On Wed, Jan 05, 2022 at 09:46:05AM +0100, David Hildenbrand wrote: > On 05.01.22 07:08, Juergen Gross wrote: > > On 04.01.22 15:31, David Hildenbrand wrote: > >> On 24.12.21 07:22, Christoph Hellwig wrote: > >>> Hi all, > >>> > >>> since the remove of the Xen tmem driver in 2019, the cleancache hooks are > >>> entirely unused, as are large parts of frontswap. This series against > >>> linux-next (with the folio changes included) removes cleancaches, and cuts > >>> down frontswap to the bits actually used by zswap. > >>> > >> > >> Just out of curiosity, why was tmem removed from Linux (or even Xen?). > >> Do you have any information? > > > > tmem never made it past the "experimental" state in the Xen hypervisor. > > Its implementation had some significant security flaws, there was no > > maintainer left, and nobody stepped up to address those issues. > > > > As a result tmem was removed from Xen. > > Interesting, thanks for sharing. I know tmem mostly from the papers and > thought it was an interesting approach in general. There was even papers > about a virtio implementation, however, actual code never appeared in > the wild :) There is a repo of it .. I can find it if you are interested - but as Juergen mentioned - I didn't have enough steam to finish up the security rework so code removed.