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Date: Fri, 05 Oct 2001 16:54:06 -0700
From: "Martin J. Bligh" <Martin.Bligh@us.ibm.com>
Reply-To: "Martin J. Bligh" <Martin.Bligh@us.ibm.com>
To: paulus@samba.org, Peter Rival <frival@zk3.dec.com>
cc: Alan Cox <alan@lxorguk.ukuu.org.uk>, torvalds@transmeta.com,
        linux-kernel@vger.kernel.org, trini@kernel.crashing.org,
        benh@kernel.crashing.org
Subject: Re: [PATCH] change name of rep_nop
Message-ID: <1573466920.1002300846@mbligh.des.sequent.com>
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>> You also need to move the call to smp_boot_cpus() below the 
>> clear_bit(...) line in smp_init().  Without it, my Wildfire doesn't get 
> 
> No, that won't work for me, because cpu_online_map is set by
> smp_boot_cpus(), at least on PPC (in fact each CPU sets its bit in
> cpu_online_map as it spins up).
> 
> There shouldn't be a race on x86 at all, because the secondary
> processors don't call init_idle until after they see that the primary
> cpu has call smp_commence.  (There is currently a race on PPC since we
> call init_idle before waiting for smp_commence, but that would not be
> your problem.)

There *is* a race on x86 - the problem is that the primary cpu can 
get to reschedule_idle before the secondarys have done init_idle.
I'm not claiming the way I fixed it is beautiful, but the race definitely
exists (I hit it) and the patch makes the problem go away. 

Sounds like rep_nop was the wrong way to spin - aplogies.

Martin.

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