[lkml]   [2011]   [May]   [16]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [GIT PULL rcu/next] rcu commits for 2.6.40

* Paul E. McKenney <> wrote:

> > And the way you can prove that it is my code rather than the arch
> > code is to show that the warning happens on your system when the
> > irq_enter()/irq_exit() calls are perfectly nested.
> So I took another look at the RCU debugfs stats you provided earlier,
> and realized that your system gets a lot more NMIs than do the ones
> that I have access to. So as a diagnostic patch, I ifdefed out the
> body of rcu_nmi_enter() and rcu_nmi_exit().

Well, but the delays are occuring all the time (and it's bisectable) and NMIs
are generally not deterministic.

I'd really suggest the creation of a revert + finegrained series on top of
core/rcu which would IMHO help us narrow this down a lot more directly than
jumping between the 'need_resched bug', 'nmi bug' and 'barrier bug' hypoteses.

( Btw., the bug still has the feeling of a need_resched/scheduling/timing
artifact to me, not barriers or NMI. )



 \ /
  Last update: 2011-05-16 09:41    [W:0.087 / U:14.216 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site