From: Peter Zijlstra <peterz@infradead.org>
To: paulmck@linux.vnet.ibm.com
Cc: Yong Zhang <yong.zhang0@gmail.com>,
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,
rostedt@goodmis.org, Valdis.Kletnieks@vt.edu,
dhowells@redhat.com, eric.dumazet@gmail.com, darren@dvhart.com,
patches@linaro.org
Subject: Re: [PATCH RFC tip/core/rcu 7/7] rcu: Quiet RCU-lockdep warnings involving interrupt disabling
Date: Tue, 06 Dec 2011 17:14:56 +0100 [thread overview]
Message-ID: <1323188096.32012.77.camel@twins> (raw)
In-Reply-To: <20111206161110.GD2325@linux.vnet.ibm.com>
On Tue, 2011-12-06 at 08:11 -0800, Paul E. McKenney wrote:
> The problem with the IRQs enabled is the following sequence:
>
> rcu_read_lock();
> /* do stuff */
> local_irq_save(flags);
> /* do more stuff */
> rcu_read_unlock();
> /* do even more stuff */
> local_irq_restore(flags);
>
> This has been legal in the past, and might well be used in places that
> -rt does not exercise, hence the desire to explicitly legalize it.
So why not make it strictly dis-allowed, even for !-rt and see what
falls over? If there's lots of fallout we might need to reconsider, but
wouldn't it be easier to all abide by the strictest rules than to try
and frob stuff like was proposed?
next prev parent reply other threads:[~2011-12-06 16:15 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-03 18:34 [PATCH tip/core/rcu 0/7] Preview of fourth set of RCU changes for 3.3 Paul E. McKenney
2011-12-03 18:34 ` [PATCH RFC tip/core/rcu 1/7] rcu: Don't check irq nesting from rcu idle entry/exit Paul E. McKenney
2011-12-03 18:34 ` [PATCH RFC tip/core/rcu 2/7] rcu: Irq nesting is always 0 on rcu_enter_idle_common Paul E. McKenney
2011-12-03 18:34 ` [PATCH RFC tip/core/rcu 3/7] rcu: Keep invoking callbacks if CPU otherwise idle Paul E. McKenney
2011-12-03 18:34 ` [PATCH RFC tip/core/rcu 4/7] rcu: Adaptive dyntick-idle preparation Paul E. McKenney
2011-12-03 18:34 ` [PATCH RFC tip/core/rcu 5/7] rcu: remove redundant rcu_cpu_stall_suppress declaration Paul E. McKenney
2011-12-03 18:34 ` [PATCH RFC tip/core/rcu 6/7] driver-core/cpu: Add cpu_is_hotpluggable() for rcutorture error analysis Paul E. McKenney
2011-12-03 21:06 ` Josh Triplett
2011-12-03 23:14 ` Paul E. McKenney
2011-12-03 18:34 ` [PATCH RFC tip/core/rcu 7/7] rcu: Quiet RCU-lockdep warnings involving interrupt disabling Paul E. McKenney
2011-12-05 9:19 ` Yong Zhang
2011-12-05 16:45 ` Paul E. McKenney
2011-12-06 1:26 ` Yong Zhang
2011-12-06 2:12 ` Paul E. McKenney
2011-12-06 3:27 ` [PATCH 1/3] kernel.h: sched: introduce might_sleep_disabled() Yong Zhang
2011-12-06 3:28 ` [PATCH 2/3] rtmutex: introduce rt_mutex_lock_irqdisabled() Yong Zhang
2011-12-06 3:29 ` [PATCH 3/3] rcu: use rt_mutex_lock_irqdisabled() in rcu_boost() Yong Zhang
2011-12-06 9:52 ` [PATCH RFC tip/core/rcu 7/7] rcu: Quiet RCU-lockdep warnings involving interrupt disabling Peter Zijlstra
2011-12-06 10:05 ` Yong Zhang
2011-12-06 10:32 ` Peter Zijlstra
2011-12-06 12:26 ` Steven Rostedt
2011-12-06 16:04 ` Paul E. McKenney
2011-12-06 16:33 ` Paul E. McKenney
2011-12-06 16:56 ` Steven Rostedt
2011-12-06 17:16 ` Paul E. McKenney
2011-12-06 10:27 ` Peter Zijlstra
2011-12-06 16:11 ` Paul E. McKenney
2011-12-06 16:14 ` Peter Zijlstra [this message]
2011-12-06 16:01 ` Paul E. McKenney
2011-12-05 9:41 ` Peter Zijlstra
2011-12-05 10:03 ` Yong Zhang
2011-12-05 16:48 ` Paul E. McKenney
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