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From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
To: Petr Mladek <pmladek@suse.com>
Cc: Tejun Heo <tj@kernel.org>, linux-mm <linux-mm@kvack.org>,
	linux-watchdog@vger.kernel.org
Subject: Re: [PATCH v6 13/20] hung_task: Convert hungtaskd into kthread worker API
Date: Thu, 26 May 2016 06:56:38 +0900	[thread overview]
Message-ID: <47fb67eb-1756-7189-0245-f59c5a4c5f41@I-love.SAKURA.ne.jp> (raw)
In-Reply-To: <1460646879-617-14-git-send-email-pmladek@suse.com>

On 2016/04/15 0:14, Petr Mladek wrote:
> This patch converts hungtaskd() in kthread worker API because
> it modifies the priority.
> 
> This patch moves one iteration of the main cycle into a self-queuing
> delayed kthread work. It does not longer check if it was called
> earlier. Instead, the work is scheduled only when needed. This
> requires storing the time of the last check into a global
> variable.

Is it guaranteed that that work is fired when timeout expires? It is
common that tasks sleep in uninterruptible state due to waiting for
memory allocations. Unless a dedicated worker like vmstat_wq is used
for watchdog, I think it might fail to report such tasks due to all
workers being busy but the system is under OOM.

  vmstat_wq = alloc_workqueue("vmstat", WQ_FREEZABLE|WQ_MEM_RECLAIM, 0);

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  reply	other threads:[~2016-05-25 21:56 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-04-14 15:14 [PATCH v6 00/20] kthread: Use kthread worker API more widely Petr Mladek
2016-04-14 15:14 ` [PATCH v6 01/20] kthread/smpboot: Do not park in kthread_create_on_cpu() Petr Mladek
2016-04-14 15:14 ` [PATCH v6 02/20] kthread: Allow to call __kthread_create_on_node() with va_list args Petr Mladek
2016-04-14 15:14 ` [PATCH v6 03/20] kthread: Add create_kthread_worker*() Petr Mladek
2016-04-14 15:14 ` [PATCH v6 04/20] kthread: Add drain_kthread_worker() Petr Mladek
2016-04-14 15:14 ` [PATCH v6 05/20] kthread: Add destroy_kthread_worker() Petr Mladek
2016-04-14 15:14 ` [PATCH v6 06/20] kthread: Detect when a kthread work is used by more workers Petr Mladek
2016-04-14 15:14 ` [PATCH v6 07/20] kthread: Initial support for delayed kthread work Petr Mladek
2016-04-14 15:14 ` [PATCH v6 08/20] kthread: Allow to cancel " Petr Mladek
2016-04-14 15:14 ` [PATCH v6 09/20] kthread: Allow to modify delayed " Petr Mladek
2016-04-14 15:14 ` [PATCH v6 10/20] kthread: Better support freezable kthread workers Petr Mladek
2016-04-14 15:14 ` [PATCH v6 11/20] mm/huge_page: Convert khugepaged() into kthread worker API Petr Mladek
2016-04-14 15:14 ` [PATCH v6 12/20] ring_buffer: Convert benchmark kthreads " Petr Mladek
2016-04-14 15:14 ` [PATCH v6 13/20] hung_task: Convert hungtaskd " Petr Mladek
2016-05-25 21:56   ` Tetsuo Handa [this message]
2016-05-27  8:33     ` Petr Mladek
2016-04-14 15:14 ` [PATCH v6 14/20] kmemleak: Convert kmemleak kthread " Petr Mladek
2016-04-14 15:14 ` [PATCH v6 15/20] ipmi: Convert kipmi " Petr Mladek
2016-04-14 15:14 ` [PATCH v6 16/20] IB/fmr_pool: Convert the cleanup thread " Petr Mladek
2016-05-18 15:36   ` Doug Ledford
2016-04-14 15:14 ` [PATCH v6 17/20] memstick/r592: Better synchronize debug messages in r592_io kthread Petr Mladek
2016-04-14 15:14 ` [PATCH v6 18/20] memstick/r592: convert r592_io kthread into kthread worker API Petr Mladek
2016-04-14 15:14 ` [PATCH v6 19/20] thermal/intel_powerclamp: Remove duplicated code that starts the kthread Petr Mladek
2016-04-14 15:14 ` [PATCH v6 20/20] thermal/intel_powerclamp: Convert the kthread to kthread worker API Petr Mladek
2016-08-25  8:33   ` Sebastian Andrzej Siewior
2016-08-25 11:37     ` Petr Mladek
2016-08-25 11:44       ` Sebastian Andrzej Siewior
2016-04-22 18:30 ` [PATCH v6 00/20] kthread: Use kthread worker API more widely Tejun Heo
2016-05-11 10:52   ` Petr Mladek
2016-05-25 20:42     ` Tejun Heo

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