Messages in this thread | | | Date | Tue, 8 May 2007 19:24:07 -0700 (PDT) | From | Christoph Lameter <> | Subject | Re: + fix-spellings-of-slab-allocator-section-in-init-kconfig.patch added to -mm tree |
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On Tue, 8 May 2007, Matt Mackall wrote:
> > > Yes. It can in fact put 512 8-byte objects in a 4k page. More > > > > So can SLUB. > > Not without at least a bit per-object of overhead. So you can either > fit 512 objects in 4160 bytes or 504 objects in 4k.
Slub uses a linked list pointer in the page struct which is NULL if all objects are allocated. There is no bit per object overhead.
> For the kmalloc case, we do have an 8-byte header, which works out to > be about 1/8th of the slop that mainline kmalloc over SLAB has on
Exactly. That overhead does not exist in SLUB. Thus SLOB is less efficient than SLUB.
> average due to power of two cache sizes. So in both cases, less > overhead than SLAB and different-sized objects can be comingled. SLUB > would be awfully hard-pressed to have lower space overhead.
Its simple and easy to do and it was done in SLUB. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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