Re: [RFC V2 SLEB 05/14] SLUB: is_kmalloc_cache

[David Rientjes <rientjes@google.com>]

On Fri, 21 May 2010, Christoph Lameter wrote:

> Index: linux-2.6/mm/slub.c
> ===================================================================
> --- linux-2.6.orig/mm/slub.c	2010-05-12 14:46:58.000000000 -0500
> +++ linux-2.6/mm/slub.c	2010-05-12 14:49:37.000000000 -0500
> @@ -312,6 +312,11 @@ static inline int oo_objects(struct kmem
>  	return x.x & OO_MASK;
>  }
>  
> +static int is_kmalloc_cache(struct kmem_cache *s)
> +{
> +	return (s < kmalloc_caches + KMALLOC_CACHES && s >= kmalloc_caches);
> +}
> +
>  #ifdef CONFIG_SLUB_DEBUG
>  /*
>   * Debug settings:
> @@ -2076,7 +2081,7 @@ static DEFINE_PER_CPU(struct kmem_cache_
>  
>  static inline int alloc_kmem_cache_cpus(struct kmem_cache *s, gfp_t flags)
>  {
> -	if (s < kmalloc_caches + KMALLOC_CACHES && s >= kmalloc_caches)
> +	if (is_kmalloc_cache(s))
>  		/*
>  		 * Boot time creation of the kmalloc array. Use static per cpu data
>  		 * since the per cpu allocator is not available yet.
> @@ -2158,8 +2163,7 @@ static int init_kmem_cache_nodes(struct 
>  	int node;
>  	int local_node;
>  
> -	if (slab_state >= UP && (s < kmalloc_caches ||
> -			s >= kmalloc_caches + KMALLOC_CACHES))
> +	if (slab_state >= UP && !is_kmalloc_cache(s))
>  		local_node = page_to_nid(virt_to_page(s));
>  	else
>  		local_node = 0;

Looks good, how about extending it to dma_kmalloc_cache() as well?
---
diff --git a/mm/slub.c b/mm/slub.c
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -2641,13 +2641,12 @@ static noinline struct kmem_cache *dma_kmalloc_cache(int index, gfp_t flags)
 	text = kasprintf(flags & ~SLUB_DMA, "kmalloc_dma-%d",
 			 (unsigned int)realsize);
 
-	s = NULL;
 	for (i = 0; i < KMALLOC_CACHES; i++)
 		if (!kmalloc_caches[i].size)
 			break;
 
-	BUG_ON(i >= KMALLOC_CACHES);
 	s = kmalloc_caches + i;
+	BUG_ON(!is_kmalloc_cache(s));
 
 	/*
 	 * Must defer sysfs creation to a workqueue because we don't know

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