[PATCH] optional ZONE_DMA: optional ZONE_DMA in the VM

Make ZONE_DMA optional in core code.

- ifdef all code for ZONE_DMA and related definitions following the example
  for ZONE_DMA32 and ZONE_HIGHMEM.

- Without ZONE_DMA, ZONE_HIGHMEM and ZONE_DMA32 we get to a ZONES_SHIFT of
  0.

- Modify the VM statistics to work correctly without a DMA zone.

- Modify slab to not create DMA slabs if there is no ZONE_DMA.

[akpm@osdl.org: cleanup]
[jdike@addtoit.com: build fix]
[apw@shadowen.org: Simplify calculation of the number of bits we need for ZONES_SHIFT]
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Cc: Andi Kleen <ak@suse.de>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Matthew Wilcox <willy@debian.org>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: Andy Whitcroft <apw@shadowen.org>
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 21 insertions, 9 deletions

diff --git a/include/linux/slab_def.h b/include/linux/slab_def.h
index 4b463e66ddea..5e4364644ed1 100644
--- a/include/linux/slab_def.h
+++ b/include/linux/slab_def.h
@@ -19,7 +19,9 @@
 struct cache_sizes {
         size_t                  cs_size;
         struct kmem_cache       *cs_cachep;
+#ifdef CONFIG_ZONE_DMA
         struct kmem_cache       *cs_dmacachep;
+#endif
 };
 extern struct cache_sizes malloc_sizes[];
 
@@ -39,9 +41,12 @@ static inline void *kmalloc(size_t size, gfp_t flags)
                         __you_cannot_kmalloc_that_much();
                 }
 found:
-                return kmem_cache_alloc((flags & GFP_DMA) ?
-                        malloc_sizes[i].cs_dmacachep :
-                        malloc_sizes[i].cs_cachep, flags);
+#ifdef CONFIG_ZONE_DMA
+                if (flags & GFP_DMA)
+                        return kmem_cache_alloc(malloc_sizes[i].cs_dmacachep,
+                                                flags);
+#endif
+                return kmem_cache_alloc(malloc_sizes[i].cs_cachep, flags);
         }
         return __kmalloc(size, flags);
 }
@@ -62,9 +67,12 @@ static inline void *kzalloc(size_t size, gfp_t flags)
                         __you_cannot_kzalloc_that_much();
                 }
 found:
-                return kmem_cache_zalloc((flags & GFP_DMA) ?
-                        malloc_sizes[i].cs_dmacachep :
-                        malloc_sizes[i].cs_cachep, flags);
+#ifdef CONFIG_ZONE_DMA
+                if (flags & GFP_DMA)
+                        return kmem_cache_zalloc(malloc_sizes[i].cs_dmacachep,
+                                                flags);
+#endif
+                return kmem_cache_zalloc(malloc_sizes[i].cs_cachep, flags);
         }
         return __kzalloc(size, flags);
 }
@@ -88,9 +96,13 @@ static inline void *kmalloc_node(size_t size, gfp_t flags, int node)
                         __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);
+#ifdef CONFIG_ZONE_DMA
+                if (flags & GFP_DMA)
+                        return kmem_cache_alloc_node(malloc_sizes[i].cs_dmacachep,
+                                                flags, node);
+#endif
+                return kmem_cache_alloc_node(malloc_sizes[i].cs_cachep,
+                                                flags, node);
         }
         return __kmalloc_node(size, flags, node);
 }