On Wed, Apr 19, 2017 at 09:03:55AM -0600, Jim Fehlig wrote: > I recently received a report of a libvirt+Xen installation reaching the pids > cgroup controller TasksMax limit > > kernel: [71282.213347] cgroup: fork rejected by pids controller in > /system.slice/libvirtd.service > > The default setting of TaskMax is 512 on this system > > # cat /sys/fs/cgroup/pids/system.slice/libvirtd.service/pids.max > 512 > > Depending on domain type and configuration, I've noticed between 5-7 tasks > (IO threads, qemu process, etc.) are created when starting a domain. It > doesn't take too many domains before the 512 limit is reached. > > LimitNOFILE was recently changed by commit 27cd763500 to support 4096 > domains. Following similar logic, would it be ok to increase TasksMax to > 32768? That would accommodate 4096 domains with 8 tasks each. TasksMax also > supports the special value of "infinity", but that seems a bit aggressive to > me. KVM uses 1 thread per vCPU, so 8 pids is probably somewhat on the low side if considering high vcpu counts. I think we could go for something like 128k pids which allows for closer to 32 vcpus per guest Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :| -- libvir-list mailing list libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list
