SLUB: Free slabs and sort partial slab lists in kmem_cache_shrink
At kmem_cache_shrink check if we have any empty slabs on the partial if so then remove them. Also--as an anti-fragmentation measure--sort the partial slabs so that the most fully allocated ones come first and the least allocated last. The next allocations may fill up the nearly full slabs. Having the least allocated slabs last gives them the maximum chance that their remaining objects may be freed. Thus we can hopefully minimize the partial slabs. I think this is the best one can do in terms antifragmentation measures. Real defragmentation (meaning moving objects out of slabs with the least free objects to those that are almost full) can be implemted by reverse scanning through the list produced here but that would mean that we need to provide a callback at slab cache creation that allows the deletion or moving of an object. This will involve slab API changes, so defer for now. Cc: Mel Gorman <mel@skynet.ie> Signed-off-by: NChristoph Lameter <clameter@sgi.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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