Re: [PATCH] rcu: Is it safe to enter an RCU read-side criticalsection?

[Christoph Lameter]

On Thu, 12 Sep 2013, Ingo Molnar wrote:

>
> * Christoph Lameter <cl@xxxxxxxxx> wrote:
>
> > On Mon, 9 Sep 2013, Ingo Molnar wrote:
> >
> > > I saw those, he posted 'needs testing' patches. He still behaved
> > > passive-aggressively, pretending that it was some difficult task to
> > > perform, as if we were pulling his teeth.
> >
> > I need your review of those. I will rediff as soon as rc1 is out to send
> > something that can be put into -next. Please tell me until then if the
> > approach is ok. I dont think we can do anything in the merge window.
>
> The patch looked OK. Have you tested it, such as using a this_cpu op on a
> PREEMPT=y kernel in a preemptible section? That should trigger the preempt
> warning.

The reason that certain __this_cpu ops were converted to raw_cpu ops is
because they triggered the preemption check. The test was done in a kvm
environment (as evident from the description).



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