Re: [patch 9/11] net: dst_entry.refcount, use, lastuse to use alloc_percpu

From: Ravikiran G Thirumalai
Date: Tue Sep 13 2005 - 18:17:45 EST


On Tue, Sep 13, 2005 at 03:12:16PM -0700, David S. Miller wrote:
> From: Ravikiran G Thirumalai <kiran@xxxxxxxxxxxx>
> Date: Tue, 13 Sep 2005 15:07:37 -0700
> ...
> But using bigrefs, no way. We have enough trouble making the data
> structures small without adding bloat like that. A busy server can
> have hundreds of thousands of dst cache entries active on it, and they
> chew up enough memory as is.
>

But even 1 Million dst cache entries would be 16+4 MB additional for a 4 cpu
box....is that too much? The alloc_percpu reimplementation interleaves
objects on cache lines, unlike the existing implementation which pads per-cpu
objects to cache lines...

If you are referring to embedded routing devices,
would they use CONFIG_NUMA or CONFIG_SMP?? (bigrefs nicely fold back to
regular atomic_t s on UPs)

Thanks,
Kiran
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