mm/damon/vaddr: support folio of neither HPAGE_PMD_SIZE nor PAGE_SIZE

DAMON virtual address space monitoring operations set treats folios having
non-HPAGE_PMD_SIZE size as having PAGE_SIZE size.  Use the exact size of
the folio.

Link: https://lkml.kernel.org/r/20230109213335.62525-3-sj@kernel.orgSigned-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/damon/vaddr.c

@@ -475,7 +475,7 @@ static int damon_young_pmd_entry(pmd_t *pmd, unsigned long addr,
 		goto out;
 	if (pte_young(*pte) || !folio_test_idle(folio) ||
 			mmu_notifier_test_young(walk->mm, addr)) {
-		*priv->folio_sz = PAGE_SIZE;
+		*priv->folio_sz = folio_size(folio);
 		priv->young = true;
 	}
 	folio_put(folio);