Re: [PATCH v2 6/8] kvm tools: Add rwlock wrapper

Pekka Enberg
2011-05-30T11:55:26Z

On Mon, May 30, 2011 at 2:49 PM, Ingo Molnar <mingo@elte.hu> wrote:
> [*] Would be nice if tools/kvm/ had a debug option to simulate 'lots
>    of RAM' as well somehow - perhaps by not pre-initializing it and
>    somehow catching all-zeroes pages and keeping them all zeroes and
>    shared? It would obviously OOM after some time but would allow me
>    to at least boot a fair deal of userspace. The motivation is that
>    i have recently received a 1 TB RAM bugreport. 1 TB of RAM mapped
>    with 2MB mappings should still be able to boot to shell on a 32
>    GB RAM testbox of mine, and survive there for some time. We could
>    even do some kernel modifications to make this kind of simulation
>    easier.

Doesn't our mmap() overcommit work for you? IIRC, Sasha booted guests
with huge amounts of overcommitted RAM.

Pekka