On Saturday, June 6, 2020 3:55:42 PM MST Chris Murphy wrote: > On Sat, Jun 6, 2020 at 10:00 AM Richard W.M. Jones <rjones@xxxxxxxxxx> > wrote: > > > > > > But let's say we also add a lower priority disk swap, then my next > > question ... > > > > > > > > > > Also does the swap partition on disk contain compressed pages, or > > > > uncompressed pages, or a mix of both? > > > > > > > > > > > > With zram there is no partition on disk, or was this question about > > > something else? > > > > > > > > ... means: Does this secondary swap partition (on disk) contain > > swapped out zram pages? Or uncompressed pages? (Or maybe the > > question just makes no sense, I don't really know.) > > > (ZRAM) > Compression is intrinsic to just the /dev/zram device. The swap code > doesn't share pages between swap devices. The higher priority device > is favored first until full. Once full, pages don't go through the > zram module, thus are not compressed, on their way to the > swap-on-disk. > > (ZSWAP) > So yeah, the swap-on-disk scenario might be better suited to a > generator that could use zswap instead, which uses an existing swap > partition and adds a write back cache (zpool) rather than a separate > device. I'm pretty sure (not 100%) that cached page are decompressed > on their way to the swap device. Also, the zpool memory cache is > preallocated, unlike zram devices. > > (I am not going to envy any who decide to implement zswap on a system > with ZFS. Wait wait wait, which zpool are you talking about?!) Which zswap are you talking about? Swap on compressed zvol has been called zswap at times. ;) - - John M. Harris, Jr. _______________________________________________ devel mailing list -- devel@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe send an email to devel-leave@xxxxxxxxxxxxxxxxxxxxxxx Fedora Code of Conduct: https://docs.fedoraproject.org/en-US/project/code-of-conduct/ List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/devel@xxxxxxxxxxxxxxxxxxxxxxx
