Commit dee5d0d5 authored by Alex Chiang's avatar Alex Chiang Committed by Linus Torvalds

mm: add numa node symlink for memory section in sysfs

Commit c04fc586 (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: default avatarAlex Chiang <achiang@hp.com>
Cc: Gary Hade <garyhade@us.ibm.com>
Cc: Badari Pulavarty <pbadari@us.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Acked-by: default avatarDavid Rientjes <rientjes@google.com>
Cc: Greg KH <greg@kroah.com>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Cc: David Rientjes <rientjes@google.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent d99be1a8
......@@ -60,6 +60,19 @@ Description:
Users: hotplug memory remove tools
https://w3.opensource.ibm.com/projects/powerpc-utils/
What: /sys/devices/system/memoryX/nodeY
Date: October 2009
Contact: Linux Memory Management list <linux-mm@kvack.org>
Description:
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 <garyhade@us.ibm.com>
......@@ -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
......@@ -160,12 +160,15 @@ Under each section, you can see 4 files.
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:
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
--------------------------------
......
......@@ -312,6 +312,7 @@ static int get_nid_for_pfn(unsigned long pfn)
/* register memory section under specified node if it spans that node */
int register_mem_sect_under_node(struct memory_block *mem_blk, int nid)
{
int ret;
unsigned long pfn, sect_start_pfn, sect_end_pfn;
if (!mem_blk)
......@@ -328,9 +329,15 @@ int register_mem_sect_under_node(struct memory_block *mem_blk, int nid)
continue;
if (page_nid != nid)
continue;
return sysfs_create_link_nowarn(&node_devices[nid].sysdev.kobj,
ret = sysfs_create_link_nowarn(&node_devices[nid].sysdev.kobj,
&mem_blk->sysdev.kobj,
kobject_name(&mem_blk->sysdev.kobj));
if (ret)
return ret;
return sysfs_create_link_nowarn(&mem_blk->sysdev.kobj,
&node_devices[nid].sysdev.kobj,
kobject_name(&node_devices[nid].sysdev.kobj));
}
/* mem section does not span the specified node */
return 0;
......@@ -359,6 +366,8 @@ int unregister_mem_sect_under_nodes(struct memory_block *mem_blk)
continue;
sysfs_remove_link(&node_devices[nid].sysdev.kobj,
kobject_name(&mem_blk->sysdev.kobj));
sysfs_remove_link(&mem_blk->sysdev.kobj,
kobject_name(&node_devices[nid].sysdev.kobj));
}
return 0;
}
......
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