Re: [PATCH] Add a text_poke syscall v2

Oleg Nesterov
2013-11-29T20:35:10Z

On 11/29, H. Peter Anvin wrote:
>
> On 11/29/2013 12:05 PM, Oleg Nesterov wrote:
> >
> > Can't we invalidate pte (so that any user will stuck in page fault),
> > update the page(s), restore the pte and drop the locks?
> >
>
> That would require a global TLB shootdown

Well, it is not really global, it is for mm_cpumask() and for good
reason?

And is it really worse than on_each_cpu(do_sync_core) and the usage
of text_mutex?

> (and wouldn't help
> shared-memory code segments, if we care about that at all.)

Well, I think this should only support the private mappings.

> It also
> means much bigger code ranges would be affected.

Yes, this is true.

Oleg.