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From:   Shakeel Butt <shakeelb@google.com>
Date:   Mon, 30 Nov 2020 12:54:51 -0800
Message-ID: <CALvZod5HFkpPK3ALTV7xq_Pu4Cj6gO=xJgCb6X0d4SsJQcgnDw@mail.gmail.com>
Subject: Re: [PATCH 2/2] mm: memcontrol: account pagetables per node
To:     Johannes Weiner <hannes@cmpxchg.org>
Cc:     Roman Gushchin <guro@fb.com>, Michal Hocko <mhocko@suse.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Linux MM <linux-mm@kvack.org>,
        LKML <linux-kernel@vger.kernel.org>
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On Mon, Nov 30, 2020 at 12:21 PM Johannes Weiner <hannes@cmpxchg.org> wrote:
>
> On Wed, Nov 25, 2020 at 04:56:03PM -0800, Shakeel Butt wrote:
> > For many workloads, pagetable consumption is significant and it makes
> > sense to expose it in the memory.stat for the memory cgroups. However at
> > the moment, the pagetables are accounted per-zone. Converting them to
> > per-node and using the right interface will correctly account for the
> > memory cgroups as well.
> >
> > Signed-off-by: Shakeel Butt <shakeelb@google.com>
>
> Agreed, this is a useful stat item to have.
>
> Just one trivial issue:
>
> > --- a/include/linux/mmzone.h
> > +++ b/include/linux/mmzone.h
> > @@ -151,7 +151,6 @@ enum zone_stat_item {
> >       NR_ZONE_UNEVICTABLE,
> >       NR_ZONE_WRITE_PENDING,  /* Count of dirty, writeback and unstable pages */
> >       NR_MLOCK,               /* mlock()ed pages found and moved off LRU */
> > -     NR_PAGETABLE,           /* used for pagetables */
> >       /* Second 128 byte cacheline */
> >       NR_BOUNCE,
> >  #if IS_ENABLED(CONFIG_ZSMALLOC)
> > @@ -206,6 +205,7 @@ enum node_stat_item {
> >  #if IS_ENABLED(CONFIG_SHADOW_CALL_STACK)
> >       NR_KERNEL_SCS_KB,       /* measured in KiB */
> >  #endif
> > +     NR_PAGETABLE,           /* used for pagetables */
> >       NR_VM_NODE_STAT_ITEMS
> >  };
>
> You need to update mm/vmstat.c::vmstat_text accordingly or
> /proc/vmstat output will be bogus.

Oh I missed that. Thanks for catching.

>
> With that fixed, please feel free to add:
> Acked-by: Johannes Weiner <hannes@cmpxchg.org>

Thanks.