Re: [PATCH] net: make SK_MEMORY_PCPU_RESERV tunable

[Lameter, Christopher]

On Tue, 27 Feb 2024, Eric Dumazet wrote:

> > sk_prot->memory_allocated points to global atomic variable:
> > atomic_long_t tcp_memory_allocated ____cacheline_aligned_in_smp;
> >
> > If increasing the per-cpu cache size from 1MB to e.g. 16MB,
> > changes to sk->sk_prot->memory_allocated can be further reduced.
> > Performance may be improved on system with many cores.
>
> This looks good, do you have any performance numbers to share ?
>
> On a host with 384 threads, 384*16 ->  6 GB of memory.

Those things also come with corresponding memories of a couple of TB...

> With this kind of use, we might need a shrinker...

Yes. No point of keeping the buffers around if the core stops doing 
networking. But to be done at times when there is no contention please. 
Isnt there something like a timeout for skbs in the network stack already?