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Date: Tue, 12 Jan 2010 01:15:31 -0800
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Subject: Re: [RFC PATCH 2/4] x86: use dmi check to treat disabled cpus as 
	hotplug cpus.
From: Yinghai Lu <yinghai@kernel.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>,
       "ananth@in.ibm.com" <ananth@in.ibm.com>, Ingo Molnar <mingo@elte.hu>,
       Thomas Gleixner <tglx@linutronix.de>, "H. Peter Anvin" <hpa@zytor.com>,
       Andrew Morton <akpm@linux-foundation.org>, linux-kernel@vger.kernel.org
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On Mon, Jan 11, 2010 at 7:13 PM, Linus Torvalds
<torvalds@linux-foundation.org> wrote:
>
>
> On Mon, 11 Jan 2010, Yinghai Lu wrote:
>>
>> some systems that have disable cpus entries because same
>>   BIOS will support 2 sockets and 4 sockets and more at
>>   same time, BIOS just leave some disable entries, but
>>   those system do not support cpu hotplug. we don't need
>>   treat disabled_cpus as hotplug cpus.
>>
>> so we can make nr_cpu_ids smaller and save more space
>>   (pcpu data allocations), and could make some systems run
>>   with logical flat instead of physical flat apic mode
>
> .. but this one I detest.
>
> We can't play games that depend on us always filling in some DMI table
> correctly. Things need to "just work".

maybe could change to list that doesn't need to treat disabled cpus as
hotplug cpus?

YH