Another huge performance improvement for many-cores systems. I removed
the last bottleneck spinlock in the VM system. This spinlock was only
locking the PQ_INACTIVE vm_page_queue for a very short period of time
but with 48 cores it was enough to limit the VM fault rate. With the
Great work!
Nonetheless I feel that the last few changes nerf a quad-core machine
way too much; you are killing 50% of what you gained in the -j48 case
for buildkernel and even worse than in the original case with -j4, which
is the most common case. buildworld -j8 on test29 also loses 50% of the
