From: Oleg Nesterov <oleg@redhat.com>
To: Tejun Heo <tj@kernel.org>
Cc: rjw@sisk.pl, menage@google.com, linux-kernel@vger.kernel.org,
arnd@arndb.de
Subject: Re: [PATCH 06/16] freezer: make exiting tasks properly unfreezable
Date: Tue, 23 Aug 2011 17:52:21 +0200 [thread overview]
Message-ID: <20110823155221.GB25808@redhat.com> (raw)
In-Reply-To: <1313763382-12341-7-git-send-email-tj@kernel.org>
Hi.
Not a comment, but the question. Probably falls into the "read the
whole series" category too.
On 08/19, Tejun Heo wrote:
>
> There's no point in freezing an exiting task.
This is not clear to me. Probably this is fine, I do not know what
the callers of freeze_processes() actually expect.
> @@ -915,6 +913,12 @@ NORET_TYPE void do_exit(long code)
>
> ptrace_event(PTRACE_EVENT_EXIT, code);
>
> + /*
> + * With ptrace notification done, there's no point in freezing from
> + * here on. Disallow freezing.
> + */
> + current->flags |= PF_NOFREEZE;
OK, but what PF_NOFREEZE actually means?
Apart from "dont try to freeze" it means "no need to freeze", yes?
IOW, try_to_freeze_tasks() can succeed even if we have a lot of
exitinig task which can make some activity, say, disk i/o. Is this
correct?
Once again, I do not understand the problem-space at all, jus I am
curious.
Thanks,
Oleg.
next prev parent reply other threads:[~2011-08-23 15:55 UTC|newest]
Thread overview: 79+ 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 [this message]
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 8:39 ` 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
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
2011-09-05 8:52 ` [BUG] CPU hotplug, freezer: Freezing of tasks failed after 20.00 seconds Srivatsa S. Bhat
2011-09-05 14:15 ` Tejun Heo
2011-09-06 5:08 ` Tejun Heo
2011-09-06 6:01 ` Rafael J. Wysocki
2011-10-02 19:13 ` Srivatsa S. Bhat
2011-10-02 19:33 ` Rafael J. Wysocki
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