Messages in this thread | | | Subject | Re: [PATCH tip/core/rcu 11/15] rcu: Avoid spurious RCU CPU stall warnings | From | Peter Zijlstra <> | Date | Fri, 07 Sep 2012 09:00:30 +0200 |
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On Thu, 2012-09-06 at 15:22 -0700, Paul E. McKenney wrote: > Ah! > > It is perfectly legal to avoid -starting- an RCU grace period for a > minute, or even longer. If RCU has nothing to do, in other words, if no > one registers any RCU callbacks, then RCU need not start a grace period. > > Of course, this would mean that it would eventually be a full minute > since the last start of a grace period. This is not a problem, after > all, Linux went through a full ten years before experiencing its first > grace period. > > But the stall-warning code just checked how long it had been since > the last start of a grace period, failing to note that this grace > period had long since completed. So it splatted out a warning. > This warning was spurious in the sense that there was no bug aside > from the missing check that the grace period was still in progress. > > And this commit fixes that bug in RCU.
OK, that makes sense.. it just looks like both Steve and me got confused by the initial changelog.
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