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From: "Rafael J. Wysocki" <rjw@sisk.pl>
To: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>,
	paul@paulmenage.org, linux-kernel@vger.kernel.org, arnd@arndb.de
Subject: Re: [PATCH 12/16] freezer: clean up freeze_processes() failure path
Date: Mon, 29 Aug 2011 09:40:37 +0200	[thread overview]
Message-ID: <201108290940.37275.rjw@sisk.pl> (raw)
In-Reply-To: <20110829072800.GC16431@mtj.dyndns.org>

On Monday, August 29, 2011, Tejun Heo wrote:
> Hello,
> 
> On Sun, Aug 28, 2011 at 08:09:01PM +0200, Oleg Nesterov wrote:
> > This was copied from cancel_, yes. but what this
> > recalc_sigpending_and_wake() can or should do?
> >
> > It looks simply pointless. It can't clear TIF_SIGPENDING,
> > it can only do the unneeded/spurious wake_up(INTERRUPTIBLE).
> 
> Yeah, I just copied it over.  It seems it got confused between
> recalc_sigpending() and recalc_sigpending_and_wake() where the latter
> can't clear TIF_SIGPENDING.  The signallable freezable kthread seems
> quite fragile.  Once TIF_SIGPENDING is set, the only way for it to be
> cleared for a kthread is going through refrigerator and if freezing
> gets canceled before that happens, the kthread will have stuck
> TIF_SIGPENDING failing interruptible sleeps.  We'll probably should
> move recalc_sigpending() to the top of refrigerator.
> 
> But that said, I don't see any in-kernel user of
> set_freezable_with_signal().  Rafael, is there scheduled to be some
> new user of this API?

I'm not aware of any.

> It would be awesome if we can drop it.

Indeed.

Thanks,
Rafael

  reply	other threads:[~2011-08-29  7:38 UTC|newest]

