Hi Jordan, kernel test robot noticed the following build errors:
[auto build test ERROR on f8f9c1f4d0c7a64600e2ca312dec824a0bc2f1da] url: https://github.com/intel-lab-lkp/linux/commits/Jordan-Niethe/mm-migrate_device-Add-migrate-PFN-flag-to-track-device-private-pages/20251231-123453 base: f8f9c1f4d0c7a64600e2ca312dec824a0bc2f1da patch link: https://lore.kernel.org/r/20251231043154.42931-4-jniethe%40nvidia.com patch subject: [PATCH v1 3/8] mm: Add helpers to create migration entries from struct pages config: openrisc-allnoconfig (https://download.01.org/0day-ci/archive/20260103/[email protected]/config) compiler: or1k-linux-gcc (GCC) 15.1.0 reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260103/[email protected]/reproduce) If you fix the issue in a separate patch/commit (i.e. not just a new version of the same patch/commit), kindly add following tags | Reported-by: kernel test robot <[email protected]> | Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/ All errors (new ones prefixed by >>): mm/rmap.c: In function 'try_to_migrate_one': >> mm/rmap.c:2542:41: error: implicit declaration of function >> 'make_writable_migration_entry_from_page'; did you mean >> 'make_readable_migration_entry_from_page'? [-Wimplicit-function-declaration] 2542 | entry = make_writable_migration_entry_from_page( | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | make_readable_migration_entry_from_page >> mm/rmap.c:2542:41: error: incompatible types when assigning to type >> 'swp_entry_t' from type 'int' vim +2542 mm/rmap.c 2275 2276 /* 2277 * @arg: enum ttu_flags will be passed to this argument. 2278 * 2279 * If TTU_SPLIT_HUGE_PMD is specified any PMD mappings will be split into PTEs 2280 * containing migration entries. 2281 */ 2282 static bool try_to_migrate_one(struct folio *folio, struct vm_area_struct *vma, 2283 unsigned long address, void *arg) 2284 { 2285 struct mm_struct *mm = vma->vm_mm; 2286 DEFINE_FOLIO_VMA_WALK(pvmw, folio, vma, address, 0); 2287 bool anon_exclusive, writable, ret = true; 2288 pte_t pteval; 2289 struct page *subpage; 2290 struct mmu_notifier_range range; 2291 enum ttu_flags flags = (enum ttu_flags)(long)arg; 2292 unsigned long pfn; 2293 unsigned long hsz = 0; 2294 2295 /* 2296 * When racing against e.g. zap_pte_range() on another cpu, 2297 * in between its ptep_get_and_clear_full() and folio_remove_rmap_*(), 2298 * try_to_migrate() may return before page_mapped() has become false, 2299 * if page table locking is skipped: use TTU_SYNC to wait for that. 2300 */ 2301 if (flags & TTU_SYNC) 2302 pvmw.flags = PVMW_SYNC; 2303 2304 /* 2305 * For THP, we have to assume the worse case ie pmd for invalidation. 2306 * For hugetlb, it could be much worse if we need to do pud 2307 * invalidation in the case of pmd sharing. 2308 * 2309 * Note that the page can not be free in this function as call of 2310 * try_to_unmap() must hold a reference on the page. 2311 */ 2312 range.end = vma_address_end(&pvmw); 2313 mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma->vm_mm, 2314 address, range.end); 2315 if (folio_test_hugetlb(folio)) { 2316 /* 2317 * If sharing is possible, start and end will be adjusted 2318 * accordingly. 2319 */ 2320 adjust_range_if_pmd_sharing_possible(vma, &range.start, 2321 &range.end); 2322 2323 /* We need the huge page size for set_huge_pte_at() */ 2324 hsz = huge_page_size(hstate_vma(vma)); 2325 } 2326 mmu_notifier_invalidate_range_start(&range); 2327 2328 while (page_vma_mapped_walk(&pvmw)) { 2329 /* PMD-mapped THP migration entry */ 2330 if (!pvmw.pte) { 2331 __maybe_unused unsigned long pfn; 2332 __maybe_unused pmd_t pmdval; 2333 2334 if (flags & TTU_SPLIT_HUGE_PMD) { 2335 split_huge_pmd_locked(vma, pvmw.address, 2336 pvmw.pmd, true); 2337 ret = false; 2338 page_vma_mapped_walk_done(&pvmw); 2339 break; 2340 } 2341 #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION 2342 pmdval = pmdp_get(pvmw.pmd); 2343 if (likely(pmd_present(pmdval))) 2344 pfn = pmd_pfn(pmdval); 2345 else 2346 pfn = softleaf_to_pfn(softleaf_from_pmd(pmdval)); 2347 2348 subpage = folio_page(folio, pfn - folio_pfn(folio)); 2349 2350 VM_BUG_ON_FOLIO(folio_test_hugetlb(folio) || 2351 !folio_test_pmd_mappable(folio), folio); 2352 2353 if (set_pmd_migration_entry(&pvmw, subpage)) { 2354 ret = false; 2355 page_vma_mapped_walk_done(&pvmw); 2356 break; 2357 } 2358 continue; 2359 #endif 2360 } 2361 2362 /* Unexpected PMD-mapped THP? */ 2363 VM_BUG_ON_FOLIO(!pvmw.pte, folio); 2364 2365 /* 2366 * Handle PFN swap PTEs, such as device-exclusive ones, that 2367 * actually map pages. 2368 */ 2369 pteval = ptep_get(pvmw.pte); 2370 if (likely(pte_present(pteval))) { 2371 pfn = pte_pfn(pteval); 2372 } else { 2373 const softleaf_t entry = softleaf_from_pte(pteval); 2374 2375 pfn = softleaf_to_pfn(entry); 2376 VM_WARN_ON_FOLIO(folio_test_hugetlb(folio), folio); 2377 } 2378 2379 subpage = folio_page(folio, pfn - folio_pfn(folio)); 2380 address = pvmw.address; 2381 anon_exclusive = folio_test_anon(folio) && 2382 PageAnonExclusive(subpage); 2383 2384 if (folio_test_hugetlb(folio)) { 2385 bool anon = folio_test_anon(folio); 2386 2387 /* 2388 * huge_pmd_unshare may unmap an entire PMD page. 2389 * There is no way of knowing exactly which PMDs may 2390 * be cached for this mm, so we must flush them all. 2391 * start/end were already adjusted above to cover this 2392 * range. 2393 */ 2394 flush_cache_range(vma, range.start, range.end); 2395 2396 /* 2397 * To call huge_pmd_unshare, i_mmap_rwsem must be 2398 * held in write mode. Caller needs to explicitly 2399 * do this outside rmap routines. 2400 * 2401 * We also must hold hugetlb vma_lock in write mode. 2402 * Lock order dictates acquiring vma_lock BEFORE 2403 * i_mmap_rwsem. We can only try lock here and 2404 * fail if unsuccessful. 2405 */ 2406 if (!anon) { 2407 VM_BUG_ON(!(flags & TTU_RMAP_LOCKED)); 2408 if (!hugetlb_vma_trylock_write(vma)) { 2409 page_vma_mapped_walk_done(&pvmw); 2410 ret = false; 2411 break; 2412 } 2413 if (huge_pmd_unshare(mm, vma, address, pvmw.pte)) { 2414 hugetlb_vma_unlock_write(vma); 2415 flush_tlb_range(vma, 2416 range.start, range.end); 2417 2418 /* 2419 * The ref count of the PMD page was 2420 * dropped which is part of the way map 2421 * counting is done for shared PMDs. 2422 * Return 'true' here. When there is 2423 * no other sharing, huge_pmd_unshare 2424 * returns false and we will unmap the 2425 * actual page and drop map count 2426 * to zero. 2427 */ 2428 page_vma_mapped_walk_done(&pvmw); 2429 break; 2430 } 2431 hugetlb_vma_unlock_write(vma); 2432 } 2433 /* Nuke the hugetlb page table entry */ 2434 pteval = huge_ptep_clear_flush(vma, address, pvmw.pte); 2435 if (pte_dirty(pteval)) 2436 folio_mark_dirty(folio); 2437 writable = pte_write(pteval); 2438 } else if (likely(pte_present(pteval))) { 2439 flush_cache_page(vma, address, pfn); 2440 /* Nuke the page table entry. */ 2441 if (should_defer_flush(mm, flags)) { 2442 /* 2443 * We clear the PTE but do not flush so potentially 2444 * a remote CPU could still be writing to the folio. 2445 * If the entry was previously clean then the 2446 * architecture must guarantee that a clear->dirty 2447 * transition on a cached TLB entry is written through 2448 * and traps if the PTE is unmapped. 2449 */ 2450 pteval = ptep_get_and_clear(mm, address, pvmw.pte); 2451 2452 set_tlb_ubc_flush_pending(mm, pteval, address, address + PAGE_SIZE); 2453 } else { 2454 pteval = ptep_clear_flush(vma, address, pvmw.pte); 2455 } 2456 if (pte_dirty(pteval)) 2457 folio_mark_dirty(folio); 2458 writable = pte_write(pteval); 2459 } else { 2460 const softleaf_t entry = softleaf_from_pte(pteval); 2461 2462 pte_clear(mm, address, pvmw.pte); 2463 2464 writable = softleaf_is_device_private_write(entry); 2465 } 2466 2467 VM_WARN_ON_FOLIO(writable && folio_test_anon(folio) && 2468 !anon_exclusive, folio); 2469 2470 /* Update