Hi Naoya, I love your patch! Perhaps something to improve: [auto build test WARNING on mmotm/master] [also build test WARNING on next-20180411] [cannot apply to v4.16] [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/Naoya-Horiguchi/mm-migrate-add-vm-event-counters-thp_migrate_-success-fail/20180412-011244 base: git://git.cmpxchg.org/linux-mmotm.git master config: i386-randconfig-a1-201814 (attached as .config) compiler: gcc-4.9 (Debian 4.9.4-2) 4.9.4 reproduce: # save the attached .config to linux build tree make ARCH=i386 All warnings (new ones prefixed by >>): mm/migrate.c: In function 'migrate_pages': >> mm/migrate.c:1426:2: warning: missing braces around initializer [-Wmissing-braces] int counts[MIGRATE_RESULT_TYPES][MIGRATE_PAGE_TYPES] = {0}; ^ mm/migrate.c:1426:2: warning: (near initialization for 'counts[0]') [-Wmissing-braces] vim +1426 mm/migrate.c 1400 1401 /* 1402 * migrate_pages - migrate the pages specified in a list, to the free pages 1403 * supplied as the target for the page migration 1404 * 1405 * @from: The list of pages to be migrated. 1406 * @get_new_page: The function used to allocate free pages to be used 1407 * as the target of the page migration. 1408 * @put_new_page: The function used to free target pages if migration 1409 * fails, or NULL if no special handling is necessary. 1410 * @private: Private data to be passed on to get_new_page() 1411 * @mode: The migration mode that specifies the constraints for 1412 * page migration, if any. 1413 * @reason: The reason for page migration. 1414 * 1415 * The function returns after 10 attempts or if no pages are movable any more 1416 * because the list has become empty or no retryable pages exist any more. 1417 * The caller should call putback_movable_pages() to return pages to the LRU 1418 * or free list only if ret != 0. 1419 * 1420 * Returns the number of pages that were not migrated, or an error code. 1421 */ 1422 int migrate_pages(struct list_head *from, new_page_t get_new_page, 1423 free_page_t put_new_page, unsigned long private, 1424 enum migrate_mode mode, int reason) 1425 { > 1426 int counts[MIGRATE_RESULT_TYPES][MIGRATE_PAGE_TYPES] = {0}; 1427 int pass = 0; 1428 struct page *page; 1429 struct page *page2; 1430 int swapwrite = current->flags & PF_SWAPWRITE; 1431 int rc; 1432 1433 if (!swapwrite) 1434 current->flags |= PF_SWAPWRITE; 1435 1436 for (pass = 0; !pass || (pass < 10 && get_count(counts, MIGRATE_RETRY)); 1437 pass++) { 1438 reset_nr_retry(counts); 1439 1440 list_for_each_entry_safe(page, page2, from, lru) { 1441 enum migrate_page_type mpt; 1442 retry: 1443 cond_resched(); 1444 1445 mpt = get_type(page); 1446 if (PageHuge(page)) 1447 rc = unmap_and_move_huge_page(get_new_page, 1448 put_new_page, private, page, 1449 pass > 2, mode, reason); 1450 else 1451 rc = unmap_and_move(get_new_page, put_new_page, 1452 private, page, pass > 2, mode, 1453 reason); 1454 1455 switch(rc) { 1456 case -ENOMEM: 1457 /* 1458 * THP migration might be unsupported or the 1459 * allocation could've failed so we should 1460 * retry on the same page with the THP split 1461 * to base pages. 1462 * 1463 * Head page is retried immediately and tail 1464 * pages are added to the tail of the list so 1465 * we encounter them after the rest of the list 1466 * is processed. 1467 */ 1468 if (PageTransHuge(page)) { 1469 lock_page(page); 1470 rc = split_huge_page_to_list(page, from); 1471 unlock_page(page); 1472 if (!rc) { 1473 list_safe_reset_next(page, page2, lru); 1474 goto retry; 1475 } 1476 } 1477 counts[MIGRATE_FAIL][mpt]++; 1478 goto out; 1479 case -EAGAIN: 1480 counts[MIGRATE_RETRY][mpt]++; 1481 break; 1482 case MIGRATEPAGE_SUCCESS: 1483 counts[MIGRATE_SUCCEED][mpt]++; 1484 break; 1485 default: 1486 /* 1487 * Permanent failure (-EBUSY, -ENOSYS, etc.): 1488 * unlike -EAGAIN case, the failed page is 1489 * removed from migration page list and not 1490 * retried in the next outer loop. 1491 */ 1492 counts[MIGRATE_FAIL][mpt]++; 1493 break; 1494 } 1495 } 1496 } 1497 rc = get_count(counts, MIGRATE_FAIL) + get_count(counts, MIGRATE_RETRY); 1498 out: 1499 update_vm_migrate_events(counts); 1500 trace_mm_migrate_pages(get_count(counts, MIGRATE_SUCCEED), rc, 1501 mode, reason); 1502 1503 if (!swapwrite) 1504 current->flags &= ~PF_SWAPWRITE; 1505 1506 return rc; 1507 } 1508 --- 0-DAY kernel test infrastructure Open Source Technology Center https://lists.01.org/pipermail/kbuild-all Intel Corporation
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