SLAB cannot pack objects as dense as SLUB and they have different
algorithm to make the choice of order. Thus the number of objects per slab
may vary between SLAB and SLUB and therefore also the choice of order to
store these objects.
Upstream SLUB uses order 0 allocations for the radix tree. MM varies
because the use of higher order allocs is more loose if the mobility
algorithms are found to be active:
2.6.23-rc8:
Name Objects Objsize Space Slabs/Part/Cpu O/S O %Fr %Ef Flg\
radix_tree_node 14281 552 9.9M 2432/948/1 7 0 38 79
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