From: Frederic Weisbecker <fweisbec@gmail.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Ingo Molnar <mingo@kernel.org>, Kevin Hilman <khilman@linaro.org>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Thomas Gleixner <tglx@linutronix.de>,
Viresh Kumar <viresh.kumar@linaro.org>
Subject: Re: [PATCH 1/5] irq_work: Let arch tell us if it can raise irq work
Date: Tue, 13 May 2014 21:33:29 +0200 [thread overview]
Message-ID: <20140513193327.GF13828@localhost.localdomain> (raw)
In-Reply-To: <20140513170942.GC5226@laptop.programming.kicks-ass.net>
On Tue, May 13, 2014 at 07:09:42PM +0200, Peter Zijlstra wrote:
> On Tue, May 13, 2014 at 04:38:37PM +0200, Frederic Weisbecker wrote:
> > We prepare for executing the full nohz kick through an irq work. But
> > if we do this as is, we'll run into conflicting tick locking: the tick
> > holds the hrtimer lock and the nohz kick may do so too.
>
> It does? How does the tick end up holding that lock?
>
> Normal hrtimer callbacks run without holding the hrtimer lock -- I made
> it so.
>
> This means tick_sched_timer() is called without hrtimer lock, and I
> don't see it taking it anywhere in tick_sched_do_timer() or
> tick_sched_handle().
Check hrtimer_interrupt(), it takes the per cpu base->lock.
next prev parent reply other threads:[~2014-05-13 19:33 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-13 14:38 [RFC PATCH 0/5] nohz: Move nohz kick out of scheduler IPI, v4 Frederic Weisbecker
2014-05-13 14:38 ` [PATCH 1/5] irq_work: Let arch tell us if it can raise irq work Frederic Weisbecker
2014-05-13 17:09 ` Peter Zijlstra
2014-05-13 19:33 ` Frederic Weisbecker [this message]
2014-05-13 20:48 ` Peter Zijlstra
2014-05-13 21:15 ` Frederic Weisbecker
2014-05-13 14:38 ` [PATCH 2/5] irq_work: Force non-lazy works to the IPI Frederic Weisbecker
2014-05-13 14:38 ` [PATCH 3/5] irq_work: Allow remote queueing Frederic Weisbecker
2014-05-13 14:38 ` [PATCH 4/5] nohz: Move full nohz kick to its own IPI Frederic Weisbecker
2014-05-13 14:38 ` [PATCH 5/5] nohz: Use IPI implicit full barrier against rq->nr_running r/w Frederic Weisbecker
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