path: root/Documentation
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authorAlex Chiang <>2009-12-14 17:59:05 -0800
committerLinus Torvalds <>2009-12-15 08:53:17 -0800
commitdee5d0d518defd0337a41f1a504428c9acc87be5 (patch)
treedeb540b5ccc58f0e83114509e17dacb281fc12e5 /Documentation
parentd99be1a8ecf377c2c9b3372d36411ad6547bbd4c (diff)
mm: add numa node symlink for memory section in sysfs
Commit c04fc586c (mm: show node to memory section relationship with symlinks in sysfs) created symlinks from nodes to memory sections, e.g. /sys/devices/system/node/node1/memory135 -> ../../memory/memory135 If you're examining the memory section though and are wondering what node it might belong to, you can find it by grovelling around in sysfs, but it's a little cumbersome. Add a reverse symlink for each memory section that points back to the node to which it belongs. Signed-off-by: Alex Chiang <> Cc: Gary Hade <> Cc: Badari Pulavarty <> Cc: Ingo Molnar <> Acked-by: David Rientjes <> Cc: Greg KH <> Cc: Randy Dunlap <> Cc: David Rientjes <> Cc: KOSAKI Motohiro <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
Diffstat (limited to 'Documentation')
2 files changed, 20 insertions, 5 deletions
diff --git a/Documentation/ABI/testing/sysfs-devices-memory b/Documentation/ABI/testing/sysfs-devices-memory
index 9fe91c02ee40..bf1627b02a03 100644
--- a/Documentation/ABI/testing/sysfs-devices-memory
+++ b/Documentation/ABI/testing/sysfs-devices-memory
@@ -60,6 +60,19 @@ Description:
Users: hotplug memory remove tools
+What: /sys/devices/system/memoryX/nodeY
+Date: October 2009
+Contact: Linux Memory Management list <>
+ When CONFIG_NUMA is enabled, a symbolic link that
+ points to the corresponding NUMA node directory.
+ For example, the following symbolic link is created for
+ memory section 9 on node0:
+ /sys/devices/system/memory/memory9/node0 -> ../../node/node0
What: /sys/devices/system/node/nodeX/memoryY
Date: September 2008
Contact: Gary Hade <>
@@ -70,4 +83,3 @@ Description:
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 bbc8a6a36921..57e7e9cc1870 100644
--- a/Documentation/memory-hotplug.txt
+++ b/Documentation/memory-hotplug.txt
@@ -160,12 +160,15 @@ Under each section, you can see 4 files.
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:
+If CONFIG_NUMA is enabled the memoryXXX/ 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
+A backlink will also be created:
+/sys/devices/system/memory/memory9/node0 -> ../../node/node0
4. Physical memory hot-add phase