Re: [RFC PATCH v9 for 4.15 01/14] Restartable sequences system call

[Paul E. McKenney]

On Fri, Oct 13, 2017 at 02:05:50PM -0700, Linus Torvalds wrote:
> On Fri, Oct 13, 2017 at 1:54 PM, Paul E. McKenney
> <paulmck@xxxxxxxxxxxxxxxxxx> wrote:
> >>
> >> And if nobody can be bothered to write the user-level code and test
> >> this patch-series, then obviously it's not important enough for the
> >> kernel to merge it.
> >
> > My guess is that it will take some time, probably measured in months,
> > to carry out this level of integration and testing to.
> 
> That would be an argument if this was a new patch series. "Wait a few months".
> 
> But that just isn't the case here.
> 
> The fact is, these patches have been floating around in one form or
> another not for a couple of months, but for years. There's a LWN
> article about it from 2015, and it wasn't new back then either (slides
> from 2013).
> 
> I wouldn't be surprised if there had been academic _papers_ written
> about the notion.
> 
> So if there  *still* is no actual real code around this, then that
> just strengthens my point - no way should we merge something where
> people haven't actually bothered to write the user-mode component for
> years and years.
> 
> It really boils down to: "if nobody can be bothered to write the user
> mode parts after several years, why should it be merged into the
> kernel"?
> 
> I don't think that's too much to ask for.

Completely and totally agreed.  This doesn't go into mainline without
being integrated into the various relevant usermode parts, and even then
not without some significant advantages having been clearly demonstrated.

The same as has been the case for the -rt patches.

							Thanx, Paul