Re: [PATCH v4 3/3] Revert "mm: numa: defer TLB flush for THP migration as long as possible"

[kbuild test robot <lkp@intel.com>]

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Hi Nadav,

[auto build test ERROR on mmotm/master]
[also build test ERROR on v4.13-rc3 next-20170731]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Nadav-Amit/mm-fixes-of-tlb_flush_pending/20170801-040423
base:   git://git.cmpxchg.org/linux-mmotm.git master
config: i386-randconfig-x009-201731 (attached as .config)
compiler: gcc-6 (Debian 6.2.0-3) 6.2.0 20160901
reproduce:
        # save the attached .config to linux build tree
        make ARCH=i386 

All errors (new ones prefixed by >>):

   In file included from include/asm-generic/bug.h:4:0,
                    from arch/x86/include/asm/bug.h:81,
                    from include/linux/bug.h:4,
                    from include/linux/mmdebug.h:4,
                    from include/linux/mm.h:8,
                    from mm/huge_memory.c:10:
   mm/huge_memory.c: In function 'do_huge_pmd_numa_page':
>> mm/huge_memory.c:1502:27: error: 'mm' undeclared (first use in this function)
     if (mm_tlb_flush_pending(mm))
                              ^
   include/linux/compiler.h:156:30: note: in definition of macro '__trace_if'
     if (__builtin_constant_p(!!(cond)) ? !!(cond) :   \
                                 ^~~~
   mm/huge_memory.c:1502:2: note: in expansion of macro 'if'
     if (mm_tlb_flush_pending(mm))
     ^~
   mm/huge_memory.c:1502:27: note: each undeclared identifier is reported only once for each function it appears in
     if (mm_tlb_flush_pending(mm))
                              ^
   include/linux/compiler.h:156:30: note: in definition of macro '__trace_if'
     if (__builtin_constant_p(!!(cond)) ? !!(cond) :   \
                                 ^~~~
   mm/huge_memory.c:1502:2: note: in expansion of macro 'if'
     if (mm_tlb_flush_pending(mm))
     ^~

