From: Frederic Weisbecker <fweisbec@gmail.com>
To: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: linux-kernel@vger.kernel.org, mingo@elte.hu,
laijs@cn.fujitsu.com, dipankar@in.ibm.com,
akpm@linux-foundation.org, mathieu.desnoyers@polymtl.ca,
josh@joshtriplett.org, niv@us.ibm.com, tglx@linutronix.de,
peterz@infradead.org, rostedt@goodmis.org,
Valdis.Kletnieks@vt.edu, dhowells@redhat.com,
eric.dumazet@gmail.com, darren@dvhart.com, patches@linaro.org
Subject: Re: [PATCH tip/core/rcu 0/6] Check for use of RCU from dyntick-idle mode
Date: Mon, 11 Jul 2011 18:03:32 +0200 [thread overview]
Message-ID: <20110711160330.GC4109@somewhere.redhat.com> (raw)
In-Reply-To: <20110708154331.GA20161@linux.vnet.ibm.com>
On Fri, Jul 08, 2011 at 08:43:31AM -0700, Paul E. McKenney wrote:
> Hello!
>
> This set of patches adds checks for use of RCU from "extended quiescent
> states" such as dyntick-idle mode. Such use is grossly illegal because
> RCU by definition ignores CPUs that are in extended quiescent states.
> In the case of dyntick-idle mode, the only way for RCU to avoid ignoring
> such CPUs would be to wake them up periodically, which would defeat the
> whole purpose of dyntick-idle mode.
>
> The good news is that Frederic got this effort started. The bad news is
> that there are several cases where RCU read-side critical sections appear
> in dyntick-idle mode.
Ok, let me send to you the patch that splits up rcu/tickless logic and I'll try
to fix up what you reported to me in ppc.
BTW, are you aware of other cases? You mentioned "several" :)
next prev parent reply other threads:[~2011-07-11 16:03 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-07-08 15:43 [PATCH tip/core/rcu 0/6] Check for use of RCU from dyntick-idle mode Paul E. McKenney
2011-07-08 15:43 ` [PATCH RFC tip/core/rcu 1/6] rcu: Detect illegal rcu dereference in extended quiescent state Paul E. McKenney
2011-07-08 15:43 ` [PATCH RFC tip/core/rcu 2/6] rcu: Inform the user about dynticks-idle mode on PROVE_RCU warning Paul E. McKenney
2011-07-08 15:43 ` [PATCH RFC tip/core/rcu 3/6] rcu: Warn when rcu_read_lock() is used in extended quiescent state Paul E. McKenney
2011-07-08 15:43 ` [PATCH RFC tip/core/rcu 4/6] rcu: Remove one layer of abstraction from PROVE_RCU checking Paul E. McKenney
2011-07-08 15:43 ` [PATCH RFC tip/core/rcu 5/6] rcu: Warn when srcu_read_lock() is used in an extended quiescent state Paul E. McKenney
2011-07-08 15:43 ` [PATCH RFC tip/core/rcu 6/6] rcu: Make srcu_read_lock_held() call common lockdep-enabled function Paul E. McKenney
2011-07-11 16:03 ` Frederic Weisbecker [this message]
2011-07-11 16:38 ` [PATCH tip/core/rcu 0/6] Check for use of RCU from dyntick-idle mode Paul E. McKenney
2011-07-11 16:44 ` Frederic Weisbecker
2011-07-11 17:00 ` Paul E. McKenney
2011-07-11 18:10 ` Frederic Weisbecker
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