diff mbox series

[v1,5/6] memcg-v1: no need for memcg locking for MGLRU

Message ID 20241025012304.2473312-6-shakeel.butt@linux.dev (mailing list archive)
State New
Headers show
Series memcg-v1: fully deprecate charge moving | expand

Commit Message

Shakeel Butt Oct. 25, 2024, 1:23 a.m. UTC 
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.

Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev>
---
 mm/vmscan.c | 11 -----------
 1 file changed, 11 deletions(-)

Comments

Roman Gushchin Oct. 25, 2024, 5:41 p.m. UTC | #1 
On Thu, Oct 24, 2024 at 06:23:02PM -0700, Shakeel Butt wrote:
> 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.
> 
> Signed-off-by: Shakeel Butt <shakeel.butt@linux.dev>

Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev>
diff mbox series

Patch

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 29c098790b01..fd7171658b63 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -3662,10 +3662,6 @@  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);
@@ -3673,8 +3669,6 @@  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);
@@ -4096,10 +4090,6 @@  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;
@@ -4144,7 +4134,6 @@  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))