+Johannes Weiner
On Tue, Jul 2, 2019 at 6:23 PM Yafang Shao <laoar.shao@xxxxxxxxx> wrote:
>
> When we calculate total statistics for memcg1_stats and memcg1_events, we
> use the the index 'i' in the for loop as the events index.
> Actually we should use memcg1_stats[i] and memcg1_events[i] as the
> events index.
>
> Fixes: 8de7ecc6483b ("memcg: reduce memcg tree traversals for stats collection")
Actually it fixes 42a300353577 ("mm: memcontrol: fix recursive
statistics correctness & scalabilty").
> Signed-off-by: Yafang Shao <laoar.shao@xxxxxxxxx>
> Cc: Shakeel Butt <shakeelb@xxxxxxxxxx>
> Cc: Michal Hocko <mhocko@xxxxxxxx>
> Cc: Yafang Shao <shaoyafang@xxxxxxxxxxxxxx>
> ---
> mm/memcontrol.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index 3ee806b..2ad94d0 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -3528,12 +3528,13 @@ static int memcg_stat_show(struct seq_file *m, void *v)
> if (memcg1_stats[i] == MEMCG_SWAP && !do_memsw_account())
> continue;
> seq_printf(m, "total_%s %llu\n", memcg1_stat_names[i],
> - (u64)memcg_page_state(memcg, i) * PAGE_SIZE);
> + (u64)memcg_page_state(memcg, memcg1_stats[i]) *
> + PAGE_SIZE);
It seems like I made the above very subtle in 8de7ecc6483b and
Johannes missed this subtlety in 42a300353577 (and I missed it in the
review).
> }
>
> for (i = 0; i < ARRAY_SIZE(memcg1_events); i++)
> seq_printf(m, "total_%s %llu\n", memcg1_event_names[i],
> - (u64)memcg_events(memcg, i));
> + (u64)memcg_events(memcg, memcg1_events[i]));
>
> for (i = 0; i < NR_LRU_LISTS; i++)
> seq_printf(m, "total_%s %llu\n", mem_cgroup_lru_names[i],
> --
> 1.8.3.1
>
Reviewed-by: Shakeel Butt <shakeelb@xxxxxxxxxx>
