From: Colin Cross <ccross@android.com>
To: Tejun Heo <tj@kernel.org>
Cc: "Linux PM list" <linux-pm@vger.kernel.org>,
lkml <linux-kernel@vger.kernel.org>,
"Rafael J. Wysocki" <rjw@sisk.pl>,
"Arve Hjønnevåg" <arve@android.com>,
"Oleg Nesterov" <oleg@redhat.com>,
"Len Brown" <len.brown@intel.com>, "Pavel Machek" <pavel@ucw.cz>,
"Jeff Layton" <jlayton@redhat.com>,
"Mandeep Baines" <msb@chromium.org>
Subject: Re: [PATCH v2 03/10] freezer: add new freezable helpers using freezer_do_not_count()
Date: Thu, 2 May 2013 21:17:21 -0700 [thread overview]
Message-ID: <CAMbhsRQ=zyop6ubouHAsb9CYV9Pdqo5x0fsga7wuuedj1mio4g@mail.gmail.com> (raw)
In-Reply-To: <20130503040934.GA16968@mtj.dyndns.org>
On Thu, May 2, 2013 at 9:09 PM, Tejun Heo <tj@kernel.org> wrote:
> Hello,
>
> On Thu, May 02, 2013 at 07:41:39PM -0700, Colin Cross wrote:
>> On Thu, May 2, 2013 at 7:16 PM, Colin Cross <ccross@android.com> wrote:
>> > This sounds the same as what ended up getting reverted in
>> > https://lkml.org/lkml/2013/3/4/221
>> > I can add the WARN_ON_ONCE to all my new calls, and leave them out of
>> > existing calls, but that seems a little odd, and will be redundant if
>> > the lockdep call in try_to_freeze goes back in in 3.11. Do you still
>> > want it in the new apis?
> ...
>> I could also put the lockdep check that was reveted back into
>> try_to_freeze(), and add a freezable_schedule_unsafe() that skips it
>> for use in the known-unsafe users in nfs, with a big comment not to
>> add new users of it.
>
> Oh yeah, that sounds like a good idea, and as for the non-ugly
> variants, at least in the mid/long term, I think it'd be best to add
> the lockdep annotation to try_to_freeze() with
> __try_to_freeze_unsafe_youre_gonna_burn_in_hell_if_you_use_this() for
> the existing users which should be gradually converted, but if that's
> too burdensome, adding warnings to the wrappers should do for now, I
> guess.
>
> And I *hope* the lockdep annotation is stricter than what was added
> before. I think it better be "no lock ever should be held at this
> point" rather than "consider this a big lock".
The previous patch (6aa9707099c4b25700940eb3d016f16c4434360d in Linus'
tree) already required that no locks be held, it wasn't using a lock
annotation.
next prev parent reply other threads:[~2013-05-03 4:17 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-05-02 1:34 [PATCH v2 00/10] optimize freezing tasks by reducing task wakeups Colin Cross
2013-05-02 1:34 ` [PATCH v2 01/10] freezer: shorten freezer sleep time using exponential backoff Colin Cross
2013-05-02 23:20 ` Tejun Heo
2013-05-02 1:35 ` [PATCH v2 02/10] freezer: skip waking up tasks with PF_FREEZER_SKIP set Colin Cross
2013-05-02 23:24 ` Tejun Heo
2013-05-03 9:24 ` Pavel Machek
2013-05-02 1:35 ` [PATCH v2 03/10] freezer: add new freezable helpers using freezer_do_not_count() Colin Cross
2013-05-02 23:55 ` Tejun Heo
2013-05-03 0:03 ` Tejun Heo
2013-05-03 2:16 ` Colin Cross
2013-05-03 2:41 ` Colin Cross
2013-05-03 4:09 ` Tejun Heo
2013-05-03 4:12 ` Tejun Heo
2013-05-03 4:17 ` Colin Cross [this message]
2013-05-03 4:20 ` Tejun Heo
2013-05-03 14:18 ` Alan Stern
2013-05-03 16:54 ` Tejun Heo
2013-05-02 1:35 ` [PATCH v2 04/10] binder: use freezable blocking calls Colin Cross
2013-05-02 1:35 ` [PATCH v2 05/10] epoll: use freezable blocking call Colin Cross
2013-05-02 1:35 ` [PATCH v2 06/10] select: " Colin Cross
2013-05-02 1:35 ` [PATCH v2 07/10] futex: " Colin Cross
2013-05-02 19:45 ` Thomas Gleixner
2013-05-03 3:12 ` Darren Hart
2013-06-25 21:15 ` [tip:core/locking] futex: Use " tip-bot for Colin Cross
2013-05-02 1:35 ` [PATCH v2 08/10] nanosleep: use " Colin Cross
2013-05-02 19:46 ` Thomas Gleixner
2013-05-02 1:35 ` [PATCH v2 09/10] sigtimedwait: " Colin Cross
2013-05-02 1:35 ` [PATCH v2 10/10] af_unix: use freezable blocking calls in read Colin Cross
2013-05-03 0:08 ` Tejun Heo
2013-05-04 19:19 ` Rafael J. Wysocki
2013-05-04 20:39 ` Tejun Heo
2013-05-04 22:23 ` Colin Cross
2013-05-05 11:23 ` Rafael J. Wysocki
2013-05-02 21:06 ` [PATCH v2 00/10] optimize freezing tasks by reducing task wakeups Rafael J. Wysocki
2013-05-03 0:10 ` Tejun Heo
2013-05-03 11:43 ` Rafael J. Wysocki
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