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Date: Tue, 22 Oct 2002 13:08:49 -0500
From: Corey Minyard <cminyard@mvista.com>
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To: Robert Love <rml@tech9.net>
CC: John Levon <levon@movementarian.org>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] NMI request/release
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Robert Love wrote:

>On Tue, 2002-10-22 at 09:02, Corey Minyard wrote:
>
>  
>
>>I looked, and the rcu code relys on turning off interrupts to avoid 
>>preemption.  So it won't work.
>>    
>>
>
>At least on the variant of RCU that is in 2.5, the RCU code does the
>read side by disabling preemption.  Nothing else.
>
In 2.5.44, stock from kernel.org, rcu_process_callbacks() calls 
local_irq_disable().  Is that just preemption disabling, now?

>The write side is the same with or without preemption - wait until all
>readers are quiescent, change the copy, etc.
>
>But anyhow, disabling interrupts should not affect NMIs, no?
>
You are correct.  disabling preemption or interrupts has no effect on NMIs.

-Corey

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