Bug#628718: linux-2.6: Swap on encrypted volume slows system to a crawl (not explicable by encryption overhead)

[Jonathan Nieder <jrnieder@gmail.com>]

Hi,

SirJective wrote:

> I'm using swap space on an LVM volume on a LUKS-encrypted partition.
> Swapping is ridiculously slow (< 1MB/s) whenever I swap to either the encrypted
> swap partition, or some file inside an encrypted partition.
> It is reasonably fast when swapping to a file on an unencrypted partition.
[...]
> The real-world impact is that, for example, when I open a huge image in iceweasel
> with other stuff already open in the background, the system virtually freezes
> up for 15 minutes or more.

Sorry to have left this hanging for so long.  Please test 3.2.4-1 from
sid or newer and if it the bug is still present, report it on
<http://bugzilla.kernel.org>, product IO/Storage, component LVM2/DM,
and let us know the bug number so we can track it.

Be sure to include:

 - steps to reproduce
 - expected result, actual result, and how the difference indicates a bug
 - which kernels you have tested and what happened with each
 - full "dmesg" output from booting and reproducing the problem with an
   affected kernel
 - supporting information
 - what kind of tests you would be able to perform to track this
   (e.g., can you try debugging patches?)
 - a link to this bug log for the full story

Thanks and hope that helps,
Jonathan