Re: [PATCH net-next 1/2] net: Keep sk->sk_forward_alloc as a proper size

Shakeel Butt
2023-05-10T19:00:20Z

On Wed, May 10, 2023 at 9:09 AM Zhang, Cathy <cathy.zhang@intel.com> wrote:
>
>
[...]
> > > >
> > > > Have you tried to increase batch sizes ?
> > >
> > > I jus picked up 256 and 1024 for a try, but no help, the overhead still exists.
> >
> > This makes no sense at all.
>
> Eric,
>
> I added a pr_info in try_charge_memcg() to print nr_pages if
> nr_pages >= MEMCG_CHARGE_BATCH, except it prints 64 during the initialization
> of instances, there is no other output during the running. That means nr_pages is not
> over 64, I guess that might be the reason why to increase MEMCG_CHARGE_BATCH
> doesn't affect this case.
>

I am assuming you increased MEMCG_CHARGE_BATCH to 256 and 1024 but
that did not help. To me that just means there is a different
bottleneck in the memcg charging codepath. Can you please share the
perf profile? Please note that memcg charging does a lot of other
things as well like updating memcg stats and checking (and enforcing)
memory.high even if you have not set memory.high.