Re: [PATCH] Driver Core: devtmpfs - kernel-maintained tmpfs-based /dev

From: Al Boldi
Date: Sat Aug 08 2009 - 05:14:15 EST


Greg KH wrote:
> On Sat, Aug 08, 2009 at 12:17:31AM +0300, Al Boldi wrote:
> > For devtmpfs to be a realistic replacement for static /dev, it has to
> > be comparable to static /dev in both speed and size.
>
> Since when is this requirement necessary? You want something for free
> in both speed and size? Well, you got it in speed, but not size, it
> will take up memory that is swapable, and a tiny ammount of non-swapable
> kernel memory for the code.

Not so tiny when you count in the hotplug dependency.

> > WRT speed, there should be no slowdown and it should be just as fast
> > as a "tar -xp < dev.tar".
>
> Again, where is this requirement coming from?
>
> Have you timed devtmpfs?

Not yet, I am still waiting for the latest patch against .30.

> > WRT size, it should not be dependent on hotplug, and instead offer
> > hotplug as an option.
>
> Um, again, who made up such a requirement? Are you running systems
> today with CONFIG_HOTPLUG disabled? If so, how well is that working for
> you?

It's working out quite well. I don't like hotplug, it's too slow. I always
turn it and module-autoloading off, to achieve a much more responsive system.


Thanks!

--
Al

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