[PATCH v2 2/4] balloon_compaction: update the NR_BALLOON_PAGES state

[Nico Pache <npache@xxxxxxxxxx>]

Update the NR_BALLOON_PAGES counter when pages are added or removed using
the balloon compaction interface.

The virtio, Vmware, and pseries-cmm balloon drivers utilize the
balloon_compaction interface to allocate and free balloon pages. Other
balloon drivers will have to maintain this counter manually.

Signed-off-by: Nico Pache <npache@xxxxxxxxxx>
---
 mm/balloon_compaction.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/mm/balloon_compaction.c b/mm/balloon_compaction.c
index 6597ebea8ae2..d3e00731e262 100644
--- a/mm/balloon_compaction.c
+++ b/mm/balloon_compaction.c
@@ -24,6 +24,7 @@ static void balloon_page_enqueue_one(struct balloon_dev_info 
*b_dev_info,
        balloon_page_insert(b_dev_info, page);
        unlock_page(page);
        __count_vm_event(BALLOON_INFLATE);
+       inc_node_page_state(page, NR_BALLOON_PAGES);
 }
 
 /**
@@ -103,6 +104,7 @@ size_t balloon_page_list_dequeue(struct balloon_dev_info 
*b_dev_info,
                __count_vm_event(BALLOON_DEFLATE);
                list_add(&page->lru, pages);
                unlock_page(page);
+               dec_node_page_state(page, NR_BALLOON_PAGES);
                n_pages++;
        }
        spin_unlock_irqrestore(&b_dev_info->pages_lock, flags);
-- 
2.48.1