Remove mpte optimization from pmap_enter_quick().

There is a race with the current locking scheme and removing
it should have no measurable performance impact.
This fixes page faults leading to panics in pmap_enter_quick_locked()
on amd64/i386.

Reviewed by: alc,jhb,peter,ps

2 files changed, 4 insertions, 6 deletions

diff --git a/sys/vm/pmap.h b/sys/vm/pmap.h
index 937fc71..57d62aa 100644
--- a/sys/vm/pmap.h
+++ b/sys/vm/pmap.h
@@ -97,8 +97,8 @@ void		 pmap_copy(pmap_t, pmap_t, vm_offset_t, vm_size_t, vm_offset_t);
 void		 pmap_copy_page(vm_page_t, vm_page_t);
 void		 pmap_enter(pmap_t, vm_offset_t, vm_page_t, vm_prot_t,
 		    boolean_t);
-vm_page_t	 pmap_enter_quick(pmap_t pmap, vm_offset_t va, vm_page_t m,
-		    vm_prot_t prot, vm_page_t mpte);
+void	 pmap_enter_quick(pmap_t pmap, vm_offset_t va, vm_page_t m,
+		    vm_prot_t prot);
 void		 pmap_enter_object(pmap_t pmap, vm_offset_t start,
 		    vm_offset_t end, vm_page_t m_start, vm_prot_t prot);
 vm_paddr_t	 pmap_extract(pmap_t pmap, vm_offset_t va);
diff --git a/sys/vm/vm_fault.c b/sys/vm/vm_fault.c
index 2484af1..9387575 100644
--- a/sys/vm/vm_fault.c
+++ b/sys/vm/vm_fault.c
@@ -953,7 +953,7 @@ vm_fault_prefault(pmap_t pmap, vm_offset_t addra, vm_map_entry_t entry)
 	int i;
 	vm_offset_t addr, starta;
 	vm_pindex_t pindex;
-	vm_page_t m, mpte;
+	vm_page_t m;
 	vm_object_t object;
 
 	if (pmap != vmspace_pmap(curthread->td_proc->p_vmspace))
@@ -968,7 +968,6 @@ vm_fault_prefault(pmap_t pmap, vm_offset_t addra, vm_map_entry_t entry)
 		starta = 0;
 	}
 
-	mpte = NULL;
 	for (i = 0; i < PAGEORDER_SIZE; i++) {
 		vm_object_t backing_object, lobject;
 
@@ -1009,8 +1008,7 @@ vm_fault_prefault(pmap_t pmap, vm_offset_t addra, vm_map_entry_t entry)
 			vm_page_lock_queues();
 			if (VM_PAGE_INQUEUE1(m, PQ_CACHE))
 				vm_page_deactivate(m);
-			mpte = pmap_enter_quick(pmap, addr, m,
-			    entry->protection, mpte);
+			pmap_enter_quick(pmap, addr, m, entry->protection);
 			vm_page_unlock_queues();
 		}
 		VM_OBJECT_UNLOCK(lobject);