linux/Documentation/ABI/testing
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
..
debugfs-pktcdvd [PATCH] pktcdvd: cleanup 2007-02-11 10:51:28 -08:00
procfs-diskstats Enhanced partition statistics: documentation update 2008-02-08 12:42:11 +01:00
sysfs-block block: Data integrity infrastructure documentation 2008-07-03 13:21:13 +02:00
sysfs-bus-css [S390] cio: Introduce modalias for css bus. 2008-07-14 10:02:05 +02:00
sysfs-bus-pci PCI: Expose PCI VPD through sysfs 2008-04-20 21:47:07 -07:00
sysfs-bus-umc uwb: document UWB and WUSB sysfs files 2008-09-17 16:54:35 +01:00
sysfs-bus-usb Merge branch 'master' into for-upstream 2008-10-20 16:07:19 +01:00
sysfs-bus-usb-devices-usbsevseg USB: Added driver for a Delcom USB 7-segment LED Display 2008-10-17 14:40:51 -07:00
sysfs-c2port Add c2 port support 2008-11-12 17:17:18 -08:00
sysfs-class [PATCH] Add kernel<->userspace ABI stability documentation 2006-06-21 12:40:47 -07:00
sysfs-class-bdi fuse: fix bdi naming conflict 2008-05-24 09:56:07 -07:00
sysfs-class-pktcdvd [PATCH] pktcdvd: cleanup 2007-02-11 10:51:28 -08:00
sysfs-class-regulator regulator: Export regulator name via sysfs 2008-10-13 21:51:53 +01:00
sysfs-class-usb_host uwb: document UWB and WUSB sysfs files 2008-09-17 16:54:35 +01:00
sysfs-class-uwb_rc uwb: add basic radio manager 2008-11-19 14:46:33 +00:00
sysfs-dev sysfs: add /sys/dev/{char,block} to lookup sysfs path by major:minor 2008-07-21 21:54:40 -07:00
sysfs-devices [PATCH] Add kernel<->userspace ABI stability documentation 2006-06-21 12:40:47 -07:00
sysfs-devices-memory mm: show node to memory section relationship with symlinks in sysfs 2009-01-06 15:59:00 -08:00
sysfs-firmware-acpi ACPI: bugfix reporting of event handler status 2008-10-28 01:53:19 -04:00
sysfs-firmware-memmap sysfs: add /sys/firmware/memmap 2008-07-08 17:55:41 +02:00
sysfs-firmware-sgi_uv sysfs: document files in /sys/firmware/sgi_uv/ 2008-09-02 19:21:40 -07:00
sysfs-gpio Documentation/ABI: /sys/class/gpio 2008-09-13 14:41:52 -07:00
sysfs-ibft Firmware: add iSCSI iBFT Support 2008-04-19 19:10:28 -07:00
sysfs-kernel-mm mm: create /sys/kernel/mm 2008-07-24 10:47:17 -07:00
sysfs-kernel-mm-hugepages hugetlb: new sysfs interface 2008-07-24 10:47:17 -07:00
sysfs-kernel-uids Documentation: create new scheduler/ subdirectory 2008-02-07 08:42:17 -08:00
sysfs-ocfs2 ocfs2: Document /sys/fs/ocfs2 2008-04-18 08:56:07 -07:00
sysfs-power [PATCH] swsusp: debugging 2006-11-03 12:27:58 -08:00
sysfs-profiling profiling: dynamically enable readprofile at runtime 2008-10-16 11:21:31 -07:00
sysfs-wusb_cbaf uwb: document UWB and WUSB sysfs files 2008-09-17 16:54:35 +01:00