When a balloon page marked PageZeroed is freed during migration, use put_page_zeroed() to propagate the zeroed hint to the buddy allocator. Previously the hint was silently lost via plain put_page().
Signed-off-by: Michael S. Tsirkin <[email protected]> Assisted-by: Claude:claude-opus-4-6 --- mm/balloon.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/mm/balloon.c b/mm/balloon.c index 96a8f1e20bc6..1bf7eb2642a9 100644 --- a/mm/balloon.c +++ b/mm/balloon.c @@ -324,7 +324,12 @@ static int balloon_page_migrate(struct page *newpage, struct page *page, balloon_page_finalize(page); spin_unlock_irqrestore(&balloon_pages_lock, flags); - put_page(page); + if (PageZeroed(page)) { + __ClearPageZeroed(page); + put_page_zeroed(page); + } else { + put_page(page); + } return 0; } -- MST
