Messages in this thread | | | Date | Wed, 4 Jan 2012 18:17:58 -0800 | From | "Paul E. McKenney" <> | Subject | Re: [PATCH] rcu: Improve detection of illegal synchronize_rcu() call from RCU read side |
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On Thu, Jan 05, 2012 at 03:06:03AM +0100, Frederic Weisbecker wrote: > On Wed, Jan 04, 2012 at 06:01:08PM -0800, Paul E. McKenney wrote: > > On Thu, Jan 05, 2012 at 02:45:20AM +0100, Frederic Weisbecker wrote: > > > On Wed, Jan 04, 2012 at 01:30:35PM -0800, Paul E. McKenney wrote: > > > > On Wed, Jan 04, 2012 at 08:03:39PM +0100, Frederic Weisbecker wrote: > > > > > Actually for the case of RCU, the wait_for_completion() called by synchronize_rcu()
[ . . . ]
> > > > > rcutiny seems to be fine with the cond_resched() call, but srcu needs > > > > > a special treatment. > > > > > > > > For the moment, I just applied rcu_lockdep_assert() everywhere -- zero > > > > cost on non-lockdep kernels, and fully handles all of the RCU simple > > > > self-deadlock cases. > > > > > > So, for RCU I'm not sure this is useful given the might_sleep() things. > > > But for srcu it is. > > > > One nice thing about the lockdep approach is that it tracks where the > > conflicting RCU read-side critical section started. But I am planning > > for these to be 3.4 material, so we do have some time to refine them. > > Yeah sure. And in any case it's still good to keep might_sleep() early > to spot other sources of illegal atomic sections (irqs disabled and co)
Agreed!
Thanx, Paul
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