 insertions, 4 deletions
diff --git a/Documentation/ABI/testing/sysfs-devices-memory b/Documentation/ABI/testing/sysfs-devices-memory
index 7a16fe1e2270..9fe91c02ee40 100644
--- a/Documentation/ABI/testing/sysfs-devices-memory
+++ b/Documentation/ABI/testing/sysfs-devices-memory
@@ -6,7 +6,6 @@ Description:
internal state of the kernel memory blocks. Files could be
added or removed dynamically to represent hot-add/remove
operations.
-
Users: hotplug memory add/remove tools
https://w3.opensource.ibm.com/projects/powerpc-utils/
@@ -19,6 +18,56 @@ Description:
This is useful for a user-level agent to determine
identify removable sections of the memory before attempting
potentially expensive hot-remove memory operation
+Users: hotplug memory remove tools
+ https://w3.opensource.ibm.com/projects/powerpc-utils/
+
+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.
+What: /sys/devices/system/memory/memoryX/phys_index
+Date: September 2008
+Contact: Badari Pulavarty <pbadari@us.ibm.com>
+Description:
+ The file /sys/devices/system/memory/memoryX/phys_index
+ is read-only and contains the section ID in hexadecimal
+ which is equivalent to decimal X contained in the
+ memory section directory name.
+
+What: /sys/devices/system/memory/memoryX/state
+Date: September 2008
+Contact: Badari Pulavarty <pbadari@us.ibm.com>
+Description:
+ The file /sys/devices/system/memory/memoryX/state
+ is read-write. When read, it's 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
Users: hotplug memory remove tools
https://w3.opensource.ibm.com/projects/powerpc-utils/
+
+What: /sys/devices/system/node/nodeX/memoryY
+Date: September 2008
+Contact: Gary Hade <garyhade@us.ibm.com>
+Description:
+ When CONFIG_NUMA is enabled
+ /sys/devices/system/node/nodeX/memoryY is a symbolic link that
+ 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
+
diff --git a/Documentation/memory-hotplug.txt b/Documentation/memory-hotplug.txt
index 168117bd6ee8..4c2ecf537a4a 100644
--- a/Documentation/memory-hotplug.txt
+++ b/Documentation/memory-hotplug.txt
@@ -124,7 +124,7 @@ config options.
This option can be kernel module too.
--------------------------------
-3 sysfs files for memory hotplug
+4 sysfs files for memory hotplug
--------------------------------
All sections have their device information under /sys/devices/system/memory as
@@ -138,11 +138,12 @@ For example, assume 1GiB section size. A device for a memory starting at
(0x100000000 / 1Gib = 4)
This device covers address range [0x100000000 ... 0x140000000)
-Under each section, you can see 3 files.
+Under each section, you can see 4 files.
/sys/devices/system/memory/memoryXXX/phys_index
/sys/devices/system/memory/memoryXXX/phys_device
/sys/devices/system/memory/memoryXXX/state
+/sys/devices/system/memory/memoryXXX/removable
'phys_index' : read-only and contains section id, same as XXX.
'state' : read-write
@@ -150,10 +151,20 @@ Under each section, you can see 3 files.
at write: user can specify "online", "offline" command
'phys_device': read-only: designed to show the name of physical memory device.
This is not well implemented now.
+'removable' : read-only: contains an integer value indicating
+ whether the memory section is removable or not
+ removable. A value of 1 indicates that the memory
+ section is removable and a value of 0 indicates that
+ it is not removable.
NOTE:
These directories/files appear after physical memory hotplug phase.
+If CONFIG_NUMA is enabled the
+/sys/devices/system/memory/memoryXXX memory section
+directories can also be accessed via symbolic links located in
+the /sys/devices/system/node/node* directories. For example:
+/sys/devices/system/node/node0/memory9 -> ../../memory/memory9
--------------------------------
4. Physical memory hot-add phase
@@ -365,7 +376,6 @@ node if necessary.
- allowing memory hot-add to ZONE_MOVABLE. maybe we need some switch like
sysctl or new control file.
- showing memory section and physical device relationship.
- - showing memory section and node relationship (maybe good for NUMA)
- showing memory section is under ZONE_MOVABLE or not
- test and make it better memory offlining.
- support HugeTLB page migration and offlining.