From 42b2eb69835b0fda797f70eb5b4fc213dbe3a7ea Mon Sep 17 00:00:00 2001 From: Usama Arif Date: Thu, 12 Dec 2024 18:33:51 +0000 Subject: mm: convert partially_mapped set/clear operations to be atomic Other page flags in the 2nd page, like PG_hwpoison and PG_anon_exclusive can get modified concurrently. Changes to other page flags might be lost if they are happening at the same time as non-atomic partially_mapped operations. Hence, make partially_mapped operations atomic. Link: https://lkml.kernel.org/r/20241212183351.1345389-1-usamaarif642@gmail.com Fixes: 8422acdc97ed ("mm: introduce a pageflag for partially mapped folios") Reported-by: David Hildenbrand Link: https://lore.kernel.org/all/e53b04ad-1827-43a2-a1ab-864c7efecf6e@redhat.com/ Signed-off-by: Usama Arif Acked-by: David Hildenbrand Acked-by: Johannes Weiner Acked-by: Roman Gushchin Cc: Barry Song Cc: Domenico Cerasuolo Cc: Jonathan Corbet Cc: Matthew Wilcox Cc: Mike Rapoport (Microsoft) Cc: Nico Pache Cc: Rik van Riel Cc: Ryan Roberts Cc: Shakeel Butt Cc: Yu Zhao Cc: Signed-off-by: Andrew Morton --- mm/huge_memory.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'mm') diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 9bb351caa619..df0c4988dd88 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -3577,7 +3577,7 @@ int split_huge_page_to_list_to_order(struct page *page, struct list_head *list, !list_empty(&folio->_deferred_list)) { ds_queue->split_queue_len--; if (folio_test_partially_mapped(folio)) { - __folio_clear_partially_mapped(folio); + folio_clear_partially_mapped(folio); mod_mthp_stat(folio_order(folio), MTHP_STAT_NR_ANON_PARTIALLY_MAPPED, -1); } @@ -3689,7 +3689,7 @@ bool __folio_unqueue_deferred_split(struct folio *folio) if (!list_empty(&folio->_deferred_list)) { ds_queue->split_queue_len--; if (folio_test_partially_mapped(folio)) { - __folio_clear_partially_mapped(folio); + folio_clear_partially_mapped(folio); mod_mthp_stat(folio_order(folio), MTHP_STAT_NR_ANON_PARTIALLY_MAPPED, -1); } @@ -3733,7 +3733,7 @@ void deferred_split_folio(struct folio *folio, bool partially_mapped) spin_lock_irqsave(&ds_queue->split_queue_lock, flags); if (partially_mapped) { if (!folio_test_partially_mapped(folio)) { - __folio_set_partially_mapped(folio); + folio_set_partially_mapped(folio); if (folio_test_pmd_mappable(folio)) count_vm_event(THP_DEFERRED_SPLIT_PAGE); count_mthp_stat(folio_order(folio), MTHP_STAT_SPLIT_DEFERRED); @@ -3826,7 +3826,7 @@ static unsigned long deferred_split_scan(struct shrinker *shrink, } else { /* We lost race with folio_put() */ if (folio_test_partially_mapped(folio)) { - __folio_clear_partially_mapped(folio); + folio_clear_partially_mapped(folio); mod_mthp_stat(folio_order(folio), MTHP_STAT_NR_ANON_PARTIALLY_MAPPED, -1); } -- cgit v1.2.3