Eric Lee / linux-smarc-t335x-v3.2

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Commit dee5d0d518defd0337a41f1a504428c9acc87be5

Authored by Alex Chiang
Committed by Linus Torvalds
1 parent d99be1a8ec

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 <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: David 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Showing 3 changed files with 30 additions and 6 deletions Side-by-side Diff

Documentation/ABI/testing/sysfs-devices-memory
Diff comments   View file @ dee5d0d
... ... @@ -60,6 +60,19 @@
60 60 Users: hotplug memory remove tools
61 61 https://w3.opensource.ibm.com/projects/powerpc-utils/
62 62  
  63 +
  64 +What: /sys/devices/system/memoryX/nodeY
  65 +Date: October 2009
  66 +Contact: Linux Memory Management list <linux-mm@kvack.org>
  67 +Description:
  68 + When CONFIG_NUMA is enabled, a symbolic link that
  69 + points to the corresponding NUMA node directory.
  70 +
  71 + For example, the following symbolic link is created for
  72 + memory section 9 on node0:
  73 + /sys/devices/system/memory/memory9/node0 -> ../../node/node0
  74 +
  75 +
63 76 What: /sys/devices/system/node/nodeX/memoryY
64 77 Date: September 2008
65 78 Contact: Gary Hade <garyhade@us.ibm.com>
Documentation/memory-hotplug.txt
Diff comments   View file @ dee5d0d
... ... @@ -160,11 +160,14 @@
160 160 NOTE:
161 161 These directories/files appear after physical memory hotplug phase.
162 162  
163   -If CONFIG_NUMA is enabled the
164   -/sys/devices/system/memory/memoryXXX memory section
165   -directories can also be accessed via symbolic links located in
166   -the /sys/devices/system/node/node* directories. For example:
  163 +If CONFIG_NUMA is enabled the memoryXXX/ directories can also be accessed
  164 +via symbolic links located in the /sys/devices/system/node/node* directories.
  165 +
  166 +For example:
167 167 /sys/devices/system/node/node0/memory9 -> ../../memory/memory9
  168 +
  169 +A backlink will also be created:
  170 +/sys/devices/system/memory/memory9/node0 -> ../../node/node0
168 171  
169 172 --------------------------------
170 173 4. Physical memory hot-add phase
... ... @@ -312,6 +312,7 @@
312 312 /* register memory section under specified node if it spans that node */
313 313 int register_mem_sect_under_node(struct memory_block *mem_blk, int nid)
314 314 {
  315 + int ret;
315 316 unsigned long pfn, sect_start_pfn, sect_end_pfn;
316 317  
317 318 if (!mem_blk)
318 319  
... ... @@ -328,9 +329,15 @@
328 329 continue;
329 330 if (page_nid != nid)
330 331 continue;
331   - return sysfs_create_link_nowarn(&node_devices[nid].sysdev.kobj,
  332 + ret = sysfs_create_link_nowarn(&node_devices[nid].sysdev.kobj,
332 333 &mem_blk->sysdev.kobj,
333 334 kobject_name(&mem_blk->sysdev.kobj));
  335 + if (ret)
  336 + return ret;
  337 +
  338 + return sysfs_create_link_nowarn(&mem_blk->sysdev.kobj,
  339 + &node_devices[nid].sysdev.kobj,
  340 + kobject_name(&node_devices[nid].sysdev.kobj));
334 341 }
335 342 /* mem section does not span the specified node */
336 343 return 0;
... ... @@ -359,6 +366,8 @@
359 366 continue;
360 367 sysfs_remove_link(&node_devices[nid].sysdev.kobj,
361 368 kobject_name(&mem_blk->sysdev.kobj));
  369 + sysfs_remove_link(&mem_blk->sysdev.kobj,
  370 + kobject_name(&node_devices[nid].sysdev.kobj));
362 371 }
363 372 return 0;
364 373 }