Increased dom0 memory requirement when using Mellanox® HCAs on Oracle VM Server

Oracle VM Servers running UEKR4u2 and upward in dom0 require at least 400MB more memory to use the Mellanox® drivers. This memory requirement is a result of the default size of the SRQ count being increased from 64K to 256K in later versions of the kernel and the scale_profile option is now enabled by default in the mlx_core module.

In the case where out-of-memory errors are observed in dom0, the maximum dom0 memory size should be increased. Alternative workarounds might involve manually setting the module parameters for the mlx4_core driver. To set these parameters, edit /etc/modprobe.d/mlx4_core.conf and set scale_profile to 0. Alternately, set log_num_srq to 16. The preferred resolution to this issue is to increase the memory allocated to dom0 on an Oracle VM Server. (Bug ID 23581534)