LinuxHelper.sched_getcpu() uses wrong syscall number: 318 (getrandom) instead of 309 (getcpu) on x86_64

[rupeshkoushik07]

In LinuxHelper.sched_getcpu(), the fallback path calls lib.syscall(318, cpu, node, null) intending to invoke getcpu. However, on x86_64 Linux:

__NR_getcpu = 309
__NR_getrandom = 318
So the code is actually invoking getrandom(2) with incorrect arguments rather than getcpu(2).

Location: net.openhft.affinity.impl.LinuxHelper, method sched_getcpu(), in the UnsatisfiedLinkError catch block.

[rupeshkoushik07]

@tgd @peter-lawrey could you please take a look at this issue when you get a chance?