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From: Tejun Heo <tj@kernel.org>
To: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	Al Viro <viro@ZenIV.linux.org.uk>, Ingo Molnar <mingo@elte.hu>,
	Mike Travis <travis@sgi.com>,
	Christoph Lameter <cl@linux-foundation.org>,
	Heiko Carstens <heiko.carstens@de.ibm.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Subject: Re: [PATCH] unbreak alpha percpu
Date: Tue, 14 Apr 2009 18:01:34 +0900	[thread overview]
Message-ID: <49E450EE.9010502@kernel.org> (raw)
In-Reply-To: <20090414094556.3af71358@skybase>

Hello, Martin.

Martin Schwidefsky wrote:
> I would like to get rid of that SHIFT_PERCPU_PTR mess. The patch from
> Ivan will allow this, it uses a dummy variable to void the effect of a
> static modifier for percpu variables in modules. The percpu variable
> itself will be defined non-static, my gut feeling is that this is a
> dirty little trick that might bite us in the future.
> Another solution which I personally would prefer is to ban the use of
> static percpu variables. Then the compiler will use the GOT to get the
> address of percpu variables without any dirty tricks.

Hmmm... even if we can make combination of DECLARE_PER_CPU() and
static DEFINE_PER_CPU() trigger compile error?  That pretty much
implements most of what the programmer intends by "static" but yeah
it's a bit convoluted.

Thanks.

-- 
tejun

      reply	other threads:[~2009-04-14  9:03 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-04-10 15:12 [PATCH] unbreak alpha percpu Al Viro
2009-04-10 15:47 ` Al Viro
2009-04-10 16:21   ` Linus Torvalds
2009-04-10 16:50     ` Al Viro
2009-04-10 17:05       ` Al Viro
2009-04-10 17:14         ` Al Viro
2009-04-10 18:05           ` Ivan Kokshaysky
2009-04-10 18:20             ` Linus Torvalds
2009-04-10 18:43               ` Tejun Heo
2009-04-10 19:02                 ` Tejun Heo
2009-04-10 19:34                   ` Ingo Molnar
2009-04-10 19:40                     ` [GIT PULL] percpu + mutex fixes Ingo Molnar
2009-04-16 10:21                       ` Al Viro
2009-04-14  7:45     ` [PATCH] unbreak alpha percpu Martin Schwidefsky
2009-04-14  9:01       ` Tejun Heo [this message]

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