[LTP] [PATCH 3/3] lib: unlimit the tmpfs size when test on small systems

[Petr Vorel]

Hi Cyril, Li,
> Hi!
> > Since commit c305a53c5 (lib: limit the size of tmpfs in LTP, Jul 9)
> > Ltp set tmpfs mount size according to the tdev.size. This cause a
> > new problem on small RAM system, which consume too much memory and
> > finally trigger OOM.

> > To fix this, let's cancel the tmpfs size limitation when MemAvailable
> > is less than twofold of tdev.size.

...
> > +	if ((tst_available_mem() / 1024) < (tdev.size * 2))
> > +		return mnt_data;

> I'm starting to think that we should do it the other way around, i.e.

> - unless the test defines .min_dev_size we should set the size for tmpfs to be really small 16MB or 32MB
> - if .min_dev_size is defined and there is not enough free memory -> TCONF
> - if .min_dev_size is not set and there is not even 64MB of free memory (for 32MB limit) -> TCONF

> I think that this is going to work because most of the tests does not
> actually consume more than a megabyte or so of the disk space for the
> actuall test, the only reason why we kept bumping the loop device size
> is that there are limits on minimal size imposed by filesystems.

Also LGTM, thanks Li for working on v2.

Kind regards,
Petr