On 19 Feb 2026, at 18:58, JP Kobryn (Meta) wrote: > There are situations where reclaim kicks in on a system with free memory. > One possible cause is a NUMA imbalance scenario where one or more nodes are > under pressure. It would help if we could easily identify such nodes. > > Move the pgscan, pgsteal, and pgrefill counters from vm_event_item to > node_stat_item to provide per-node reclaim visibility. With these counters > as node stats, the values are now displayed in the per-node section of > /proc/zoneinfo, which allows for quick identification of the affected > nodes. > > /proc/vmstat continues to report the same counters, aggregated across all > nodes. But the ordering of these items within the readout changes as they > move from the vm events section to the node stats section. > > Memcg accounting of these counters is preserved. The relocated counters > remain visible in memory.stat alongside the existing aggregate pgscan and > pgsteal counters. > > However, this change affects how the global counters are accumulated. > Previously, the global event count update was gated on !cgroup_reclaim(), > excluding memcg-based reclaim from /proc/vmstat. Now that > mod_lruvec_state() is being used to update the counters, the global > counters will include all reclaim. This is consistent with how pgdemote > counters are already tracked. > > Finally, the virtio_balloon driver is updated to use > global_node_page_state() to fetch the counters, as they are no longer > accessible through the vm_events array. > > Signed-off-by: JP Kobryn <[email protected]> > Suggested-by: Johannes Weiner <[email protected]> > Acked-by: Michael S. Tsirkin <[email protected]> > Reviewed-by: Vlastimil Babka (SUSE) <[email protected]> > --- > v5: > - rebase onto mm/mm-new > > v4: > https://lore.kernel.org/linux-mm/[email protected]/ > - remove unused memcg var from scan_folios() > > v3: > https://lore.kernel.org/linux-mm/[email protected]/ > - additionally move PGREFILL to node stats > > v2: > https://lore.kernel.org/linux-mm/[email protected]/ > - update commit message > - add entries to memory_stats array > - add switch cases in memcg_page_state_output_unit() > > v1: > https://lore.kernel.org/linux-mm/[email protected]/ > > drivers/virtio/virtio_balloon.c | 8 ++--- > include/linux/mmzone.h | 13 ++++++++ > include/linux/vm_event_item.h | 13 -------- > mm/memcontrol.c | 56 +++++++++++++++++++++++---------- > mm/vmscan.c | 39 ++++++++--------------- > mm/vmstat.c | 26 +++++++-------- > 6 files changed, 82 insertions(+), 73 deletions(-) >
Acked-by: Zi Yan <[email protected]> Best Regards, Yan, Zi
