diff options
Diffstat (limited to 'mm/migrate.c')
| -rw-r--r-- | mm/migrate.c | 54 |
1 files changed, 45 insertions, 9 deletions
diff --git a/mm/migrate.c b/mm/migrate.c index 8f99fcea99..a8c6f466e3 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -113,7 +113,7 @@ bool isolate_movable_page(struct page *page, isolate_mode_t mode) if (!mops->isolate_page(&folio->page, mode)) goto out_no_isolated; - /* Driver shouldn't use PG_isolated bit of page->flags */ + /* Driver shouldn't use the isolated flag */ WARN_ON_ONCE(folio_test_isolated(folio)); folio_set_isolated(folio); folio_unlock(folio); @@ -629,7 +629,7 @@ void folio_migrate_flags(struct folio *newfolio, struct folio *folio) folio_migrate_ksm(newfolio, folio); /* * Please do not reorder this without considering how mm/ksm.c's - * get_ksm_page() depends upon ksm_migrate_page() and PageSwapCache(). + * ksm_get_folio() depends upon ksm_migrate_page() and PageSwapCache(). */ if (folio_test_swapcache(folio)) folio_clear_swapcache(folio); @@ -1438,7 +1438,7 @@ static int unmap_and_move_huge_page(new_folio_t get_new_folio, * semaphore in write mode here and set TTU_RMAP_LOCKED * to let lower levels know we have taken the lock. */ - mapping = hugetlb_page_mapping_lock_write(&src->page); + mapping = hugetlb_folio_mapping_lock_write(src); if (unlikely(!mapping)) goto unlock_put_anon; @@ -1666,6 +1666,40 @@ static int migrate_pages_batch(struct list_head *from, cond_resched(); /* + * The rare folio on the deferred split list should + * be split now. It should not count as a failure: + * but increment nr_failed because, without doing so, + * migrate_pages() may report success with (split but + * unmigrated) pages still on its fromlist; whereas it + * always reports success when its fromlist is empty. + * stats->nr_thp_failed should be increased too, + * otherwise stats inconsistency will happen when + * migrate_pages_batch is called via migrate_pages() + * with MIGRATE_SYNC and MIGRATE_ASYNC. + * + * Only check it without removing it from the list. + * Since the folio can be on deferred_split_scan() + * local list and removing it can cause the local list + * corruption. Folio split process below can handle it + * with the help of folio_ref_freeze(). + * + * nr_pages > 2 is needed to avoid checking order-1 + * page cache folios. They exist, in contrast to + * non-existent order-1 anonymous folios, and do not + * use _deferred_list. + */ + if (nr_pages > 2 && + !list_empty(&folio->_deferred_list)) { + if (try_split_folio(folio, split_folios) == 0) { + nr_failed++; + stats->nr_thp_failed += is_thp; + stats->nr_thp_split += is_thp; + stats->nr_split++; + continue; + } + } + + /* * Large folio migration might be unsupported or * the allocation might be failed so we should retry * on the same folio with the large folio split @@ -2035,7 +2069,8 @@ struct folio *alloc_migration_target(struct folio *src, unsigned long private) gfp_mask = htlb_modify_alloc_mask(h, gfp_mask); return alloc_hugetlb_folio_nodemask(h, nid, - mtc->nmask, gfp_mask); + mtc->nmask, gfp_mask, + htlb_allow_alloc_fallback(mtc->reason)); } if (folio_test_large(src)) { @@ -2073,6 +2108,7 @@ static int do_move_pages_to_node(struct list_head *pagelist, int node) struct migration_target_control mtc = { .nid = node, .gfp_mask = GFP_HIGHUSER_MOVABLE | __GFP_THISNODE, + .reason = MR_SYSCALL, }; err = migrate_pages(pagelist, alloc_migration_target, NULL, @@ -2128,7 +2164,7 @@ static int add_page_for_migration(struct mm_struct *mm, const void __user *p, goto out_putfolio; err = -EACCES; - if (page_mapcount(page) > 1 && !migrate_all) + if (folio_likely_mapped_shared(folio) && !migrate_all) goto out_putfolio; err = -EBUSY; @@ -2581,11 +2617,11 @@ int migrate_misplaced_folio(struct folio *folio, struct vm_area_struct *vma, /* * Don't migrate file folios that are mapped in multiple processes * with execute permissions as they are probably shared libraries. - * To check if the folio is shared, ideally we want to make sure - * every page is mapped to the same process. Doing that is very - * expensive, so check the estimated mapcount of the folio instead. + * + * See folio_likely_mapped_shared() on possible imprecision when we + * cannot easily detect if a folio is shared. */ - if (folio_estimated_sharers(folio) != 1 && folio_is_file_lru(folio) && + if (folio_likely_mapped_shared(folio) && folio_is_file_lru(folio) && (vma->vm_flags & VM_EXEC)) goto out; |