Re: [RFC, PATCH] SLAB : [NUMA] keep nodeid in struct page instead of struct slab

From: Andi Kleen
Date: Wed Mar 21 2007 - 12:09:19 EST


On Wed, Mar 21, 2007 at 10:22:31AM +0100, Eric Dumazet wrote:
> In order to avoid a cache miss in kmem_cache_free() on NUMA and reduce hot path length, we could exploit the following common facts.
>
> 1) MAX_NUMNODES <= 64
>
> 2) alignment of 'struct kmem_cache *' can be >= 64
>
> The following patch changes the page->lru.next to contain not only the 'struct kmem_cache *' pointer, but also the nodeid in the low order bits.
>

It might be cleaner to just put it into flags on 64bit. There is enough
space there and we don't really care about 32bit NUMA machines.

-Andi
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