Push down page queues lock acquisition in pmap_enter_object() and

pmap_is_referenced().  Eliminate the corresponding page queues lock
acquisitions from vm_map_pmap_enter() and mincore(), respectively.  In
mincore(), this allows some additional cases to complete without ever
acquiring the page queues lock.

Assert that the page is managed in pmap_is_referenced().

On powerpc/aim, push down the page queues lock acquisition from
moea*_is_modified() and moea*_is_referenced() into moea*_query_bit().
Again, this will allow some additional cases to complete without ever
acquiring the page queues lock.

Reorder a few statements in vm_page_dontneed() so that a race can't lead
to an old reference persisting.  This scenario is described in detail by a
comment.

Correct a spelling error in vm_page_dontneed().

Assert that the object is locked in vm_page_clear_dirty(), and restrict the
page queues lock assertion to just those cases in which the page is
currently writeable.

Add object locking to vnode_pager_generic_putpages().  This was the one
and only place where vm_page_clear_dirty() was being called without the
object being locked.

Eliminate an unnecessary vm_page_lock() around vnode_pager_setsize()'s call
to vm_page_clear_dirty().

Change vnode_pager_generic_putpages() to the modern-style of function
definition.  Also, change the name of one of the parameters to follow
virtual memory system naming conventions.

Reviewed by:	kib

1 files changed, 10 insertions, 3 deletions

diff --git a/sys/vm/vm_mmap.c b/sys/vm/vm_mmap.c
index 99d5059..3d72123 100644
--- a/sys/vm/vm_mmap.c
+++ b/sys/vm/vm_mmap.c
@@ -912,11 +912,18 @@ RestartScan:
 					vm_page_dirty(m);
 				if (m->dirty != 0)
 					mincoreinfo |= MINCORE_MODIFIED_OTHER;
-				vm_page_lock_queues();
+				/*
+				 * The first test for PG_REFERENCED is an
+				 * optimization.  The second test is
+				 * required because a concurrent pmap
+				 * operation could clear the last reference
+				 * and set PG_REFERENCED before the call to
+				 * pmap_is_referenced(). 
+				 */
 				if ((m->flags & PG_REFERENCED) != 0 ||
-				    pmap_is_referenced(m))
+				    pmap_is_referenced(m) ||
+				    (m->flags & PG_REFERENCED) != 0)
 					mincoreinfo |= MINCORE_REFERENCED_OTHER;
-				vm_page_unlock_queues();
 			}
 			if (object != NULL)
 				VM_OBJECT_UNLOCK(object);