Re: 2.4/2.6/ppc/powerpc/8245/8347e

[linas@austin.ibm.com (Linas Vepstas)]

On Mon, Jul 09, 2007 at 05:47:23PM +0200, Marc Leeman wrote:
> 
> Disabling this replaces the advanced SLAB allocator and
> kmalloc support with the drastically simpler SLOB allocator.
> SLOB is more space efficient but does not scale well and is
> more susceptible to fragmentation. 
> --------
> 
> I was expecting a lower DMM performance but wasn't expecting such a
> drain on kernel/network load.

OK, to be clear: you seem to be saying that using the SLOB instead
of the SLAB allocator results in such terrible memory fragmentation
that network performance is degraded by large factors (2x or 5x or
something like that, if I remember your earlier emails). Is that right?

I thought I heard about some memory-defrag patches being posted.  
What happens if these are used together with SLOB? Does one regain the
lost performance? Perhaps maybe one gets even better performance?

--linas