On 04/06/2018 05:37 PM, Shakeel Butt wrote:
>> @@ -2482,7 +2494,7 @@ static inline bool should_continue_reclaim(struct
>> pglist_data *pgdat,
>> static bool pgdat_memcg_congested(pg_data_t *pgdat, struct mem_cgroup
>> return test_bit(PGDAT_CONGESTED, &pgdat->flags) ||
>> - (memcg && test_memcg_bit(PGDAT_CONGESTED, memcg));
>> + (memcg && memcg_congested(pgdat, memcg));
> I am wondering if we should check all ancestors for congestion as
> well. Maybe a parallel memcg reclaimer might have set some ancestor of
> this memcg to congested.
Why? If ancestor is congested but its child (the one we currently reclaim) is
it could mean only 2 things:
- Either child use mostly anon and inactive file lru is small (file_lru >>
priority == 0)
so it's not congested.
- Or the child was congested recently (at the time when ancestor scanned this
but not anymore. So the information from ancestor is simply outdated.