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Date: Mon, 21 Jun 2010 11:28:33 -0700
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Subject: Re: [PATCH UPDATED] sched: adjust when cpu_active and cpuset 
	configurations are updated during cpu on/offlining
From: Tony Luck <tony.luck@intel.com>
To: Tejun Heo <tj@kernel.org>
Cc: Ingo Molnar <mingo@elte.hu>, Peter Zijlstra <peterz@infradead.org>,
       lkml <linux-kernel@vger.kernel.org>
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On Tue, Jun 8, 2010 at 12:46 PM, Tejun Heo <tj@kernel.org> wrote:
> * Ingo's test discovered __cpuinit/exit markups were incorrect.
>  Fixed.

No it isn't :-(

> +static int __cpuexit cpuset_cpu_active(struct notifier_block *nfb,
> +                                      unsigned long action, void *hcpu)
...
> +static int __cpuexit cpuset_cpu_inactive(struct notifier_block *nfb,
> +                                        unsigned long action, void *hcpu)

This patch arrived in linux-next (tag next-20100621) and breaks the
ia64 build for configurations where CONFIG_HOTPLUG_CPU=n
with the following cryptic error:

`.cpuexit.text' referenced in section `.IA_64.unwind.cpuexit.text' of
kernel/built-in.o: defined in discarded section `.cpuexit.text' of
kernel/built-in.o

This is because ia64 link stage drops __exit functions from
built-in code (under the logic that they can never be called).

Is the problem in the !CONFIG_HOTPLUG_CPU definition of
hotcpu_notifier() in <linux/cpu.h> which still references the
function argument:

#define hotcpu_notifier(fn, pri)        do { (void)(fn); } while (0)

Or should these functions not be marked __cpuexit?

-Tony