added initial slab code to the kernel. It is still unused, and there is still no VM interaction.

git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@20832 a95241bf-73f2-0310-859d-f6bbb57e9c96

headers/private/kernel/slab/Strategy.h

@@ -0,0 +1,53 @@
+/*
+ * Copyright 2007, Hugo Santos. All Rights Reserved.
+ * Distributed under the terms of the MIT License.
+ *
+ * Authors:
+ *      Hugo Santos, [email protected]
+ */
+
+#ifndef _SLAB_STRATEGY_H_
+#define _SLAB_STRATEGY_H_
+
+#include <slab/Base.h>
+
+
+template<typename Backend>
+class BaseCacheStrategy {
+protected:
+	typedef cache_object_link	ObjectLink;
+	typedef cache_slab			BaseSlab;
+
+	BaseCacheStrategy(base_cache *parent)
+		: fParent(parent) {}
+
+	size_t SlabSize(size_t tailSpace) const
+	{
+		size_t pageCount = (kMinimumSlabItems * fParent->object_size
+			+ tailSpace) / Backend::kPageSize;
+		if (pageCount < 1)
+			pageCount = 1;
+		return pageCount * Backend::kPageSize;
+	}
+
+	struct Slab : BaseSlab {
+		typename Backend::AllocationID id;
+	};
+
+	BaseSlab *_ConstructSlab(Slab *slab, void *pages, size_t tailSpace,
+		ObjectLink *(*getLink)(void *parent, void *object), void *parent)
+	{
+		return base_cache_construct_slab(fParent, slab, pages,
+			SlabSize(tailSpace) - tailSpace, getLink, parent);
+	}
+
+	void _DestructSlab(BaseSlab *slab)
+	{
+		base_cache_destruct_slab(fParent, slab);
+		Backend::FreePages(fParent, ((Slab *)slab)->id);
+	}
+
+	base_cache *fParent;
+};
+
+#endif