Re: [PATCH 3/3] memcg: reduce size of memcg vmstats structures

[Andrew Morton]

On Wed, 7 Sep 2022 19:35:10 -0700 Shakeel Butt <shakeelb@xxxxxxxxxx> wrote:

> On Tue, Sep 6, 2022 at 9:36 PM Shakeel Butt <shakeelb@xxxxxxxxxx> wrote:
> >
> [...]
> >
> >  static unsigned long memcg_events_local(struct mem_cgroup *memcg, int event)
> >  {
> >         long x = 0;
> >         int cpu;
> > +       int index = memcg_events_index(event);
> > +
> > +       if (index < 0)
> > +               return 0;
> >
> >         for_each_possible_cpu(cpu)
> >                 x += per_cpu(memcg->vmstats_percpu->events[event], cpu);
> 
> Andrew, can you please replace 'event' in the above line with 'index'?
> I had this correct in the original single patch but messed up while
> breaking up that patch into three patches for easier review.

No probs.

From: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Subject: memcg-reduce-size-of-memcg-vmstats-structures-fix
Date: Thu Sep  8 03:35:53 PM PDT 2022

fix memcg_events_local() array index, per Shakeel

Link: https://lkml.kernel.org/r/CALvZod70Mvxr+Nzb6k0yiU2RFYjTD=0NFhKK-Eyp+5ejd1PSFw@xxxxxxxxxxxxxx
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Muchun Song <songmuchun@xxxxxxxxxxxxx>
Cc: Roman Gushchin <roman.gushchin@xxxxxxxxx>
Cc: Shakeel Butt <shakeelb@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---

 mm/memcontrol.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/mm/memcontrol.c~memcg-reduce-size-of-memcg-vmstats-structures-fix
+++ a/mm/memcontrol.c
@@ -921,7 +921,7 @@ static unsigned long memcg_events_local(
 		return 0;
 
 	for_each_possible_cpu(cpu)
-		x += per_cpu(memcg->vmstats_percpu->events[event], cpu);
+		x += per_cpu(memcg->vmstats_percpu->events[index], cpu);
 	return x;
 }
 
_