From: Chris Metcalf <cmetcalf@mellanox.com>
To: Daniel Thompson <daniel.thompson@linaro.org>
Cc: Russell King <linux@arm.linux.org.uk>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Andrew Morton <akpm@osdl.org>,
<linux-kernel@vger.kernel.org>, Aaron Tomlin <atomlin@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
Daniel Lezcano <daniel.lezcano@linaro.org>
Subject: Re: [PATCH 2/4] nmi_backtrace: generate one-line reports for idle cpus
Date: Mon, 7 Mar 2016 12:05:00 -0500 [thread overview]
Message-ID: <56DDB4BC.3040301@mellanox.com> (raw)
In-Reply-To: <56DD3B3D.1010404@linaro.org>
On 03/07/2016 03:26 AM, Daniel Thompson wrote:
>> Chris Metcalf wrote:
>> +static DEFINE_PER_CPU(bool, cpu_idling);
>> +
>> +/* Was the cpu was in the low-level idle code when interrupted? */
>> +bool in_cpu_idle(void)
>> +{
>> + return this_cpu_read(cpu_idling);
>
> I think we continue to need the code to identify a core that is
> running an interrupt handler. Interrupts are not masked at the point
> we set cpu_idling to false meaning we can easily be preempted before
> we clear the flag.
Yes, good catch. However, mooted by PeterZ wanting to keep any extra
state-switching code out of the idle path. See my reply to him for more
on that.
--
Chris Metcalf, Mellanox Technologies
http://www.mellanox.com
next prev parent reply other threads:[~2016-03-07 17:05 UTC|newest]
Thread overview: 121+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-29 21:40 [PATCH 0/4] improvements to the nmi_backtrace code Chris Metcalf
2016-02-29 21:40 ` Chris Metcalf
2016-02-29 21:40 ` [PATCH 1/4] nmi_backtrace: add more trigger_*_cpu_backtrace() methods Chris Metcalf
2016-02-29 21:40 ` Chris Metcalf
2016-02-29 21:40 ` [PATCH 2/4] nmi_backtrace: generate one-line reports for idle cpus Chris Metcalf
2016-03-01 14:23 ` Daniel Thompson
2016-03-01 16:01 ` Chris Metcalf
2016-03-07 8:26 ` Daniel Thompson
2016-03-07 17:05 ` Chris Metcalf [this message]
2016-03-07 9:48 ` Peter Zijlstra
2016-03-07 17:38 ` Chris Metcalf
2016-03-07 20:43 ` Peter Zijlstra
2016-03-16 17:02 ` [PATCH v2 0/4] improvements to the nmi_backtrace code Chris Metcalf
2016-03-16 17:02 ` Chris Metcalf
2016-03-16 17:02 ` Chris Metcalf
2016-03-16 17:02 ` Chris Metcalf
2016-03-16 17:02 ` [PATCH v2 1/4] nmi_backtrace: add more trigger_*_cpu_backtrace() methods Chris Metcalf
2016-03-16 17:02 ` Chris Metcalf
2016-03-17 19:36 ` Peter Zijlstra
2016-03-17 19:36 ` Peter Zijlstra
2016-03-17 22:31 ` Chris Metcalf
2016-03-17 22:31 ` Chris Metcalf
2016-03-17 22:38 ` Peter Zijlstra
2016-03-17 22:38 ` Peter Zijlstra
2016-03-17 22:41 ` Chris Metcalf
2016-03-17 22:41 ` Chris Metcalf
2016-03-17 23:14 ` Peter Zijlstra
2016-03-17 23:14 ` Peter Zijlstra
2016-03-17 22:55 ` Paul E. McKenney
2016-03-17 22:55 ` Paul E. McKenney
2016-03-17 23:09 ` Peter Zijlstra
2016-03-17 23:09 ` Peter Zijlstra
2016-03-17 23:11 ` Peter Zijlstra
2016-03-17 23:11 ` Peter Zijlstra
2016-03-18 0:28 ` Paul E. McKenney
2016-03-18 0:28 ` Paul E. McKenney
2016-03-18 0:17 ` Chris Metcalf
2016-03-18 0:17 ` Chris Metcalf
2016-03-18 0:33 ` Paul E. McKenney
2016-03-18 0:33 ` Paul E. McKenney
2016-03-18 9:40 ` Daniel Thompson
2016-03-18 9:40 ` Daniel Thompson
2016-03-18 23:54 ` Paul E. McKenney
2016-03-18 23:54 ` Paul E. McKenney
2016-03-16 17:02 ` [PATCH v2 2/4] nmi_backtrace: do a local dump_stack() instead of a self-NMI Chris Metcalf
2016-03-16 17:02 ` Chris Metcalf
2016-03-16 17:02 ` [PATCH v2 3/4] arch/tile: adopt the new nmi_backtrace framework Chris Metcalf
