Re: RCU stall when using function_graph

From: Steven Rostedt
Date: Wed Aug 16 2017 - 12:41:48 EST


On Wed, 16 Aug 2017 09:32:28 -0700
"Paul E. McKenney" <paulmck@xxxxxxxxxxxxxxxxxx> wrote:

> Let me see if I understand you... About halfway to the stall limit,
> RCU triggers an irq_work (on each CPU that has not yet passed through
> a quiescent state, IPIing them in turn?), and if the irq_work has
> not completed by the end of the stall limit, RCU adds that to its
> stall-warning message.

Doesn't even have to be half way through. It could be done at the
limit, and then wait a little more.

>
> Or am I missing something here?

No, I think that's what I was suggesting.

-- Steve