[systemd-devel] [PATCH] swap: introduce Discard property

[Zbigniew Jędrzejewski-Szmek]

On Mon, Sep 29, 2014 at 02:41:28PM +0200, Zbigniew Jędrzejewski-Szmek wrote:
> On Mon, Sep 29, 2014 at 01:23:30PM +0200, Jan Synacek wrote:
> > Jan Synacek <jsynacek at redhat.com> writes:
> > > Zbigniew Jędrzejewski-Szmek <zbyszek at in.waw.pl> writes:
> > >> On Wed, Sep 24, 2014 at 02:29:05PM +0200, Jan Synacek wrote:
> > >>> Process possible "discard" values from /etc/fstab.
> > >> Hm, wouldn't it be enough to simply pass through the options like with
> > >> mounts, using the Options= option? This might be less work and be more
> > >> flexible.
> > >>
> > >> Zbyszek
> > >
> > > Swap options are special in that they're processed and used by the
> > > swapon(8) command. You cannot pass swapon -o <options>, as you can to
> > > ordinary mounts. And how many options for swapon, that at the same time
> > > can be specified in /etc/fstab, do we really care about? I'm not sure.
> > 
> > Ping, could anybody comment, please?
> C'mon, it's been four days, two of that being the weekend.
> 
> But actually, I've been looking at your patch... and the situation is
> "complicated". I now have a patch series which fixes a buglets in swap
> support, but I got stuck on a one which I don't know how to work around.
> Namely, we rely on being able to read back the settings of the swap device,
> but there appears to be no way to do that for discard settings.
I pushed your patch with some significant changes, and some follow-up
cleanups.  Please check that things work for you.

The problem with reading but back discards settings remains.

Zbyszek