[PATCH] um: implement arch_sync_kernel_mappings

[Johannes Berg]

On Tue, 2021-03-16 at 10:49 +0000, Anton Ivanov wrote:
> > > I get slightly better performance on userspace,
> > > etc compared to your patch. It is marginal -
> > > sub 1% close to the experimental error.
> > 
> > Why does that even affect userspace at all, btw? We're talking about
> > kernel mappings?
> 
> My userspace tests do heavy IO.

OK, but even then, my patch should be an improvement on anything that
needs updated ranges since it avoids the segfault(s), and not really
make anything worse that *doesn't*?

But then again, I'm not sure you said that this patch was an improvement
or not for your workload?

johannes