Implement idle zeroing of pages. I've been tinkering with this

on and off since John Dyson left his work-in-progress.

It is off by default for now.  sysctl vm.zeroidle_enable=1 to turn it on.

There are some hacks here to deal with the present lack of preemption - we
yield after doing a small number of pages since we wont preempt otherwise.

This is basically Matt's algorithm [with hysteresis] with an idle process
to call it in a similar way it used to be called from the idle loop.

I cleaned up the includes a fair bit here too.

1 files changed, 1 insertions, 0 deletions

diff --git a/sys/vm/vm_page.c b/sys/vm/vm_page.c
index 5ea1f55..61d821f 100644
--- a/sys/vm/vm_page.c
+++ b/sys/vm/vm_page.c
@@ -477,6 +477,7 @@ vm_page_free(vm_page_t m)
 {
 	vm_page_flag_clear(m, PG_ZERO);
 	vm_page_free_toq(m);
+	vm_page_zero_idle_wakeup();
 }
 
 /*