The patch titled
Subject: memcg-v1: no need for memcg locking for MGLRU
has been added to the -mm mm-unstable branch. Its filename is
memcg-v1-no-need-for-memcg-locking-for-mglru.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/memcg-v1-no-need-for-memcg-locking-for-mglru.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Shakeel Butt <shakeel.butt@xxxxxxxxx>
Subject: memcg-v1: no need for memcg locking for MGLRU
Date: Thu, 24 Oct 2024 18:23:02 -0700
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@xxxxxxxxx
Signed-off-by: Shakeel Butt <shakeel.butt@xxxxxxxxx>
Reviewed-by: Roman Gushchin <roman.gushchin@xxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Muchun Song <muchun.song@xxxxxxxxx>
Cc: Yosry Ahmed <yosryahmed@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/vmscan.c | 11 -----------
1 file changed, 11 deletions(-)
--- a/mm/vmscan.c~memcg-v1-no-need-for-memcg-locking-for-mglru
+++ a/mm/vmscan.c
@@ -3662,10 +3662,6 @@ static void walk_mm(struct mm_struct *mm
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
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
}
}
- /* 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
}
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))
_
Patches currently in -mm which might be from shakeel.butt@xxxxxxxxx are
mm-optimize-truncation-of-shadow-entries.patch
mm-optimize-invalidation-of-shadow-entries.patch
mm-truncate-reset-xa_has_values-flag-on-each-iteration.patch
memcg-add-tracing-for-memcg-stat-updates.patch
memcg-add-tracing-for-memcg-stat-updates-v2.patch
memcg-v1-fully-deprecate-move_charge_at_immigrate.patch
memcg-v1-remove-charge-move-code.patch
memcg-v1-no-need-for-memcg-locking-for-dirty-tracking.patch
memcg-v1-no-need-for-memcg-locking-for-writeback-tracking.patch
memcg-v1-no-need-for-memcg-locking-for-mglru.patch
memcg-v1-remove-memcg-move-locking-code.patch
