Acquire the page lock around all remaining calls to vm_page_free() on

managed pages that didn't already have that lock held.  (Freeing an
unmanaged page, such as the various pmaps use, doesn't require the page
lock.)

This allows a change in vm_page_remove()'s locking requirements.  It now
expects the page lock to be held instead of the page queues lock.
Consequently, the page queues lock is no longer required at all by callers
to vm_page_rename().

Discussed with: kib

1 files changed, 8 insertions, 4 deletions

diff --git a/sys/vm/vm_page.c b/sys/vm/vm_page.c
index a77dc13..cc34c1b 100644
--- a/sys/vm/vm_page.c
+++ b/sys/vm/vm_page.c
@@ -791,7 +791,7 @@ vm_page_remove(vm_page_t m)
 	vm_page_t root;
 
 	if ((m->flags & PG_UNMANAGED) == 0)
-		mtx_assert(&vm_page_queue_mtx, MA_OWNED);
+		vm_page_lock_assert(m, MA_OWNED);
 	if ((object = m->object) == NULL)
 		return;
 	VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
@@ -2234,11 +2234,11 @@ vm_page_cowfault(vm_page_t m)
 
  retry_alloc:
 	pmap_remove_all(m);
+	vm_page_unlock_queues();
 	vm_page_remove(m);
 	mnew = vm_page_alloc(object, pindex, VM_ALLOC_NORMAL | VM_ALLOC_NOBUSY);
 	if (mnew == NULL) {
 		vm_page_insert(m, object, pindex);
-		vm_page_unlock_queues();
 		vm_page_unlock(m);
 		VM_OBJECT_UNLOCK(object);
 		VM_WAIT;
@@ -2261,7 +2261,12 @@ vm_page_cowfault(vm_page_t m)
 		 * waiting to allocate a page.  If so, put things back 
 		 * the way they were 
 		 */
+		vm_page_unlock(m);
+		vm_page_lock(mnew);
+		vm_page_lock_queues();
 		vm_page_free(mnew);
+		vm_page_unlock_queues();
+		vm_page_unlock(mnew);
 		vm_page_insert(m, object, pindex);
 	} else { /* clear COW & copy page */
 		if (!so_zerocp_fullpage)
@@ -2270,9 +2275,8 @@ vm_page_cowfault(vm_page_t m)
 		vm_page_dirty(mnew);
 		mnew->wire_count = m->wire_count - m->cow;
 		m->wire_count = m->cow;
+		vm_page_unlock(m);
 	}
-	vm_page_unlock_queues();
-	vm_page_unlock(m);
 }
 
 void