diff -Naur linux-2.6.28/mm/precache.c linux-2.6.28-tmem/mm/precache.c
--- linux-2.6.28/mm/precache.c	1969-12-31 17:00:00.000000000 -0700
+++ linux-2.6.28-tmem/mm/precache.c	2009-01-05 18:07:10.000000000 -0700
@@ -0,0 +1,106 @@
+/*
+ * linux/mm/precache.c
+ *
+ * Copyright (C) 2008 Dan Magenheimer, Oracle Corp.
+ */
+
+#include <linux/precache.h>
+#include <linux/module.h>
+#include <asm/xen/hypercall.h>
+#include <asm/xen/hypervisor.h>
+#include <xen/page.h>
+#include <xen/interface/xen.h>
+#include "tmem.h"
+
+static int precache_auto_allocate = 0;
+
+int precache_put(struct address_space *mapping, unsigned long index,
+ struct page *page)
+{
+	uint32_t tmem_pool = mapping->host->i_sb->precache_poolid;
+ 	uint64_t obj = (unsigned long) mapping->host->i_ino;
+	uint32_t ind = (uint32_t) index;
+	unsigned long mfn = pfn_to_mfn(page_to_pfn(page));
+
+	if ((int32_t)tmem_pool < 0) {
+		if (!precache_auto_allocate) return 0;
+		/* a put on a non-existent precache will auto-allocate one */
+		if ((tmem_pool = tmem_new_pool(0,0,0)) < 0)
+			return 0;
+		printk("Mapping superblock for s_id=%s to precache_id=%d\n",
+				mapping->host->i_sb->s_id, tmem_pool);
+		mapping->host->i_sb->precache_poolid = tmem_pool;
+	}
+	if (ind != index) return 0;
+
+	mb();
+	return tmem_op(TMEM_PUT_PAGE, tmem_pool, obj, ind, mfn, 0, 0, 0);
+}
+
+int precache_get(struct address_space *mapping, unsigned long index,
+ struct page *empty_page)
+{
+	uint32_t tmem_pool = mapping->host->i_sb->precache_poolid;
+ 	uint64_t obj = (unsigned long) mapping->host->i_ino;
+	uint32_t ind = (uint32_t) index;
+	unsigned long mfn = pfn_to_mfn(page_to_pfn(empty_page));
+
+	if ((int32_t)tmem_pool < 0) return 0;
+	if (ind != index) return 0;
+
+	return tmem_op(TMEM_GET_PAGE, tmem_pool, obj, ind, mfn, 0, 0, 0);
+}
+EXPORT_SYMBOL(precache_get);
+
+int precache_flush(struct address_space *mapping, unsigned long index)
+{
+	uint32_t tmem_pool = mapping->host->i_sb->precache_poolid;
+ 	uint64_t obj = (unsigned long) mapping->host->i_ino;
+	uint32_t ind = (uint32_t) index;
+
+	if ((int32_t)tmem_pool < 0) return 0;
+	if (ind != index) return 0;
+
+	return tmem_op(TMEM_FLUSH_PAGE, tmem_pool, obj, ind, 0, 0, 0, 0);
+}
+EXPORT_SYMBOL(precache_flush);
+
+int precache_flush_inode(struct address_space *mapping)
+{
+	uint32_t tmem_pool = mapping->host->i_sb->precache_poolid;
+ 	uint64_t obj = (unsigned long) mapping->host->i_ino;
+
+	if ((int32_t)tmem_pool < 0) return 0;
+
+	return tmem_op(TMEM_FLUSH_OBJECT, tmem_pool, obj, 0, 0, 0, 0, 0);
+}
+EXPORT_SYMBOL(precache_flush_inode);
+
+int precache_flush_filesystem(struct super_block *sb)
+{
+	uint32_t tmem_pool = sb->precache_poolid;
+	int ret;
+
+	if ((int32_t)tmem_pool < 0) return 0;
+	ret = tmem_op(TMEM_DESTROY_POOL, tmem_pool, 0, 0, 0, 0, 0, 0);
+	if (!ret) return 0;
+	printk("Unmapping superblock for s_id=%s from precache_id=%d\n",
+		sb->s_id, ret);
+	sb->precache_poolid = 0;
+	return 1;
+}
+EXPORT_SYMBOL(precache_flush_filesystem);
+
+void precache_init(struct super_block *sb)
+{
+	sb->precache_poolid = tmem_new_pool(0,0,0);
+}
+EXPORT_SYMBOL(precache_init);
+
+void shared_precache_init(struct super_block *sb, char *uuid)
+{
+	uint64_t uuid_lo = *(uint64_t *)uuid;
+	uint64_t uuid_hi = *(uint64_t *)(&uuid[8]);
+	sb->precache_poolid = tmem_new_pool(uuid_lo,uuid_hi,TMEM_POOL_SHARED);
+}
+EXPORT_SYMBOL(shared_precache_init);