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

From: Matt Mackall
Date: Wed May 13 2009 - 15:57:03 EST


On Wed, May 13, 2009 at 03:39:11PM -0400, Jeff Garzik wrote:
> 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

If you want. I was also looking to avoid the fight that happened when
I submitted an equivalent patch a couple years back.

--
Mathematics is the supreme nostalgia of our time.
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