linux/include
Gary Hade c04fc586c1 mm: show node to memory section relationship with symlinks in sysfs
Show node to memory section relationship with symlinks in sysfs

Add /sys/devices/system/node/nodeX/memoryY symlinks for all
the memory sections located on nodeX.  For example:
/sys/devices/system/node/node1/memory135 -> ../../memory/memory135
indicates that memory section 135 resides on node1.

Also revises documentation to cover this change as well as updating
Documentation/ABI/testing/sysfs-devices-memory to include descriptions
of memory hotremove files 'phys_device', 'phys_index', and 'state'
that were previously not described there.

In addition to it always being a good policy to provide users with
the maximum possible amount of physical location information for
resources that can be hot-added and/or hot-removed, the following
are some (but likely not all) of the user benefits provided by
this change.
Immediate:
  - Provides information needed to determine the specific node
    on which a defective DIMM is located.  This will reduce system
    downtime when the node or defective DIMM is swapped out.
  - Prevents unintended onlining of a memory section that was
    previously offlined due to a defective DIMM.  This could happen
    during node hot-add when the user or node hot-add assist script
    onlines _all_ offlined sections due to user or script inability
    to identify the specific memory sections located on the hot-added
    node.  The consequences of reintroducing the defective memory
    could be ugly.
  - Provides information needed to vary the amount and distribution
    of memory on specific nodes for testing or debugging purposes.
Future:
  - Will provide information needed to identify the memory
    sections that need to be offlined prior to physical removal
    of a specific node.

Symlink creation during boot was tested on 2-node x86_64, 2-node
ppc64, and 2-node ia64 systems.  Symlink creation during physical
memory hot-add tested on a 2-node x86_64 system.

Signed-off-by: Gary Hade <garyhade@us.ibm.com>
Signed-off-by: Badari Pulavarty <pbadari@us.ibm.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-06 15:59:00 -08:00
..
acpi cpumask: convert shared_cpu_map in acpi_processor* structs to cpumask_var_t 2009-01-03 19:15:40 +01:00
asm-arm [ARM] S3C24XX: Move mci.h to arch/arm/plat-s3c24xx/include/plat 2008-10-30 10:17:16 +00:00
asm-frv frv: define __fls 2009-01-03 16:14:05 +10:30
asm-generic Merge branch 'cpus4096-for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-01-02 11:44:09 -08:00
asm-h8300
asm-m32r m32r: define __fls 2009-01-03 16:16:54 +10:30
asm-m68k m68k: define __fls 2009-01-01 10:12:18 +10:30
asm-mn10300 mn10300: define __fls 2009-01-03 16:19:03 +10:30
asm-xtensa xtensa: define __fls 2009-01-03 16:21:08 +10:30
crypto crypto: aes - Precompute tables 2008-12-25 11:05:13 +11:00
drm drm: Add a debug node for vblank state. 2008-12-29 17:47:27 +10:00
keys KEYS: Disperse linux/key_ui.h 2008-11-14 10:39:13 +11:00
linux mm: show node to memory section relationship with symlinks in sysfs 2009-01-06 15:59:00 -08:00
math-emu
media V4L/DVB (10141): v4l2: debugging API changed to match against driver name instead of ID. 2009-01-02 17:11:52 -02:00
mtd
net ipv6: Fix sporadic sendmsg -EINVAL when sending to multicast groups. 2009-01-04 16:04:39 -08:00
pcmcia
rdma
rxrpc
scsi [SCSI] fcoe: Fibre Channel over Ethernet 2008-12-29 11:24:33 -06:00
sound V4L/DVB (10135): v4l2: introduce v4l2_file_operations. 2009-01-02 17:11:12 -02:00
trace sched, trace: update trace_sched_wakeup() 2008-12-25 13:10:21 +01:00
video video: sh_mobile_lcdcfb deferred io support 2008-12-22 18:44:48 +09:00
xen xen: clean up asm/xen/hypervisor.h 2008-12-16 21:50:31 +01:00
Kbuild