Re: [gentoo-user] activating swap by udev event

[SpaceCake]

This is a shame but the idea coming from Windows world. In Win7/Vista there
is a feature called ready boost which I suppose do something similar... or
maybe not :) the main goal is to break the bottleneck of the slow HDD, but
it is maybe a better idea to put some part of the system on a SDHC card
which can reside in my bulting SD slot :) I know, this is also removable :)

L:


2010/7/1 Albert Hopkins <marduk@×××××××××××.org>

> On Thu, 2010-07-01 at 18:06 +0200, Nils Larsson wrote:
> > tor 2010-07-01 klockan 08:49 -0700 skrev Bill Longman:
> > > On 07/01/2010 08:44 AM, SpaceCake wrote:
> > > > So, it solves the first problem, identifiying the device, but how can
> I
> > > > tell to udev to use always /dev/sds (for example) for this device?
> >
> > You need to have the udev rule or the script that it runs look at
> > something specific(the swaplabel for instance).
> >
> > > > I'm thinking how can I instruct udev to turn off swap when the device
> is
> > > > removed, but this is another story :)
> >
> > I tried doing exactly what you're doing now awhile ago and this is where
> > I got stuck, swapoff needs the deivce node(path) to still exist, it
> > can't disable swap without it. I could never get swapoff to run before
> > udev removed the device node, so I ended up with the system thinking(or
> > at least reporting) that it had loads more swap than it actually did.
>
> This is a bad thing to do.  If you have pages swapped out to the device
> and you remove the device before putting those pages elsewhere then you
> have effectively hosed your system.  If it doesn't fail immediately then
> as soon as the kernel tries to swap in those pages and finds out the
> device it's on can't be accessed then you are in for a world of pain.
>
> I guess the deeper question (although entirely rhetorical AFAIC) is why
> would someone want to swap out to a removable device?
>
>
>