Reorder struct sysentvec

[trasz]

Summary

Reorder struct sysentvec so that commonly accessed fields are close
together.

[kib]

What is the point ? Is this based on any measurements ? I see it as an arbitrary tweaking that does not serve any obvious purpose.

[trasz]

The point is to avoid unnecessary cache misses. No measurements yet; syscall overhead is still to big to make stuff like that noticeable. I'm not in a hurry with this patch though, so let's wait until I can show that it makes a difference (or show that it doesn't).