Re: [Xen-devel] disabling irqs in a non-preemptive OS

To:	Matthew Fioravante <Matthew.Fioravante@xxxxxxxxxx>, "xen-devel@xxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxx>
Subject:	Re: [Xen-devel] disabling irqs in a non-preemptive OS
From:	Keir Fraser <keir.fraser@xxxxxxxxxxxxx>
Date:	Fri, 01 Jan 2010 09:01:59 +0000
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On 31/12/2009 23:16, "Matthew Fioravante" <Matthew.Fioravante@xxxxxxxxxx>
wrote:

> mini-os is a uniprocessor and non-preemptive OS so unless your thread
> blocks, an irq handler (in this case event channel handler) will never
> be run and thus won't be able to touch your critical sections.

What makes you think that? 'Non-preemptive' doesn't mean that you can't be
interrupted by irq context. That's why they're called interrupts!

 -- Keir

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Re: [Xen-devel] disabling irqs in a non-preemptive OS