mm: count reclaimable pages per BDI

Count per BDI reclaimable pages; nr_reclaimable = nr_dirty + nr_unstable.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 2 insertions, 0 deletions

diff --git a/fs/buffer.c b/fs/buffer.c
index faceb5eecca9..86e58b1dcd9c 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -710,6 +710,8 @@ static int __set_page_dirty(struct page *page,
 
                 if (mapping_cap_account_dirty(mapping)) {
                         __inc_zone_page_state(page, NR_FILE_DIRTY);
+                        __inc_bdi_stat(mapping->backing_dev_info,
+                                        BDI_RECLAIMABLE);
                         task_io_account_write(PAGE_CACHE_SIZE);
                 }
                 radix_tree_tag_set(&mapping->page_tree,