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

From: Paul E. McKenney
Date: Mon Sep 09 2013 - 09:50:52 EST


On Mon, Sep 09, 2013 at 09:41:32AM -0400, Steven Rostedt wrote:
> On Mon, 9 Sep 2013 15:29:02 +0200
> Frederic Weisbecker <fweisbec@xxxxxxxxx> wrote:
>
>
> > No, putting that on the task_struct won't help much in this regard I think.
> > Regular schedule() calls don't change that per cpu state.
>
> But is there a place that it would need to?
>
> I mean, if RCU is not tracking a CPU, is it safe to call schedule().
> And then how would the new task know that RCU is ignoring that CPU?

Guys, RCU really is tracking per-CPU state with the rcu_dynticks.dynticks
field.

Thanx, Paul

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