From: "Kohli, Gaurav" <gkohli@codeaurora.org>
To: Peter Zijlstra <peterz@infradead.org>, Oleg Nesterov <oleg@redhat.com>
Cc: tglx@linutronix.de, mpe@ellerman.id.au, mingo@kernel.org,
bigeasy@linutronix.de, linux-kernel@vger.kernel.org,
linux-arm-msm@vger.kernel.org,
Neeraj Upadhyay <neeraju@codeaurora.org>,
Will Deacon <will.deacon@arm.com>
Subject: Re: [PATCH v1] kthread/smpboot: Serialize kthread parking against wakeup
Date: Thu, 7 Jun 2018 14:00:53 +0530 [thread overview]
Message-ID: <1ebda1e3-dae3-9e86-ad92-e1acdead23be@codeaurora.org> (raw)
In-Reply-To: <20180606185920.GI12198@hirez.programming.kicks-ass.net>
HI ,
In the latest patch mentioned, k should be their instead of p:
-WARN_ON_ONCE(!wait_task_inactive(p, TASK_PARKED))
+WARN_ON_ONCE(!wait_task_inactive(k, TASK_PARKED))
Regards
Gaurav
On 6/7/2018 12:29 AM, Peter Zijlstra wrote:
> On Wed, Jun 06, 2018 at 03:51:16PM +0200, Oleg Nesterov wrote:
>> IIUC, this will only affect smpboot_update_cpumask_percpu_thread() which can hit
>> an already parked thread, but it doesn't need to wait.
>>
>> And it seems that smpboot_update_cpumask_percpu_thread() in turn needs some cleanups.
>> Hmm. and its single user: kernel/watchdog.c.
>>
>> And speaking of watchdog.c, can't we simply kill the "watchdog/%u" threads? This is
>> off-topic, but can't watchdog_timer_fn() use stop_one_cpu_nowait(watchdog) ?
>>
>> And I really think we should unexport kthread_park/unpark(), only smpboot_thread_fn()
>> should use them. kthread() should not play with __kthread_parkme(). And even
>> KTHREAD_SHOULD_PARK must die, I mean it should live in struct smp_hotplug_thread,
>> not in struct kthread.
>>
>> OK, this is off-topic too.
>
>> And, let me repeat, can't we avoid complete_all() ?
>
> Yes, or at least if that watchdog crap is the only user.
>
> I have most of the patch reworking watchdog.c to use stop_one_cpu*(),
> and that cleans up lots -- of course, I've not tested it yet, so it
> could also be breaking lots :-)
>
--
Qualcomm India Private Limited, on behalf of Qualcomm Innovation Center,
Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project.
next prev parent reply other threads:[~2018-06-07 8:31 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-25 8:33 [PATCH v1] kthread/smpboot: Serialize kthread parking against wakeup Gaurav Kohli
2018-04-25 20:09 ` Peter Zijlstra
2018-04-26 4:04 ` Kohli, Gaurav
2018-04-26 9:14 ` Peter Zijlstra
2018-04-26 8:41 ` Peter Zijlstra
2018-04-26 8:57 ` Peter Zijlstra
2018-04-26 15:53 ` Kohli, Gaurav
2018-04-30 11:17 ` Peter Zijlstra
2018-05-01 7:50 ` Kohli, Gaurav
2018-05-01 10:18 ` Peter Zijlstra
2018-05-01 10:40 ` Peter Zijlstra
2018-05-01 10:40 ` Kohli, Gaurav
2018-05-01 11:31 ` Peter Zijlstra
2018-05-01 11:46 ` Kohli, Gaurav
2018-05-01 13:19 ` Peter Zijlstra
2018-05-02 5:15 ` Kohli, Gaurav
2018-05-02 8:20 ` Peter Zijlstra
2018-05-02 10:13 ` Kohli, Gaurav
2018-05-07 11:09 ` Kohli, Gaurav
2018-05-07 11:23 ` Kohli, Gaurav
2018-06-05 11:13 ` Kohli, Gaurav
2018-06-05 15:08 ` Oleg Nesterov
2018-06-05 15:22 ` Peter Zijlstra
2018-06-05 15:40 ` Peter Zijlstra
2018-06-05 16:35 ` Oleg Nesterov
2018-06-05 18:21 ` Kohli, Gaurav
2018-06-05 20:13 ` Peter Zijlstra
2018-06-06 13:51 ` Oleg Nesterov
2018-06-06 15:03 ` Peter Zijlstra
2018-06-06 15:04 ` Peter Zijlstra
2018-06-06 15:22 ` Peter Zijlstra
2018-06-06 18:59 ` Peter Zijlstra
2018-06-07 8:30 ` Kohli, Gaurav [this message]
2018-05-01 10:44 ` Peter Zijlstra
2018-04-26 16:02 ` Andrea Parri
2018-04-26 16:18 ` Oleg Nesterov
2018-04-30 11:20 ` Peter Zijlstra
2018-04-30 11:56 ` Peter Zijlstra
2018-04-28 6:43 ` [lkp-robot] [kthread/smpboot] cad8e99675: inconsistent{IN-HARDIRQ-W}->{HARDIRQ-ON-W}usage kernel test robot
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