The patch titled Subject: mm: vmscan : pgdemote vmstat is not getting updated when MGLRU is enabled. has been added to the -mm mm-hotfixes-unstable branch. Its filename is mm-vmscan-pgdemote-vmstat-is-not-getting-updated-when-mglru-is-enabled.patch

This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches...

This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------ From: Donet Tom donettom@linux.ibm.com Subject: mm: vmscan : pgdemote vmstat is not getting updated when MGLRU is enabled. Date: Thu, 9 Jan 2025 00:05:39 -0600

When MGLRU is enabled, the pgdemote_kswapd, pgdemote_direct, and pgdemote_khugepaged stats in vmstat are not being updated.

Commit f77f0c751478 ("mm,memcg: provide per-cgroup counters for NUMA balancing operations") moved the pgdemote vmstat update from demote_folio_list() to shrink_inactive_list(), which is in the normal LRU path. As a result, the pgdemote stats are updated correctly for the normal LRU but not for MGLRU.

To address this, we have added the pgdemote stat update in the evict_folios() function, which is in the MGLRU path. With this patch, the pgdemote stats will now be updated correctly when MGLRU is enabled.

Without this patch vmstat output when MGLRU is enabled ====================================================== pgdemote_kswapd 0 pgdemote_direct 0 pgdemote_khugepaged 0

With this patch vmstat output when MGLRU is enabled =================================================== pgdemote_kswapd 43234 pgdemote_direct 4691 pgdemote_khugepaged 0

Link: https://lkml.kernel.org/r/20250109060540.451261-1-donettom@linux.ibm.com Fixes: f77f0c751478 ("mm,memcg: provide per-cgroup counters for NUMA balancing operations") Signed-off-by: Donet Tom donettom@linux.ibm.com Acked-by: Yu Zhao yuzhao@google.com Cc: Aneesh Kumar K.V (Arm) aneesh.kumar@kernel.org Cc: David Rientjes rientjes@google.com Cc: Johannes Weiner hannes@cmpxchg.org Cc: Kaiyang Zhao kaiyang2@cs.cmu.edu Cc: Michal Hocko mhocko@kernel.org Cc: Muchun Song muchun.song@linux.dev Cc: Ritesh Harjani (IBM) ritesh.list@gmail.com Cc: Roman Gushchin roman.gushchin@linux.dev Cc: Shakeel Butt shakeel.butt@linux.dev Cc: Wei Xu weixugc@google.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---

mm/vmscan.c | 3 +++ 1 file changed, 3 insertions(+)

--- a/mm/vmscan.c~mm-vmscan-pgdemote-vmstat-is-not-getting-updated-when-mglru-is-enabled +++ a/mm/vmscan.c @@ -4646,6 +4646,9 @@ retry: reset_batch_size(walk); }

+ __mod_lruvec_state(lruvec, PGDEMOTE_KSWAPD + reclaimer_offset(), + stat.nr_demoted); + item = PGSTEAL_KSWAPD + reclaimer_offset(); if (!cgroup_reclaim(sc)) __count_vm_events(item, reclaimed); _

Patches currently in -mm which might be from donettom@linux.ibm.com are

mm-vmscan-pgdemote-vmstat-is-not-getting-updated-when-mglru-is-enabled.patch mm-migrate-removed-unused-argument-vma-from-migrate_misplaced_folio.patch selftests-mm-added-new-test-cases-to-the-migration-test.patch