Re: Ping: [PATCH] Qemu: migration: Not bind RAM info with active migration status

Hi Daniel, Thanks for your reply :-) Please see my words below. On 2021/1/4 19:58, Daniel P. Berrangé wrote: > On Fri, Dec 18, 2020 at 04:38:22PM +0800, Keqian Zhu wrote: >> Hi Daniel and Jiri, >> >> On 2020/12/8 18:31, Jiri Denemark wrote: >>> On Tue, Dec 08, 2020 at 09:27:39 +0000, Daniel P. Berrangé wrote: >>>> On Tue, Dec 08, 2020 at 10:06:25AM +0800, zhukeqian wrote: >>>>> >>>>> On 2020/12/7 18:38, Daniel P. Berrangé wrote: >>>>>> On Mon, Dec 07, 2020 at 09:55:53AM +0800, zhukeqian wrote: >>>>>>> Hi Daniel, >> [...] >> >>>>> >>>>> Hi Daniel, >>>>> >>>>> The purpose is to remove this failure check for QEMU v2.12. >>>>> In QEMU commit 65ace0604551, it decoupled the RAM status from the active migration status. >>>>> >>>>> The usage scenario is querying migration status at destination side, which may contain >>>>> active migration status, but without RAM status, so we will see that libvirt report error here. >>>> >>>> I'm confused, because AFAIK, libvirt does not need to run >>>> query-migrate on the destination, so there shouldn't be anything >>>> that needs fixing. >>> >>> Moreover, you can't even request migration statistics on the destination >>> manually because libvirt blocks that: >>> >>> # virsh domjobinfo nest >>> error: Operation not supported: migration statistics are available only >>> on the source host >>> >>> Jirka >>> >>> . >>> >> Sorry for delay reply. >> >> The purpose of QEMU commit 65ace0604551 (migration: add postcopy total blocktime into query-migrate) >> is to query some postcopy related information on destination side. >> >> We can call query-migrate on destination side *after* migration complete, thanks. > > But nothing in libvirt ever tries to call query-migrate on the dest > side. Yes, but the dest side does not always act as dest. After migration completion, the dest side enters to a normal status and libvirt does not forbid us to query migration status. Before QEMU commit 65ace0604551, we can successfully query the migration status, which is MIGRATION_STATUS_NONE. But this commit will return valid status (MIGRATION_STATUS_COMPLETED) without ram info, causing libvirt reports error (migration was active, but no RAM info was set). > > Do you have more patches that add such calls ? If so, then please send a > patch series that does the full job. I do not add new feature to libvirt, but just manually execute query-migrate on dest side *after migration completion* will trigger this problem.