Re: [PATCH 5/6] mm: memcontrol: per-lruvec stats infrastructure

[Vladimir Davydov]

On Tue, May 30, 2017 at 02:17:23PM -0400, Johannes Weiner wrote:
> lruvecs are at the intersection of the NUMA node and memcg, which is
> the scope for most paging activity.
> 
> Introduce a convenient accounting infrastructure that maintains
> statistics per node, per memcg, and the lruvec itself.
> 
> Then convert over accounting sites for statistics that are already
> tracked in both nodes and memcgs and can be easily switched.
> 
> Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx>
> ---
>  include/linux/memcontrol.h | 238 +++++++++++++++++++++++++++++++++++++++------
>  include/linux/vmstat.h     |   1 -
>  mm/memcontrol.c            |   6 ++
>  mm/page-writeback.c        |  15 +--
>  mm/rmap.c                  |   8 +-
>  mm/workingset.c            |   9 +-
>  6 files changed, 225 insertions(+), 52 deletions(-)
> 
...
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index 9c68a40c83e3..e37908606c0f 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -4122,6 +4122,12 @@ static int alloc_mem_cgroup_per_node_info(struct mem_cgroup *memcg, int node)
>  	if (!pn)
>  		return 1;
>  
> +	pn->lruvec_stat = alloc_percpu(struct lruvec_stat);
> +	if (!pn->lruvec_stat) {
> +		kfree(pn);
> +		return 1;
> +	}
> +
>  	lruvec_init(&pn->lruvec);
>  	pn->usage_in_excess = 0;
>  	pn->on_tree = false;

I don't see the matching free_percpu() anywhere, forget to patch
free_mem_cgroup_per_node_info()?

Other than that and with the follow-up fix applied, this patch
is good IMO.

Acked-by: Vladimir Davydov <vdavydov.dev@xxxxxxxxx>