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/mm-vmscan-pgdemote-vmstat-is-not-getting-updated-when-mglru-is-enabled.patch
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@xxxxxxxxxxxxx>
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@xxxxxxxxxxxxx
Fixes: f77f0c751478 ("mm,memcg: provide per-cgroup counters for NUMA balancing operations")
Signed-off-by: Donet Tom <donettom@xxxxxxxxxxxxx>
Acked-by: Yu Zhao <yuzhao@xxxxxxxxxx>
Cc: Aneesh Kumar K.V (Arm) <aneesh.kumar@xxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Kaiyang Zhao <kaiyang2@xxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Muchun Song <muchun.song@xxxxxxxxx>
Cc: Ritesh Harjani (IBM) <ritesh.list@xxxxxxxxx>
Cc: Roman Gushchin <roman.gushchin@xxxxxxxxx>
Cc: Shakeel Butt <shakeel.butt@xxxxxxxxx>
Cc: Wei Xu <weixugc@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
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@xxxxxxxxxxxxx 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
