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
Fixes: f77f0c751478 ("mm,memcg: provide per-cgroup counters for NUMA balancing operations")
Signed-off-by: Donet Tom <donettom@xxxxxxxxxxxxx>
Great minds think alike, It's excatly same with mine[0] :) There is another bug[1] as well.[0] https://lore.kernel.org/linux-mm/20250110122133.423481-2-lizhijian@xxxxxxxxxxx/ [1] https://lore.kernel.org/linux-mm/20250110122133.423481-1-lizhijian@xxxxxxxxxxx/
Feel free to add vvv if your patch is accepted at last.Tested-by: Li Zhijian <lizhijian@xxxxxxxxxxx> Reviewed-by: Li Zhijian <lizhijian@xxxxxxxxxxx>
--- mm/vmscan.c <https://lore.kernel.org/lkml/20250109060540.451261-1-donettom@xxxxxxxxxxxxx/#Z31mm:vmscan.c> | 3 +++ 1 filechanged <https://lore.kernel.org/lkml/20250109060540.451261-1-donettom@xxxxxxxxxxxxx/#related>, 3 insertions(+)diff <https://lore.kernel.org/lkml/20250109060540.451261-1-donettom@xxxxxxxxxxxxx/#iZ31mm:vmscan.c> --git a/mm/vmscan.c b/mm/vmscan.c index 9a859b7d18d7..b1ec5ece067e 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -4642,6 +4642,9 @@ static int evict_folios(struct lruvec *lruvec, struct scan_control *sc, int swap 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); --
