Re: [PATCH v4 03/19] mm: memcg: convert vmstat slab counters to bytes

Vlastimil Babka
2020-05-27T11:43:20Z

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)