From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>,
linux-kernel@vger.kernel.org, mingo@kernel.org,
laijs@cn.fujitsu.com, dipankar@in.ibm.com,
akpm@linux-foundation.org, mathieu.desnoyers@efficios.com,
josh@joshtriplett.org, tglx@linutronix.de, dhowells@redhat.com,
edumazet@google.com, dvhart@linux.intel.com, fweisbec@gmail.com,
oleg@redhat.com, bobby.prani@gmail.com
Subject: Re: [PATCH v3 tip/core/rcu 1/9] rcu: Add call_rcu_tasks()
Date: Sat, 9 Aug 2014 09:05:10 -0700 [thread overview]
Message-ID: <20140809160510.GK5821@linux.vnet.ibm.com> (raw)
In-Reply-To: <20140809084439.05778e33@gandalf.local.home>
On Sat, Aug 09, 2014 at 08:44:39AM -0400, Steven Rostedt wrote:
> On Sat, 9 Aug 2014 08:15:14 +0200
> Peter Zijlstra <peterz@infradead.org> wrote:
>
>
> > As for idle tasks, I'm not sure about those, I think that we should say
> > NO to anything that would require waking idle CPUs, push the pain to
> > ftrace/kprobes, we should _not_ be waking idle cpus.
>
> I agree, but I haven't had a chance to review the patch set (will
> probably do that on Monday, just got back from vacation last week and
> was inundated by other things).
Let me get v5 out first. I expect to have it out by end of Monday.
> Does the idle waking happen only when
> there's something queued in the call_rcu_tasks()? It should definitely
> not be waking all the time. That's just wrong.
>
> But if it only wakes when something is queued, it wouldn't be burdening
> anything, unless it is needed.
Indeed, idle waking only happens when there is an RCU-tasks grace period
in progress. No RCU-tasks grace period, no RCU-tasks idle waking.
Thanx, Paul
next prev parent reply other threads:[~2014-08-09 16:16 UTC|newest]
Thread overview: 122+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-31 21:54 [PATCH v3 tip/core/rcu 0/9 Paul E. McKenney
2014-07-31 21:55 ` [PATCH v3 tip/core/rcu 1/9] rcu: Add call_rcu_tasks() Paul E. McKenney
2014-07-31 21:55 ` [PATCH v3 tip/core/rcu 2/9] rcu: Provide cond_resched_rcu_qs() to force quiescent states in long loops Paul E. McKenney
2014-07-31 21:55 ` [PATCH v3 tip/core/rcu 3/9] rcu: Add synchronous grace-period waiting for RCU-tasks Paul E. McKenney
2014-08-01 15:09 ` Oleg Nesterov
2014-08-01 18:32 ` Paul E. McKenney
2014-08-01 19:44 ` Paul E. McKenney
2014-08-02 14:47 ` Oleg Nesterov
2014-08-02 22:58 ` Paul E. McKenney
2014-08-06 0:57 ` Steven Rostedt
2014-08-06 1:21 ` Paul E. McKenney
2014-08-06 8:47 ` Peter Zijlstra
2014-08-06 12:09 ` Paul E. McKenney
2014-08-06 16:30 ` Peter Zijlstra
2014-08-06 22:45 ` Paul E. McKenney
2014-08-07 8:45 ` Peter Zijlstra
2014-08-07 15:00 ` Paul E. McKenney
2014-08-07 15:26 ` Peter Zijlstra
2014-08-07 17:27 ` Peter Zijlstra
2014-08-07 18:46 ` Peter Zijlstra
2014-08-07 19:49 ` Steven Rostedt
2014-08-07 19:53 ` Steven Rostedt
2014-08-07 20:08 ` Peter Zijlstra
2014-08-07 21:18 ` Steven Rostedt
2014-08-08 6:40 ` Peter Zijlstra
2014-08-08 14:12 ` Steven Rostedt
2014-08-08 14:28 ` Paul E. McKenney
2014-08-09 10:56 ` Masami Hiramatsu
2014-08-08 14:34 ` Peter Zijlstra
2014-08-08 14:58 ` Steven Rostedt
2014-08-08 15:16 ` Peter Zijlstra
2014-08-08 15:39 ` Steven Rostedt
2014-08-08 16:01 ` Peter Zijlstra
2014-08-08 16:10 ` Steven Rostedt
2014-08-08 16:17 ` Peter Zijlstra
2014-08-08 16:40 ` Steven Rostedt
2014-08-08 16:52 ` Peter Zijlstra
2014-08-08 16:27 ` Peter Zijlstra
2014-08-08 16:39 ` Paul E. McKenney
2014-08-08 16:49 ` Steven Rostedt
