On 26/07/18 01:07, Boris Ostrovsky wrote: > On 07/25/2018 02:56 PM, Andrew Cooper wrote: >> On 25/07/18 17:29, Juergen Gross wrote: >>> On 25/07/18 18:12, Roger Pau Monné wrote: >>>> On Wed, Jul 25, 2018 at 05:05:35PM +0300, berca...@amazon.com wrote: >>>>> On 07/25/2018 05:02 PM, Wei Liu wrote: >>>>>> On Wed, Jul 25, 2018 at 03:41:11PM +0200, Juergen Gross wrote: >>>>>>> On 25/07/18 15:35, Roger Pau Monné wrote: >>>>>>>>> What could be causing the available memory loss problem? >>>>>>>> That seems to be Linux aggressively ballooning out memory, you go from >>>>>>>> 7129M total memory to 246M. Are you creating a lot of domains? >>>>>>> This might be related to the tools thinking dom0 is a PV domain. >>>>>> Good point. >>>>>> >>>>>> In that case, xenstore-ls -fp would also be useful. The output should >>>>>> show the balloon target for Dom0. >>>>>> >>>>>> You can also try to set the autoballoon to off in /etc/xen/xl.cfg to see >>>>>> if it makes any difference. >>>>>> >>>>>> Wei. >>>>> Also tried setting autoballooning off, but it had no effect. >>>> This is a Linux/libxl issue that I'm not sure what's the best way to >>>> solve. Linux has the following 'workaround' in the balloon driver: >>>> >>>> err = xenbus_scanf(XBT_NIL, "memory", "static-max", "%llu", >>>> &static_max); >>>> if (err != 1) >>>> static_max = new_target; >>>> else >>>> static_max >>= PAGE_SHIFT - 10; >>>> target_diff = xen_pv_domain() ? 0 >>>> : static_max - balloon_stats.target_pages; >>> Hmm, shouldn't PVH behave the same way as PV here? I don't think >>> there is memory missing for PVH, opposed to HVM's firmware memory. >>> >>> Adding Boris for a second opinion. > > (Notwithstanding Andrews' rant below ;-)) > > I am trying to remember --- what memory were we trying not to online for > HVM here?
The problem was to not online memory automatically which was added later via hotplug (especially NVDIMMs). This happened as the reported memory sizes via E820 map and hypervisor differed due to HVM's firmware memory. So the initial target size was larger than the initial memory size reported via E820 map. This led to automatic ballooning up when a NVDIMM was added to the HVM guest. Juergen _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