Thread overview: 89+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-08-19 14:16 [PATCHSET] freezer: fix various bugs and simplify implementation Tejun Heo
2011-08-19 14:16 ` [PATCH 01/16] freezer: fix current->state restoration race in refrigerator() Tejun Heo
2011-08-19 15:52   ` Oleg Nesterov
2011-08-19 16:11     ` Tejun Heo
2011-08-19 21:08   ` Rafael J. Wysocki
2011-08-20  8:13     ` Tejun Heo
2011-08-19 14:16 ` [PATCH 02/16] freezer: don't unnecessarily set PF_NOFREEZE explicitly Tejun Heo
2011-08-19 16:43   ` Gustavo Padovan
2011-08-22 15:05   ` Samuel Ortiz
2011-08-19 14:16 ` [PATCH 03/16] freezer: unexport refrigerator() and update try_to_freeze() slightly Tejun Heo
2011-08-19 14:16 ` [PATCH 04/16] freezer: implement and use kthread_freezable_should_stop() Tejun Heo
2011-08-19 20:07   ` Henrique de Moraes Holschuh
2011-08-21 19:14   ` Oleg Nesterov
2011-08-22  9:53     ` Tejun Heo
2011-08-23 15:42       ` Oleg Nesterov
2011-08-19 14:16 ` [PATCH 05/16] freezer: rename thaw_process() to __thaw_task() and simplify the implementation Tejun Heo
2011-08-19 15:37   ` Paul Menage
2011-08-24  2:28   ` Matt Helsley
2011-08-19 14:16 ` [PATCH 06/16] freezer: make exiting tasks properly unfreezable Tejun Heo
2011-08-23 15:52   ` Oleg Nesterov
2011-08-23 19:44     ` Tejun Heo
2011-08-24 14:14       ` Oleg Nesterov
2011-08-25 15:59         ` Tejun Heo
2011-08-25 16:56           ` Oleg Nesterov
2011-08-25 21:01             ` Rafael J. Wysocki
2011-08-25 21:54               ` Tejun Heo
2011-08-26 21:09                 ` Rafael J. Wysocki
2011-08-27 10:35                   ` Tejun Heo
2011-08-27 10:51                     ` Rafael J. Wysocki
2011-08-27 11:02                       ` Tejun Heo
2011-08-27 12:22                         ` Rafael J. Wysocki
2011-08-25 21:52             ` Tejun Heo
2011-08-24 22:34   ` Matt Helsley
2011-08-25 15:25     ` Oleg Nesterov
2011-08-25 16:11     ` Tejun Heo
2011-08-19 14:16 ` [PATCH 07/16] freezer: don't distinguish nosig tasks on thaw Tejun Heo
2011-08-19 21:14   ` Rafael J. Wysocki
2011-08-20  8:10     ` Tejun Heo
2011-08-20  8:10     ` Tejun Heo
2011-08-20  8:39       ` Rafael J. Wysocki
2011-08-20  8:39       ` Rafael J. Wysocki
2011-08-19 21:14   ` Rafael J. Wysocki
2011-08-19 14:16 ` [PATCH 08/16] freezer: use dedicated lock instead of task_lock() + memory barrier Tejun Heo
2011-08-28 17:51   ` Oleg Nesterov
2011-08-28 18:21     ` Oleg Nesterov
2011-08-29  7:20     ` Tejun Heo
2011-08-19 14:16 ` [PATCH 09/16] freezer: make freezing indicate freeze condition in effect Tejun Heo
2011-08-28 17:56   ` Oleg Nesterov
2011-08-29  7:31     ` Tejun Heo
2011-08-29 17:44     ` Oleg Nesterov
2011-08-19 14:16 ` [PATCH 10/16] freezer: fix set_freezable[_with_signal]() race Tejun Heo
2011-08-28 18:01   ` Oleg Nesterov
2011-08-29  7:38     ` Tejun Heo
2011-08-19 14:16 ` [PATCH 11/16] freezer: kill PF_FREEZING Tejun Heo
2011-08-19 14:16 ` [PATCH 12/16] freezer: clean up freeze_processes() failure path Tejun Heo
2011-08-28 18:09   ` Oleg Nesterov
2011-08-29  7:28     ` Tejun Heo
2011-08-29  7:40       ` Rafael J. Wysocki [this message]
2011-08-19 14:16 ` [PATCH 13/16] cgroup_freezer: prepare for removal of TIF_FREEZE Tejun Heo
2011-08-19 15:40   ` Paul Menage
2011-08-28 17:39   ` Oleg Nesterov
2011-08-29  6:30     ` Tejun Heo
2011-08-19 14:16 ` [PATCH 14/16] freezer: make freezing() test freeze conditions in effect instead " Tejun Heo
2011-08-19 15:43   ` Paul Menage
2011-08-29 15:49   ` Oleg Nesterov
2011-08-29 15:56     ` Oleg Nesterov
2011-08-29 16:30       ` Oleg Nesterov
2011-08-29 16:17     ` Oleg Nesterov
2011-08-19 14:16 ` [PATCH 15/16] freezer: remove now unused TIF_FREEZE Tejun Heo
2011-08-19 14:16 ` [PATCH 16/16] freezer: remove should_send_signal() and update frozen() Tejun Heo
2011-08-19 14:23 ` [PATCHSET] freezer: fix various bugs and simplify implementation Tejun Heo
2011-08-19 15:34   ` Paul Menage
2011-08-19 16:25   ` Tejun Heo
2011-08-24  1:10     ` Matt Helsley
2011-08-19 21:00 ` Rafael J. Wysocki
2011-08-20  8:14   ` Tejun Heo
2011-08-20  8:14   ` Tejun Heo
2011-09-05  6:49   ` [BUG] CPU hotplug, freezer: Freezing of tasks failed after 20.00 seconds Srivatsa S. Bhat
2011-09-05  8:52   ` Srivatsa S. Bhat
2011-09-05  8:52   ` Srivatsa S. Bhat
2011-09-05 14:15     ` Tejun Heo
2011-09-06  5:08       ` Tejun Heo
2011-09-06  5:08       ` Tejun Heo
2011-09-06  6:01         ` Rafael J. Wysocki
2011-09-06  6:01         ` Rafael J. Wysocki
2011-10-02 19:13           ` Srivatsa S. Bhat
2011-10-02 19:33             ` Rafael J. Wysocki
2011-09-05 14:15     ` Tejun Heo
2011-08-19 21:00 ` [PATCHSET] freezer: fix various bugs and simplify implementation Rafael J. Wysocki

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