linux/drivers/base
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
..
power Merge git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core-2.6 2008-10-16 12:40:26 -07:00
attribute_container.c
base.h
bus.c
class.c
core.c
cpu.c cpumask: fix compile error when CONFIG_NR_CPUS is not defined 2009-01-03 19:15:41 +01:00
dd.c
devres.c
dma-mapping.c
driver.c
firmware_class.c
firmware.c
hypervisor.c
init.c
iommu.c add frontend implementation for the IOMMU API 2009-01-03 14:10:09 +01:00
isa.c
Kconfig
Makefile select IOMMU_API when DMAR and/or AMD_IOMMU is selected 2009-01-03 14:10:09 +01:00
map.c
memory.c mm: show node to memory section relationship with symlinks in sysfs 2009-01-06 15:59:00 -08:00
module.c
node.c mm: show node to memory section relationship with symlinks in sysfs 2009-01-06 15:59:00 -08:00
platform.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core-2.6 2008-10-16 12:40:26 -07:00
sys.c sysfs: Fix return values for sysdev_store_{ulong,int} 2008-10-29 15:03:49 -07:00
topology.c cpumask: change cpumask_scnprintf, cpumask_parse_user, cpulist_parse, and cpulist_scnprintf to take pointers. 2008-12-13 21:20:25 +10:30
transport_class.c