high watermark before we lower rss */ 2471 update_hiwater_rss(mm); 2472 2473 if (PageHWPoison(subpage)) { 2474 VM_WARN_ON_FOLIO(folio_is_device_private(folio), folio); 2475 2476 pteval = swp_entry_to_pte(make_hwpoison_entry(subpage)); 2477 if (folio_test_hugetlb(folio)) { 2478 hugetlb_count_sub(folio_nr_pages(folio), mm); 2479 set_huge_pte_at(mm, address, pvmw.pte, pteval, 2480 hsz); 2481 } else { 2482 dec_mm_counter(mm, mm_counter(folio)); 2483 set_pte_at(mm, address, pvmw.pte, pteval); 2484 } 2485 } else if (likely(pte_present(pteval)) && pte_unused(pteval) && 2486 !userfaultfd_armed(vma)) { 2487 /* 2488 * The guest indicated that the page content is of no 2489 * interest anymore. Simply discard the pte, vmscan 2490 * will take care of the rest. 2491 * A future reference will then fault in a new zero 2492 * page. When userfaultfd is active, we must not drop 2493 * this page though, as its main user (postcopy 2494 * migration) will not expect userfaults on already 2495 * copied pages. 2496 */ 2497 dec_mm_counter(mm, mm_counter(folio)); 2498 } else { 2499 swp_entry_t entry; 2500 pte_t swp_pte; 2501 2502 /* 2503 * arch_unmap_one() is expected to be a NOP on 2504 * architectures where we could have PFN swap PTEs, 2505 * so we'll not check/care. 2506 */ 2507 if (arch_unmap_one(mm, vma, address, pteval) < 0) { 2508 if (folio_test_hugetlb(folio)) 2509 set_huge_pte_at(mm, address, pvmw.pte, 2510 pteval, hsz); 2511 else 2512 set_pte_at(mm, address, pvmw.pte, pteval); 2513 ret = false; 2514 page_vma_mapped_walk_done(&pvmw); 2515 break; 2516 } 2517 2518 /* See folio_try_share_anon_rmap_pte(): clear PTE first. */ 2519 if (folio_test_hugetlb(folio)) { 2520 if (anon_exclusive && 2521 hugetlb_try_share_anon_rmap(folio)) { 2522 set_huge_pte_at(mm, address, pvmw.pte, 2523 pteval, hsz); 2524 ret = false; 2525 page_vma_mapped_walk_done(&pvmw); 2526 break; 2527 } 2528 } else if (anon_exclusive && 2529 folio_try_share_anon_rmap_pte(folio, subpage)) { 2530 set_pte_at(mm, address, pvmw.pte, pteval); 2531 ret = false; 2532 page_vma_mapped_walk_done(&pvmw); 2533 break; 2534 } 2535 2536 /* 2537 * Store the pfn of the page in a special migration 2538 * pte. do_swap_page() will wait until the migration 2539 * pte is removed and then restart fault handling. 2540 */ 2541 if (writable) > 2542 entry = > make_writable_migration_entry_from_page( 2543 subpage); 2544 else if (anon_exclusive) 2545 entry = make_readable_exclusive_migration_entry_from_page( 2546 subpage); 2547 else 2548 entry = make_readable_migration_entry_from_page( 2549 subpage); 2550 if (likely(pte_present(pteval))) { 2551 if (pte_young(pteval)) 2552 entry = make_migration_entry_young(entry); 2553 if (pte_dirty(pteval)) 2554 entry = make_migration_entry_dirty(entry); 2555 swp_pte = swp_entry_to_pte(entry); 2556 if (pte_soft_dirty(pteval)) 2557 swp_pte = pte_swp_mksoft_dirty(swp_pte); 2558 if (pte_uffd_wp(pteval)) 2559 swp_pte = pte_swp_mkuffd_wp(swp_pte); 2560 } else { 2561 swp_pte = swp_entry_to_pte(entry); 2562 if (pte_swp_soft_dirty(pteval)) 2563 swp_pte = pte_swp_mksoft_dirty(swp_pte); 2564 if (pte_swp_uffd_wp(pteval)) 2565 swp_pte = pte_swp_mkuffd_wp(swp_pte); 2566 } 2567 if (folio_test_hugetlb(folio)) 2568 set_huge_pte_at(mm, address, pvmw.pte, swp_pte, 2569 hsz); 2570 else 2571 set_pte_at(mm, address, pvmw.pte, swp_pte); 2572 trace_set_migration_pte(address, pte_val(swp_pte), 2573 folio_order(folio)); 2574 /* 2575 * No need to invalidate here it will synchronize on 2576 * against the special swap migration pte. 2577 */ 2578 } 2579 2580 if (unlikely(folio_test_hugetlb(folio))) 2581 hugetlb_remove_rmap(folio); 2582 else 2583 folio_remove_rmap_pte(folio, subpage, vma); 2584 if (vma->vm_flags & VM_LOCKED) 2585 mlock_drain_local(); 2586 folio_put(folio); 2587 } 2588 2589 mmu_notifier_invalidate_range_end(&range); 2590 2591 return ret; 2592 } 2593 -- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests/wiki
