Bug 1829711

Summary: Remove "migrate-set-cache-size" QMP command
Product: Red Hat Enterprise Linux Advanced Virtualization Reporter: Li Xiaohui <xiaohli>
Component: qemu-kvmAssignee: Amnon Ilan <ailan>
qemu-kvm sub component: Live Migration QA Contact: Li Xiaohui <xiaohli>
Status: CLOSED UPSTREAM Docs Contact:
Severity: low    
Priority: low CC: chayang, ehabkost, fjin, jdenemar, jinzhao, jtomko, juzhang, pkrempa, qzhang, virt-maint, xianwang
Version: 8.2   
Target Milestone: rc   
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
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Last Closed: 2020-07-07 00:33:29 UTC Type: Bug
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Bug Depends On: 1845012    
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Description Li Xiaohui 2020-04-30 07:31:52 UTC 
"migrate-set-cache-size" is deprecated since QEMU 2.11.0 and libvirt will stop using it (see bug 1845012).  We can remove the QMP command once libvirt stops using it.
Comment 5 Eduardo Habkost 2020-06-15 18:10:48 UTC 
(In reply to Li Xiaohui from comment #0)
> Description of problem:
> "migrate-set-cache-size" is deprecated since qemu-4.2 from qemu.org [1] and
> should be replaced by 'migrate-set-parameters'. 
> https://wiki.qemu.org/ChangeLog/4.2#Migration

Now I noticed this BZ is assigned to the qemu-kvm component.  Can you clarify what's the purpose of this BZ?  Where exactly the command still needs to be replaced?
Comment 6 Li Xiaohui 2020-06-16 02:13:47 UTC 
(In reply to Eduardo Habkost from comment #5)
> (In reply to Li Xiaohui from comment #0)
> > Description of problem:
> > "migrate-set-cache-size" is deprecated since qemu-4.2 from qemu.org [1] and
> > should be replaced by 'migrate-set-parameters'. 
> > https://wiki.qemu.org/ChangeLog/4.2#Migration
> 
> Now I noticed this BZ is assigned to the qemu-kvm component.  Can you
> clarify what's the purpose of this BZ?  
Now migrate-set-cache-size command still can be used in qemu-kvm-5.0, but libvirt have removed it from v4.3.0+.
I think we need do corresponding action to remove it from qemu side, so file this bz.

> Where exactly the command still needs to be replaced?
it should be replaced by "migrate_set_parameter xbzrle-cache-size xx"
Comment 7 Jiri Denemark 2020-06-16 07:49:40 UTC 
migrate-set-cache-size (and the corresponding query command) could still be
used by the dedicated libvirt APIs. When the cache size is passed as a
parameter to the migration API, libvirt will use xbzrle-cache-size instead.

However, there are patches on review upstream which replace several deprecated
QMP commands with the corresponding parameters for migrate-set-parameters and
query-migrate-parameters:

    https://www.redhat.com/archives/libvir-list/2020-June/msg00444.html

We also have several BZs that track these changes in libvirt:

    https://bugzilla.redhat.com/show_bug.cgi?id=1829543
    https://bugzilla.redhat.com/show_bug.cgi?id=1829544
    https://bugzilla.redhat.com/show_bug.cgi?id=1829545
    https://bugzilla.redhat.com/show_bug.cgi?id=1845012
Comment 9 Eduardo Habkost 2020-06-17 22:47:08 UTC 
(In reply to Li Xiaohui from comment #6)
> > Now I noticed this BZ is assigned to the qemu-kvm component.  Can you
> > clarify what's the purpose of this BZ?  
> Now migrate-set-cache-size command still can be used in qemu-kvm-5.0, but
> libvirt have removed it from v4.3.0+.
> I think we need do corresponding action to remove it from qemu side, so file
> this bz.

Thanks.  I will update the bug summary and description to indicate that the goal is to remove the QMP command from QEMU, but this is very low priority.