syscall is to query the CPU number and the NUMA domain the calling
thread is currently running on. The third argument is ignored.
It doesn't do anything regarding scheduling - it's literally
just a way to query the current state, without any guarantees
you won't get rescheduled an opcode later.
This unbreaks Java from CentOS 8
(java-11-openjdk-11.0.5.10-0.el8_0.x86_64).
Reviewed by: kib
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D22972
cc50333011