From 45e3ee045f3872212a689fd7d4cd5efff7dd57cb Mon Sep 17 00:00:00 2001 From: Shakeel Butt Date: Thu, 24 Oct 2024 18:23:02 -0700 Subject: [PATCH] memcg-v1: no need for memcg locking for MGLRU While updating the generation of the folios, MGLRU requires that the folio's memcg association remains stable. With the charge migration deprecated, there is no need for MGLRU to acquire locks to keep the folio and memcg association stable. Link: https://lkml.kernel.org/r/20241025012304.2473312-6-shakeel.butt@linux.dev Signed-off-by: Shakeel Butt Reviewed-by: Roman Gushchin Cc: Hugh Dickins Cc: Johannes Weiner Cc: Michal Hocko Cc: Muchun Song Cc: Yosry Ahmed Signed-off-by: Andrew Morton --- mm/vmscan.c | 11 ----------- 1 file changed, 11 deletions(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index 8d1301c0f22a..a1b64ef1d8b1 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -3665,10 +3665,6 @@ static void walk_mm(struct mm_struct *mm, struct lru_gen_mm_walk *walk) if (walk->seq != max_seq) break; - /* folio_update_gen() requires stable folio_memcg() */ - if (!mem_cgroup_trylock_pages(memcg)) - break; - /* the caller might be holding the lock for write */ if (mmap_read_trylock(mm)) { err = walk_page_range(mm, walk->next_addr, ULONG_MAX, &mm_walk_ops, walk); @@ -3676,8 +3672,6 @@ static void walk_mm(struct mm_struct *mm, struct lru_gen_mm_walk *walk) mmap_read_unlock(mm); } - mem_cgroup_unlock_pages(); - if (walk->batched) { spin_lock_irq(&lruvec->lru_lock); reset_batch_size(walk); @@ -4099,10 +4093,6 @@ bool lru_gen_look_around(struct page_vma_mapped_walk *pvmw) } } - /* folio_update_gen() requires stable folio_memcg() */ - if (!mem_cgroup_trylock_pages(memcg)) - return true; - arch_enter_lazy_mmu_mode(); pte -= (addr - start) / PAGE_SIZE; @@ -4147,7 +4137,6 @@ bool lru_gen_look_around(struct page_vma_mapped_walk *pvmw) } arch_leave_lazy_mmu_mode(); - mem_cgroup_unlock_pages(); /* feedback from rmap walkers to page table walkers */ if (mm_state && suitable_to_scan(i, young)) -- 2.49.0