Subject: Re: [PATCH] [resend] drivers/net: remove network drivers' last few uses of IRQF_SAMPLE_RANDOM

From: Jeff Garzik <[email-masked]>
Date: Wed, 13 May 2009 15:39:11 -0400

Matt Mackall wrote:
> On Wed, May 13, 2009 at 12:17:29AM -0700, Chris Peterson wrote:
>>> The future model will continue to sample network
>>> devices on theory that they -might- be less than 100% observable and
>>> that can only increase our total (unmeasurable) amount of entropy.
>> That sounds reasonable to me. So should all net drivers now specify
>> IRQF_SAMPLE_RANDOM?
>>
>> Or even simpler: could request_irq() assume IRQF_SAMPLE_RANDOM for any
>> interrupt that is not (say) IRQF_IRQPOLL or IRQF_PERCPU?
> 
> Maybe. We don't want IRQ latency to suffer. So before we turn on
> sampling of -all- sources, we need to make sampling lighter weight and
> we need a way to say 'we have enough' so that we're not consuming CPU
> when our pools are 'full'. We could turn it on now and rely on the
> current trickle logic, but it's nice to have the water main off when
> doing significant plumbing.

So, until such time, let's be consistent in net driver land and not 
IRQF_SAMPLE_RANDOM.

	Jeff