Re: [PATCH v3 4/8] memcg: reduce memory for the lruvec and memcg stats

[Shakeel Butt <shakeel.butt@linux.dev>]

On Tue, Apr 30, 2024 at 10:41:01AM -0700, Yosry Ahmed wrote:
> On Tue, Apr 30, 2024 at 10:38 AM Shakeel Butt <shakeel.butt@linux.dev> wrote:
> >
> > On Tue, Apr 30, 2024 at 01:41:38AM -0700, Yosry Ahmed wrote:
> > > On Mon, Apr 29, 2024 at 11:06 PM Shakeel Butt <shakeel.butt@linux.dev> wrote:
> > > >
> > [...]
> > > > +
> > > > +#define NR_MEMCG_NODE_STAT_ITEMS ARRAY_SIZE(memcg_node_stat_items)
> > > > +#define NR_MEMCG_STATS (NR_MEMCG_NODE_STAT_ITEMS + ARRAY_SIZE(memcg_stat_items))
> > > > +static int8_t mem_cgroup_stats_index[MEMCG_NR_STAT] __read_mostly;
> > >
> > > NR_MEMCG_STATS and MEMCG_NR_STAT are awfully close and have different
> > > meanings. I think we should come up with better names (sorry nothing
> > > comes to mind) or add a comment to make the difference more obvious.
> > >
> >
> > How about the following comment?
> 
> The comment LGTM. I prefer renaming them though if someone can come up
> with better names.
> 

I will be posting v4 and will change the name (still thinking about the
name) becasuse:

> > > > +static void init_memcg_stats(void)
> > > > +{
> > > > +       int8_t i, j = 0;
> > > > +
> > > > +       /* Switch to short once this failure occurs. */
> > > > +       BUILD_BUG_ON(NR_MEMCG_STATS >= 127 /* INT8_MAX */);

The above should be MEMCG_NR_STAT instead of NR_MEMCG_STATS.