Bug 1308744
| Summary: | [RFE] PAPR Hash Page Table (HPT) resizing (RHV) | |||
|---|---|---|---|---|
| Product: | Red Hat Enterprise Virtualization Manager | Reporter: | Karen Noel <knoel> | |
| Component: | ovirt-engine | Assignee: | Michal Skrivanek <michal.skrivanek> | |
| Status: | CLOSED ERRATA | QA Contact: | Liran Rotenberg <lrotenbe> | |
| Severity: | medium | Docs Contact: | ||
| Priority: | medium | |||
| Version: | 4.0.0 | CC: | bugproxy, dgibson, eedri, gveitmic, hannsj_uhl, libvirt-maint, lsurette, mavital, mdeng, michal.skrivanek, michen, mtessun, qzhang, Rhev-m-bugs, royoung, sbonazzo, srevivo, tburke, virt-bugs, virt-maint, xuhan, xuma | |
| Target Milestone: | ovirt-4.3.0 | Keywords: | FutureFeature, TestOnly, ZStream | |
| Target Release: | --- | Flags: | mavital:
testing_plan_complete+
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| Hardware: | ppc64le | |||
| OS: | Linux | |||
| Whiteboard: | ||||
| Fixed In Version: | Doc Type: | Enhancement | ||
| Doc Text: | Story Points: | --- | ||
| Clone Of: | 1308743 | |||
| : | 1624911 (view as bug list) | Environment: | ||
| Last Closed: | 2019-05-08 12:36:47 UTC | Type: | Bug | |
| Regression: | --- | Mount Type: | --- | |
| Documentation: | --- | CRM: | ||
| Verified Versions: | Category: | --- | ||
| oVirt Team: | Virt | RHEL 7.3 requirements from Atomic Host: | ||
| Cloudforms Team: | --- | Target Upstream Version: | ||
| Embargoed: | ||||
| Bug Depends On: | 1305398, 1308743 | |||
| Bug Blocks: | 1248279, 1284775, 1577865, 1624911 | |||
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Description
Karen Noel
2016-02-15 22:33:13 UTC
*** Bug 1308746 has been marked as a duplicate of this bug. *** The resize-hpt=required machine option in qemu might be useful for RHEV to determine if the guest supports HPT resizing. With that option qemu will refuse to boot a guest which does not support it (exiting with an error during boot). So, RHEV could boot with that option, then if the boot fails adjust the max memory size down and restart with without the option to run the non-HPT-resize aware guest. Obviously RHEV might then want to cache the value, and/or pre-populate it when it knows the distro / version of the guest. Note that the necessary qemu and kvm parts for this are now merged downstream. That least only libvirt work as a prerequisite (which should be relatively simple) to use this in RHV. It should be possible to unblock this. The qemu and libvirt changes are merged and released downstream, and seem to be working well (after some initial bugs were found and fixed). There shouldn't be a lot that's needed on the oVirt / RHV side. Basically qemu and the guest should negotiate HPT resizing automatically, and it will be triggered automatically when memory is hotplugged or unplugged. libvirt should correctly handle locked memory allocation for it. The only real impact for RHV is that for guests which do support HPT resizing, it can (again) freely use a large maximum memory size without that causing allocation of excessively sized HPTs any more. I guess we do not really need to change anything on RHV side. Since the bug was opened we added a notion of max memory (upper hotplug limit) for all platforms and use a conservative default of 4x the configured memory. That helped "enough" with the original problem, for sane VMs we're not allocating 4TB(2TB on ppc) blindly, and user have a way how to change that when they do not plan to use hotplug at all With the HPT resizing implemented we will just see more VMs to fit into the host as the default overhead of counting with 4x as much memory is gone. But that's entirely transparent to the end user, it will just "work better" now. Michal, Great, sounds like we're in agreement. Verified on PPC environment. Reference to verification: https://bugzilla.redhat.com/show_bug.cgi?id=1228543 https://bugzilla.redhat.com/show_bug.cgi?id=515840 We cloned this bug to 4.2.6, I wasn't sure if the status for the 4.3 should stay verified or move back to ON_QA, please update if QE plans to verify it also on 4.3 (In reply to Eyal Edri from comment #12) > We cloned this bug to 4.2.6, I wasn't sure if the status for the 4.3 should > stay verified or move back to ON_QA, please update if QE plans to verify it > also on 4.3 You can keep it on modified as it is a medium and TestOnly Thanks moving back to Modified so QE can test it for 4.3 As comment #9, the tests passed on 4.3 environment. Power9 hosts, RHEL7.6 ovirt-engine-4.3.0-0.6.alpha2.el7.noarch vdsm-4.30.4-1.el7ev.ppc64le Moving to verified. Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://access.redhat.com/errata/RHEA-2019:1085 |