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Date: Tue, 01 Feb 2005 08:53:30 -0800
From: Nate Lawson <nate@root.org>
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To: Joseph Koshy <joseph.koshy@gmail.com>
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cc: FreeBSD Current <freebsd-current@freebsd.org>
Subject: Re: patch: please test buildkernel
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Joseph Koshy wrote:
>>+#ifdef SMP
>>+       /* Schedule ourselves on the indicated cpu. */
>>+       mtx_lock_spin(&sched_lock);
>>+       sched_bind(curthread, cpu_id);
>>+       mtx_unlock_spin(&sched_lock);
>>+#endif
> 
> ...
> 
>>+#ifdef SMP
>>+       mtx_lock_spin(&sched_lock);
>>+       sched_unbind(curthread);
>>+       mtx_unlock_spin(&sched_lock);
>>+#endif
> 
> 
> This will break if 'curthread' is already bound.  
> 
> I ended up solving this problem with a new interface 'sched_is_bound()': 
> 
>    http://perforce.freebsd.org/changeView.cgi?CH=63367
> 
> The cleaner alternative would probably have 'sched_bind()' return the
> previous CPU binding state.

Not a problem for me since no code in the kernel calls this interface 
after sched_bind().  I agree this is a general problem that should be 
solved but I think it's fine to bring in cpufreq without solving it first.

-- 
Nate