On 30.06.25 18:01, Lorenzo Stoakes wrote:
On Mon, Jun 30, 2025 at 02:59:46PM +0200, David Hildenbrand wrote:
Let the page freeing code handle clearing the page type.
Why is this advantageous? We want to keep the page marked offline for longer?
Less code? ;)
I will add:
"Being able to identify balloon pages until actually freed is a
requirement for upcoming movable_ops migration changes."
Note that the documentation is extended in patch #27 to mention that.
Acked-by: Zi Yan <ziy@xxxxxxxxxx>
Acked-by: Harry Yoo <harry.yoo@xxxxxxxxxx>
Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
On assumption this UINT_MAX stuff is sane :)) I mean this is straightforward I
guess:
> > Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@xxxxxxxxxx>
---
include/linux/balloon_compaction.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/linux/balloon_compaction.h b/include/linux/balloon_compaction.h
index b9f19da37b089..bfc6e50bd004b 100644
--- a/include/linux/balloon_compaction.h
+++ b/include/linux/balloon_compaction.h
@@ -140,7 +140,7 @@ static inline void balloon_page_finalize(struct page *page)
__ClearPageMovable(page);
set_page_private(page, 0);
}
- __ClearPageOffline(page);
+ /* PageOffline is sticky until the page is freed to the buddy. */
OK so we are relying on this UINT_MAX thing in free_pages_prepare() to handle this.
Yes. Resetting the page_type -> _mapcount to the initial value -1.
--
Cheers,
David / dhildenb
