Back out a few more uvm changes, especially wrt swap usage.

This unbreaks m68k m88k sparc and perhaps others, which eventually froze
when hitting swap.
Tested by various people on various platforms.
ok art@

1 files changed, 37 insertions, 51 deletions

diff --git a/sys/uvm/uvm_pdaemon.c b/sys/uvm/uvm_pdaemon.c
index 42fa8b0809d..6d8d8719d6b 100644
--- a/sys/uvm/uvm_pdaemon.c
+++ b/sys/uvm/uvm_pdaemon.c
@@ -1,5 +1,5 @@
-/*	$OpenBSD: uvm_pdaemon.c,v 1.21 2001/12/19 08:58:07 art Exp $	*/
-/*	$NetBSD: uvm_pdaemon.c,v 1.30 2001/03/09 01:02:12 chs Exp $	*/
+/*	$OpenBSD: uvm_pdaemon.c,v 1.22 2002/01/02 22:23:25 miod Exp $	*/
+/*	$NetBSD: uvm_pdaemon.c,v 1.23 2000/08/20 10:24:14 bjh21 Exp $	*/
 
 /* 
  * Copyright (c) 1997 Charles D. Cranor and Washington University.
@@ -164,12 +164,12 @@ uvmpd_tune()
 {
 	UVMHIST_FUNC("uvmpd_tune"); UVMHIST_CALLED(pdhist);
 
-	uvmexp.freemin = uvmexp.npages / 20;
+	uvmexp.freemin = uvmexp.npages / 30;
 
-	/* between 16k and 256k */
+	/* between 16k and 512k */
 	/* XXX:  what are these values good for? */
 	uvmexp.freemin = max(uvmexp.freemin, (16*1024) >> PAGE_SHIFT);
-	uvmexp.freemin = min(uvmexp.freemin, (256*1024) >> PAGE_SHIFT);
+	uvmexp.freemin = min(uvmexp.freemin, (512*1024) >> PAGE_SHIFT);
 
 	/* Make sure there's always a user page free. */
 	if (uvmexp.freemin < uvmexp.reserve_kernel + 1)
@@ -248,8 +248,16 @@ uvm_pageout(void *arg)
 		 * scan if needed
 		 */
 
+#ifdef UBC
 		if (uvmexp.free + uvmexp.paging < uvmexp.freetarg ||
+		    uvmexp.inactive < uvmexp.inactarg ||
+		    uvm_pgcnt_vnode >
+		    (uvmexp.active + uvmexp.inactive + uvmexp.wired +
+		     uvmexp.free) * 13 / 16) {
+#else
+		if (uvmexp.free < uvmexp.freetarg ||
 		    uvmexp.inactive < uvmexp.inactarg) {
+#endif
 			uvmpd_scan();
 		}
 
@@ -369,7 +377,7 @@ uvmpd_scan_inactive(pglst)
 	struct vm_anon *anon;
 	boolean_t swap_backed;
 	vaddr_t start;
-	int dirtyreacts, t;
+	int dirtyreacts;
 	UVMHIST_FUNC("uvmpd_scan_inactive"); UVMHIST_CALLED(pdhist);
 
 	/*
@@ -438,7 +446,9 @@ uvmpd_scan_inactive(pglst)
 
 			/*
 			 * move referenced pages back to active queue and
-			 * skip to next page.
+			 * skip to next page (unlikely to happen since
+			 * inactive pages shouldn't have any valid mappings
+			 * and we cleared reference before deactivating).
 			 */
 
 			if (pmap_is_referenced(p)) {
@@ -448,35 +458,6 @@ uvmpd_scan_inactive(pglst)
 			}
 
