linux/arch/sh
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
..
boards sh: mach-sh03: Fix up pata_platform build breakage. 2008-12-22 18:44:49 +09:00
boot sh: FTRACE renamed to FUNCTION_TRACER. 2008-10-31 16:20:36 +09:00
cchips sh: Switch HD64461 from hw_interrupt_type to irq_chip 2008-12-22 18:43:50 +09:00
configs sh: Add a simple edosk7705_defconfig for build testing. 2008-12-22 18:44:46 +09:00
drivers sh: dma: Kill off ISA DMA wrapper. 2008-12-22 18:44:47 +09:00
include Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-cpumask into merge-rr-cpumask 2009-01-03 18:53:31 +01:00
kernel 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
lib sh: Add plain udivsi3 (not _i4*) for gcc-4.1 and lower. 2008-12-22 18:43:53 +09:00
lib64 sh: Provide sdivsi3/udivsi3/udivdi3 for sh64, kill off libgcc linking. 2008-12-22 18:44:05 +09:00
math-emu sh: Fix up the math-emu build. 2007-06-11 15:57:42 +09:00
mm mm: show node to memory section relationship with symlinks in sysfs 2009-01-06 15:59:00 -08:00
oprofile sh: oprofile: Fix up the module build. 2008-12-22 19:32:27 +09:00
tools sh: Consolidate rsk7203/7201 in to a new mach-rsk. 2008-12-22 18:44:02 +09:00
Kconfig sh: dma: Kill off ISA DMA wrapper. 2008-12-22 18:44:47 +09:00
Kconfig.cpu sh: Disable big endian for SH-5. 2008-02-14 14:22:10 +09:00
Kconfig.debug sh: Conditionalize the code dumper on CONFIG_DUMP_CODE. 2008-12-22 18:44:47 +09:00
Makefile sh: mach-rsk: Use uImage generation by default for rsk7201/7203. 2008-12-22 18:44:49 +09:00