Display additional information /proc/pid/smaps

This patch includes some additional information to smaps:

Anonymous pages, mapped pages, highest mapping count (to see how many
processes may be using a vma). For NUMA show a map of the nodes on which
the memory was allocated.

This patch can safely display the policy information of a vma because
the mmap_sem readlock is held which prevents the policy layer from
modifying policy under us.

Signed-off-by: Christoph Lameter <christoph@lameter.com>

Index: linux-2.6.13-rc4-mm1/fs/proc/task_mmu.c
===================================================================
--- linux-2.6.13-rc4-mm1.orig/fs/proc/task_mmu.c	2005-08-05 08:47:31.000000000 -0700
+++ linux-2.6.13-rc4-mm1/fs/proc/task_mmu.c	2005-08-05 08:52:34.000000000 -0700
@@ -158,6 +158,10 @@
 	unsigned long shared_dirty;
 	unsigned long private_clean;
 	unsigned long private_dirty;
+	unsigned long anon;
+	unsigned long mapped;
+	unsigned long mapcount_max;
+	unsigned long node[MAX_NUMNODES];
 };
 
 static void smaps_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
@@ -167,6 +171,7 @@
 	pte_t *pte, ptent;
 	unsigned long pfn;
 	struct page *page;
+	int count;
 
 	pte = pte_offset_map(pmd, addr);
 	do {
@@ -191,6 +196,15 @@
 			else
 				mss->private_clean += PAGE_SIZE;
 		}
+
+		count = page_mapcount(page);
+		if (count)
+			mss->mapped += PAGE_SIZE;
+		if (count > mss->mapcount_max)
+			mss->mapcount_max = count;
+		if (PageAnon(page))
+			mss->anon += PAGE_SIZE;
+		mss->node[page_to_nid(page)] += PAGE_SIZE;
 	} while (pte++, addr += PAGE_SIZE, addr != end);
 	pte_unmap(pte - 1);
 	cond_resched_lock(&vma->vm_mm->page_table_lock);
@@ -246,10 +260,15 @@
 
 static int show_smap(struct seq_file *m, void *v)
 {
+	struct task_struct *task = m->private;
 	struct vm_area_struct *vma = v;
 	struct mm_struct *mm = vma->vm_mm;
 	unsigned long vma_len = (vma->vm_end - vma->vm_start);
 	struct mem_size_stats mss;
+#ifdef CONFIG_NUMA
+	int n;
+	char buffer[50];
+#endif
 
 	memset(&mss, 0, sizeof mss);
 
@@ -267,13 +286,33 @@
 		   "Shared_Clean:  %8lu kB\n"
 		   "Shared_Dirty:  %8lu kB\n"
 		   "Private_Clean: %8lu kB\n"
-		   "Private_Dirty: %8lu kB\n",
+		   "Private_Dirty: %8lu kB\n"
+		   "Anonymous:     %8lu kB\n"
+		   "Mapped:        %8lu kB\n"
+		   "MaxMapCount:   %8lu\n",
 		   vma_len >> 10,
 		   mss.resident >> 10,
 		   mss.shared_clean  >> 10,
 		   mss.shared_dirty  >> 10,
 		   mss.private_clean >> 10,
-		   mss.private_dirty >> 10);
+		   mss.private_dirty >> 10,
+		   mss.anon >> 10,
+		   mss.mapped >> 10,
+		   mss.mapcount_max);
+#ifdef CONFIG_NUMA
+	for_each_node(n)
+		if (mss.node[n])
+			seq_printf(m, "Node%-4d:      %8lu kB\n",
+					n, mss.node[n]);
+	/*
+	 * It is safe to access the memory policy of a vma since
+	 * we do hold a read lock on mmap sem which protect from
+	 * changes to the policy in a vma.
+	 */
+	if (mpol_to_str(buffer, sizeof(buffer),
+			get_vma_policy(task, vma, vma->vm_start)) >=0)
+		seq_printf(m, "Memory_Policy: %s\n", buffer);
+#endif
 	return 0;
 }