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Date: Mon, 19 Nov 2001 12:23:42 -0800
From: Matthew Dobson <colpatch@us.ibm.com>
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To: george anzinger <george@mvista.com>
CC: Mike Kravetz <kravetz@us.ibm.com>,
        Davide Libenzi <davidel@xmailserver.org>,
        lse-tech@lists.sourceforge.net, lkml <linux-kernel@vger.kernel.org>
Subject: Re: [Lse-tech] Re: Real Time Runqueue
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george anzinger wrote:
> A couple of addition points.  There should be an API to declare cpu
> affinity, and cpu affinity should be passed thru fork and exec.  You may
> need to be god (root) to use the API however.  (I think cpu affinity is
> currently passed thru fork and exec, by the way.)

There is...  there is a launch_policy patch on
http://sourceforge.net/projects/lse, that offers 2 ways of setting a processes
CPU affinity.  A process can muck around with its own affinity through prctl(),
and root can muck around with the CPU affinity of any process through
/proc/<pid>/cpus_allowed and /proc/<pid>/launch_policy.  And the launch_policy
*is* inherited from parent to child.

The cpus_allowed part comes from Andrew Morton and controls the processes
affinity.  I've extended that to include the launch_policy part which sets the
affinity to be passed on through fork/exec.

Enjoy!

-matt
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