[PATCH] count bounce buffer pages in vmstat

This is a patch for counting the number of pages for bounce buffers.  It's
shown in /proc/vmstat.

Currently, the number of bounce pages are not counted anywhere.  So, if
there are many bounce pages, it seems that there are leaked pages.  And
it's difficult for a user to imagine the usage of bounce pages.  So, it's
meaningful to show # of bouce pages.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

2 files changed, 3 insertions, 0 deletions

diff --git a/mm/highmem.c b/mm/highmem.c
index d01276506b00..400911599468 100644
--- a/mm/highmem.c
+++ b/mm/highmem.c
@@ -325,6 +325,7 @@ static void bounce_end_io(struct bio *bio, mempool_t *pool, int err)
                         continue;
 
                 mempool_free(bvec->bv_page, pool);      
+                dec_page_state(nr_bounce);
         }
 
         bio_endio(bio_orig, bio_orig->bi_size, err);
@@ -405,6 +406,7 @@ static void __blk_queue_bounce(request_queue_t *q, struct bio **bio_orig,
                 to->bv_page = mempool_alloc(pool, q->bounce_gfp);
                 to->bv_len = from->bv_len;
                 to->bv_offset = from->bv_offset;
+                inc_page_state(nr_bounce);
 
                 if (rw == WRITE) {
                         char *vto, *vfrom;
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 04a35b3d3262..80ce7f2104df 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1897,6 +1897,7 @@ static char *vmstat_text[] = {
         "allocstall",
 
         "pgrotated",
+        "nr_bounce",
 };
 
 static void *vmstat_start(struct seq_file *m, loff_t *pos)