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From: Tejun Heo <tj@kernel.org>
To: Rusty Russell <rusty@rustcorp.com.au>
Cc: mingo@elte.hu, linux-kernel@vger.kernel.org, x86@kernel.org,
	ink@jurassic.park.msu.ru, rth@twiddle.net,
	linux@arm.linux.org.uk, hskinnemoen@atmel.com,
	cooloney@kernel.org, starvik@axis.com, jesper.nilsson@axis.com,
	dhowells@redhat.com, ysato@users.sourceforge.jp,
	tony.luck@intel.com, takata@linux-m32r.org, geert@linux-m68k.org,
	monstr@monstr.eu, ralf@linux-mips.org, kyle@mcmartin.ca,
	benh@kernel.crashing.org, paulus@samba.org,
	schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com,
	lethal@linux-sh.org, davem@davemloft.net, jdike@addtoit.com,
	chris@zankel.net, Jens Axboe <jens.axboe@oracle.com>,
	Dave Jones <davej@redhat.com>,
	Jeremy Fitzhardinge <jeremy@xensource.com>,
	linux-mm <linux-mm@kvack.org>
Subject: Re: [PATCH 3/7] percpu: clean up percpu variable definitions
Date: Tue, 26 May 2009 01:07:16 +0900	[thread overview]
Message-ID: <4A1AC234.9020307@kernel.org> (raw)
In-Reply-To: <200905251537.35981.rusty@rustcorp.com.au>

Rusty Russell wrote:
> On Wed, 20 May 2009 05:07:35 pm Tejun Heo wrote:
>> Percpu variable definition is about to be updated such that
>>
>> * percpu symbols must be unique even the static ones
>>
>> * in-function static definition is not allowed
> 
> That spluttering noise is be choking on the title of this patch :)
> 
> Making these pseudo statics is in no way a cleanup.  How about we just
> say "they can't be static" and do something like:
> 
> /* Sorry, can't be static: that breaks archs which need these weak. */
> #define DEFINE_PER_CPU(type, var) \
> 	extern typeof(type) var; DEFINE_PER_CPU_SECTION(type, name, "")

Heh... well, even though I authored the patch, I kind of agree with
you.  Maybe it would be better to simply disallow static declaration /
definition at all.  I wanted to give a go at the original idea as it
seemed to have some potential.  The result isn't too disappointing but
I can't really say there are distinctively compelling advantages to
justify the added complexity and subtlety.

What do others think?  Is everyone happy with going extern only?

Thanks.

-- 
tejun

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  reply	other threads:[~2009-05-25 16:08 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <1242805059-18338-1-git-send-email-tj@kernel.org>
2009-05-20  7:37 ` Tejun Heo
2009-05-20  9:17   ` Jens Axboe
2009-05-25  6:07   ` Rusty Russell
2009-05-25 16:07     ` Tejun Heo [this message]
     [not found] <1243846708-805-1-git-send-email-tj@kernel.org>
2009-06-01  8:58 ` Tejun Heo
2009-06-01  9:40   ` David Miller
2009-06-01 11:36     ` Tejun Heo
2009-06-02  5:08       ` Benjamin Herrenschmidt
2009-06-05  4:25         ` Tejun Heo
2009-06-11 10:45           ` Jesper Nilsson
2009-06-17  2:28             ` Tejun Heo
2009-06-10 18:30     ` H. Peter Anvin

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