On Thu, Jul 11, 2019 at 09:32:59AM -0400, Yafang Shao wrote:
> After commit 815744d75152 ("mm: memcontrol: don't batch updates of local VM stats and events"),
> the local VM counters is not in sync with the hierarchical ones.
>
> Bellow is one example in a leaf memcg on my server (with 8 CPUs),
> inactive_file 3567570944
> total_inactive_file 3568029696
> We can find that the deviation is very great, that is because the 'val' in
> __mod_memcg_state() is in pages while the effective value in
> memcg_stat_show() is in bytes.
> So the maximum of this deviation between local VM stats and total VM
> stats can be (32 * number_of_cpu * PAGE_SIZE), that may be an unacceptable
> great value.
>
> We should keep the local VM stats in sync with the total stats.
> In order to keep this behavior the same across counters, this patch updates
> __mod_lruvec_state() and __count_memcg_events() as well.
>
> Signed-off-by: Yafang Shao <laoar.shao@xxxxxxxxx>
> Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
> Cc: Michal Hocko <mhocko@xxxxxxxxxx>
> Cc: Vladimir Davydov <vdavydov.dev@xxxxxxxxx>
> Cc: Yafang Shao <shaoyafang@xxxxxxxxxxxxxx>
Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>
