From: Oliver Neukum <oliver@neukum.name>
To: Daniel Phillips <phillips@arcor.de>,
Roman Zippel <zippel@linux-m68k.org>
Cc: Jamie Lokier <lk@tantalophile.demon.co.uk>,
Alexander Viro <viro@math.psu.edu>,
Rusty Russell <rusty@rustcorp.com.au>,
<linux-kernel@vger.kernel.org>
Subject: Re: [RFC] Raceless module interface
Date: Thu, 12 Sep 2002 11:10:47 +0200 [thread overview]
Message-ID: <200209121110.47246.oliver@neukum.name> (raw)
In-Reply-To: <E17pCKQ-0007Sz-00@starship>
> To make this work, we rely on the rule that no module code may
> sleep/schedule unless it first increments a counter. The counter
> incremented will, at present, be the module->count, but that is entirely
> up to the module itself; module.c will no longer care how it keeps
> track, as long as it does.
>
> With config_preempt code, we must additionally disable preemption until
> the module quiescence test has completed. I'm not going to go further
> into this, because this is deep scheduling-fu, and I haven't got working
> code to show yet. Suffice to say that we have the technology to build a
> magic_wait_for_quiescence, and we must now proceed to do that. (Robert,
> are you reading?) A noncounting module uses the test as follows, in its
> cleanup_function:
>
> unregister_callpoints(...);
> magic_wait_for_quiescence();
> return cleanup_foo(...);
Please correct me if I am wrong, but ...
Task A Task B counter
call_module() +1
schedule() still 1
unregister_callpoints() still 1
magic_wait_for_quiescence(); still 1
call_module_second_func() -> Won't work
So by trying to unregister a module you make a module unusable
for an unspecified amount of time.
Regards
Oliver
next prev parent reply other threads:[~2002-09-12 8:35 UTC|newest]
Thread overview: 90+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-09-04 18:02 Question about pseudo filesystems Jamie Lokier
2002-09-07 12:00 ` Daniel Phillips
2002-09-07 13:36 ` Alexander Viro
2002-09-07 18:27 ` Jamie Lokier
2002-09-07 19:47 ` Alexander Viro
2002-09-08 2:21 ` Jamie Lokier
2002-09-08 2:43 ` Alexander Viro
2002-09-15 1:41 ` Moving a mount point (was Re: Question about pseudo filesystems) Rob Landley
2002-09-08 16:00 ` Question about pseudo filesystems Daniel Phillips
2002-09-09 19:48 ` Jamie Lokier
2002-09-09 20:06 ` Daniel Phillips
2002-09-10 0:44 ` Jamie Lokier
2002-09-10 1:40 ` Daniel Phillips
2002-09-10 1:56 ` Jamie Lokier
2002-09-10 2:53 ` Daniel Phillips
2002-09-10 3:26 ` Jamie Lokier
2002-09-10 3:47 ` Daniel Phillips
2002-09-10 9:15 ` Daniel Phillips
2002-09-10 10:17 ` Roman Zippel
2002-09-11 18:35 ` [RFC] Raceless module interface Daniel Phillips
2002-09-11 18:53 ` Oliver Neukum
2002-09-11 19:20 ` Daniel Phillips
2002-09-11 20:29 ` Oliver Neukum
2002-09-11 21:15 ` Daniel Phillips
2002-09-11 21:26 ` Jamie Lokier
2002-09-11 21:47 ` Daniel Phillips
2002-09-12 1:42 ` Rusty Russell
2002-09-12 2:09 ` Jamie Lokier
2002-09-12 3:13 ` Rusty Russell
2002-09-12 3:47 ` Daniel Phillips
2002-09-12 3:53 ` Alexander Viro
2002-09-12 4:11 ` Daniel Phillips
2002-09-12 4:40 ` Rusty Russell
2002-09-12 5:27 ` Daniel Phillips
2002-09-12 14:46 ` Gerhard Mack
2002-09-13 0:39 ` Rusty Russell
2002-09-13 2:23 ` Daniel Phillips
2002-09-12 5:35 ` Rusty Russell
2002-09-12 4:52 ` Rusty Russell
2002-09-12 5:58 ` Daniel Phillips
2002-09-12 7:00 ` Rusty Russell
2002-09-13 8:18 ` Helge Hafting
2002-09-12 3:32 ` Daniel Phillips
2002-09-12 1:31 ` Rusty Russell
2002-09-12 9:10 ` Oliver Neukum [this message]
2002-09-12 11:27 ` Roman Zippel
2002-09-12 13:03 ` Rusty Russell
2002-09-12 13:44 ` Roman Zippel
2002-09-13 1:30 ` Rusty Russell
2002-09-13 2:19 ` Daniel Phillips
2002-09-13 6:51 ` Rusty Russell
2002-09-13 13:34 ` Daniel Phillips
2002-09-13 13:52 ` Thunder from the hill
2002-09-13 14:09 ` Daniel Phillips
2002-09-13 14:33 ` Thunder from the hill
2002-09-13 14:44 ` Daniel Phillips
2002-09-13 14:59 ` Thunder from the hill
2002-09-13 15:17 ` Daniel Phillips
2002-09-13 15:27 ` Thunder from the hill
2002-09-13 15:37 ` Daniel Phillips
2002-09-16 2:17 ` Rusty Russell
2002-09-16 16:13 ` Daniel Phillips
2002-09-16 16:36 ` Understanding the Principles of Argumentation #3 Daniel Phillips
2002-09-16 16:42 ` Robinson Maureira Castillo
2002-09-16 17:29 ` Cort Dougan
2002-09-16 22:31 ` David Woodhouse
2002-10-01 14:13 ` Daniel Phillips
2002-10-01 14:27 ` David Woodhouse
2002-09-13 15:59 ` [RFC] Raceless module interface Daniel Phillips
2002-09-13 3:14 ` David Gibson
2002-09-13 10:35 ` Roman Zippel
2002-09-13 13:53 ` Daniel Phillips
2002-09-13 15:13 ` Roman Zippel
2002-09-13 15:30 ` Daniel Phillips
2002-09-13 15:55 ` Roman Zippel
2002-09-13 16:09 ` Daniel Phillips
2002-09-13 16:39 ` Thunder from the hill
2002-09-13 17:12 ` Daniel Phillips
2002-09-16 0:24 ` Bill Davidsen
2002-09-16 1:49 ` Rusty Russell
2002-09-16 21:36 ` Roman Zippel
2002-09-16 21:48 ` Daniel Phillips
2002-09-16 22:44 ` Roman Zippel
2002-09-11 15:28 ` Question about pseudo filesystems Bill Davidsen
2002-09-11 19:36 ` Daniel Phillips
2002-09-09 20:12 ` Daniel Phillips
2002-09-09 22:56 ` Jamie Lokier
2002-09-10 1:39 ` Alexander Viro
2002-09-09 20:18 ` Daniel Phillips
2002-09-10 6:48 ` Kai Henningsen
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