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Date: Mon, 05 Oct 2009 10:55:27 -0700
From: Julian Elischer <julian@elischer.org>
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To: Tom Judge <tom@tomjudge.com>
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Cc: freebsd-hackers@freebsd.org
Subject: Re: Kernel Thread Lock Question
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Tom Judge wrote:
> Do I need to hold the per thread lock here? (This is for 7.1)
> 
> PROC_LOCK(p);
> //mtx_lock_spin(&sched_lock);
> breakout = 0;
> FOREACH_THREAD_IN_PROC(p, td) {
>    thread_lock(td);
>    if (!TD_ON_RUNQ(td) &&
>            !TD_IS_RUNNING(td) &&
>            !TD_IS_SLEEPING(td)) {
>        breakout = 1;
>        thread_unlock(td);
>        break;
>    }
>    thread_unlock(td);
> }
> //mtx_unlock_spin(&sched_lock);
> PROC_UNLOCK(p);
> 

"probably not" because the value in the status word can change just 
after you release it anyhow so your result does not have to be 
consistent with anything, just with itself.

> 
> Thanks
> 
> Tom
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