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Subject: Re: [PATCH v4 03/19] mm: memcg: convert vmstat slab counters to bytes
To:     Roman Gushchin <guro@fb.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Christoph Lameter <cl@linux.com>
Cc:     Johannes Weiner <hannes@cmpxchg.org>,
        Michal Hocko <mhocko@kernel.org>,
        Shakeel Butt <shakeelb@google.com>, linux-mm@kvack.org,
        kernel-team@fb.com, linux-kernel@vger.kernel.org
References: <20200526214227.989341-1-guro@fb.com>
 <20200526214227.989341-4-guro@fb.com>
From:   Vlastimil Babka <vbabka@suse.cz>
Message-ID: <a0a6c013-3a08-86f5-46a4-808a8c63a50a@suse.cz>
Date:   Wed, 27 May 2020 13:43:16 +0200
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On 5/26/20 11:42 PM, Roman Gushchin wrote:
> In order to prepare for per-object slab memory accounting, convert
> NR_SLAB_RECLAIMABLE and NR_SLAB_UNRECLAIMABLE vmstat items to bytes.
> 
> To make it obvious, rename them to NR_SLAB_RECLAIMABLE_B and
> NR_SLAB_UNRECLAIMABLE_B (similar to NR_KERNEL_STACK_KB).
> 
> Internally global and per-node counters are stored in pages,
> however memcg and lruvec counters are stored in bytes.
> This scheme may look weird, but only for now. As soon as slab
> pages will be shared between multiple cgroups, global and
> node counters will reflect the total number of slab pages.
> However memcg and lruvec counters will be used for per-memcg
> slab memory tracking, which will take separate kernel objects
> in the account. Keeping global and node counters in pages helps
> to avoid additional overhead.
> 
> The size of slab memory shouldn't exceed 4Gb on 32-bit machines,
> so it will fit into atomic_long_t we use for vmstats.
> 
> Signed-off-by: Roman Gushchin <guro@fb.com>

You didn't add Acked-by: Johannes Weiner <hannes@cmpxchg.org>
( see 20200507204137.GC161043@cmpxchg.org )
(Noticed thanks to the great 'b4 am' and 'git range-diff' tools)

Reviewed-by: Vlastimil Babka <vbabka@suse.cz>