Fragmentation index is a value that makes sense when an allocation of a
given size would fail. The index indicates whether an allocation failure is
due to a lack of memory (values towards 0) or due to external fragmentation
(value towards 1). 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-zone
basis via /proc/pagetypeinfo.
The index is normally calculated as a value between 0 and 1 which is
obviously unsuitable within the kernel. Instead, the first three decimal
places are used as a value between 0 and 1000 for an integer approximation.
Signed-off-by: Mel Gorman<mel@xxxxxxxxx>