Eliminated many redundant vm_map_lookup operations for vm_mmap.

Speed up for vfs_bio -- addition of a routine bqrelse to greatly diminish
	overhead for merged cache.
Efficiency improvement for vfs_cluster.  It used to do alot of redundant
	calls to cluster_rbuild.
Correct the ordering for vrele of .text and release of credentials.
Use the selective tlb update for 486/586/P6.
Numerous fixes to the size of objects allocated for files.  Additionally,
	fixes in the various pagers.
Fixes for proper positioning of vnode_pager_setsize in msdosfs and ext2fs.
Fixes in the swap pager for exhausted resources.  The pageout code
	will not as readily thrash.
Change the page queue flags (PG_ACTIVE, PG_INACTIVE, PG_FREE, PG_CACHE) into
	page queue indices (PQ_ACTIVE, PQ_INACTIVE, PQ_FREE, PQ_CACHE),
	thereby improving efficiency of several routines.
Eliminate even more unnecessary vm_page_protect operations.
Significantly speed up process forks.
Make vm_object_page_clean more efficient, thereby eliminating the pause
	that happens every 30seconds.
Make sequential clustered writes B_ASYNC instead of B_DELWRI even in the
	case of filesystems mounted async.
Fix a panic with busy pages when write clustering is done for non-VMIO
	buffers.

1 files changed, 38 insertions, 28 deletions

diff --git a/sys/vm/swap_pager.c b/sys/vm/swap_pager.c
index 1fc7f85..25b608d 100644
--- a/sys/vm/swap_pager.c
+++ b/sys/vm/swap_pager.c
@@ -39,7 +39,7 @@
  * from: Utah $Hdr: swap_pager.c 1.4 91/04/30$
  *
  *	@(#)swap_pager.c	8.9 (Berkeley) 3/21/94
- * $Id: swap_pager.c,v 1.57 1995/12/14 09:54:52 phk Exp $
+ * $Id: swap_pager.c,v 1.58 1995/12/17 07:19:55 bde Exp $
  */
 
 /*
@@ -302,13 +302,13 @@ swap_pager_alloc(handle, size, prot, offset)
 			 * rip support of "named anonymous regions" out altogether.
 			 */
 			object = vm_object_allocate(OBJT_SWAP,
-				OFF_TO_IDX(offset+ PAGE_SIZE - 1 + size));
+				OFF_TO_IDX(offset + PAGE_SIZE - 1) + size);
 			object->handle = handle;
 			(void) swap_pager_swp_alloc(object, M_WAITOK);
 		}
 	} else {
 		object = vm_object_allocate(OBJT_SWAP,
-			OFF_TO_IDX(offset + PAGE_SIZE - 1 + size));
+			OFF_TO_IDX(offset + PAGE_SIZE - 1) + size);
 		(void) swap_pager_swp_alloc(object, M_WAITOK);
 	}
 
