Re: [PATCH 04/16] slab: remove nodeid in struct slab

From: Joonsoo Kim
Date: Fri Aug 23 2013 - 02:49:32 EST


On Thu, Aug 22, 2013 at 05:51:58PM +0000, Christoph Lameter wrote:
> On Thu, 22 Aug 2013, Joonsoo Kim wrote:
>
> > @@ -1099,8 +1098,7 @@ static void drain_alien_cache(struct kmem_cache *cachep,
> >
> > static inline int cache_free_alien(struct kmem_cache *cachep, void *objp)
> > {
> > - struct slab *slabp = virt_to_slab(objp);
> > - int nodeid = slabp->nodeid;
> > + int nodeid = page_to_nid(virt_to_page(objp));
> > struct kmem_cache_node *n;
> > struct array_cache *alien = NULL;
> > int node;
>
> virt_to_page is a relatively expensive operation. How does this affect
> performance?

Previous code, that is virt_to_slab(), already do virt_to_page().
So this doesn't matter at all.

Thanks.

>
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