 			/*
-			 * enforce the minimum thresholds on different
-			 * types of memory usage.  if reusing the current
-			 * page would reduce that type of usage below its
-			 * minimum, reactivate the page instead and move
-			 * on to the next page.
-			 */
-
-			t = uvmexp.active + uvmexp.inactive + uvmexp.free;
-			if (p->uanon &&
-			    uvmexp.anonpages <= (t * uvmexp.anonmin) >> 8) {
-				uvm_pageactivate(p);
-				uvmexp.pdreanon++;
-				continue;
-			}
-			if (p->uobject && UVM_OBJ_IS_VTEXT(p->uobject) &&
-			    uvmexp.vtextpages <= (t * uvmexp.vtextmin) >> 8) {
-				uvm_pageactivate(p);
-				uvmexp.pdrevtext++;
-				continue;
-			}
-			if (p->uobject && UVM_OBJ_IS_VNODE(p->uobject) &&
-			    !UVM_OBJ_IS_VTEXT(p->uobject) &&
-			    uvmexp.vnodepages <= (t * uvmexp.vnodemin) >> 8) {
-				uvm_pageactivate(p);
-				uvmexp.pdrevnode++;
-				continue;
-			}
-
-			/*
 			 * first we attempt to lock the object that this page
 			 * belongs to.  if our attempt fails we skip on to
 			 * the next page (no harm done).  it is important to
@@ -537,17 +518,10 @@ uvmpd_scan_inactive(pglst)
 
 			/*
 			 * we now have the object and the page queues locked.
-			 * the page is not busy.  remove all the permissions
-			 * from the page so we can sync the modified info
-			 * without any race conditions.  if the page is clean
-			 * we can free it now and continue.
+			 * the page is not busy.   if the page is clean we
+			 * can free it now and continue.
 			 */
 
-			pmap_page_protect(p, VM_PROT_NONE);
-			if ((p->flags & PG_CLEAN) != 0 && pmap_is_modified(p)) {
-				p->flags &= ~PG_CLEAN;
-			}
-
 			if (p->flags & PG_CLEAN) {
 				if (p->pqflags & PQ_SWAPBACKED) {
 					/* this page now lives only in swap */
@@ -556,6 +530,8 @@ uvmpd_scan_inactive(pglst)
 					simple_unlock(&uvm.swap_data_lock);
 				}
 
+				/* zap all mappings with pmap_page_protect... */
+				pmap_page_protect(p, VM_PROT_NONE);
 				uvm_pagefree(p);
 				uvmexp.pdfreed++;
 
@@ -638,12 +614,15 @@ uvmpd_scan_inactive(pglst)
 			 * the page we are looking at is dirty.   we must
 			 * clean it before it can be freed.  to do this we
 			 * first mark the page busy so that no one else will
-			 * touch the page.
+			 * touch the page.   we write protect all the mappings
+			 * of the page so that no one touches it while it is
+			 * in I/O.
 			 */
 
 			swap_backed = ((p->pqflags & PQ_SWAPBACKED) != 0);
 			p->flags |= PG_BUSY;		/* now we own it */
 			UVM_PAGE_OWN(p, "scan_inactive");
+			pmap_page_protect(p, VM_PROT_READ);
 			uvmexp.pgswapout++;
 
 			/*
@@ -816,6 +795,7 @@ uvmpd_scan_inactive(pglst)
 			continue;
 		}
 
+#ifdef UBC
 		if (result == VM_PAGER_ERROR &&
 		    curproc == uvm.pagedaemon_proc) {
 			uvm_lock_pageq();
@@ -823,6 +803,7 @@ uvmpd_scan_inactive(pglst)
 			uvm_pageactivate(p);
 			continue;
 		}
+#endif
 
 		/*
 		 * clean up "p" if we have one
@@ -859,6 +840,12 @@ uvmpd_scan_inactive(pglst)
 					simple_lock(&uobj->vmobjlock);
 			}
 
+#ifdef DIAGNOSTIC
+			if (result == VM_PAGER_UNLOCK)
+				panic("pagedaemon: pageout returned "
+				    "invalid 'unlock' code");
+#endif
+
 			/* handle PG_WANTED now */
 			if (p->flags & PG_WANTED)
 				/* still holding object lock */
@@ -1108,13 +1095,12 @@ uvmpd_scan()
 		}
 
 		/*
-		 * If the page has not been referenced since the
-		 * last scan, deactivate the page if there is a
-		 * shortage of inactive pages.
+		 * deactivate this page if there's a shortage of
+		 * inactive pages.
 		 */
 
-		if (inactive_shortage > 0 &&
-		    pmap_clear_reference(p) == FALSE) {
+		if (inactive_shortage > 0) {
+			pmap_page_protect(p, VM_PROT_NONE);
 			/* no need to check wire_count as pg is "active" */
 			uvm_pagedeactivate(p);
 			uvmexp.pddeact++;