Reduce the scope of the page queues lock and the number of

PG_REFERENCED changes in vm_pageout_object_deactivate_pages().
Simplify this function's inner loop using TAILQ_FOREACH(), and shorten
some of its overly long lines.  Update a stale comment.

Assert that PG_REFERENCED may be cleared only if the object containing
the page is locked.  Add a comment documenting this.

Assert that a caller to vm_page_requeue() holds the page queues lock,
and assert that the page is on a page queue.

Push down the page queues lock into pmap_ts_referenced() and
pmap_page_exists_quick().  (As of now, there are no longer any pmap
functions that expect to be called with the page queues lock held.)

Neither pmap_ts_referenced() nor pmap_page_exists_quick() should ever
be passed an unmanaged page.  Assert this rather than returning "0"
and "FALSE" respectively.

ARM:

Simplify pmap_page_exists_quick() by switching to TAILQ_FOREACH().

Push down the page queues lock inside of pmap_clearbit(), simplifying
pmap_clear_modify(), pmap_clear_reference(), and pmap_remove_write().
Additionally, this allows for avoiding the acquisition of the page
queues lock in some cases.

PowerPC/AIM:

moea*_page_exits_quick() and moea*_page_wired_mappings() will never be
called before pmap initialization is complete.  Therefore, the check
for moea_initialized can be eliminated.

Push down the page queues lock inside of moea*_clear_bit(),
simplifying moea*_clear_modify() and moea*_clear_reference().

The last parameter to moea*_clear_bit() is never used.  Eliminate it.

PowerPC/BookE:

Simplify mmu_booke_page_exists_quick()'s control flow.

Reviewed by:	kib@

1 files changed, 15 insertions, 9 deletions

diff --git a/sys/sparc64/sparc64/pmap.c b/sys/sparc64/sparc64/pmap.c
index 7769bdc..736602c 100644
--- a/sys/sparc64/sparc64/pmap.c
+++ b/sys/sparc64/sparc64/pmap.c
@@ -1789,20 +1789,25 @@ pmap_page_exists_quick(pmap_t pm, vm_page_t m)
 {
 	struct tte *tp;
 	int loops;
+	boolean_t rv;
 
-	mtx_assert(&vm_page_queue_mtx, MA_OWNED);
-	if ((m->flags & (PG_FICTITIOUS | PG_UNMANAGED)) != 0)
-		return (FALSE);
+	KASSERT((m->flags & (PG_FICTITIOUS | PG_UNMANAGED)) == 0,
+	    ("pmap_page_exists_quick: page %p is not managed", m));
 	loops = 0;
+	rv = FALSE;
+	vm_page_lock_queues();
 	TAILQ_FOREACH(tp, &m->md.tte_list, tte_link) {
 		if ((tp->tte_data & TD_PV) == 0)
 			continue;
-		if (TTE_GET_PMAP(tp) == pm)
-			return (TRUE);
+		if (TTE_GET_PMAP(tp) == pm) {
+			rv = TRUE;
+			break;
+		}
 		if (++loops >= 16)
 			break;
 	}
-	return (FALSE);
+	vm_page_unlock_queues();
+	return (rv);
 }
 
 /*
@@ -1878,10 +1883,10 @@ pmap_ts_referenced(vm_page_t m)
 	u_long data;
 	int count;
 
-	mtx_assert(&vm_page_queue_mtx, MA_OWNED);
-	if ((m->flags & (PG_FICTITIOUS | PG_UNMANAGED)) != 0)
-		return (0);
+	KASSERT((m->flags & (PG_FICTITIOUS | PG_UNMANAGED)) == 0,
+	    ("pmap_ts_referenced: page %p is not managed", m));
 	count = 0;
+	vm_page_lock_queues();
 	if ((tp = TAILQ_FIRST(&m->md.tte_list)) != NULL) {
 		tpf = tp;
 		do {
@@ -1895,6 +1900,7 @@ pmap_ts_referenced(vm_page_t m)
 				break;
 		} while ((tp = tpn) != NULL && tp != tpf);
 	}
+	vm_page_unlock_queues();
 	return (count);
 }