Re: [Qemu-devel] [RFC PATCH RDMA support v4: 03/10] more verbose documentation of the RDMA transport

[Michael S. Tsirkin]

On Tue, Mar 19, 2013 at 06:14:45PM +0100, Paolo Bonzini wrote:
> Il 19/03/2013 18:09, Michael R. Hines ha scritto:
> > Allowing QEMU to swap due to a cgroup limit during migration is a viable
> > overcommit option?
> > 
> > I'm trying to keep an open mind, but that would kill the migration
> > time.....

Maybe not if you have a fast SSD, or are using swap in RAM or compressed
swap or ...

> Would it swap?  Doesn't the kernel back all zero pages with a single
> copy-on-write page?  If that still accounts towards cgroup limits, it
> would be a bug.
> 
> Old kernels do not have a shared zero hugepage, and that includes some
> distro kernels.  Perhaps that's the problem.
> 
> Paolo

AFAIK for zero pages, yes. I'm not sure what the problem is either.

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MST