Updated mdev

Rob Landley rob at landley.net
Tue Dec 13 09:12:01 UTC 2005

On Tuesday 13 December 2005 02:27, Frank Sorenson wrote:
> Rob,
> If you haven't already completed a rewrite, here's my improved version.
>  I believe I address all the issues you've mentioned.  I've also cleaned
> it up, fixed small bugs, tested more thoroughly, etc.  This code
> probably still needs some significant cleaning-up, but...!

Um, I took your previous version and extensively rewrote it myself.

> >>>All this stuff with netlink needs a CONFIG_ and #ifdefs.
> Done (not sure if it's right, but it's done! :)
> CONFIG_HOTPLUG now selects whether or not to do the whole kernel-netlink
> bit that detects hotplug.  Configged out, it appears to save about 1500
> bytes.

I chopped out the hotplug with an eye to adding it back later.  Is the netlink 
stuff the only way to do this, or does /sbin/hotplug still work?

> I left in a TODO comment where we'd address this.  _Real_ udev appears
> to use inotify to check for updates to the config files, but that seems
> like overkill.  We could either load at startup, or re-read each time a
> device is added.

Do we really want a persistent daemon eating memory?

I planned to re-mmap the config file each time and re-parse the sucker again, 
on the theory that it's _short_, we stop at the first hit anyway, and the 
data should stay in the page cache.

We really don't have to worry about scaling to IBM mainframes with 2 million 
devices.  They can use Greg KH's version of udev.

> Frank

Steve Ballmer: Innovation!  Inigo Montoya: You keep using that word.
I do not think it means what you think it means.

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