Re: Expensive tcp_collapse with high tcp_rmem limit

[Eric Dumazet]

On Thu, Jan 6, 2022 at 10:52 AM Eric Dumazet <edumazet@xxxxxxxxxx> wrote:

> I think that you should first look if you are under some kind of attack [1]
>
> Eventually you would still have to make room, involving expensive copies.
>
> 12% of 16MB is still a lot of memory to copy.
>
> [1] Detecting an attack signature could allow you to zap the socket
> and save ~16MB of memory per flow.

I forgot to ask, have you set tcp_min_snd_mss to a sensible value ?

https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net.git/commit/?id=5f3e2bf008c2221478101ee72f5cb4654b9fc363