With new refcounting VMAs can start or end in the middle of huge page.
We need to modify code to call split_huge_page() properly.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
---
mm/migrate.c | 26 ++++++++++++++++++++++----
1 file changed, 22 insertions(+), 4 deletions(-)
diff --git a/mm/migrate.c b/mm/migrate.c
index f1a12ced2531..4dc941100388 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -1235,7 +1235,7 @@ static int do_move_page_to_node_array(struct mm_struct *mm,
vma = find_vma(mm, pp->addr);
if (!vma || pp->addr < vma->vm_start || !vma_migratable(vma))
goto set_status;
-
+retry:
page = follow_page(vma, pp->addr, FOLL_GET);
err = PTR_ERR(page);
@@ -1246,9 +1246,27 @@ static int do_move_page_to_node_array(struct mm_struct *mm,
if (!page)
goto set_status;
- if (PageTransHuge(page) && split_huge_page(page)) {
- err = -EBUSY;
- goto set_status;
+ if (PageTransCompound(page)) {
+ struct page *head_page = compound_head(page);
+
+ /*
+ * split_huge_page() wants pin to be only on head page
+ */
+ if (page != head_page) {
+ get_page(head_page);
+ put_page(page);
+ }
+
+ err = split_huge_page(head_page);
+ if (err) {
+ put_page(head_page);
+ goto set_status;
+ }
+
+ if (page != head_page) {
+ put_page(head_page);
+ goto retry;
+ }
}
/* Use PageReserved to check for zero page */
--
2.1.1
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