[PATCH 1/2] mm: factor out the numa mapping rebuilding into a new helper

[Baolin Wang <baolin.wang@linux.alibaba.com>]

To support large folio's numa balancing, factor out the numa mapping rebuilding
into a new helper as a preparation.

Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
---
 mm/memory.c | 22 +++++++++++++++-------
 1 file changed, 15 insertions(+), 7 deletions(-)

diff --git a/mm/memory.c b/mm/memory.c
index 62ee4a15092a..c30fb4b95e15 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -5054,6 +5054,20 @@ int numa_migrate_prep(struct folio *folio, struct vm_fault *vmf,
 	return mpol_misplaced(folio, vmf, addr);
 }
 
+static void numa_rebuild_single_mapping(struct vm_fault *vmf, struct vm_area_struct *vma,
+					bool writable)
+{
+	pte_t pte, old_pte;
+
+	old_pte = ptep_modify_prot_start(vma, vmf->address, vmf->pte);
+	pte = pte_modify(old_pte, vma->vm_page_prot);
+	pte = pte_mkyoung(pte);
+	if (writable)
+		pte = pte_mkwrite(pte, vma);
+	ptep_modify_prot_commit(vma, vmf->address, vmf->pte, old_pte, pte);
+	update_mmu_cache_range(vmf, vma, vmf->address, vmf->pte, 1);
+}
+
 static vm_fault_t do_numa_page(struct vm_fault *vmf)
 {
 	struct vm_area_struct *vma = vmf->vma;
@@ -5159,13 +5173,7 @@ static vm_fault_t do_numa_page(struct vm_fault *vmf)
 	 * Make it present again, depending on how arch implements
 	 * non-accessible ptes, some can allow access by kernel mode.
 	 */
-	old_pte = ptep_modify_prot_start(vma, vmf->address, vmf->pte);
-	pte = pte_modify(old_pte, vma->vm_page_prot);
-	pte = pte_mkyoung(pte);
-	if (writable)
-		pte = pte_mkwrite(pte, vma);
-	ptep_modify_prot_commit(vma, vmf->address, vmf->pte, old_pte, pte);
-	update_mmu_cache_range(vmf, vma, vmf->address, vmf->pte, 1);
+	numa_rebuild_single_mapping(vmf, vma, writable);
 	pte_unmap_unlock(vmf->pte, vmf->ptl);
 	goto out;
 }
-- 
2.39.3