#ubuntu-s390x 2017-08-30
<hws> cpaelzer: Test
<cpaelzer> hws: exactly
<cpaelzer> and after a long discussion like
<cpaelzer> 1
<cpaelzer> 2
<cpaelzer> 3
<cpaelzer> you could highlight more people to read the above via
<cpaelzer> hws: ^^
<cpaelzer> hws: btw I also created a bug for a kernel contrib by borntraeger around KVM and zero pages
<cpaelzer> hws: you should have a mail to mirror that back
<cpaelzer> are you the right one to do so?
<cpaelzer> (the mirroring)
<hws> cpaelzer: already done
<cpaelzer> great
<cpaelzer> while we are here - good morning borntraeger
<hws> cpaelzer: already an answer available :)
<cpaelzer> borntraeger: the alignment patch on qemu missed 2.10 as many others did this release
<cpaelzer> borntraeger: did you hear anything on an earlier than usual 2.10.1 and if so any date rumors?
<borntraeger> cpaelzer, only wishes, but no facts
<cpaelzer> hws: the update didn't flow down to me through the tool yet
<cpaelzer> borntraeger: ok, that is my state - thanks
<hws> cpaelzer: just to shortcut..... FWIW, this fix is only necessary if you have guest that use storage keys - e.g. an 16.04 guest should not trigger this problem.
<cpaelzer> hws: do we have any linux guests that use storgae keys in the meantime?
<cpaelzer> I might have lost track
<hws> cpaelzer: question for christian...
<cpaelzer> and as a HV host it is a bit weird, as you can only make "so much" assumption on your guests
<cpaelzer> who says no one uses a Ubuntu Xenial as host in 2020 (still supported then) with a new Guest that suddenly uses stroage keys
<cpaelzer> ...
<cpaelzer> anyway this is just the sort of discussion that I wanted on that bugzilla
<cpaelzer> for a more permanent documentation of the case
<cpaelzer> and since it is mirrored now this will happen
<cpaelzer> I don't mind loosing a few hours for the mirroring
<borntraeger> cpaelzer, hws no current Linux guest uses storage keys
<borntraeger> sles 11 and rhel6 do
<borntraeger> sles12, rhel7 ubuntu 16.04 do not
<cpaelzer> well the old one before we removed it
<cpaelzer> so since there is no intention to add storage keys back in Linux or host non Linux (not intention I'd know of) - the TL;DR is "not needed"?
<borntraeger> cpaelzer, unless you want to support some old debians as guest or so
<cpaelzer> borntraeger: did anybody check if there really is no perf impact?
<cpaelzer> I know that over time all pages will be used
<cpaelzer> but I thought the zero page would still be overloaded
<cpaelzer> or is even the fix
<cpaelzer> only active on storage key using guests
<cpaelzer> borntraeger: and so it is not only "not needed" but even when applied "not actively changing" the zero page handling as long as you have only "new" guests?
<borntraeger> cpaelzer, if a guest has a pattern of only reading a page, it will be a zero page inside the guest
<borntraeger> cpaelzer, the fix is to not use zero pages in the host to back guest pages
