X-Git-Url: http://drtracing.org/?a=blobdiff_plain;f=mm%2Fhuge_memory.c;h=9c0b17295ba039da0b7e9cc1fb852822ba46172c;hb=0f74d82d80e653545f4190c96a25f3b6751a8370;hp=70e7429fd8ea81eca9c9eab3c1277f69ee0c7cbe;hpb=1667918b6483b12a6496bf54151b827b8235d7b1;p=deliverable%2Flinux.git

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 70e7429fd8ea..9c0b17295ba0 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -882,6 +882,7 @@ int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm,
 		ret = 0;
 		goto out_unlock;
 	}
+
 	if (unlikely(pmd_trans_splitting(pmd))) {
 		/* split huge page running from under us */
 		spin_unlock(src_ptl);
@@ -1299,6 +1300,17 @@ int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
 	if (unlikely(!pmd_same(pmd, *pmdp)))
 		goto out_unlock;
 
+	/*
+	 * If there are potential migrations, wait for completion and retry
+	 * without disrupting NUMA hinting information. Do not relock and
+	 * check_same as the page may no longer be mapped.
+	 */
+	if (unlikely(pmd_trans_migrating(*pmdp))) {
+		spin_unlock(ptl);
+		wait_migrate_huge_page(vma->anon_vma, pmdp);
+		goto out;
+	}
+
 	page = pmd_page(pmd);
 	BUG_ON(is_huge_zero_page(page));
 	page_nid = page_to_nid(page);
@@ -1329,12 +1341,7 @@ int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
 			goto clear_pmdnuma;
 	}
 
-	/*
-	 * If there are potential migrations, wait for completion and retry. We
-	 * do not relock and check_same as the page may no longer be mapped.
-	 * Furtermore, even if the page is currently misplaced, there is no
-	 * guarantee it is still misplaced after the migration completes.
-	 */
+	/* Migration could have started since the pmd_trans_migrating check */
 	if (!page_locked) {
 		spin_unlock(ptl);
 		wait_on_page_locked(page);