lkml.org 
[lkml]   [2007]   [May]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
DateTue, 8 May 2007 19:24:07 -0700 (PDT)
FromChristoph Lameter <>
SubjectRe: + fix-spellings-of-slab-allocator-section-in-init-kconfig.patch added to -mm tree
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/

\
 
 \ /
  Last update: 2007-05-09 04:27    [from the cache]
©2003-2010