Re: [CRIU] [PATCH] Add VDSO time function support for x86 32-bitkernel

[Pavel Emelyanov]

On 12/14/2012 06:20 AM, Andy Lutomirski wrote:
> On Thu, Dec 13, 2012 at 6:18 PM, H. Peter Anvin <hpa@xxxxxxxxx> wrote:
>> Wouldn't the vdso get mapped already and could be mremap()'d.  If we
> really need more control I'd almost push for a device/filesystem node
> that could be mmapped the usual way.
> 
> Hmm.  That may work, but it'll still break ABI.  I'm not sure that
> criu is stable enough yet that we should care.  Criu people?

It's not yet, but we'd still appreciate the criu-friendly vdso redesign.

> (In brief summary: how annoying would it be if the vdso was no longer
> just a bunch of constant bytes that lived somewhere?)

It depends on what vdso is going to be. In the perfect case it should
a) be mremap-able to any address (or be at fixed address _forever_, but
   I assume this is not feasible);
b) have entry points at fixed (or somehow movable) places.

I admit that I didn't understand your question properly, if I did,
please correct me.

Thanks,
Pavel
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