smaps: account swap entries

Show the amount of swap for each vma.  This can be used to see where all the
swap goes.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Matt Mackall <mpm@selenic.com>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/proc/task_mmu.c

@@ -338,8 +338,7 @@ const struct file_operations proc_maps_operations = {
 #define PSS_SHIFT 12
 
 #ifdef CONFIG_PROC_PAGE_MONITOR
-struct mem_size_stats
-{
+struct mem_size_stats {
 	struct vm_area_struct *vma;
 	unsigned long resident;
 	unsigned long shared_clean;
@@ -347,6 +346,7 @@ struct mem_size_stats
 	unsigned long private_clean;
 	unsigned long private_dirty;
 	unsigned long referenced;
+	unsigned long swap;
 	u64 pss;
 };
 
@@ -363,6 +363,12 @@ static int smaps_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
 	pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
 	for (; addr != end; pte++, addr += PAGE_SIZE) {
 		ptent = *pte;
+
+		if (is_swap_pte(ptent)) {
+			mss->swap += PAGE_SIZE;
+			continue;
+		}
+
 		if (!pte_present(ptent))
 			continue;
 
@@ -421,7 +427,8 @@ static int show_smap(struct seq_file *m, void *v)
 		   "Shared_Dirty:   %8lu kB\n"
 		   "Private_Clean:  %8lu kB\n"
 		   "Private_Dirty:  %8lu kB\n"
-		   "Referenced:     %8lu kB\n",
+		   "Referenced:     %8lu kB\n"
+		   "Swap:           %8lu kB\n",
 		   (vma->vm_end - vma->vm_start) >> 10,
 		   mss.resident >> 10,
 		   (unsigned long)(mss.pss >> (10 + PSS_SHIFT)),
@@ -429,7 +436,8 @@ static int show_smap(struct seq_file *m, void *v)
 		   mss.shared_dirty  >> 10,
 		   mss.private_clean >> 10,
 		   mss.private_dirty >> 10,
-		   mss.referenced >> 10);
+		   mss.referenced >> 10,
+		   mss.swap >> 10);
 
 	return ret;
 }