Re: [PATCH] kmalloc_percpu

David S. Miller (davem@redhat.com)
05 May 2003 19:11:59 -0700

On Mon, 2003-05-05 at 18:52, Andrew Morton wrote:
> Rusty Russell <rusty@rustcorp.com.au> wrote:
> > OK. It has a size restriction: PERCPU_POOL_SIZE is the maximum total
> > kmalloc_percpu + static DECLARE_PER_CPU you'll get, ever. This is the
> > main downside. It's allocated at boot.
>
> And is subject to fragmentation.
>
> Is it not possible to go allocate another N * PERCPU_POOL_SIZE from
> slab if it runs out?

No, then you go back to things requireing multiple levels of
dereferencing. It's hard to realloc() because you have to
freeze the whole kernel to do that properly, and that is not
simple at all.

I think the fixed size pool is perfectly reasonable.

-- 
David S. Miller <davem@redhat.com>
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