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From: Terence Ripperda <TRipperda@nvidia.com>
Reply-To: Terence Ripperda <tripperda@nvidia.com>
To: Manfred Spraul <manfred@colorfullife.com>
Cc: Terence Ripperda <TRipperda@nvidia.com>, linux-kernel@vger.kernel.org
Date: Wed, 4 Sep 2002 11:17:43 -0500
Subject: Re: lockup on Athlon systems, kernel race condition?
Message-ID: <20020904161743.GB750@hygelac>
References: <3D752DA3.6030000@colorfullife.com> <20020903220424.GL2343@hygelac> <3D762156.5050907@colorfullife.com>
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On Wed, Sep 04, 2002 at 05:05:58PM +0200, manfred@colorfullife.com wrote:
> What was cpu1 doing? There are 3 loops in smp_call_function:
> spin_lock(&call_lock), and 2 while loops with barrier() [first one for 
> IPI arrival, second one for synchroneous ipi's. TLB flush is sync].

it was spinning on the first barrier loop, waiting for verification of the IPI arrival:

        /* Wait for response */
        while (atomic_read(&data.started) != cpus)
                barrier();


Terence
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