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c04fc586c1
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>
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| .. | ||
| debugfs-pktcdvd | ||
| procfs-diskstats | ||
| sysfs-block | ||
| sysfs-bus-css | ||
| sysfs-bus-pci | ||
| sysfs-bus-umc | ||
| sysfs-bus-usb | ||
| sysfs-bus-usb-devices-usbsevseg | ||
| sysfs-c2port | ||
| sysfs-class | ||
| sysfs-class-bdi | ||
| sysfs-class-pktcdvd | ||
| sysfs-class-regulator | ||
| sysfs-class-usb_host | ||
| sysfs-class-uwb_rc | ||
| sysfs-dev | ||
| sysfs-devices | ||
| sysfs-devices-memory | ||
| sysfs-firmware-acpi | ||
| sysfs-firmware-memmap | ||
| sysfs-firmware-sgi_uv | ||
| sysfs-gpio | ||
| sysfs-ibft | ||
| sysfs-kernel-mm | ||
| sysfs-kernel-mm-hugepages | ||
| sysfs-kernel-uids | ||
| sysfs-ocfs2 | ||
| sysfs-power | ||
| sysfs-profiling | ||
| sysfs-wusb_cbaf | ||