Re: [patch 09/10] Remove the SLOB allocator for 2.6.23

On Mon, 9 Jul 2007 09:06:46 -0700 (PDT) Christoph Lameter <clameter@xxxxxxx> wrote:

But yes the power of
two caches are a necessary design feature of SLAB/SLUB that allows O(1)
operations of kmalloc slabs which in turns causes memory wastage because
of rounding of the alloc to the next power of two.

I've frequently wondered why we don't just create more caches for kmalloc:
make it denser than each-power-of-2-plus-a-few-others-in-between.

I assume the tradeoff here is better packing versus having a ridiculous
number of caches. Is there any other cost?

Because even having 1024 caches wouldn't consume a terrible amount of
memory and I bet it would result in aggregate savings.

Of course, a scheme which creates kmalloc caches on-demand would be better,
but that would kill our compile-time cache selection, I suspect.
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