diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 2fb328880b50..a1d345f1680c 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -3718,8 +3718,8 @@ static unsigned long deferred_split_scan(struct shrinker *shrink, struct deferred_split *ds_queue = &pgdata->deferred_split_queue; unsigned long flags; LIST_HEAD(list); - struct folio *folio, *next; - int split = 0; + struct folio *folio, *next, *prev = NULL; + int split = 0, removed = 0; #ifdef CONFIG_MEMCG if (sc->memcg) @@ -3775,15 +3775,28 @@ next: */ if (!did_split && !folio_test_partially_mapped(folio)) { list_del_init(&folio->_deferred_list); - ds_queue->split_queue_len--; + removed++; + } else { + /* + * That unlocked list_del_init() above would be unsafe, + * unless its folio is separated from any earlier folios + * left on the list (which may be concurrently unqueued) + * by one safe folio with refcount still raised. + */ + swap(folio, prev); } - folio_put(folio); + if (folio) + folio_put(folio); } spin_lock_irqsave(&ds_queue->split_queue_lock, flags); list_splice_tail(&list, &ds_queue->split_queue); + ds_queue->split_queue_len -= removed; spin_unlock_irqrestore(&ds_queue->split_queue_lock, flags); + if (prev) + folio_put(prev); + /* * Stop shrinker if we didn't split any page, but the queue is empty. * This can happen if pages were freed under us. diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 7845c64a2c57..2703227cce88 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -4631,8 +4631,7 @@ static void uncharge_folio(struct folio *folio, struct uncharge_gather *ug) VM_BUG_ON_FOLIO(folio_test_lru(folio), folio); VM_BUG_ON_FOLIO(folio_order(folio) > 1 && !folio_test_hugetlb(folio) && - !list_empty(&folio->_deferred_list) && - folio_test_partially_mapped(folio), folio); + !list_empty(&folio->_deferred_list), folio); /* * Nobody should be changing or seriously looking at diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 94a2ffe28008..5e108ae755cc 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -961,9 +961,8 @@ static int free_tail_page_prepare(struct page *head_page, struct page *page) break; case 2: /* the second tail page: deferred_list overlaps ->mapping */ - if (unlikely(!list_empty(&folio->_deferred_list) && - folio_test_partially_mapped(folio))) { - bad_page(page, "partially mapped folio on deferred list"); + if (unlikely(!list_empty(&folio->_deferred_list))) { + bad_page(page, "on deferred list"); goto out; } break;