Messages in this thread | | | Date | Tue, 24 Feb 2009 20:43:56 -0800 | From | "Paul E. McKenney" <> | Subject | Re: [PATCH] v3 Teach RCU that idle task is not quiscent state at boot |
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On Wed, Feb 25, 2009 at 05:12:59AM +0100, Nick Piggin wrote: > Looks OK to me. It's a bit "theoretically" displeasing that > you still treat synchronize_rcu as a gp even after we spawn > some kernel threads. > > ... but it probably isn't worth trying to rearrange the boot > code just to make this look better. I can't see any actual > problems that could arise, as the threads should not have > had a chance to run yet.
And if rcuclassic or rcutree on a UP system, even if threads have had a chance to run, it is OK to treat synchronize_rcu() as a grace period, since it has the opportunity to block.
> I wonder if you couldn't put in a WARN_ON(nr_context_switches() > 0) > in rcu_idle_now_means_idle() just in case?
Makes a lot of sense -- updated and am firing off the tests!
Thanx, Paul
> On Tue, Feb 24, 2009 at 04:29:37PM -0800, Paul E. McKenney wrote: > > This patch fixes a bug located by Vegard Nossum with the aid of > > kmemcheck, updated based on review comments from Nick Piggin, > > Ingo Molnar, and Andrew Morton.
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