[PATCH] slub: Don't throw away partial remote slabs if there is no local memory

[David Laight]

> From: Anton Blanchard
> We noticed a huge amount of slab memory consumed on a large ppc64 box:
> 
> Slab:            2094336 kB
> 
> Almost 2GB. This box is not balanced and some nodes do not have local
> memory, causing slub to be very inefficient in its slab usage.
> 
> Each time we call kmem_cache_alloc_node slub checks the per cpu slab,
> sees it isn't node local, deactivates it and tries to allocate a new
> slab. ...
...
>  	if (unlikely(!node_match(page, node))) {
>  		stat(s, ALLOC_NODE_MISMATCH);
> 		deactivate_slab(s, page, c->freelist);
> 		c->page = NULL;
> 		c->freelist = NULL;
> 		goto new_slab;
>  	}

Why not just delete the entire test?
Presumably some time a little earlier no local memory was available.
Even if there is some available now, it is very likely that some won't
be available again in the near future.

	David.