svn commit: r287550 - head/sys/vm

[Alan Cox]

Author: alc
Date: Tue Sep  8 04:18:57 2015
New Revision: 287550
URL: https://svnweb.freebsd.org/changeset/base/287550

Log:
  To simplify upcoming changes to the inactive queue scan, change the code
  so that there is only one place where pages are freed and only one place
  where pages are moved to the tail of the queue.
  
  Reviewed by:	kib
  Sponsored by:	EMC / Isilon Storage Division

Modified:
  head/sys/vm/vm_pageout.c

Modified: head/sys/vm/vm_pageout.c
==============================================================================
--- head/sys/vm/vm_pageout.c	Tue Sep  8 02:02:08 2015	(r287549)
+++ head/sys/vm/vm_pageout.c	Tue Sep  8 04:18:57 2015	(r287550)
@@ -1178,12 +1178,8 @@ unlock_page:
 		 * Invalid pages can be easily freed. They cannot be
 		 * mapped, vm_page_free() asserts this.
 		 */
-		if (m->valid == 0) {
-			vm_page_free(m);
-			PCPU_INC(cnt.v_dfree);
-			--page_shortage;
-			goto drop_page;
-		}
+		if (m->valid == 0)
+			goto free_page;
 
 		/*
 		 * If the page has been referenced and the object is not dead,
@@ -1214,12 +1210,8 @@ unlock_page:
  				 */
 				m->act_count += act_delta + ACT_ADVANCE;
 				goto drop_page;
-			} else if ((object->flags & OBJ_DEAD) == 0) {
-				vm_pagequeue_lock(pq);
-				queues_locked = TRUE;
-				vm_page_requeue_locked(m);
-				goto drop_page;
-			}
+			} else if ((object->flags & OBJ_DEAD) == 0)
+				goto requeue_page;
 		}
 
 		/*
@@ -1240,6 +1232,7 @@ unlock_page:
 			/*
 			 * Clean pages can be freed.
 			 */
+free_page:
 			vm_page_free(m);
 			PCPU_INC(cnt.v_dfree);
 			--page_shortage;
@@ -1266,6 +1259,7 @@ unlock_page:
 			 * the thrash point for a heavily loaded machine.
 			 */
 			m->flags |= PG_WINATCFLS;
+requeue_page:
 			vm_pagequeue_lock(pq);
 			queues_locked = TRUE;
 			vm_page_requeue_locked(m);
@@ -1287,12 +1281,8 @@ unlock_page:
 				pageout_ok = vm_page_count_min();
 			else
 				pageout_ok = TRUE;
-			if (!pageout_ok) {
-				vm_pagequeue_lock(pq);
-				queues_locked = TRUE;
-				vm_page_requeue_locked(m);
-				goto drop_page;
-			}
+			if (!pageout_ok)
+				goto requeue_page;
 			error = vm_pageout_clean(m);
 			/*
 			 * Decrement page_shortage on success to account for