staging: ramster: xvmalloc allocation files

RAMster implements peer-to-peer transcendent memory, allowing a "cluster"
of kernels to dynamically pool their RAM.

Zcache is in the process of converting allocators, from xvmalloc to zsmalloc.
Further, RAMster V5 testing to date has been done only with xvmalloc.
To avoid merging problems, a linux-3.2 copy of xvmalloc is incorporated by
this patch.  Later patches will be able to eliminate xvmalloc and use zsmalloc.
Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/ramster/xvmalloc.h

+/*
+ * xvmalloc memory allocator
+ *
+ * Copyright (C) 2008, 2009, 2010  Nitin Gupta
+ *
+ * This code is released using a dual license strategy: BSD/GPL
+ * You can choose the licence that better fits your requirements.
+ *
+ * Released under the terms of 3-clause BSD License
+ * Released under the terms of GNU General Public License Version 2.0
+ */
+
+#ifndef _XV_MALLOC_H_
+#define _XV_MALLOC_H_
+
+#include <linux/types.h>
+
+struct xv_pool;
+
+struct xv_pool *xv_create_pool(void);
+void xv_destroy_pool(struct xv_pool *pool);
+
+int xv_malloc(struct xv_pool *pool, u32 size, struct page **page,
+			u32 *offset, gfp_t flags);
+void xv_free(struct xv_pool *pool, struct page *page, u32 offset);
+
+u32 xv_get_object_size(void *obj);
+u64 xv_get_total_size_bytes(struct xv_pool *pool);
+
+#endif

drivers/staging/ramster/xvmalloc_int.h

+/*
+ * xvmalloc memory allocator
+ *
+ * Copyright (C) 2008, 2009, 2010  Nitin Gupta
+ *
+ * This code is released using a dual license strategy: BSD/GPL
+ * You can choose the licence that better fits your requirements.
+ *
+ * Released under the terms of 3-clause BSD License
+ * Released under the terms of GNU General Public License Version 2.0
+ */
+
+#ifndef _XV_MALLOC_INT_H_
+#define _XV_MALLOC_INT_H_
+
+#include <linux/kernel.h>
+#include <linux/types.h>
+
+/* User configurable params */
+
+/* Must be power of two */
+#ifdef CONFIG_64BIT
+#define XV_ALIGN_SHIFT 3
+#else
+#define XV_ALIGN_SHIFT	2
+#endif
+#define XV_ALIGN	(1 << XV_ALIGN_SHIFT)
+#define XV_ALIGN_MASK	(XV_ALIGN - 1)
+
+/* This must be greater than sizeof(link_free) */
+#define XV_MIN_ALLOC_SIZE	32
+#define XV_MAX_ALLOC_SIZE	(PAGE_SIZE - XV_ALIGN)
+
+/*
+ * Free lists are separated by FL_DELTA bytes
+ * This value is 3 for 4k pages and 4 for 64k pages, for any
+ * other page size, a conservative (PAGE_SHIFT - 9) is used.
+ */
+#if PAGE_SHIFT == 16
+#define FL_DELTA_SHIFT 4
+#else
+#define FL_DELTA_SHIFT (PAGE_SHIFT - 9)
+#endif
+#define FL_DELTA	(1 << FL_DELTA_SHIFT)
+#define FL_DELTA_MASK	(FL_DELTA - 1)
+#define NUM_FREE_LISTS	((XV_MAX_ALLOC_SIZE - XV_MIN_ALLOC_SIZE) \
+				/ FL_DELTA + 1)
+
+#define MAX_FLI		DIV_ROUND_UP(NUM_FREE_LISTS, BITS_PER_LONG)
+
+/* End of user params */
+
+enum blockflags {
+	BLOCK_FREE,
+	PREV_FREE,
+	__NR_BLOCKFLAGS,
+};
+
+#define FLAGS_MASK	XV_ALIGN_MASK
+#define PREV_MASK	(~FLAGS_MASK)
+
+struct freelist_entry {
+	struct page *page;
+	u16 offset;
+	u16 pad;
+};
+
+struct link_free {
+	struct page *prev_page;
+	struct page *next_page;
+	u16 prev_offset;
+	u16 next_offset;
+};
+
+struct block_header {
+	union {
+		/* This common header must be XV_ALIGN bytes */
+		u8 common[XV_ALIGN];
+		struct {
+			u16 size;
+			u16 prev;
+		};
+	};
+	struct link_free link;
+};
+
+struct xv_pool {
+	ulong flbitmap;
+	ulong slbitmap[MAX_FLI];
+	u64 total_pages;	/* stats */
+	struct freelist_entry freelist[NUM_FREE_LISTS];
+	spinlock_t lock;
+};
+
+#endif