Re: [PATCH v2] mm: memcg/slab: Fix root memcg vmstats

[David Rientjes]

On Tue, 10 Nov 2020, Muchun Song wrote:

> If we reparent the slab objects to the root memcg, when we free
> the slab object, we need to update the per-memcg vmstats to keep
> it correct for the root memcg. Now this at least affects the vmstat
> of NR_KERNEL_STACK_KB for !CONFIG_VMAP_STACK when the thread stack
> size is smaller than the PAGE_SIZE.
> 
> Fixes: ec9f02384f60 ("mm: workingset: fix vmstat counters for shadow nodes")
> Signed-off-by: Muchun Song <songmuchun@xxxxxxxxxxxxx>
> Acked-by: Roman Gushchin <guro@xxxxxx>

Acked-by: David Rientjes <rientjes@xxxxxxxxxx>

I assume that without this fix that the root memcg's vmstat would always 
be inflated if we reparented?  If that's accurate, perhaps this is 
deserving of a

Cc: stable@xxxxxxxxxxxxxxx # 5.3+