From fd603ae11e72fcaeec9266522f416c37b43bd1c4 Mon Sep 17 00:00:00 2001 From: Muchun Song Date: Mon, 10 Nov 2025 16:17:55 +0800 Subject: [PATCH] mm: thp: replace folio_memcg() with folio_memcg_charged() Patch series "reparent the THP split queue", v6. In the future, we will reparent LRU folios during memcg offline to eliminate dying memory cgroups, which requires reparenting the THP split queue to its parent memcg. Similar to list_lru, the split queue is relatively independent and does not need to be reparented along with objcg and LRU folios (holding objcg lock and lru lock). Therefore, we can apply the same mechanism as list_lru to reparent the split queue first when memcg is offine. The first three patches in this series are separated from the series "Eliminate Dying Memory Cgroup" [1], mainly to do some cleanup and preparatory work. The last patch reparents the THP split queue to its parent memcg during memcg offline. This patch (of 4): folio_memcg_charged() is intended for use when the user is unconcerned about the returned memcg pointer. It is more efficient than folio_memcg(). Therefore, replace folio_memcg() with folio_memcg_charged(). Link: https://lkml.kernel.org/r/56624d537520e33e5a6b3755238b3dfb959a52ee.1762762324.git.zhengqi.arch@bytedance.com Link: https://lore.kernel.org/all/20250415024532.26632-1-songmuchun@bytedance.com/ [1] Signed-off-by: Muchun Song Signed-off-by: Qi Zheng Acked-by: Johannes Weiner Acked-by: Shakeel Butt Acked-by: David Hildenbrand Reviewed-by: Roman Gushchin Reviewed-by: Harry Yoo Cc: Baolin Wang Cc: Barry Song Cc: Dev Jain Cc: Hugh Dickins Cc: Lance Yang Cc: Liam Howlett Cc: Lorenzo Stoakes Cc: Michal Hocko Cc: Nico Pache Cc: Ryan Roberts Cc: Wei Yang Cc: Zi Yan Cc: Muchun Song Signed-off-by: Andrew Morton --- mm/huge_memory.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index e38b0d5e3102f..9758171d49c99 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -4127,7 +4127,7 @@ bool __folio_unqueue_deferred_split(struct folio *folio) bool unqueued = false; WARN_ON_ONCE(folio_ref_count(folio)); - WARN_ON_ONCE(!mem_cgroup_disabled() && !folio_memcg(folio)); + WARN_ON_ONCE(!mem_cgroup_disabled() && !folio_memcg_charged(folio)); ds_queue = get_deferred_split_queue(folio); spin_lock_irqsave(&ds_queue->split_queue_lock, flags); -- 2.47.3