vm_object: use iterator in populate()

[dougm]

Summary

Use an iterator instead of tailq pointers in vm_object_populate().

[dougm]

sys/vm/vm_object.c

2156

I can't use VM_RADIX_FOREACH because when page[start] is NULL, the loop should end but VM_RADIX_FORALL would just start with the first page > start.

I can't use VM_RADIX_FORALL because the original code can skip gaps of null pages, and FORALL cannot.

[kib]

sys/vm/vm_object.c

2156

Perhaps add this text to the commit message, if not as a comment into the code.

[dougm]

Use the same iterator for grabbing and for unbusying. Use VM_RADIX_FORALL with an upper bound.

[alc]

sys/vm/vm_object.c

2155