vim +/mm +1502 mm/huge_memory.c

  1403	
  1404	/* NUMA hinting page fault entry point for trans huge pmds */
  1405	int do_huge_pmd_numa_page(struct vm_fault *vmf, pmd_t pmd)
  1406	{
  1407		struct vm_area_struct *vma = vmf->vma;
  1408		struct anon_vma *anon_vma = NULL;
  1409		struct page *page;
  1410		unsigned long haddr = vmf->address & HPAGE_PMD_MASK;
  1411		int page_nid = -1, this_nid = numa_node_id();
  1412		int target_nid, last_cpupid = -1;
  1413		bool page_locked;
  1414		bool migrated = false;
  1415		bool was_writable;
  1416		int flags = 0;
  1417	
  1418		vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd);
  1419		if (unlikely(!pmd_same(pmd, *vmf->pmd)))
  1420			goto out_unlock;
  1421	
  1422		/*
  1423		 * If there are potential migrations, wait for completion and retry
  1424		 * without disrupting NUMA hinting information. Do not relock and
  1425		 * check_same as the page may no longer be mapped.
  1426		 */
  1427		if (unlikely(pmd_trans_migrating(*vmf->pmd))) {
  1428			page = pmd_page(*vmf->pmd);
  1429			if (!get_page_unless_zero(page))
  1430				goto out_unlock;
  1431			spin_unlock(vmf->ptl);
  1432			wait_on_page_locked(page);
  1433			put_page(page);
  1434			goto out;
  1435		}
  1436	
  1437		page = pmd_page(pmd);
  1438		BUG_ON(is_huge_zero_page(page));
  1439		page_nid = page_to_nid(page);
  1440		last_cpupid = page_cpupid_last(page);
  1441		count_vm_numa_event(NUMA_HINT_FAULTS);
  1442		if (page_nid == this_nid) {
  1443			count_vm_numa_event(NUMA_HINT_FAULTS_LOCAL);
  1444			flags |= TNF_FAULT_LOCAL;
  1445		}
  1446	
  1447		/* See similar comment in do_numa_page for explanation */
  1448		if (!pmd_savedwrite(pmd))
  1449			flags |= TNF_NO_GROUP;
  1450	
  1451		/*
  1452		 * Acquire the page lock to serialise THP migrations but avoid dropping
  1453		 * page_table_lock if at all possible
  1454		 */
  1455		page_locked = trylock_page(page);
  1456		target_nid = mpol_misplaced(page, vma, haddr);
  1457		if (target_nid == -1) {
  1458			/* If the page was locked, there are no parallel migrations */
  1459			if (page_locked)
  1460				goto clear_pmdnuma;
  1461		}
  1462	
  1463		/* Migration could have started since the pmd_trans_migrating check */
  1464		if (!page_locked) {
  1465			page_nid = -1;
  1466			if (!get_page_unless_zero(page))
  1467				goto out_unlock;
  1468			spin_unlock(vmf->ptl);
  1469			wait_on_page_locked(page);
  1470			put_page(page);
  1471			goto out;
  1472		}
  1473	
  1474		/*
  1475		 * Page is misplaced. Page lock serialises migrations. Acquire anon_vma
  1476		 * to serialises splits
  1477		 */
  1478		get_page(page);
  1479		spin_unlock(vmf->ptl);
  1480		anon_vma = page_lock_anon_vma_read(page);
  1481	
  1482		/* Confirm the PMD did not change while page_table_lock was released */
  1483		spin_lock(vmf->ptl);
  1484		if (unlikely(!pmd_same(pmd, *vmf->pmd))) {
  1485			unlock_page(page);
  1486			put_page(page);
  1487			page_nid = -1;
  1488			goto out_unlock;
  1489		}
  1490	
  1491		/* Bail if we fail to protect against THP splits for any reason */
  1492		if (unlikely(!anon_vma)) {
  1493			put_page(page);
  1494			page_nid = -1;
  1495			goto clear_pmdnuma;
  1496		}
  1497	
  1498		/*
  1499		 * The page_table_lock above provides a memory barrier
  1500		 * with change_protection_range.
  1501		 */
> 1502		if (mm_tlb_flush_pending(mm))
  1503			flush_tlb_range(vma, haddr, haddr + HPAGE_PMD_SIZE);
  1504	
  1505		/*
  1506		 * Migrate the THP to the requested node, returns with page unlocked
  1507		 * and access rights restored.
  1508		 */
  1509		spin_unlock(vmf->ptl);
  1510		migrated = migrate_misplaced_transhuge_page(vma->vm_mm, vma,
  1511					vmf->pmd, pmd, vmf->address, page, target_nid);
  1512		if (migrated) {
  1513			flags |= TNF_MIGRATED;
  1514			page_nid = target_nid;
  1515		} else
  1516			flags |= TNF_MIGRATE_FAIL;
  1517	
  1518		goto out;
  1519	clear_pmdnuma:
  1520		BUG_ON(!PageLocked(page));
  1521		was_writable = pmd_savedwrite(pmd);
  1522		pmd = pmd_modify(pmd, vma->vm_page_prot);
  1523		pmd = pmd_mkyoung(pmd);
  1524		if (was_writable)
  1525			pmd = pmd_mkwrite(pmd);
  1526		set_pmd_at(vma->vm_mm, haddr, vmf->pmd, pmd);
  1527		update_mmu_cache_pmd(vma, vmf->address, vmf->pmd);
  1528		unlock_page(page);
  1529	out_unlock:
  1530		spin_unlock(vmf->ptl);
  1531	
  1532	out:
  1533		if (anon_vma)
  1534			page_unlock_anon_vma_read(anon_vma);
  1535	
  1536		if (page_nid != -1)
  1537			task_numa_fault(last_cpupid, page_nid, HPAGE_PMD_NR,
  1538					flags);
  1539	
  1540		return 0;
  1541	}
  1542	

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

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