diff -upN reference/fs/proc/base.c current/fs/proc/base.c
--- reference/fs/proc/base.c	2004-03-11 14:35:11.000000000 -0800
+++ current/fs/proc/base.c	2004-04-29 10:39:26.000000000 -0700
@@ -58,6 +58,7 @@ enum pid_directory_inos {
 	PROC_TGID_STAT,
 	PROC_TGID_STATM,
 	PROC_TGID_MAPS,
+	PROC_TGID_MAPS_STATS,
 	PROC_TGID_MOUNTS,
 	PROC_TGID_WCHAN,
 #ifdef CONFIG_SECURITY
@@ -81,6 +82,7 @@ enum pid_directory_inos {
 	PROC_TID_STAT,
 	PROC_TID_STATM,
 	PROC_TID_MAPS,
+	PROC_TID_MAPS_STATS,
 	PROC_TID_MOUNTS,
 	PROC_TID_WCHAN,
 #ifdef CONFIG_SECURITY
@@ -112,6 +114,7 @@ static struct pid_entry tgid_base_stuff[
 	E(PROC_TGID_STAT,      "stat",    S_IFREG|S_IRUGO),
 	E(PROC_TGID_STATM,     "statm",   S_IFREG|S_IRUGO),
 	E(PROC_TGID_MAPS,      "maps",    S_IFREG|S_IRUGO),
+	E(PROC_TGID_MAPS_STATS,"maps_stats", S_IFREG|S_IRUGO),
 	E(PROC_TGID_MEM,       "mem",     S_IFREG|S_IRUSR|S_IWUSR),
 	E(PROC_TGID_CWD,       "cwd",     S_IFLNK|S_IRWXUGO),
 	E(PROC_TGID_ROOT,      "root",    S_IFLNK|S_IRWXUGO),
@@ -134,6 +137,7 @@ static struct pid_entry tid_base_stuff[]
 	E(PROC_TID_STAT,       "stat",    S_IFREG|S_IRUGO),
 	E(PROC_TID_STATM,      "statm",   S_IFREG|S_IRUGO),
 	E(PROC_TID_MAPS,       "maps",    S_IFREG|S_IRUGO),
+	E(PROC_TID_MAPS_STATS, "maps_stats", S_IFREG|S_IRUGO),
 	E(PROC_TID_MEM,        "mem",     S_IFREG|S_IRUSR|S_IWUSR),
 	E(PROC_TID_CWD,        "cwd",     S_IFLNK|S_IRWXUGO),
 	E(PROC_TID_ROOT,       "root",    S_IFLNK|S_IRWXUGO),
@@ -473,6 +477,25 @@ static struct file_operations proc_maps_
 	.release	= seq_release,
 };
 
+extern struct seq_operations proc_pid_maps_stats_op;
+static int maps_stats_open(struct inode *inode, struct file *file)
+{
+	struct task_struct *task = proc_task(inode);
+	int ret = seq_open(file, &proc_pid_maps_stats_op);
+	if (!ret) {
+		struct seq_file *m = file->private_data;
+		m->private = task;
+	}
+	return ret;
+}
+
+static struct file_operations proc_maps_stats_operations = {
+	.open		= maps_stats_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= seq_release,
+};
+
 extern struct seq_operations mounts_op;
 static int mounts_open(struct inode *inode, struct file *file)
 {
@@ -1353,6 +1376,10 @@ static struct dentry *proc_pident_lookup
 		case PROC_TGID_MAPS:
 			inode->i_fop = &proc_maps_operations;
 			break;
+		case PROC_TID_MAPS_STATS:
+		case PROC_TGID_MAPS_STATS:
+			inode->i_fop = &proc_maps_stats_operations;
+			break;
 		case PROC_TID_MEM:
 		case PROC_TGID_MEM:
 			inode->i_op = &proc_mem_inode_operations;
diff -upN reference/fs/proc/task_mmu.c current/fs/proc/task_mmu.c
--- reference/fs/proc/task_mmu.c	2004-02-04 16:24:24.000000000 -0800
+++ current/fs/proc/task_mmu.c	2004-04-29 10:39:26.000000000 -0700
@@ -112,6 +112,115 @@ static int show_map(struct seq_file *m, 
 	return 0;
 }
 
