This should be safer than not setting the buffer size when using older libpcap versions that might have a very small default buffer size, and should place too much of a burden on hosts that use a new libpcap (even 1000 guests with CTRL_IP_LEARNING turned on would only use 128MB more memory than they do now).
I just tried setting the buffer size to 256k instead of 128k, and everything works. I posted a patch:
https:/ /www.redhat. com/archives/ libvir- list/2018- April/msg02459. html
This should be safer than not setting the buffer size when using older libpcap versions that might have a very small default buffer size, and should place too much of a burden on hosts that use a new libpcap (even 1000 guests with CTRL_IP_LEARNING turned on would only use 128MB more memory than they do now).
Does this seem reasonable?