Advance the state of pmap locking on alpha, amd64, and i386.

 - Enable recursion on the page queues lock.  This allows calls to
   vm_page_alloc(VM_ALLOC_NORMAL) and UMA's obj_alloc() with the page
   queues lock held.  Such calls are made to allocate page table pages
   and pv entries.
 - The previous change enables a partial reversion of vm/vm_page.c
   revision 1.216, i.e., the call to vm_page_alloc() by vm_page_cowfault()
   now specifies VM_ALLOC_NORMAL rather than VM_ALLOC_INTERRUPT.
 - Add partial locking to pmap_copy().  (As a side-effect, pmap_copy()
   should now be faster on i386 SMP because it no longer generates IPIs
   for TLB shootdown on the other processors.)
 - Complete the locking of pmap_enter() and pmap_enter_quick().  (As of now,
   all changes to a user-level pmap on alpha, amd64, and i386 are performed
   with appropriate locking.)

1 files changed, 3 insertions, 6 deletions

diff --git a/sys/vm/vm_page.c b/sys/vm/vm_page.c
index 5ecc221..e9adf50 100644
--- a/sys/vm/vm_page.c
+++ b/sys/vm/vm_page.c
@@ -204,7 +204,8 @@ vm_page_startup(vm_offset_t vaddr)
 	/*
 	 * Initialize the locks.
 	 */
-	mtx_init(&vm_page_queue_mtx, "vm page queue mutex", NULL, MTX_DEF);
+	mtx_init(&vm_page_queue_mtx, "vm page queue mutex", NULL, MTX_DEF |
+	    MTX_RECURSE);
 	mtx_init(&vm_page_queue_free_mtx, "vm page queue free mutex", NULL,
 	    MTX_SPIN);
 
@@ -1657,11 +1658,7 @@ vm_page_cowfault(vm_page_t m)
 
  retry_alloc:
 	vm_page_remove(m);
-	/*
-	 * An interrupt allocation is requested because the page
-	 * queues lock is held. 
-	 */
-	mnew = vm_page_alloc(object, pindex, VM_ALLOC_INTERRUPT);
+	mnew = vm_page_alloc(object, pindex, VM_ALLOC_NORMAL);
 	if (mnew == NULL) {
 		vm_page_insert(m, object, pindex);
 		vm_page_unlock_queues();