+static int show_map_stats(struct seq_file *m, void *v)
+{
+	unsigned long pfn, vaddr, vma_end, end, pgds = 0, pmds = 0, ptes = 0;
+	unsigned long total_pages = 0, zero_pages = 0, not_present = 0;
+	unsigned long mapping = 0, multi_count = 0, single_count = 0, none = 0;
+	unsigned long node_pages[MAX_NUMNODES];
+	struct vm_area_struct *vma = v;
+	struct mm_struct *mm = vma->vm_mm;
+	pgd_t *pgd_p, *pgd_start, *pgd_end;
+	pmd_t *pmd_p, *pmd_start, *pmd_end;
+	pte_t *pte_p, *pte_start, *pte_end;
+	pte_t pte;
+	struct page *page;
+	int node;
+
+	show_map(m, v);
+
+	for (node = 0; node < numnodes; ++node)
+		node_pages[node] = 0;
+
+	if (!mm) {
+		seq_printf(m, "mm is NULL!\n");
+		return 0;
+	}
+	if (is_vm_hugetlb_page(vma))
+		return 0;
+
+	spin_lock(&mm->page_table_lock);
+
+	vaddr = vma->vm_start & PAGE_MASK;
+	/* "vma->vm_end - 1" is the last valid address. */
+	vma_end = (vma->vm_end - 1) & PAGE_MASK;
+
+	/* Loop over the pgd entries */
+	pgd_start = pgd_offset(mm, vaddr);
+	pgd_end = pgd_offset(mm, vma_end);
+	for (pgd_p = pgd_start; pgd_p <= pgd_end; pgd_p++,
+			vaddr = (vaddr+PGDIR_SIZE) & PGDIR_MASK) {
+		++pgds;
+
+		if (pgd_none(*pgd_p) || pgd_bad(*pgd_p))
+			continue;
+
+		/* Loop over the pmd entries */
+		pmd_start = pmd_offset(pgd_p, vaddr);
+		end = min(vma_end, ((vaddr+PGDIR_SIZE) & PGDIR_MASK) - 1);
+		pmd_end = pmd_offset(pgd_p, end);
+		for (pmd_p = pmd_start; pmd_p <= pmd_end; pmd_p++,
+				vaddr = (vaddr+PMD_SIZE) & PMD_MASK) {
+			++pmds;
+
+			if (pmd_none(*pmd_p) || pmd_bad (*pmd_p))
+				continue;
+
+			/* Loop over the pte entries */
+			pte_start = pte_offset_map(pmd_p, vaddr);
+			end = min(vma_end, ((vaddr+PMD_SIZE) & PMD_MASK) - 1);
+			pte_end = pte_offset_kernel(pmd_p, end);
+			for (pte_p = pte_start; pte_p <= pte_end; pte_p++,
+					vaddr += PAGE_SIZE) {
+				++ptes;
+
+				pte = *pte_p;
+				++total_pages;
+				if (pte_none(pte)) {
+					++none;
+					continue;
+				}
+				if (pte_present(pte)) {
+					pfn = pte_pfn(pte);
+					if (!pfn) {
+						++zero_pages;
+						continue;
+					}
+					if (!pfn_valid(pfn)) {
+						continue;
+					}
+					node_pages[pfn_to_nid(pfn)]++;
+					page = pfn_to_page(pfn);
+					/* if (PageDirect(page))
+					 *	single_count++;
+					 * else 
+					 *	multi_count++;
+					 */
+					/* all mapping should be the same */
+					mapping = (unsigned long) page->mapping;
+				} else {
+					++not_present;
+				}
+			}
+			pte_unmap(pte_start);
+		}
+	}
+	spin_unlock(&mm->page_table_lock);
+
+	seq_printf(m, "    mapping: %08lx\n", mapping);
+	seq_printf(m, "%5lu zero:%lu none:%lu absent:%lu single:%lu multi:%lu\n", 
+			total_pages, none, zero_pages, not_present, 
+			single_count, multi_count);
+#ifdef CONFIG_NUMA
+	seq_printf(m, "    NUMA: ");
+	for (node = 0; node < numnodes; ++node)
+		seq_printf(m, "%d:%lu ", node, node_pages[node]);
+	seq_printf(m, "\n");
+#endif
+
+	return 0;
+}
+
 static void *m_start(struct seq_file *m, loff_t *pos)
 {
 	struct task_struct *task = m->private;
@@ -165,3 +274,11 @@ struct seq_operations proc_pid_maps_op =
 	.stop	= m_stop,
 	.show	= show_map
 };
+
+struct seq_operations proc_pid_maps_stats_op = {
+	.start	= m_start,
+	.next	= m_next,
+	.stop	= m_stop,
+	.show	= show_map_stats
+};
+
diff -upN reference/include/linux/rmap.h current/include/linux/rmap.h
--- reference/include/linux/rmap.h	2004-04-29 10:39:10.000000000 -0700
+++ current/include/linux/rmap.h	2004-04-29 10:39:26.000000000 -0700
@@ -8,8 +8,8 @@
 #include <linux/config.h>
 #include <linux/linkage.h>
 
-#define rmap_lock(page)    bit_spin_lock(PG_rmaplock, &(page)->flags)
-#define rmap_unlock(page)  bit_spin_unlock(PG_rmaplock, &(page)->flags)
+#define rmap_lock(page)    bit_spin_lock(PG_rmaplock, (unsigned long *)&(page)->flags)
+#define rmap_unlock(page)  bit_spin_unlock(PG_rmaplock, (unsigned long *)&(page)->flags)
 
 #ifdef CONFIG_MMU