On 29/08/18 07:33, Steven Haigh wrote: > When playing with NUMA support recently, I noticed a host would always hang > when trying to create a cpupool for the second NUMA node in the system. > > I was using the following commands: > # xl cpupool-create name=\"Pool-1\" sched=\"credit2\ > # xl cpupool-cpu-remove Pool-0 node:1 > # xl cpupool-cpu-add Pool-1 node:1 > > After the last command, the system would hang - requiring a hard reset of the > machine to fix. > > I tried a different variation with the same result: > # xl cpupool-create name=\"Pool-1\" sched=\"credit2\ > # xl cpupool-cpu-remove Pool-0 node:1 > # xl cpupool-cpu-add Pool-1 12 > > It turns out that the RAM was installed sub-optimally in this machine. A > partial output from 'xl info -n' shows: > numa_info : > node: memsize memfree distances > 0: 67584 62608 10,21 > 1: 0 0 21,10 > > A machine where we could get this working every time shows: > node: memsize memfree distances > 0: 34816 30483 10,21 > 1: 32768 32125 21,10 > > As we can deduce RAM misconfigurations in this scenario, I believe we should > check to ensure that RAM configuration / layout is sane *before* attempting > to > split the system and print a warning. > > This would prevent a hard system freeze in this scenario.
RAM placement should not matter here. As the name already suggests cpupools do assignment of cpus. RAM allocated will be preferred taken from a local node, but this shouldn't be mandatory for success. Would it be possible to use a debug hypervisor (e.g. 4.12-unstable) for generating a verbose log (hypervisor boot parameter "loglvl=all") and sending the complete hypervisor log? Juergen _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
