Re: [RFC v2 0/2] swait: add idle to make idle-hacks on kthreads explicit

From: Paul E. McKenney
Date: Thu Jun 15 2017 - 19:43:50 EST


On Fri, Jun 16, 2017 at 01:26:19AM +0200, Luis R. Rodriguez wrote:
> On Thu, Jun 15, 2017 at 02:57:17PM -0700, Paul E. McKenney wrote:
> > On Thu, Jun 15, 2017 at 11:48:18AM -0700, Luis R. Rodriguez wrote:
> > > While reviewing RCU's interruptible swaits I noticed signals were actually
> > > not expected. Paul explained that the reason signals are not expected is
> > > we use kthreads, which don't get signals, furthermore the code avoided the
> > > uninterruptible swaits as otherwise it would contribute to the system load
> > > average on idle, bumping it from 0 to 2 or 3 (depending on preemption).
> > >
> > > Since this can be confusing its best to be explicit about the requirements and
> > > goals. This patch depends on the other killable swaits [0] recently proposed as
> > > well interms of context. Thee patch can however be tested independently if
> > > the hunk is addressed separately.
> > >
> > > [0] https://lkml.kernel.org/r/20170614222017.14653-3-mcgrof@xxxxxxxxxx
> >
> > Tested-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
> >
> > Are you looking to push these or were you wanting me to?
>
> I'd be happy for you to take them.

OK, let's see if we can get some Acked-by's or Reviewed-by's from the
relevant people.

For but one example, Eric, does this look good to you or are adjustments
needed?

Thanx, Paul