Re: [PATCH 0/2] x86/context-tracking: Remove last remaining calls to exception_enter/exception_exit()

[Frederic Weisbecker <frederic@kernel.org>]

On Mon, Jan 06, 2020 at 04:05:46PM +0100, Peter Zijlstra wrote:
> On Fri, Dec 27, 2019 at 05:36:10PM +0100, Frederic Weisbecker wrote:
> > Thanks to the cleanups from Andy Lutomirski over the years, those calls
> > can now be removed. This will allow for nice things in the future for
> > x86 support on full nohz:
> > 
> > * Remove TIF_NOHZ and use a per-cpu switch to enable, disable context
> >   tracking.
> > 
> > * Avoid context tracking on housekeepers.
> > 
> > * Dynamically enable/disable context tracking on CPU on runtime and
> >   therefore allow runtime enable/disable of nohz_full
> > 
> > * Make nohz_full a property of cpuset.
> > 
> > Frederic Weisbecker (2):
> >   x86/context-tracking: Remove exception_enter/exit() from
> >     do_page_fault()
> >   x86/context-tracking: Remove exception_enter/exit() from
> >     KVM_PV_REASON_PAGE_NOT_PRESENT async page fault
> 
> Thanks, these look good to me.
> 
> Did I tell you about my 'TODO' item vs text_poke_sync() ? Basically, we
> can avoid sending the IPI to NOHZ_FULL user CPUs, provided we make their
> enter_from_user_mode() do the sync_core().

Yeah I believe I saw some email about that somewhere. I hope I didn't miss
a patch about that. Anyway, whether past or future patch, I'll happily review that :-)