From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
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>
---
include/linux/page-flags.h | 1 +
mm/highmem.c | 2 ++
mm/page_alloc.c | 1 +
3 files changed, 4 insertions(+)
diff -puN include/linux/page-flags.h~count-bounce-buffer-pages-in-vmstat include/linux/page-flags.h
--- 25/include/linux/page-flags.h~count-bounce-buffer-pages-in-vmstat 2005-04-26 23:49:04.159291184 -0700
+++ 25-akpm/include/linux/page-flags.h 2005-04-26 23:49:29.364459416 -0700
@@ -131,6 +131,7 @@ struct page_state {
unsigned long allocstall; /* direct reclaim calls */
unsigned long pgrotated; /* pages rotated to tail of the LRU */
+ unsigned long nr_bounce; /* pages for bounce buffers */
};
extern void get_page_state(struct page_state *ret);
diff -puN mm/highmem.c~count-bounce-buffer-pages-in-vmstat mm/highmem.c
--- 25/mm/highmem.c~count-bounce-buffer-pages-in-vmstat 2005-04-26 23:49:04.160291032 -0700
+++ 25-akpm/mm/highmem.c 2005-04-26 23:49:04.166290120 -0700
@@ -325,6 +325,7 @@ static void bounce_end_io(struct bio *bi
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_q
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 -puN mm/page_alloc.c~count-bounce-buffer-pages-in-vmstat mm/page_alloc.c
--- 25/mm/page_alloc.c~count-bounce-buffer-pages-in-vmstat 2005-04-26 23:49:04.162290728 -0700
+++ 25-akpm/mm/page_alloc.c 2005-04-26 23:49:49.571387496 -0700
@@ -2010,6 +2010,7 @@ static char *vmstat_text[] = {
"allocstall",
"pgrotated",
+ "nr_bounce",
};
static void *vmstat_start(struct seq_file *m, loff_t *pos)
_