Add a special page zero entry point intended to be called via the single

threaded VM pagezero kthread outside of Giant.  For some platforms, this
is really easy since it can just use the direct mapped region.  For others,
IPI sending is involved or there are other issues, so grab Giant when
needed.

We still have preemption issues to deal with, but Alan Cox has an
interesting suggestion on how to minimize the problem on x86.

Use Luigi's hack for preserving the (lack of) priority.

Turn the idle zeroing back on since it can now actually do something useful
outside of Giant in many cases.

1 files changed, 16 insertions, 0 deletions

diff --git a/sys/ia64/ia64/pmap.c b/sys/ia64/ia64/pmap.c
index 1ccac9c..7f70184 100644
--- a/sys/ia64/ia64/pmap.c
+++ b/sys/ia64/ia64/pmap.c
@@ -2035,6 +2035,22 @@ pmap_zero_page_area(vm_page_t m, int off, int size)
 	bzero((char *)(caddr_t)va + off, size);
 }
 
+
+/*
+ *	pmap_zero_page_idle zeros the specified hardware page by
+ *	mapping it into virtual memory and using bzero to clear
+ *	its contents.  This is for the vm_idlezero process.
+ */
+
+void
+pmap_zero_page_area(vm_page_t m)
+{
+	vm_offset_t va = IA64_PHYS_TO_RR7(VM_PAGE_TO_PHYS(m));
+	bzero((caddr_t) va, PAGE_SIZE);
+}
+
+
+/*
 /*
  *	pmap_copy_page copies the specified (machine independent)
  *	page by mapping the page into virtual memory and using