Re: [PATCH] speedy boot from usb devices

[Kalin KOZHUHAROV]

David N. Welton wrote:
> Paulo Marques <pmarques@xxxxxxxxxxxx> writes:
>
>
> > David N. Welton wrote:
>
>
> > >        Works like so: whenever a block device comes on line, it
> > >        signals this fact to a wait queue, so that the init
> > >        process can stop and wait for slow devices, in particular
> > >        things such as USB storage devices, which are much slower
> > >        than IDE devices.  The init process checks the list of
> > >        available devices and compares it with the desired root
> > >        device, and if there is a match, proceeds with the
> > >        initialization process, secure in the knowledge that the
> > >        device in question has been brought up.  This is useful if
> > >        one wants to boot quickly from a USB storage device
> > >        without a trimmed-down kernel, and without going through
> > >        the whole initrd slog.
> > I find this to be very useful. I always found the "sleep for a while
> > until the device we want appears" approach very cumbersome.

I hope it works. I tried to hack some delay on my own, but without success :-(
Will try this patch.

> Glad to hear someone likes it.
>
>
> > However, after looking at your patch, it seems that having a
> > get_blkdevs() function that alloc's an array of strings, and return
> > it to a function that only compares the strings against the name it
> > is looking for and drops the array altogether, is a little overkill.
> > Why not have a simple blkdev_exists(char *name) function in genhd.c,
> > call it directly, and drop the match_root_name() function
> > completely?
>
>
> Sure, that's probably better.  Maybe "blkdev_is_online"?  I'll see if
> I can do it tommorow.

Waiting :-)
I am planing to run a Gentoo-based small dist off a 128MB USB flash.

> I'm also a bit dubious of having the wait queue floating around as a
> global, but don't know the kernel well enough to find it a better
> home.

Thumbs up!

Kalin.

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