@@ -1266,6 +1266,7 @@ swap_pager_putpages(object, m, count, sync, rtvals)
 		swap_pager_free.tqh_first->spc_list.tqe_next->spc_list.tqe_next == NULL) {
 		s = splbio();
 		if (curproc == pageproc) {
+retryfree:
 			/*
 			 * pageout daemon needs a swap control block
 			 */
@@ -1273,33 +1274,42 @@ swap_pager_putpages(object, m, count, sync, rtvals)
 			/*
 			 * if it does not get one within a short time, then
 			 * there is a potential deadlock, so we go-on trying
-			 * to free pages.
+			 * to free pages.  It is important to block here as opposed
+			 * to returning, thereby allowing the pageout daemon to continue.
+			 * It is likely that pageout daemon will start suboptimally
+			 * reclaiming vnode backed pages if we don't block.  Since the
+			 * I/O subsystem is probably already fully utilized, might as
+			 * well wait.
 			 */
-			tsleep(&swap_pager_free, PVM, "swpfre", hz/10);
-			swap_pager_sync();
-			if (swap_pager_free.tqh_first == NULL ||
-				swap_pager_free.tqh_first->spc_list.tqe_next == NULL ||
-				swap_pager_free.tqh_first->spc_list.tqe_next->spc_list.tqe_next == NULL) {
-				splx(s);
-				return VM_PAGER_AGAIN;
+			if (tsleep(&swap_pager_free, PVM, "swpfre", hz/5)) {
+				swap_pager_sync();
+				if (swap_pager_free.tqh_first == NULL ||
+					swap_pager_free.tqh_first->spc_list.tqe_next == NULL ||
+					swap_pager_free.tqh_first->spc_list.tqe_next->spc_list.tqe_next == NULL) {
+					splx(s);
+					return VM_PAGER_AGAIN;
+				}
+			} else {
+			/*
+			 * we make sure that pageouts aren't taking up all of
+			 * the free swap control blocks.
+			 */
+				swap_pager_sync();
+				if (swap_pager_free.tqh_first == NULL ||
+					swap_pager_free.tqh_first->spc_list.tqe_next == NULL ||
+					swap_pager_free.tqh_first->spc_list.tqe_next->spc_list.tqe_next == NULL) {
+					goto retryfree;
+				}
 			}
-		} else
+		} else {
 			pagedaemon_wakeup();
-		while (swap_pager_free.tqh_first == NULL ||
-			swap_pager_free.tqh_first->spc_list.tqe_next == NULL ||
-			swap_pager_free.tqh_first->spc_list.tqe_next->spc_list.tqe_next == NULL) {
-			if (curproc == pageproc) {
-			    swap_pager_needflags |= SWAP_FREE_NEEDED_BY_PAGEOUT;
-			    if((cnt.v_free_count + cnt.v_cache_count) > cnt.v_free_reserved)
-					wakeup(&cnt.v_free_count);
-			}
-
-			swap_pager_needflags |= SWAP_FREE_NEEDED;
-			tsleep(&swap_pager_free, PVM, "swpfre", 0);
-			if (curproc == pageproc)
-				swap_pager_sync();
-			else
+			while (swap_pager_free.tqh_first == NULL ||
+				swap_pager_free.tqh_first->spc_list.tqe_next == NULL ||
+				swap_pager_free.tqh_first->spc_list.tqe_next->spc_list.tqe_next == NULL) {
+				swap_pager_needflags |= SWAP_FREE_NEEDED;
+				tsleep(&swap_pager_free, PVM, "swpfre", 0);
 				pagedaemon_wakeup();
+			}
 		}
 		splx(s);
 	}
@@ -1436,7 +1446,7 @@ swap_pager_putpages(object, m, count, sync, rtvals)
 				 * optimization, if a page has been read
 				 * during the pageout process, we activate it.
 				 */
-				if ((m[i]->flags & PG_ACTIVE) == 0 &&
+				if ((m[i]->queue != PQ_ACTIVE) &&
 				    ((m[i]->flags & (PG_WANTED|PG_REFERENCED)) ||
 				    pmap_is_referenced(VM_PAGE_TO_PHYS(m[i])))) {
 					vm_page_activate(m[i]);
@@ -1542,7 +1552,7 @@ swap_pager_finish(spc)
 		for (i = 0; i < spc->spc_count; i++) {
 			pmap_clear_modify(VM_PAGE_TO_PHYS(spc->spc_m[i]));
 			spc->spc_m[i]->dirty = 0;
-			if ((spc->spc_m[i]->flags & PG_ACTIVE) == 0 &&
+			if ((spc->spc_m[i]->queue != PQ_ACTIVE) &&
 			    ((spc->spc_m[i]->flags & PG_WANTED) || pmap_is_referenced(VM_PAGE_TO_PHYS(spc->spc_m[i]))))
 				vm_page_activate(spc->spc_m[i]);
 		}