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

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Message-ID: <20170605175354.GB8547@cmpxchg.org>
Date:   Mon, 5 Jun 2017 13:53:54 -0400
From:   Johannes Weiner <hannes@...xchg.org>
To:     Vladimir Davydov <vdavydov.dev@...il.com>
Cc:     Josef Bacik <josef@...icpanda.com>, Michal Hocko <mhocko@...e.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Rik van Riel <riel@...hat.com>, linux-mm@...ck.org,
        cgroups@...r.kernel.org, linux-kernel@...r.kernel.org,
        kernel-team@...com
Subject: Re: [PATCH 5/6] mm: memcontrol: per-lruvec stats infrastructure

On Sat, Jun 03, 2017 at 08:50:02PM +0300, Vladimir Davydov wrote:
> 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@...xchg.org>
> > ---
> >  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()?

Yes, I missed that.

---

>From 4d09a522a2182acae4e36ded4211d05defd75b74 Mon Sep 17 00:00:00 2001
From: Johannes Weiner <hannes@...xchg.org>
Date: Mon, 5 Jun 2017 10:59:41 -0400
Subject: [PATCH] mm: memcontrol: per-lruvec stats infrastructure fix 3

As pointed out, there is a missing free_percpu() for the lruvec_stat
object in the memcg's per node info. Add this.

Signed-off-by: Johannes Weiner <hannes@...xchg.org>
---
 mm/memcontrol.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index e37908606c0f..093fe7e06e51 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -4139,7 +4139,10 @@ static int alloc_mem_cgroup_per_node_info(struct mem_cgroup *memcg, int node)
 
 static void free_mem_cgroup_per_node_info(struct mem_cgroup *memcg, int node)
 {
-	kfree(memcg->nodeinfo[node]);
+	struct mem_cgroup_per_node *pn = memcg->nodeinfo[node];
+
+	free_percpu(pn->lruvec_stat);
+	kfree(pn);
 }
 
 static void __mem_cgroup_free(struct mem_cgroup *memcg)
-- 
2.13.0