Use the vm_page_wired() predicate where appropriate.

[markj]

Summary

This is a follow-up for D19247. I would like to minimize naked accesses to wire_count
as much as possible, since D20486 makes use of several bits in that field to
store special references.

[alc]

Where is vm_page_wired() defined?

[markj]

In D20485#442354, @alc wrote:

Where is vm_page_wired() defined?

In D19247, I renamed it from vm_page_held().

[alc]

In D20485#442381, @markj wrote:

In D20485#442354, @alc wrote:

Where is vm_page_wired() defined?

In D19247, I renamed it from vm_page_held().

Okay.

[kib]

Could you please update the diff to include the definition if vm_page_wired() ? I expect it to be trivial.

[markj]

Add a vm_page_wired() definition and rebase on FreeBSD head
instead of D19247.

[markj]

In D20485#442437, @kib wrote:

Could you please update the diff to include the definition if vm_page_wired() ? I expect it to be trivial.

I rebased the change so that it does not depend on the hold/wire count merge diff. Once this diff is committed, I will rebase that diff.