2016-03-16 17:02 ` [PATCH v2 4/4] nmi_backtrace: generate one-line reports for idle cpus Chris Metcalf
2016-03-16 17:02 ` Chris Metcalf
2016-03-16 17:02 ` Chris Metcalf
2016-03-16 18:46 ` kbuild test robot
2016-03-16 18:46 ` kbuild test robot
2016-03-16 18:46 ` kbuild test robot
2016-03-16 18:46 ` kbuild test robot
2016-03-21 15:38 ` Peter Zijlstra
2016-03-21 15:38 ` Peter Zijlstra
2016-03-21 15:38 ` Peter Zijlstra
2016-03-21 15:46 ` Chris Metcalf
2016-03-21 15:46 ` Chris Metcalf
2016-03-21 15:46 ` Chris Metcalf
2016-03-21 15:46 ` Chris Metcalf
2016-03-21 15:42 ` Peter Zijlstra
2016-03-21 15:42 ` Peter Zijlstra
2016-03-21 16:15 ` Chris Metcalf
2016-03-21 16:15 ` Chris Metcalf
2016-03-21 16:15 ` Chris Metcalf
2016-03-21 16:32 ` Peter Zijlstra
2016-03-21 16:32 ` Peter Zijlstra
2016-03-21 17:12 ` Chris Metcalf
2016-03-21 17:12 ` Chris Metcalf
2016-03-21 17:12 ` Chris Metcalf
2016-03-21 17:12 ` Chris Metcalf
2016-03-21 17:17 ` Peter Zijlstra
2016-03-21 17:17 ` Peter Zijlstra
2016-03-21 16:48 ` Peter Zijlstra
2016-03-21 16:48 ` Peter Zijlstra
2016-03-21 21:49 ` Peter Zijlstra
2016-03-21 21:49 ` Peter Zijlstra
2016-03-22 17:19 ` [PATCH v3 0/4] improvements to the nmi_backtrace code Chris Metcalf
2016-03-22 17:19 ` Chris Metcalf
2016-03-22 17:19 ` Chris Metcalf
2016-03-22 17:19 ` Chris Metcalf
2016-03-22 17:19 ` [PATCH v3 1/4] nmi_backtrace: add more trigger_*_cpu_backtrace() methods Chris Metcalf
2016-03-22 17:19 ` Chris Metcalf
2016-03-22 17:19 ` [PATCH v3 2/4] nmi_backtrace: do a local dump_stack() instead of a self-NMI Chris Metcalf
2016-03-22 17:19 ` Chris Metcalf
2016-03-22 17:19 ` [PATCH v3 3/4] arch/tile: adopt the new nmi_backtrace framework Chris Metcalf
2016-03-22 17:19 ` [PATCH v3 4/4] nmi_backtrace: generate one-line reports for idle cpus Chris Metcalf
2016-03-22 17:19 ` Chris Metcalf
2016-03-22 17:19 ` Chris Metcalf
2016-03-22 17:30 ` Peter Zijlstra
2016-03-22 17:30 ` Peter Zijlstra
2016-03-22 22:28 ` Rafael J. Wysocki
2016-03-22 22:28 ` Rafael J. Wysocki
2016-03-22 22:31 ` Rafael J. Wysocki
2016-03-22 22:31 ` Rafael J. Wysocki
2016-03-22 22:45 ` Peter Zijlstra
2016-03-22 22:45 ` Peter Zijlstra
2016-03-23 0:50 ` Rafael J. Wysocki
2016-03-23 0:50 ` Rafael J. Wysocki
2016-03-23 7:53 ` Peter Zijlstra
2016-03-23 7:53 ` Peter Zijlstra
2016-03-30 17:16 ` [PATCH v4 0/4] improvements to the nmi_backtrace code Chris Metcalf
2016-03-30 17:16 ` Chris Metcalf
2016-03-30 17:16 ` Chris Metcalf
2016-03-30 17:16 ` Chris Metcalf
2016-03-30 17:16 ` [PATCH v4 1/4] nmi_backtrace: add more trigger_*_cpu_backtrace() methods Chris Metcalf
2016-03-30 17:16 ` Chris Metcalf
2016-03-30 17:16 ` [PATCH v4 2/4] nmi_backtrace: do a local dump_stack() instead of a self-NMI Chris Metcalf
2016-03-30 17:16 ` Chris Metcalf
2016-03-30 17:16 ` [PATCH v4 3/4] arch/tile: adopt the new nmi_backtrace framework Chris Metcalf
2016-03-30 17:16 ` [PATCH v4 4/4] nmi_backtrace: generate one-line reports for idle cpus Chris Metcalf
2016-03-30 17:16 ` Chris Metcalf
2016-03-30 17:16 ` Chris Metcalf
2016-02-29 21:40 ` [PATCH 3/4] nmi_backtrace: do a local dump_stack() instead of a self-NMI Chris Metcalf
2016-02-29 21:40 ` Chris Metcalf
2016-02-29 21:40 ` [PATCH 4/4] arch/tile: adopt the new nmi_backtrace framework Chris Metcalf
2016-03-01 0:49 ` [PATCH 0/4] improvements to the nmi_backtrace code Andrew Morton
2016-03-01 0:49 ` Andrew Morton
2016-03-01 10:01 ` Petr Mladek
2016-03-01 10:01 ` Petr Mladek
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