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Re: [Xen-devel] [RFC] irq rate limit

To: Qing He <qing.he@xxxxxxxxx>, "xen-devel@xxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxx>
Subject: Re: [Xen-devel] [RFC] irq rate limit
From: Keir Fraser <keir.fraser@xxxxxxxxxxxxx>
Date: Wed, 09 Sep 2009 09:48:24 +0100
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On 09/09/2009 09:48, "Qing He" <qing.he@xxxxxxxxx> wrote:

> This is a poc patch of guest irq ratelimit. The main motivation is
> to ensure Xen's responsiveness during an irq storm, that caused by
> improper hardware or drivers. If one interrupt is fired at a high
> rate (>10k/10ms in the poc), it is disabled until the next periodic
> timer_fn. A global generation counter is used to minimize overhead.

What's the generation counter for? Why not just zero desc->rl_cnt in the
timer handler?

 -- Keir



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