[ovirt-users] Re: numa pinning and reserved hugepages (1G) Bug in scheduler calculation or decision ?

Hi, this is a bug in the scheduler. Currently, it ignores hugepages when evaluating NUMA pinning. There is a bugzilla ticket[1] that was originally reported as a similar case, but then later the reporter changed it. Could you open a new bugzilla ticket and attach the details from this email? As a workaround, if you don't want to migrate the VM or you are sure that it can run on the target host, you can clone a cluster policy and remove the 'NUMA' filter. (In Administration -> Configure -> Scheduling Policies). [1] - https://bugzilla.redhat.com/show_bug.cgi?id=1720558 Best regards, Andrej On Wed, 21 Aug 2019 at 12:16, Ralf Schenk <rs(a)databay.de <mailto:rs@databay.de>> wrote: Hello List, i ran into problems using numa-pinning and reserved hugepages. - My EPYC 7281 based Servers (Dual Socket) have 8 Numa-Nodes each having 32 GB of memory for a total of 256 GB System Memory - I'm using 192 x 1 GB hugepages reserved on the kernel cmdline default_hugepagesz=1G hugepagesz=1G hugepages=192 This reserves 24 hugepages on each numa-node. I wanted to pin a MariaDB VM using 32 GB (Custom Property hugepages=1048576) to numa-nodes 0-3 of CPU-Socket 1. Pinning in GUI etc. no problem. When trying to start the vm this can't be done since ovirt claims that the host can't fullfill the memory requirements - which is simply not correct since there were > 164 hugepages free. It should have taken 8 hugepages from each numa node 0-3 to fullfill the 32 GB Memory requirement. I also freed the system completely from other VM's but that didn't work either. Is it possible that the scheduler only takes into account the "free memory" (as seen in numactl -H below) *not reserved* by hugepages for its decisions ? Since the host has only < 8 GB of free mem per numa-node I can understand that VM was not able to start under that condition. VM is runnig and using 32 hugepages without pinning but a warning states "VM dbserver01b does not fit to a single NUMA node on host myhost.mydomain.de <http://myhost.mydomain.de>;. This may negatively impact its performance. Consider using vNUMA and NUMA pinning for this VM." This is the numa Hardware Layout and hugepages usage now with other VM's running: from cat /proc/meminfo HugePages_Total:     192 HugePages_Free:      160 HugePages_Rsvd:        0 HugePages_Surp:        0 I can confirm that also under the condition of running other VM's there are at least 8 hugepages free for each numa-node 0-3: grep "" /sys/devices/system/node/*/hugepages/hugepages-1048576kB/free_hugepages /sys/devices/system/node/node0/hugepages/hugepages-1048576kB/free_hugepages:8 /sys/devices/system/node/node1/hugepages/hugepages-1048576kB/free_hugepages:23 /sys/devices/system/node/node2/hugepages/hugepages-1048576kB/free_hugepages:20 /sys/devices/system/node/node3/hugepages/hugepages-1048576kB/free_hugepages:22 /sys/devices/system/node/node4/hugepages/hugepages-1048576kB/free_hugepages:16 /sys/devices/system/node/node5/hugepages/hugepages-1048576kB/free_hugepages:5 /sys/devices/system/node/node6/hugepages/hugepages-1048576kB/free_hugepages:19 /sys/devices/system/node/node7/hugepages/hugepages-1048576kB/free_hugepages:24 numactl -h: available: 8 nodes (0-7) node 0 cpus: 0 1 2 3 32 33 34 35 node 0 size: 32673 MB node 0 free: 3779 MB node 1 cpus: 4 5 6 7 36 37 38 39 node 1 size: 32767 MB node 1 free: 6162 MB node 2 cpus: 8 9 10 11 40 41 42 43 node 2 size: 32767 MB node 2 free: 6698 MB node 3 cpus: 12 13 14 15 44 45 46 47 node 3 size: 32767 MB node 3 free: 1589 MB node 4 cpus: 16 17 18 19 48 49 50 51 node 4 size: 32767 MB node 4 free: 2630 MB node 5 cpus: 20 21 22 23 52 53 54 55 node 5 size: 32767 MB node 5 free: 2487 MB node 6 cpus: 24 25 26 27 56 57 58 59 node 6 size: 32767 MB node 6 free: 3279 MB node 7 cpus: 28 29 30 31 60 61 62 63 node 7 size: 32767 MB node 7 free: 5513 MB node distances: node   0   1   2   3   4   5   6   7   0:  10  16  16  16  32  32  32  32   1:  16  10  16  16  32  32  32  32   2:  16  16  10  16  32  32  32  32   3:  16  16  16  10  32  32  32  32   4:  32  32  32  32  10  16  16  16   5:  32  32  32  32  16  10  16  16   6:  32  32  32  32  16  16  10  16   7:  32  32  32  32  16  16  16  10 -- *Ralf Schenk* fon +49 (0) 24 05 / 40 83 70 fax +49 (0) 24 05 / 40 83 759 mail *rs(a)databay.de* <mailto:rs@databay.de>   *Databay AG* Jens-Otto-Krag-Straße 11 D-52146 Würselen *www.databay.de* <http://www.databay.de> Sitz/Amtsgericht Aachen • HRB:8437 • USt-IdNr.: DE 210844202 Vorstand: Ralf Schenk, Dipl.-Ing. Jens Conze, Aresch Yavari, Dipl.-Kfm. Philipp Hermanns Aufsichtsratsvorsitzender: Wilhelm Dohmen ------------------------------------------------------------------------ _______________________________________________ Users mailing list -- users(a)ovirt.org <mailto:users@ovirt.org> To unsubscribe send an email to users-leave(a)ovirt.org <mailto:users-leave@ovirt.org> Privacy Statement: https://www.ovirt.org/site/privacy-policy/ oVirt Code of Conduct: https://www.ovirt.org/community/about/community-guidelines/ List Archives: https://lists.ovirt.org/archives/list/users@ovirt.org/message/GXIWD6B6E3U...