2013-07-03 21:21:17

by Raymond Jennings

Subject: [problem?] swapon: swap partition/volume size capped at 32G?

Ok, so I just upgraded to 3.10.0 (gentoo system) and made a nice big
64GiB swap volume on lvm as usual.

Suddenly, swapon doesn't recognize more than 32GiB, as top lists only
that much swap space.

swapon using *two* separate 32GiB partitions works fine, but for some
reason a swap partition bigger than 32GiB isn't fully recognized.

Previous kernel versions IIRC recognized the entire swap partition.

Is something wrong or is this new behavior standard?

2013-07-04 18:15:23

by Raymond Jennings

Subject: Re: [problem?] swapon: swap partition/volume size capped at 32G?

On Wed, 2013-07-03 at 14:21 -0700, Raymond Jennings wrote:
> Ok, so I just upgraded to 3.10.0 (gentoo system) and made a nice big
> 64GiB swap volume on lvm as usual.
>
> Suddenly, swapon doesn't recognize more than 32GiB, as top lists only
> that much swap space.
>
> swapon using *two* separate 32GiB partitions works fine, but for some
> reason a swap partition bigger than 32GiB isn't fully recognized.
>
> Previous kernel versions IIRC recognized the entire swap partition.
>
> Is something wrong or is this new behavior standard?
>
Hold on a minute, I just found out something ate my kernel config and
turned off PAE when I upgraded.

This in turn shrunk my pte's from 64 bits to 32 bits and is probably
what killed >32G swap extents.