One way to measure the efficiency of memory reclaim is to look at the ratio (pgscan+pfrefill)/pgsteal. However at the moment these stats are not updated consistently at the system level and the ratio of these are not very meaningful. The pgsteal and pgscan are updated for only global reclaim while pgrefill gets updated for global as well as cgroup reclaim. Please note that this difference is only for system level vmstats. The cgroup stats returned by memory.stat are actually consistent. The cgroup's pgsteal contains number of reclaimed pages for global as well as cgroup reclaim. So, one way to get the system level stats is to get these stats from root's memory.stat but root does not expose that interface. Also for !CONFIG_MEMCG machines /proc/vmstat is the only way to get these stats. So, make these stats consistent. Signed-off-by: Shakeel Butt <shakeelb@xxxxxxxxxx> --- mm/vmscan.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index cc555903a332..51f7d1efc912 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1943,8 +1943,7 @@ shrink_inactive_list(unsigned long nr_to_scan, struct lruvec *lruvec, reclaim_stat->recent_scanned[file] += nr_taken; item = current_is_kswapd() ? PGSCAN_KSWAPD : PGSCAN_DIRECT; - if (!cgroup_reclaim(sc)) - __count_vm_events(item, nr_scanned); + __count_vm_events(item, nr_scanned); __count_memcg_events(lruvec_memcg(lruvec), item, nr_scanned); spin_unlock_irq(&pgdat->lru_lock); @@ -1957,8 +1956,7 @@ shrink_inactive_list(unsigned long nr_to_scan, struct lruvec *lruvec, spin_lock_irq(&pgdat->lru_lock); item = current_is_kswapd() ? PGSTEAL_KSWAPD : PGSTEAL_DIRECT; - if (!cgroup_reclaim(sc)) - __count_vm_events(item, nr_reclaimed); + __count_vm_events(item, nr_reclaimed); __count_memcg_events(lruvec_memcg(lruvec), item, nr_reclaimed); reclaim_stat->recent_rotated[0] += stat.nr_activate[0]; reclaim_stat->recent_rotated[1] += stat.nr_activate[1]; -- 2.26.2.526.g744177e7f7-goog
