X86_64 : 8 CPU limitation on Vanilla release

[Brice GIBOUDEAU]

Hello,

I'm reaching out to you about a limitation on the X86_64 target.

We use this version to operate large scale Wireguard VPNs on VMs and physical servers (DELL & HP). The actual limitation of 8 CPU is the only reason why we have to recompile OpenWRT. This 8 CPU limitation makes perfect sense for most targets to save flash/memory  space but x86_64 have less physical limitations and most CPUs have more than 8 cores/threads.

Is it an option to raise this limitation to 64 to fit most available CPU on the market ?
I'm not very use to patch submission but if it's needed I can try to do it.

What I can see the cost is an overhead 8KB memory and kernel size per extra CPU so (64-8)x8=448KB addition. X86_64 have less limitations than other architecture and enabling more CPUs should be ok for this platform.

The change needed is below:
---------------------------------------

diff -a target/linux/x86/64/config-5.4.orig target/linux/x86/64/config-5.4
313c313
< CONFIG_NR_CPUS=8
---
> CONFIG_NR_CPUS=64

Regards,
MiNuS_89​