Re: linux-next: build failure after merge of the final tree (slabtree related)

[David Rientjes]

On Wed, 25 Aug 2010, Christoph Lameter wrote:

> Since the percpu allocator does not provide early allocation in UP
> mode (only in SMP configurations) use __get_free_page() to improvise
> a compound page allocation that can be later freed via kfree().
> 
> Compound pages will be released when the cpu caches are resized.
> 
> Signed-off-by: Christoph Lameter <cl@xxxxxxxxx>
> 
> ---
>  mm/slub.c |    6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> Index: linux-2.6/mm/slub.c
> ===================================================================
> --- linux-2.6.orig/mm/slub.c	2010-08-24 20:07:12.766010774 -0500
> +++ linux-2.6/mm/slub.c	2010-08-24 20:15:46.304130417 -0500
> @@ -2064,8 +2064,24 @@
> 
>  static inline int alloc_kmem_cache_cpus(struct kmem_cache *s)
>  {
> +#ifdef CONFIG_SMP
> +	/*
> +	 * Will use reserve that does not require slab operation during
> +	 * early boot.
> +	 */
>  	BUILD_BUG_ON(PERCPU_DYNAMIC_EARLY_SIZE <
>  			SLUB_PAGE_SHIFT * sizeof(struct kmem_cache_cpu));
> +#else
> +	/*
> +	 * Special hack for UP mode. allocpercpu() falls back to kmalloc
> +	 * operations. So we cannot use that before the slab allocator is up
> +	 * Simply get the smallest possible compound page. The page will be
> +	 * released via kfree() when the cpu caches are resized later.
> +	 */
> +	if (slab_state < UP)
> +		s->cpu_slab = (__percpu void *)__get_free_page(GFP_NOWAIT, 1);

__get_free_pages() takes an order argument.

> +	else
> +#endif
> 
>  	s->cpu_slab = alloc_percpu(struct kmem_cache_cpu);
> 
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/