From: Stephen Hemminger <shemminger@osdl.org>
To: Rusty Russell <rusty@rustcorp.com.au>
Cc: davem@redhat.com, arjanv@redhat.com, torvalds@transmeta.com,
greg@kroah.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] Remove module reference counting.
Date: Fri, 25 Jul 2003 12:26:51 -0700 [thread overview]
Message-ID: <20030725122651.4aedc768.shemminger@osdl.org> (raw)
In-Reply-To: <20030725173900.D7DE12C2A9@lists.samba.org>
On Fri, 25 Jul 2003 04:00:18 +1000
Rusty Russell <rusty@rustcorp.com.au> wrote:
> Hi all,
>
> When the initial module patch was submitted, it made modules
> start isolated, so they would not be accessible until (if)
> initialization had succeeded. This broke partition scanning, and was
> immediately reverted, leaving us with a module reference count scheme
> identical to the previous one (just a faster implementation): we still
> have cases where modules can be access on failed load.
>
> Then Dave decided that the work of reference counting network
> driver modules everywhere is too invasive, so network driver modules
> now have zero reference counts always. The idea is that if you don't
> want the module removed, don't do it. ie. only remove the module if
> there's a bug, or you want to replace it.
>
> If module removal is to be a rare and unusual event, it
> doesn't seem so sensible to go to great lengths in the code to handle
> just that case. In fact, it's easier to leave the module memory in
> place, and not have the concept of parts of the kernel text (and some
> types of kernel data) vanishing.
>
> Polite feedback welcome,
> Rusty.
> --
There are two possible objections to this:
* Some developers keep the same kernel running and load/unload then reload
a new driver when debugging. This would break probably or at least cause
a large amount of kernel growth. Not that big an issue for me personally
but driver writers seem to get hit with all the changes.
* Drivers might get sloppy about not cleaning up timers and data structures
-- more than they are already. You might want to have a kernel debug option
that overwrite's the unloaded text with something guaranteed to cause an
oops.
next prev parent reply other threads:[~2003-07-25 19:11 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-07-24 18:00 [PATCH] Remove module reference counting Rusty Russell
2003-07-25 17:47 ` David S. Miller
2003-07-27 18:50 ` Rusty Russell
2003-07-25 17:54 ` Greg KH
2003-07-25 19:11 ` Greg KH
2003-07-25 19:26 ` Stephen Hemminger [this message]
2003-07-25 19:32 ` Greg KH
2003-07-25 22:26 ` Rusty Russell
2003-07-26 19:31 ` Linus Torvalds
2003-07-26 19:37 ` Arjan van de Ven
2003-07-27 5:38 ` Aschwin Marsman
2003-07-27 11:10 ` Alan Cox
2003-07-27 11:09 ` Alan Cox
2003-07-27 19:34 ` Rusty Russell
2003-07-27 21:47 ` Arjan van de Ven
2003-07-28 0:01 ` Alan Cox
2003-07-28 0:12 ` Bill Nottingham
2003-07-28 11:38 ` Alan Cox
2003-07-29 20:33 ` Rusty Russell
2003-07-30 1:55 ` Greg KH
2003-07-30 14:40 ` Alan Cox
2003-07-28 11:40 ` Alan Cox
2003-07-28 18:11 ` Gianni Tedesco
2003-07-28 19:03 ` Mike Fedyk
2003-08-01 2:39 ` Linus Torvalds
2003-07-25 23:24 ` Alan Cox
2003-07-27 18:48 ` Rusty Russell
2003-07-25 22:43 ` Gianni Tedesco
2003-07-25 23:37 ` Bernd Eckenfels
2003-07-26 20:18 ` Rusty Russell
2003-07-28 11:51 ` Rahul Karnik
2003-07-28 23:13 ` Rusty Russell
2003-07-29 2:39 ` Rahul Karnik
2003-07-29 2:10 Perez-Gonzalez, Inaky
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