On Mon, 2011-05-30 at 14:55 +0300, Pekka Enberg wrote: > On Mon, May 30, 2011 at 2:49 PM, Ingo Molnar <mingo@xxxxxxx> 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. It should. I can (easily) boot 64GB guest on my 4GB laptop. We fail at >64GB due to an issue with our mappings (I haven't investigated it yet) - not due to running out of memory. -- Sasha. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
