The hugepages are no longer a hook, but part of the code base. They can be configured via engine property `hugepages`, where the value of property is size of the pages in KiB (1048576 = 1G, 2048 = 2M). Specifying any other size not supported by the architecture (or just "1") will use platform's default hugepage size. On Mon, Sep 18, 2017 at 11:39 AM, Gianluca Cecchi <gianluca.cecchi(a)gmail.com&gt; wrote:

Sorry for late reply, I had not time to give feedback until now On Mon, Sep 18, 2017 at 10:33 PM, Arik Hadas <ahadas(a)redhat.com&gt; wrote: And in fact it seems I have not this in 4.1.5 engine: # engine-config -l | grep -i huge # In case it is ok for upcoming 4.2/master, how am I supposed to use it? I would like to use hugepages at VM level, not engine. Or do you mean that in 4.2 if I set it and specify 2M for the engine parameter named "hugepages", then automatically I will see a custom property inside the VM config section, or where? Any screenshot of this? In the mean time I'm using the "old" style with the hook I found here: http://resources.ovirt.org/pub/ovirt-4.1/rpm/el7/noarch/ vdsm-hook-qemucmdline-4.19.31-1.el7.centos.noarch.rpm and vdsm-hook-hugepages-4.19.31-1.el7.centos.noarch.rpm It works but it seems not to be correctly integrated with what the hosts sees... an example On hypervisor I set 90000 huge pages In 3 VMs I want to configure 34Gb of Huge Pages and total memory of 64Gb, so I set 17408 in their Huge Pages custom property Before starting any VM on hypervisor I see # cat /proc/meminfo |grep -i huge AnonHugePages: 0 kB HugePages_Total: 90000 HugePages_Free: 90000 HugePages_Rsvd: 0 HugePages_Surp: 0 Hugepagesize: 2048 kB When I start the first VM there is the first anomaly: It becomes: # cat /proc/meminfo |grep -i huge AnonHugePages: 0 kB HugePages_Total: 107408 HugePages_Free: 74640 HugePages_Rsvd: 0 HugePages_Surp: 0 Hugepagesize: 2048 kB So apparently it allocates 17408 further huge pages, without using the part of the 90000 it already has free. But I think this is actually a bug in what /proc shows and not real usage (see below) perhaps? Also, it seems it has allocated 64Gb, the entire size of the VM memory and not only the 34Gb part... I don't know if this is correct and in case expected... because eventually I can choose to increase the number of huge pages of the VM.. Inside the VM vm1 itself it seems correct view: [root@vm1 ~]# cat /proc/meminfo |grep -i huge AnonHugePages: 0 kB HugePages_Total: 17408 HugePages_Free: 17408 HugePages_Rsvd: 0 HugePages_Surp: 0 Hugepagesize: 2048 kB Note that if I run again on host: # sysctl -p /etc/sysctl.d/10-huge-pages.conf it seems it adjusts itself.. decreasing the total huge pages that in theory it is not possible...? # cat /proc/meminfo |grep -i huge AnonHugePages: 0 kB HugePages_Total: 90000 HugePages_Free: 57232 HugePages_Rsvd: 0 HugePages_Surp: 0 Hugepagesize: 2048 kB Again it seems it has allocated 32768 huge pages so 64Gb that is the total memory of the VM, I start now the second VM vm2: At hypervisor level I have now: # cat /proc/meminfo |grep -i huge AnonHugePages: 0 kB HugePages_Total: 107408 HugePages_Free: 41872 HugePages_Rsvd: 0 HugePages_Surp: 0 Hugepagesize: 2048 kB So again an increment of 17408 huge pages in the total line and a new allocation of 64Gb of huge pages (total huge pages allocated 32768+32768) BTW now the free output on host shows: # free total used free shared buff/cache available Mem: 264016436 233105820 29194036 190460 1716580 29747272 Swap: 4194300 0 4194300 with "only" 29Gb free and if I try to run the third VM vm3 I get in fact the error message: " Error while executing action: vm3: - Cannot run VM. There is no host that satisfies current scheduling constraints. See below for details: - The host ovirt1 did not satisfy internal filter Memory because its available memory is too low (33948 MB) to run the VM. " Again I run on host: # sysctl -p /etc/sysctl.d/10-huge-pages.conf The memory situation on host becomes: # cat /proc/meminfo |grep -i huge AnonHugePages: 0 kB HugePages_Total: 90000 HugePages_Free: 24464 HugePages_Rsvd: 0 HugePages_Surp: 0 Hugepagesize: 2048 kB # free total used free shared buff/cache available Mem: 264016436 197454740 64844616 190460 1717080 65398696 Swap: 4194300 0 4194300 [root@rhevora1 downloaded_from_upstream]# And I can boot now the third VM vm3, with the memory ouput on host becoming: # cat /proc/meminfo |grep -i huge AnonHugePages: 0 kB HugePages_Total: 107408 HugePages_Free: 9104 HugePages_Rsvd: 0 HugePages_Surp: 0 Hugepagesize: 2048 kB # free total used free shared buff/cache available Mem: 264016436 233484996 28810096 190564 1721344 29365052 Swap: 4194300 0 4194300 If I "adjust" with" # sysctl -p /etc/sysctl.d/10-huge-pages.conf vm.hugetlb_shm_group = 36 vm.nr_hugepages = 90000 I get now: # cat /proc/meminfo |grep -i huge AnonHugePages: 0 kB HugePages_Total: 98304 HugePages_Free: 0 HugePages_Rsvd: 0 HugePages_Surp: 8304 Hugepagesize: 2048 kB # free total used free shared buff/cache available Mem: 264016436 214838508 47453540 190564 1724388 48010936 Swap: 4194300 0 4194300 with a total of 90000 and 8304 pages in line "HugePages_Surp: " for which I don't ever know the exact meaning... Any comment? Thanks, Gianluca