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>
Subject: Re: [PATCH v2 03/10] freezer: add new freezable helpers using freezer_do_not_count()
Date: Thu, 2 May 2013 19:16:59 -0700 [thread overview]
Message-ID: <CAMbhsRSFjUvkXq66pYs_nYN5At7yB4sFM+cpxLgUF_Yns54J5A@mail.gmail.com> (raw)
In-Reply-To: <20130503000358.GX19814@mtj.dyndns.org>
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?
On Thu, May 2, 2013 at 5:03 PM, Tejun Heo <tj@kernel.org> wrote:
> On Thu, May 02, 2013 at 04:55:05PM -0700, Tejun Heo wrote:
>> So, the freezable interface can't be something that people can use
>> casually. It is something which should be carefully and strategically
>> deployed where we *know* that lock dependency risks don't exist or at
>> least are acceptable. I'm a bit weary that this patch is expanding
>> the interface a lot that they now look like the equivalents of normal
>> schedule calls. Not exactly sure what to do here but can we please at
>> least have RED BOLD BLINKING comments which scream to people not to
>> use these unless they know what they're doing?
>
> Maybe we should trigger WARN_ON_ONCE() if lockdep_depth() > 0 by
> default and have ugly variants which can be used if the caller is sure
> that it's okay possibly with list of locks which are held?
>
> --
> tejun
next prev parent reply other threads:[~2013-05-03 2:17 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 [this message]
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
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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