Re: ia64-cpu-hotplug-cpu_present.patch?

From: Ashok Raj <>
Date: 2004-04-29 00:52:55
On Tue, Apr 27, 2004 at 10:57:41PM -0700, Paul Jackson wrote:

Hi Paul,

sorry for the trouble. I will try to address them, and will try to resolve the compile problem
you are having.

> I cannot find any mention of it on lkml or any other email list that
> either Google or I track.
> Is there some backdoor path to Andrew's patch directory I don't know of ;)?

I sent the patch to linux-ia64, but forgot to copy lkml. No... i did not buy crispy
cream for andrew.. although that did cross my mine :-)

Some of the points you raise, i will look into, but here is a quick summary fo Paul's top 10

cpu_present is required so that when cpu_up is called in smp_init() we dont call for all
possible cpu's but just for cpu's physically present. 

cpu_possible - indicates cpu may be available, but may not be present in the system. Hence
different from phys_cpu_present_mask

cpu_possible wont change dynamically but present_map can change depending on the arrival of 
cpu's in a system. I implemented it for only ia64, and expection is that ACPI or its equilvalent
would populate cpu_present_map dynamically.

In architectures that dont have cpu_hotplug capability, i have kept cpu_present and possible the same.

Once i take a look at the failures, i will send you an updated patch. again really sorry for the

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Received on Wed Apr 28 10:55:29 2004

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