From: Frederic Weisbecker <fweisbec@gmail.com>
To: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Steven Rostedt <rostedt@goodmis.org>,
John Stultz <john.stultz@linaro.org>,
Alex Shi <alex.shi@linaro.org>, Kevin Hilman <khilman@linaro.org>
Subject: Re: [PATCH 05/13] rcu: Fix unraised IPI to timekeeping CPU
Date: Wed, 18 Dec 2013 15:56:12 +0100 [thread overview]
Message-ID: <20131218145610.GE18464@localhost.localdomain> (raw)
In-Reply-To: <20131218142240.GP19211@linux.vnet.ibm.com>
On Wed, Dec 18, 2013 at 06:22:40AM -0800, Paul E. McKenney wrote:
> >
> > Exactly, the interrupt alone is sufficient and the tick is reevaluated
> > on irq_exit().
>
> But if that is the case, why do you need the change to scheduler_ipi()
> in patch 07/13? Just having received any sort of IPI should suffice.
Because scheduler_ipi() conditionally calls irq_enter() and irq_exit()
(I wonder if that's a good idea btw, is that here to deal with spurious
scheduler IPIs of some sort?)
And it's convenient because it can be called anywhere, even when irqs
are disabled, unlike kernel/smp.c IPIs.
But I agree it's kind of an abuse of scheduler_ipi() here. Well I'm going
to develop that in my answers to Peter as he has concerns precisely about that.
Thanks.
next prev parent reply other threads:[~2013-12-18 14:56 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-12-17 22:51 [RFC PATCH 00/13] nohz: Use sysidle detection to let the timekeeper sleep Frederic Weisbecker
2013-12-17 22:51 ` [PATCH 01/13] tick: Rename tick_check_idle() to tick_irq_enter() Frederic Weisbecker
2014-01-25 14:22 ` [tip:timers/urgent] " tip-bot for Frederic Weisbecker
2013-12-17 22:51 ` [PATCH 02/13] time: New helper to check CPU eligibility to handle timekeeping Frederic Weisbecker
2013-12-17 22:51 ` [PATCH 03/13] rcu: Exclude all potential timekeepers from sysidle detection Frederic Weisbecker
2013-12-17 23:27 ` Paul E. McKenney
2013-12-17 23:49 ` Frederic Weisbecker
2013-12-18 11:43 ` Peter Zijlstra
2013-12-18 11:46 ` Peter Zijlstra
2013-12-18 14:15 ` Paul E. McKenney
2013-12-18 16:24 ` Frederic Weisbecker
2013-12-17 22:51 ` [PATCH 04/13] tick: Use timekeeping_cpu() to elect the CPU handling timekeeping duty Frederic Weisbecker
2013-12-17 23:55 ` Paul E. McKenney
2013-12-17 22:51 ` [PATCH 05/13] rcu: Fix unraised IPI to timekeeping CPU Frederic Weisbecker
2013-12-17 23:21 ` Paul E. McKenney
2013-12-18 14:13 ` Frederic Weisbecker
2013-12-18 14:22 ` Paul E. McKenney
2013-12-18 14:56 ` Frederic Weisbecker [this message]
2013-12-18 15:11 ` Peter Zijlstra
2013-12-18 15:58 ` Frederic Weisbecker
2013-12-18 12:12 ` Peter Zijlstra
2013-12-18 15:38 ` Frederic Weisbecker
2013-12-18 15:45 ` Christoph Hellwig
2013-12-18 17:10 ` Peter Zijlstra
2013-12-17 22:51 ` [PATCH 06/13] nohz: Introduce full dynticks' default timekeeping target Frederic Weisbecker
2013-12-17 23:54 ` Paul E. McKenney
2013-12-17 22:51 ` [PATCH 07/13] sched: Enable IPI reception on timekeeper under nohz full system Frederic Weisbecker
2013-12-17 23:52 ` Paul E. McKenney
2013-12-18 14:49 ` Frederic Weisbecker
2013-12-18 15:50 ` Paul E. McKenney
2013-12-18 10:06 ` Peter Zijlstra
2013-12-17 22:51 ` [PATCH 08/13] nohz: Get timekeeping max deferment outside jiffies_lock Frederic Weisbecker
2014-01-25 14:22 ` [tip:timers/urgent] " tip-bot for Frederic Weisbecker
2013-12-17 22:51 ` [PATCH 09/13] nohz: Allow timekeeper's tick to stop when all full dynticks CPUs are idle Frederic Weisbecker
2013-12-17 23:51 ` Paul E. McKenney
2013-12-18 14:36 ` Frederic Weisbecker
2013-12-18 15:29 ` Paul E. McKenney
2013-12-17 22:51 ` [PATCH 10/13] nohz: Hand over timekeeping duty on cpu offlining Frederic Weisbecker
2013-12-17 23:40 ` Paul E. McKenney
2013-12-18 14:19 ` Frederic Weisbecker
2013-12-18 12:30 ` Peter Zijlstra
2013-12-18 16:43 ` Frederic Weisbecker
2013-12-17 22:51 ` [PATCH 11/13] nohz: Wake up timekeeper on exit from sysidle state Frederic Weisbecker
2013-12-17 23:34 ` Paul E. McKenney
2013-12-17 23:52 ` Frederic Weisbecker
2013-12-17 22:51 ` [PATCH 12/13] nohz: Allow all CPUs outside nohz_full range to do timekeeping Frederic Weisbecker
2013-12-17 23:32 ` Paul E. McKenney
2013-12-17 22:51 ` [PATCH 13/13] nohz_full: fix code style issue of tick_nohz_full_stop_tick Frederic Weisbecker
2013-12-18 2:04 ` [RFC PATCH 00/13] nohz: Use sysidle detection to let the timekeeper sleep Alex Shi
2013-12-18 10:19 ` Peter Zijlstra
2013-12-18 14:18 ` Paul E. McKenney
2013-12-18 17:43 ` Frederic Weisbecker
2013-12-18 21:29 ` Andy Lutomirski
2013-12-18 21:49 ` Paul E. McKenney
2013-12-18 21:53 ` Andy Lutomirski
2013-12-18 21:57 ` Paul E. McKenney
2013-12-18 22:55 ` Andy Lutomirski
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