Messages in this thread | | | Date | Wed, 5 Nov 2008 12:36:09 -0800 | From | Andrew Morton <> | Subject | Re: [PATCH] [REPOST #2] mm: show node to memory section relationship with symlinks in sysfs |
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On Mon, 3 Nov 2008 15:48:08 -0800 Gary Hade <garyhade@us.ibm.com> wrote:
> > 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. > > Supersedes the "mm: show memory section to node relationship in sysfs" > patch posted on 05 Sept 2008 which created node ID containing 'node' > files in /sys/devices/system/memory/memoryX instead of symlinks. > Changed from files to symlinks due to feedback that symlinks were > more consistent with the sysfs way. > > ... > > Documentation/ABI/testing/sysfs-devices-memory | 51 +++++++ > Documentation/memory-hotplug.txt | 16 +- > arch/ia64/mm/init.c | 2 > arch/powerpc/mm/mem.c | 2 > arch/s390/mm/init.c | 2 > arch/sh/mm/init.c | 3 > arch/x86/mm/init_32.c | 2 > arch/x86/mm/init_64.c | 2 > drivers/base/memory.c | 19 +- > drivers/base/node.c | 100 +++++++++++++++ > include/linux/memory.h | 6 > include/linux/memory_hotplug.h | 2 > include/linux/node.h | 13 + > mm/memory_hotplug.c | 9 - > 14 files changed, 205 insertions(+), 24 deletions(-)
Dumb question: why do this with a symlink forest instead of, say, cat /proc/sys/vm/mem-sections?
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