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author | Mel Gorman <mel@csn.ul.ie> | 2010-05-24 14:32:26 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-05-25 08:06:59 -0700 |
commit | f1a5ab1210579e2d3ac8c0c227645823af5aafb0 (patch) | |
tree | c646a3d58150eab1a8280d02e6254ef6b90a6f37 /drivers/md | |
parent | d7a5752c0c19750312efab3a2a80d350e11fa4a2 (diff) | |
download | op-kernel-dev-f1a5ab1210579e2d3ac8c0c227645823af5aafb0.zip op-kernel-dev-f1a5ab1210579e2d3ac8c0c227645823af5aafb0.tar.gz |
mm: export fragmentation index via debugfs
The fragmentation fragmentation index, is only meaningful if an allocation
would fail and indicates what the failure is due to. A value of -1 such
as in many of the examples above states that the allocation would succeed.
If it would fail, the value is between 0 and 1. A value tending towards
0 implies the allocation failed due to a lack of memory. A value tending
towards 1 implies it failed due to external fragmentation.
For the most part, the huge page size will be the size of interest but not
necessarily so it is exported on a per-order and per-zo basis via
/sys/kernel/debug/extfrag/extfrag_index
> cat /sys/kernel/debug/extfrag/extfrag_index
Node 0, zone DMA -1.000 -1.000 -1.000 -1.000 -1.000 -1.000 -1.000 -1.00
Node 0, zone Normal -1.000 -1.000 -1.000 -1.000 -1.000 -1.000 -1.000 0.954
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Acked-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Christoph Lameter <cl@linux-foundation.org>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/md')
0 files changed, 0 insertions, 0 deletions