Re: [RFC] Make need_resched() return true when rcu_urgent_qs requested
From: Paul E. McKenney
Date: Thu Jul 19 2018 - 13:10:02 EST
On Wed, Jul 18, 2018 at 09:37:12AM -0700, Paul E. McKenney wrote:
> On Wed, Jul 18, 2018 at 06:01:51PM +0200, David Woodhouse wrote:
> > On Wed, 2018-07-18 at 08:36 -0700, Paul E. McKenney wrote:
> > > And I finally did get some near misses from an earlier commit, so we
> > > should consider your patch to be officially off the hook.
> >
> > Yay, I like it when it's not my fault. I'll redo it with the ifdef
> > CONFIG_NO_HZ_FULL.
>
> Hey, I didn't say it wasn't your fault, only that it -officially- wasn't
> your fault. ;-)
And I believe that I found my bug in this commit (lots more testing still
required, but the preponderance of evidence and all that):
2cc0c7f07143 ("rcu: Eliminate ->rcu_qs_ctr from the rcu_dynticks structure")
So it really isn't your fault.
Of course, the real reason for the lack of fault on your part will not
because I believe I found the bug elsewhere, but instead because I will
be dropping your patch (and mine as well) on Frederic's advice. ;-)
Thanx, Paul