balloon_compaction: update the NR_BALLOON_PAGES state

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.

Link: https://lkml.kernel.org/r/20250314213757.244258-3-npache@redhat.com
Signed-off-by: Nico Pache <npache@redhat.com>
Cc: Alexander Atanasov <alexander.atanasov@virtuozzo.com>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: David Hildenbrand <david@redhat.com>
Cc: Dexuan Cui <decui@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Juegren Gross <jgross@suse.com>
Cc: Kanchana P Sridhar <kanchana.p.sridhar@intel.com>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Wei Liu <wei.liu@kernel.org>
Cc: Michael Kelley <mhklinux@outlook.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/balloon_compaction.c b/mm/balloon_compaction.c
index 6597ebea8ae2ac1fc5ce079bad418d96070eec75..d3e00731e262840a35753656fbe9ef1362dfb269 100644 (file)
--- 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);