lkml.org 
[lkml]   [2007]   [May]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: + fix-spellings-of-slab-allocator-section-in-init-kconfig.patch added to -mm tree
On Wed, 9 May 2007, Nick Piggin wrote:

> > Exactly. That overhead does not exist in SLUB. Thus SLOB is less efficient
> > than SLUB.
>
> What you trade for that is that one page page can only serve one slab.

Right.

> For small systems, I would not be surprised if that was less space
> efficient, even just looking at kmalloc caches in isolation. Or do you
> have numbers to support your conclusion?

No I do not have any number beyond the efficiency calculations based on
whole slabs. We would have to do some experiments to figure out how much
space is actually wasted through partial slabs.

If you just do straight allocation on a UP system then there is at maximum
one partial slab per slabcache with SLUB.

The situation becomes different with allocation and frees. Then we may
have lots of partial slabs that we allocate from. But the SLOB approach
also will have holes to manage. So I do not see how this could be a
benefit unless you only have a few precious pages and you need to put
multiple object sizes into it. A 4M system still has 1000 pages.

-
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 05:01    [W:0.094 / U:0.124 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site