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

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

Documentation/ABI/testing/sysfs-devices-memory

+13 −1
Original line number Diff line number Diff line
@@ -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

Documentation/memory-hotplug.txt

+7 −4
Original line number Diff line number Diff line
@@ -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

--------------------------------

drivers/base/node.c

+10 −1
Original line number Diff line number Diff line
@@ -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;

}