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Date: Mon, 21 Jun 2010 14:15:51 -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>,
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On Mon, Jun 21, 2010 at 1:55 PM, Tejun Heo <tj@kernel.org> wrote:
> I see.  I think the right solution is removing __cpuexit but it's kind
> of silly to have different rules on different architectures.  On x86,
> __cpuexit currently means "you can drop it if you're not gonna be
> removing cpus after system boot"; IOW, __cpuexit is strict subset of
> __cpuinit.  If you define it as "don't include it in the text at all
> if cpus are not gonna be removed", it actually forces you to carry
> more text in the running system.  Is there any reason ia64 drops them
> during linking?

The history is that __exit functions are those that are called on module
unload.  When a driver is built-in to the kernel, it can obviously never
be unloaded. Therefore the __exit code must just be bloat for the built-in
case.

A system built with CONFIG_HOTPLUG_CPU=n meets the requirement
that cpus will not be removed after system boot. So why do I need to
include the __cpuexit code that should only be used to remove cpus?

-Tony