Re: + fix-spellings-of-slab-allocator-section-in-init-kconfig.patchadded to -mm tree

From: Christoph Lameter
Date: Tue May 08 2007 - 20:51:37 EST


On Tue, 8 May 2007, Matt Mackall wrote:

> First, SLOB no longer runs on SMP because SLAB grew some RCU-related
> hair. So it now effectively has no locks at all!

Well it seems that SLOB was not well maintained. RCU has been around for a
long time and SLOB has not been updated to cope with it.

> Third, I don't think it's possible even in theory for a SLAB-like
> allocator to be as efficient as SLOB simply due to the constraints of
> putting only objects of the same size on a given page. So consider me
> skeptical on the density claim.

SLUB can put 32 objects sized 128 byte each in a 4k page. Can SLOB do
the same?

> It is usually better to use SLUB simply because you're more likely to
> have 1GB of RAM rather than 4MB.

SLUB should be perfectly fine for that environment provided you
adjust the cacheline alignment and switch off SLUB debugging.
define L1_CACHE_BYTES to be 4 or so.

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