From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Sasha Levin <levinsasha928@gmail.com>,
linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] rcu: Improve detection of illegal synchronize_rcu() call from RCU read side
Date: Wed, 4 Jan 2012 18:17:58 -0800 [thread overview]
Message-ID: <20120105021758.GS2448@linux.vnet.ibm.com> (raw)
In-Reply-To: <20120105020601.GE1143@somewhere>
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
next prev parent reply other threads:[~2012-01-05 2:18 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-26 12:16 INFO: task rcuc/0:7 blocked for more than 120 seconds Sasha Levin
2011-12-26 16:31 ` Paul E. McKenney
2011-12-26 16:37 ` Frederic Weisbecker
2011-12-26 19:56 ` Paul E. McKenney
2012-01-04 19:03 ` [PATCH] rcu: Improve detection of illegal synchronize_rcu() call from RCU read side Frederic Weisbecker
2012-01-04 21:30 ` Paul E. McKenney
2012-01-05 1:45 ` Frederic Weisbecker
2012-01-05 2:01 ` Paul E. McKenney
2012-01-05 2:06 ` Frederic Weisbecker
2012-01-05 2:17 ` Paul E. McKenney [this message]
2011-12-27 9:13 ` INFO: task rcuc/0:7 blocked for more than 120 seconds Sasha Levin
2011-12-28 4:29 ` Paul E. McKenney
2012-01-03 20:27 ` Paul E. McKenney
2012-01-03 20:37 ` Greg KH
2012-01-03 21:38 ` Paul E. McKenney
2012-01-03 21:50 ` Greg KH
2012-01-03 22:26 ` Paul E. McKenney
2012-01-03 22:33 ` Paul E. McKenney
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