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>

5 files changed, 16 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,
diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index 82d7ee98c675..0cf9d1cd9bd2 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -447,6 +447,7 @@ nfs_mark_request_commit(struct nfs_page *req)
                         NFS_PAGE_TAG_COMMIT);
         spin_unlock(&inode->i_lock);
         inc_zone_page_state(req->wb_page, NR_UNSTABLE_NFS);
+        inc_bdi_stat(req->wb_page->mapping->backing_dev_info, BDI_RECLAIMABLE);
         __mark_inode_dirty(inode, I_DIRTY_DATASYNC);
 }
 
@@ -533,6 +534,8 @@ static void nfs_cancel_commit_list(struct list_head *head)
         while(!list_empty(head)) {
                 req = nfs_list_entry(head->next);
                 dec_zone_page_state(req->wb_page, NR_UNSTABLE_NFS);
+                dec_bdi_stat(req->wb_page->mapping->backing_dev_info,
+                                BDI_RECLAIMABLE);
                 nfs_list_remove_request(req);
                 clear_bit(PG_NEED_COMMIT, &(req)->wb_flags);
                 nfs_inode_remove_request(req);
@@ -1193,6 +1196,8 @@ nfs_commit_list(struct inode *inode, struct list_head *head, int how)
                 nfs_list_remove_request(req);
                 nfs_mark_request_commit(req);
                 dec_zone_page_state(req->wb_page, NR_UNSTABLE_NFS);
+                dec_bdi_stat(req->wb_page->mapping->backing_dev_info,
+                                BDI_RECLAIMABLE);
                 nfs_clear_page_tag_locked(req);
         }
         return -ENOMEM;
@@ -1218,6 +1223,8 @@ static void nfs_commit_done(struct rpc_task *task, void *calldata)
                 nfs_list_remove_request(req);
                 clear_bit(PG_NEED_COMMIT, &(req)->wb_flags);
                 dec_zone_page_state(req->wb_page, NR_UNSTABLE_NFS);
+                dec_bdi_stat(req->wb_page->mapping->backing_dev_info,
+                                BDI_RECLAIMABLE);
 
                 dprintk("NFS: commit (%s/%Ld %d@%Ld)",
                         req->wb_context->path.dentry->d_inode->i_sb->s_id,
diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h
index f7677ff80cc5..bfae09d2a1eb 100644
--- a/include/linux/backing-dev.h
+++ b/include/linux/backing-dev.h
@@ -27,6 +27,7 @@ enum bdi_state {
 typedef int (congested_fn)(void *, int);
 
 enum bdi_stat_item {
+        BDI_RECLAIMABLE,
         NR_BDI_STAT_ITEMS
 };
 
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index d821321326e3..9b3c4ee62abf 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -827,6 +827,8 @@ int __set_page_dirty_nobuffers(struct page *page)
                         WARN_ON_ONCE(!PagePrivate(page) && !PageUptodate(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,
@@ -961,6 +963,8 @@ int clear_page_dirty_for_io(struct page *page)
                  */
                 if (TestClearPageDirty(page)) {
                         dec_zone_page_state(page, NR_FILE_DIRTY);
+                        dec_bdi_stat(mapping->backing_dev_info,
+                                        BDI_RECLAIMABLE);
                         return 1;
                 }
                 return 0;
diff --git a/mm/truncate.c b/mm/truncate.c
index 5cdfbc1a59fd..ff78505453d4 100644
--- a/mm/truncate.c
+++ b/mm/truncate.c
@@ -72,6 +72,8 @@ void cancel_dirty_page(struct page *page, unsigned int account_size)
                 struct address_space *mapping = page->mapping;
                 if (mapping && mapping_cap_account_dirty(mapping)) {
                         dec_zone_page_state(page, NR_FILE_DIRTY);
+                        dec_bdi_stat(mapping->backing_dev_info,
+                                        BDI_RECLAIMABLE);
                         if (account_size)
                                 task_io_account_cancelled_write(account_size);
                 }