[RFC 2/8] slab allocator: Make DMA support configurable

Christoph Lameter
2006-07-08T00:07:52Z

Support slab without ZONE_SLAB.

If CONFIG_ZONE_DMA is not defined then drop support for ZONE_DMA from
the slab allocator.

Do not create the special DMA slab series for kmalloc and always
return memory from ZONE_NORMAL.

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

Index: linux-2.6.17-mm6/mm/slab.c
===================================================================
--- linux-2.6.17-mm6.orig/mm/slab.c 2006-07-03 13:47:22.651238848 -0700
+++ linux-2.6.17-mm6/mm/slab.c 2006-07-03 21:39:07.050259199 -0700
@@ -650,11 +650,17 @@ EXPORT_SYMBOL(malloc_sizes);
/* Must match cache_sizes above. Out of line to keep cache footprint low. */
struct cache_names {
char *name;
+#ifdef CONFIG_ZONE_DMA
char *name_dma;
+#endif
};

static struct cache_names __initdata cache_names[] = {
+#ifdef CONFIG_ZONE_DMA
#define CACHE(x) { .name = "size-" #x, .name_dma = "size-" #x "(DMA)" },
+#else
+#define CACHE(x) { .name = "size-" #x },
+#endif
#include <linux/kmalloc_sizes.h>
{NULL,}
#undef CACHE
@@ -729,7 +735,7 @@ static inline struct kmem_cache *__find_
#endif
while (size > csizep->cs_size)
csizep++;
-
+#ifdef CONFIG_ZONE_DMA
/*
* Really subtle: The last entry with cs->cs_size==ULONG_MAX
* has cs_{dma,}cachep==NULL. Thus no special case
@@ -737,6 +743,7 @@ static inline struct kmem_cache *__find_
*/
if (unlikely(gfpflags & GFP_DMA))
return csizep->cs_dmacachep;
+#endif
return csizep->cs_cachep;
}

@@ -1395,13 +1402,14 @@ void __init kmem_cache_init(void)
ARCH_KMALLOC_FLAGS|SLAB_PANIC,
NULL, NULL);
}
-
+#ifdef CONFIG_ZONE_DMA
sizes->cs_dmacachep = kmem_cache_create(names->name_dma,
sizes->cs_size,
ARCH_KMALLOC_MINALIGN,
ARCH_KMALLOC_FLAGS|SLAB_CACHE_DMA|
SLAB_PANIC,
NULL, NULL);
+#endif
sizes++;
names++;
}
@@ -2179,8 +2187,10 @@ kmem_cache_create (const char *name, siz
cachep->slab_size = slab_size;
cachep->flags = flags;
cachep->gfpflags = 0;
+#ifdef CONFIG_ZONE_DMA
if (flags & SLAB_CACHE_DMA)
cachep->gfpflags |= GFP_DMA;
+#endif
cachep->buffer_size = size;

if (flags & CFLGS_OFF_SLAB)
@@ -2498,10 +2508,12 @@ static void cache_init_objs(struct kmem_

static void kmem_flagcheck(struct kmem_cache *cachep, gfp_t flags)
{
+#ifdef CONFIG_ZONE_DMA
if (flags & SLAB_DMA)
BUG_ON(!(cachep->gfpflags & GFP_DMA));
else
BUG_ON(cachep->gfpflags & GFP_DMA);
+#endif
}

static void *slab_get_obj(struct kmem_cache *cachep, struct slab *slabp,
Index: linux-2.6.17-mm6/include/linux/slab.h
===================================================================
--- linux-2.6.17-mm6.orig/include/linux/slab.h 2006-07-03 21:27:34.756012776 -0700
+++ linux-2.6.17-mm6/include/linux/slab.h 2006-07-03 22:07:16.857980432 -0700
@@ -72,7 +72,9 @@ extern const char *kmem_cache_name(kmem_
struct cache_sizes {
size_t cs_size;
kmem_cache_t *cs_cachep;
+#ifdef CONFIG_ZONE_DMA
kmem_cache_t *cs_dmacachep;
+#endif
};
extern struct cache_sizes malloc_sizes[];

@@ -146,9 +148,13 @@ static inline void *kmalloc(size_t size,
__you_cannot_kmalloc_that_much();
}
found:
+#ifdef CONFIG_ZONE_DMA
return kmem_cache_alloc((flags & GFP_DMA) ?
malloc_sizes[i].cs_dmacachep :
malloc_sizes[i].cs_cachep, flags);
+#else
+ return kmem_cache_alloc(malloc_sizes[i].cs_cachep, flags);
+#endif
}
return __kmalloc(size, flags);
}
@@ -176,9 +182,13 @@ static inline void *kzalloc(size_t size,
__you_cannot_kzalloc_that_much();
}
found:
+#ifdef CONFIG_ZONE_DMA
return kmem_cache_zalloc((flags & GFP_DMA) ?
malloc_sizes[i].cs_dmacachep :
malloc_sizes[i].cs_cachep, flags);
+#else
+ return kmem_cache_zalloc(malloc_sizes[i].cs_cachep, flags);
+#endif
}
return __kzalloc(size, flags);
}