SLUB: i386 support

SLUB cannot run on i386 at this point because i386 uses the page->private and
page->index field of slab pages for the pgd cache.

Make SLUB run on i386 by replacing the pgd slab cache with a quicklist.
Limit the changes as much as possible. Leave the improvised linked list in place
etc etc. This has been working here for a couple of weeks now.

Acked-by: William Lee Irwin III <wli@holomorphy.com>
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/asm-i386/pgtable.h b/include/asm-i386/pgtable.h
index edce9d5..2394589 100644
--- a/include/asm-i386/pgtable.h
+++ b/include/asm-i386/pgtable.h
@@ -35,17 +35,16 @@
 #define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page))
 extern unsigned long empty_zero_page[1024];
 extern pgd_t swapper_pg_dir[1024];
-extern struct kmem_cache *pgd_cache;
 extern struct kmem_cache *pmd_cache;
 extern spinlock_t pgd_lock;
 extern struct page *pgd_list;
+void check_pgt_cache(void);
 
 void pmd_ctor(void *, struct kmem_cache *, unsigned long);
-void pgd_ctor(void *, struct kmem_cache *, unsigned long);
-void pgd_dtor(void *, struct kmem_cache *, unsigned long);
 void pgtable_cache_init(void);
 void paging_init(void);
 
+
 /*
  * The Linux x86 paging architecture is 'compile-time dual-mode', it
  * implements both the traditional 2-level x86 page tables and the