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From: Andrew Morton <akpm@osdl.org>
To: davidm@hpl.hp.com
Cc: arnd@arndb.de, rusty@rustcorp.com.au, linux-arch@vger.kernel.org,
	epasch@de.ibm.com, hare@suse.de
Subject: Re: static DEFINE_PER_CPU vs. modules
Date: Tue, 4 May 2004 12:03:17 -0700	[thread overview]
Message-ID: <20040504120317.36d45341.akpm@osdl.org> (raw)
In-Reply-To: <16535.50431.820664.953078@napali.hpl.hp.com>

David Mosberger <davidm@napali.hpl.hp.com> wrote:
>
> >>>>> On Tue, 4 May 2004 16:17:29 +0200, Arnd Bergmann <arnd@arndb.de> said:
> 
>   Arnd> On Tuesday 04 May 2004 04:38, Andrew Morton wrote:
>   >> Arnd Bergmann <arnd@arndb.de> wrote:
>   >> >
>   >> > The idea I had for preventing the same bug from happening
>   >> >  in the future is to provoke a compile error for modules using
>   >> >  'static DEFINE_PER_CPU', see patch below.
> 
>   >> It's not a big success with CONFIG_SMP=n.
> 
>   >> kernel/fork.c:55: warning: return-type defaults to `int'
>   >> kernel/fork.c: In function `__PER_CPU_NOSTATIC':
> 
>   Arnd> Sorry about that, I accidentally defined __PER_CPU_NOSTATIC
>   Arnd> inside '#ifdef CONFIG_SMP'. This now builds with and without
>   Arnd> SMP.
> 
> I do not understand why such a patch should get accepted.  In general,
> it makes no sense at all to disallow static per-CPU variables.  If
> some platforms are broken, fine, put a workaround _for that platform_
> in, but don't prevent the others from doing the sane thing.
> 

Because s390 can use (almost) all modules.  It's like the "atomic_t only
holds 24-bits because of sparc32" thing which we lived with for ages.

We can certainly live with this workaround, but it would be nice to find
something better. per-module per-cpu data sections?

  reply	other threads:[~2004-05-04 19:04 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-05-03 15:41 static DEFINE_PER_CPU vs. modules Arnd Bergmann
2004-05-03 17:50 ` David Mosberger
2004-05-03 18:01   ` Richard Henderson
2004-05-03 18:37     ` David Mosberger
2004-05-03 22:24       ` Arnd Bergmann
2004-05-03 23:12         ` David Mosberger
2004-05-04  8:56           ` Arnd Bergmann
2004-05-04  2:38 ` Andrew Morton
2004-05-04 14:17   ` Arnd Bergmann
2004-05-04 16:29     ` David Mosberger
2004-05-04 19:03       ` Andrew Morton [this message]
2004-05-04 19:15         ` David Mosberger
2004-05-04 19:23           ` Andrew Morton
2004-05-04 19:45             ` David Mosberger
2004-05-05  8:21               ` Arnd Bergmann
2004-05-05  8:29                 ` Andrew Morton
2004-05-05  9:24                   ` Arnd Bergmann
2004-05-05  9:33                 ` Rusty Russell
2004-05-05 16:17                 ` David Mosberger
2004-05-05  3:18         ` Richard Henderson
  -- strict thread matches above, loose matches on Subject: below --
2004-05-05 17:42 Martin Schwidefsky

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