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Date: Tue, 30 Apr 2024 10:45:06 -0700
From: Shakeel Butt <shakeel.butt@linux.dev>
To: "T.J. Mercier" <tjmercier@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>, 
	Johannes Weiner <hannes@cmpxchg.org>, Michal Hocko <mhocko@kernel.org>, 
	Roman Gushchin <roman.gushchin@linux.dev>, Muchun Song <muchun.song@linux.dev>, 
	Yosry Ahmed <yosryahmed@google.com>, kernel-team@meta.com, linux-mm@kvack.org, 
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 4/8] memcg: reduce memory for the lruvec and memcg
 stats
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References: <20240430060612.2171650-1-shakeel.butt@linux.dev>
 <20240430060612.2171650-5-shakeel.butt@linux.dev>
 <CABdmKX0jGpZ4VSvQrLDB9ntLEb-tJTWFEfVLC5ukkZDi1CK2yQ@mail.gmail.com>
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On Tue, Apr 30, 2024 at 10:30:51AM -0700, T.J. Mercier wrote:
> On Mon, Apr 29, 2024 at 11:06 PM Shakeel Butt <shakeel.butt@linux.dev> wrote:
> >
> > +
> > +static inline int memcg_stats_index(int idx)
> > +{
> > +       return mem_cgroup_stats_index[idx] - 1;
> 
> Could this just be: return mem_cgroup_stats_index[idx];
> with a postfix increment of j in init_memcg_stats instead of prefix increment?
> 

The -1 is basically for error checking but I will do a followup patch to
initialize the array/indirection-table with -1 and remove the
subtraction from the fast path.

Thanks for the review.