Re: memcgroup lruvec_lru_size scaling issue

[Tim Chen <tim.c.chen@linux.intel.com>]

On 10/14/19 3:14 PM, Andrew Morton wrote:
> On Mon, 14 Oct 2019 20:31:07 +0200 Michal Hocko <mhocko@kernel.org> wrote:
> 
>> Please put all that to the changelog. It would be also great to see
>> whether that really scales with the number of cgroups if that is easy to
>> check with your benchmark.
> 
> I restored this, with some changelog additions.
> 
> Tim, please send along any updates you'd like to make to this, along
> with tested-by, acked-by, etc.
> 
> I added the Fixes: tag.  Do we think this is serious enough to warrant
> backporting into -stable trees?  I suspect so, as any older-tree
> maintainer who spies this change will say "hell yeah".

Johannes' changes that introduced the sum over all percpu counters
in lruvec_lru_size only got merged recently in 5.2. I tested 5.1 kernel and
it does not have this particular scalability issue.

So backport is only needed for 5.2 stable. 

Feel free to add 

Acked-by: Tim Chen <tim.c.chen@linux.intel.com>
Tested-by: Tim Chen <tim.c.chen@linux.intel.com>

Thanks.

Tim