From: "Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>
To: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Meelis Roos <mroos@linux.ee>,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
"cpufreq@vger.kernel.org" <cpufreq@vger.kernel.org>,
"linux-pm@vger.kernel.org" <linux-pm@vger.kernel.org>,
Linux Kernel list <linux-kernel@vger.kernel.org>
Subject: Re: 3.15-rc2: longhaul cpufreq stalls tasks for 120s+
Date: Fri, 25 Apr 2014 13:45:11 +0530 [thread overview]
Message-ID: <535A198F.3040009@linux.vnet.ibm.com> (raw)
In-Reply-To: <CAKohpom5K0ZdCxqyArVNbDSrf824__izwjBNq+Xb9RGB-pqnag@mail.gmail.com>
On 04/25/2014 10:11 AM, Viresh Kumar wrote:
> On 25 April 2014 00:33, Meelis Roos <mroos@linux.ee> wrote:
>
>> [ 240.140176] INFO: task kworker/0:1:116 blocked for more than 120 seconds.
>> [ 240.140353] Not tainted 3.15.0-rc2-dirty #37
>> [ 240.140485] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
>> [ 240.140687] kworker/0:1 D cf6afd50 0 116 2 0x00000000
>> [ 240.140938] Workqueue: events od_dbs_timer
>> [ 240.141103] cf6afd98 00000082 00000002 cf6afd50 c1040d91 cf6affec cf6ad310 cf6ad310
>> [ 240.142479] c1286dcb 00000002 cf6afd70 c1040f14 00000000 ce460b30 00000282 00000046
>> [ 240.143011] 00000282 ce460b30 cf6afd78 c1040f39 cf6afd88 00000282 cf6afdb0 ce460b30
>> [ 240.143544] Call Trace:
>> [ 240.143706] [<c1040d91>] ? mark_held_locks+0x4b/0x61
>> [ 240.143883] [<c1286dcb>] ? _raw_spin_unlock_irqrestore+0x33/0x3f
>> [ 240.144043] [<c1040f14>] ? trace_hardirqs_on_caller+0x16d/0x187
>> [ 240.144203] [<c1040f39>] ? trace_hardirqs_on+0xb/0xd
>> [ 240.144358] [<c1284145>] schedule+0x5d/0x5f
>> [ 240.144527] [<c11eaa67>] cpufreq_freq_transition_begin+0x4a/0x9d
>> [ 240.144687] [<c103e1b0>] ? __wake_up_sync+0x14/0x14
>> [ 240.144860] [<d06722d5>] longhaul_setstate+0x88/0x2f1 [longhaul]
>> [ 240.145023] [<c1036d43>] ? srcu_notifier_call_chain+0x1a/0x1c
>> [ 240.145186] [<c11eaab2>] ? cpufreq_freq_transition_begin+0x95/0x9d
>> [ 240.145350] [<d06725ba>] longhaul_target+0x7c/0x8b [longhaul]
>> [ 240.145511] [<c11eae78>] __cpufreq_driver_target+0xfe/0x148
>
> Am I reading it correctly? It looks like we are starting another transition
> from notifier chain, but I couldn't figure out how from code.
>
Indeed, its a case of double invocation of the _begin() and _end()
notifiers. I developed a patchset to fix this in longhaul, powernow-k6 and k7
drivers, before seeing your patchset that does the same thing. However, looking
closer, I don't completely agree with the approach you used to fix the issue,
so I'll post my patches as well (which have a different design).
Regards,
Srivatsa S. Bhat
next prev parent reply other threads:[~2014-04-25 8:15 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-04-24 9:56 3.15-rc2: longhaul cpufreq stalls tasks for 120s+ Meelis Roos
2014-04-24 10:10 ` Viresh Kumar
2014-04-24 10:16 ` Meelis Roos
2014-04-24 10:29 ` Viresh Kumar
2014-04-24 11:17 ` Meelis Roos
2014-04-24 10:47 ` Srivatsa S. Bhat
2014-04-24 19:03 ` Meelis Roos
2014-04-24 19:44 ` Srivatsa S. Bhat
2014-04-25 6:44 ` Viresh Kumar
2014-04-25 4:41 ` Viresh Kumar
2014-04-25 8:15 ` Srivatsa S. Bhat [this message]
2014-04-25 7:31 ` Viresh Kumar
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