2014-08-08 16:51 ` Peter Zijlstra
2014-08-08 17:09 ` Paul E. McKenney
2014-08-08 16:43 ` Steven Rostedt
2014-08-08 16:50 ` Peter Zijlstra
2014-08-08 17:27 ` Steven Rostedt
2014-08-09 10:36 ` Masami Hiramatsu
2014-08-07 20:06 ` Peter Zijlstra
2014-07-31 21:55 ` [PATCH v3 tip/core/rcu 4/9] rcu: Export RCU-tasks APIs to GPL modules Paul E. McKenney
2014-07-31 21:55 ` [PATCH v3 tip/core/rcu 5/9] rcutorture: Add torture tests for RCU-tasks Paul E. McKenney
2014-07-31 21:55 ` [PATCH v3 tip/core/rcu 6/9] rcutorture: Add RCU-tasks test cases Paul E. McKenney
2014-07-31 21:55 ` [PATCH v3 tip/core/rcu 7/9] rcu: Add stall-warning checks for RCU-tasks Paul E. McKenney
2014-07-31 21:55 ` [PATCH v3 tip/core/rcu 8/9] rcu: Improve RCU-tasks energy efficiency Paul E. McKenney
2014-07-31 21:55 ` [PATCH v3 tip/core/rcu 9/9] documentation: Add verbiage on RCU-tasks stall warning messages Paul E. McKenney
2014-07-31 23:57 ` [PATCH v3 tip/core/rcu 1/9] rcu: Add call_rcu_tasks() Frederic Weisbecker
2014-08-01 2:04 ` Paul E. McKenney
2014-08-01 15:06 ` Frederic Weisbecker
2014-08-01 1:15 ` Lai Jiangshan
2014-08-01 1:59 ` Paul E. McKenney
2014-08-01 1:31 ` Lai Jiangshan
2014-08-01 2:11 ` Paul E. McKenney
2014-08-01 14:11 ` Oleg Nesterov
2014-08-01 18:28 ` Paul E. McKenney
2014-08-01 18:40 ` Oleg Nesterov
2014-08-02 23:00 ` Paul E. McKenney
2014-08-03 12:57 ` Oleg Nesterov
2014-08-03 22:03 ` Paul E. McKenney
2014-08-04 13:29 ` Oleg Nesterov
2014-08-04 13:48 ` Paul E. McKenney
2014-08-01 18:57 ` Oleg Nesterov
2014-08-02 22:50 ` Paul E. McKenney
2014-08-02 14:56 ` Oleg Nesterov
2014-08-02 22:57 ` Paul E. McKenney
2014-08-03 13:33 ` Oleg Nesterov
2014-08-03 22:05 ` Paul E. McKenney
2014-08-04 0:37 ` Lai Jiangshan
2014-08-04 1:09 ` Paul E. McKenney
2014-08-04 13:25 ` Oleg Nesterov
2014-08-04 13:51 ` Paul E. McKenney
2014-08-04 13:52 ` Paul E. McKenney
2014-08-04 13:32 ` Oleg Nesterov
2014-08-04 19:28 ` Paul E. McKenney
2014-08-04 19:32 ` Oleg Nesterov
2014-08-04 1:28 ` Lai Jiangshan
2014-08-04 7:46 ` Peter Zijlstra
2014-08-04 8:18 ` Lai Jiangshan
2014-08-04 11:50 ` Paul E. McKenney
2014-08-04 12:25 ` Peter Zijlstra
2014-08-04 12:37 ` Paul E. McKenney
2014-08-04 14:56 ` Peter Zijlstra
2014-08-05 0:47 ` Lai Jiangshan
2014-08-05 21:55 ` Paul E. McKenney
2014-08-06 0:27 ` Lai Jiangshan
2014-08-06 0:48 ` Paul E. McKenney
2014-08-06 0:33 ` Lai Jiangshan
2014-08-06 0:51 ` Paul E. McKenney
2014-08-06 22:48 ` Paul E. McKenney
2014-08-07 8:49 ` Peter Zijlstra
2014-08-07 15:43 ` Paul E. McKenney
2014-08-07 16:32 ` Peter Zijlstra
2014-08-07 17:48 ` Paul E. McKenney
2014-08-08 19:13 ` Peter Zijlstra
2014-08-08 20:58 ` Paul E. McKenney
2014-08-09 6:15 ` Peter Zijlstra
2014-08-09 12:44 ` Steven Rostedt
2014-08-09 16:05 ` Paul E. McKenney [this message]
2014-08-09 16:01 ` Paul E. McKenney
2014-08-09 18:19 ` Peter Zijlstra
2014-08-09 18:24 ` Peter Zijlstra
2014-08-10 1:29 ` Paul E. McKenney
2014-08-10 8:14 ` Peter Zijlstra
2014-08-11 3:30 ` Paul E. McKenney
2014-08-11 11:57 ` Peter Zijlstra
2014-08-11 16:15 ` Paul E. McKenney
2014-08-10 1:26 ` Paul E. McKenney
2014-08-10 8:12 ` Peter Zijlstra
2014-08-10 16:46 ` Peter Zijlstra
2014-08-11 3:28 ` Paul E. McKenney
2014-08-11 3:23 ` Paul E. McKenney
2014-08-09 18:33 ` Peter Zijlstra
2014-08-10 1:38 ` Paul E. McKenney
2014-08-10 15:00 ` Peter Zijlstra
2014-08-11 3:37 ` Paul E. McKenney
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