[PATCH RFC v2 18/18] virtio_balloon: mark deflated pages as pre-zeroed

[Michael S. Tsirkin]

Mark deflated pages as pre-zeroed when host_zeroes_pages is set.
Use put_page_hint() with PGHINT_ZEROED during deflation so the
freed pages carry PG_zeroed in the buddy allocator, allowing the
next allocation to skip redundant zeroing.

Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
Assisted-by: Claude:claude-opus-4-6
Assisted-by: cursor-agent:GPT-5.4-xhigh
---
 drivers/virtio/virtio_balloon.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
index 2e524bf6f934..9b35203f579d 100644
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -299,7 +299,10 @@ static void release_pages_balloon(struct virtio_balloon *vb,
 
 	list_for_each_entry_safe(page, next, pages, lru) {
 		list_del(&page->lru);
-		put_page(page); /* balloon reference */
+		if (host_zeroes_pages)
+			put_page_hint(page, PGHINT_ZEROED);
+		else
+			put_page(page);
 	}
 }
 
-- 
MST