Re: Low TCP throughput due to vmpressure with swap enabled

Yu Zhao
2022-11-22T19:00:03Z

On Mon, Nov 21, 2022 at 5:53 PM Ivan Babrou <ivan@cloudflare.com> wrote:
>
> Hello,
>
> We have observed a negative TCP throughput behavior from the following commit:
>
> * 8e8ae645249b mm: memcontrol: hook up vmpressure to socket pressure
>
> It landed back in 2016 in v4.5, so it's not exactly a new issue.
>
> The crux of the issue is that in some cases with swap present the
> workload can be unfairly throttled in terms of TCP throughput.
>
> I am able to reproduce this issue in a VM locally on v6.1-rc6 with 8
> GiB of RAM with zram enabled.

Hi Ivan,

If it's not too much trouble, could you try again with the following?
CONFIG_LRU_GEN=y
CONFIG_LRU_GEN_ENABLED=y

I haven't tried it myself. But I'll fix whatever doesn't work for you,
since your team is on the top of my customer list :)

Thanks.