| Subject | Re: [PATCH tip/core/rcu 11/15] rcu: Avoid spurious RCU CPU stall warnings | From | Steven Rostedt <> | Date | Thu, 06 Sep 2012 11:07:29 -0400 |
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On Thu, 2012-09-06 at 16:56 +0200, Peter Zijlstra wrote: > On Thu, 2012-08-30 at 11:56 -0700, Paul E. McKenney wrote: > > > > If a given CPU avoids the idle loop but also avoids starting a new > > RCU grace period for a full minute, RCU can issue spurious RCU CPU > > stall warnings. This commit fixes this issue by adding a check for > > ongoing grace period to avoid these spurious stall warnings. > > How would it avoid starting a new period for over a minute? fqs should > happen, right? And holding rcu_read_lock() for over a minute surely is a > bug.
I can see this happening in test cases, but it would seem weird on a normal system. That is, for preempt rcu, having a process scheduled out holding an rcu_read_lock() for over a minute could happen on a really stressed out system. But for such a case, I don't think a warning is out of question.
-- Steve
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