Re: [PATCH v2] core, x86: Add user return notifiers

Peter Zijlstra
2009-09-22T16:50:21Z

On Tue, 2009-09-22 at 16:32 +0200, Ingo Molnar wrote:
> * Avi Kivity <avi@redhat.com> wrote:
>
> > On 09/19/2009 09:40 AM, Avi Kivity wrote:
> >> Add a general per-cpu notifier that is called whenever the kernel is
> >> about to return to userspace. The notifier uses a thread_info flag
> >> and existing checks, so there is no impact on user return or context
> >> switch fast paths.
> >>
> >
> > Ingo/Peter?
>
> Would be nice to convert some existing open-coded return-to-user-space
> logic to this facility. One such candidate would be lockdep_sys_exit?

And here I was thinking this was one of the hottest code paths in the
whole kernel...