Re: [RFC][PATCH 00/26] sched/numa

Peter Zijlstra
2012-03-19T13:27:11Z

On Mon, 2012-03-19 at 14:04 +0100, Andrea Arcangeli wrote:
> If you boot with memcg compiled in, that's taking an equivalent amount
> of memory per-page.
>
> If you can bear the memory loss when memcg is compiled in even when
> not enabled, you sure can bear it on NUMA systems that have lots of
> memory, so it's perfectly ok to sacrifice a bit of it so that it
> performs like not-NUMA but you still have more memory than not-NUMA.
>
I think the overhead of memcg is quite insane as well. And no I cannot
bear that and have it disabled in all my kernels.

NUMA systems having lots of memory is a false argument, that doesn't
mean we can just waste tons of it, people pay good money for that
memory, they want to use it.

I fact, I know that HPC people want things like swap-over-nfs so they
can push infrequently running system crap out into swap so they can get
these few extra megabytes of memory. And you're proposing they give up
~100M just like that?