[PATCH 2/2] slab: optimize kmalloc_node the same way as kmalloc

[PATCH 2/2] slab: optimize kmalloc_node the same way as kmalloc

[Christoph Hellwig]

Signed-off-by: Christoph Hellwig <hch@lst.de>

Index: linux-2.6/include/linux/slab.h
===================================================================
--- linux-2.6.orig/include/linux/slab.h	2006-07-26 15:30:49.000000000 +0200
+++ linux-2.6/include/linux/slab.h	2006-07-26 15:42:49.000000000 +0200
@@ -213,7 +213,30 @@
 
 #ifdef CONFIG_NUMA
 extern void *kmem_cache_alloc_node(kmem_cache_t *, gfp_t flags, int node);
-extern void *kmalloc_node(size_t size, gfp_t flags, int node);
+extern void *__kmalloc_node(size_t size, gfp_t flags, int node);
+
+static inline void *kmalloc_node(size_t size, gfp_t flags, int node)
+{
+	if (__builtin_constant_p(size)) {
+		int i = 0;
+#define CACHE(x) \
+		if (size <= x) \
+			goto found; \
+		else \
+			i++;
+#include "kmalloc_sizes.h"
+#undef CACHE
+		{
+			extern void __you_cannot_kmalloc_that_much(void);
+			__you_cannot_kmalloc_that_much();
+		}
+found:
+		return kmem_cache_alloc_node((flags & GFP_DMA) ?
+			malloc_sizes[i].cs_dmacachep :
+			malloc_sizes[i].cs_cachep, flags, node);
+	}
+	return __kmalloc_node(size, flags, node);
+}
 #else
 static inline void *kmem_cache_alloc_node(kmem_cache_t *cachep, gfp_t flags, int node)
 {
Index: linux-2.6/mm/slab.c
===================================================================
--- linux-2.6.orig/mm/slab.c	2006-07-26 15:25:28.000000000 +0200
+++ linux-2.6/mm/slab.c	2006-07-26 15:42:49.000000000 +0200
@@ -3317,7 +3317,7 @@
 }
 EXPORT_SYMBOL(kmem_cache_alloc_node);
 
-void *kmalloc_node(size_t size, gfp_t flags, int node)
+void *__kmalloc_node(size_t size, gfp_t flags, int node)
 {
 	struct kmem_cache *cachep;
 

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Re: [PATCH 2/2] slab: optimize kmalloc_node the same way as kmalloc

[Pekka Enberg]

On 8/4/06, Christoph Hellwig <hch@lst.de> wrote:
> +static inline void *kmalloc_node(size_t size, gfp_t flags, int node)

[snip]

I think the optimization was left out on purpose as kmalloc_node() is
slow anyway. No objections from me though.

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Re: [PATCH 2/2] slab: optimize kmalloc_node the same way as kmalloc

[Christoph Lameter]

On Fri, 4 Aug 2006, Christoph Hellwig wrote:

> Signed-off-by: Christoph Hellwig <hch@lst.de>

I actually posted almost the same patch a year ago. But note that 
kmalloc_node() does not use cpucaches and therefore does not
have the speed of kmalloc()

Acked-by: Christoph Lameter <clameter@sgi.com>

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