Added ability to detect sequential faults and DTRT. (swap_pager.c)

Added hook for pmap_prefault() and use symbolic constant for new third argument to vm_page_alloc() (vm_fault.c, various) Changed the way that upages and page tables are held. (vm_glue.c) Fixed architectural flaw in allocating pages at interrupt time that was introduced with the merged cache changes. (vm_page.c, various) Adjusted some algorithms to acheive better paging performance and to accomodate the fix for the architectural flaw mentioned above. (vm_pageout.c) Fixed pbuf handling problem, changed policy on handling read-behind page. (vnode_pager.c) Submitted by: John Dyson
svn path=/head/; revision=5841
2024-10-19 02:29:40 +00:00 · 1995-01-24 10:14:09 +00:00 · 1995-01-24 10:14:09 +00:00 · 6d40c3d394 · 2020-12-20 02:59:44 +00:00
commit 6d40c3d394
parent e5501f43a5
11 changed files with 105 additions and 78 deletions
--- 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 1.22 1995/01/09 16:05:33 davidg Exp $
+ * $Id: swap_pager.c,v 1.23 1995/01/10 07:32:43 davidg Exp $
 */

 /*
@ -894,6 +894,7 @@ swap_pager_input(swp, m, count, reqpage)
 	vm_offset_t paging_offset;
 	vm_object_t object;
 	int reqaddr[count];
+	int sequential;

 	int first, last;
 	int failed;
@ -901,6 +902,7 @@ swap_pager_input(swp, m, count, reqpage)

 	object = m[reqpage]->object;
 	paging_offset = object->paging_offset;
+	sequential = (m[reqpage]->offset == (object->last_read + PAGE_SIZE));
 	/*
 	 * First determine if the page exists in the pager if this is a sync
 	 * read.  This quickly handles cases where we are following shadow
@ -947,7 +949,7 @@ swap_pager_input(swp, m, count, reqpage)
 	failed = 0;
 	first = 0;
 	for (i = reqpage - 1; i >= 0; --i) {
-		if (failed || (reqaddr[i] == SWB_EMPTY) ||
+		if (sequential || failed || (reqaddr[i] == SWB_EMPTY) ||
 		    (swb[i]->swb_valid & (1 << off[i])) == 0 ||
 		    (reqaddr[i] != (reqaddr[reqpage] + (i - reqpage) * btodb(PAGE_SIZE))) ||
 		    ((reqaddr[i] / dmmax) != reqdskregion)) {
@ -1105,6 +1107,7 @@ swap_pager_input(swp, m, count, reqpage)
 	pmap_qremove(kva, count);

 	if (spc) {
+		m[reqpage]->object->last_read = m[reqpage]->offset;
 		if (bp->b_flags & B_WANTED)
 			wakeup((caddr_t) bp);
 		/*
@ -1141,9 +1144,11 @@ swap_pager_input(swp, m, count, reqpage)
 					 * results, it is best to deactivate
 					 * the readahead pages.
 					 */
-					if ((i == reqpage - 1) || (i == reqpage + 1))
+/*
+					if (sequential || (i == reqpage - 1) || (i == reqpage + 1))
 						vm_page_activate(m[i]);
 					else
+*/
 						vm_page_deactivate(m[i]);

 					/*
@ -1155,6 +1160,9 @@ swap_pager_input(swp, m, count, reqpage)
 					PAGE_WAKEUP(m[i]);
 				}
 			}
+
+			m[reqpage]->object->last_read = m[count-1]->offset;
+
 			/*
 			 * If we're out of swap space, then attempt to free
 			 * some whenever pages are brought in. We must clear
--- a/sys/vm/vm_fault.c
+++ b/sys/vm/vm_fault.c
@ -66,7 +66,7 @@
 * any improvements or extensions that they make and grant Carnegie the
 * rights to redistribute these changes.
 *
- * $Id: vm_fault.c,v 1.14 1995/01/09 16:05:39 davidg Exp $
+ * $Id: vm_fault.c,v 1.15 1995/01/10 07:32:45 davidg Exp $
 */

 /*
@ -320,7 +320,7 @@ RetryFault:;
 			 * Allocate a new page for this object/offset pair.
 			 */

-			m = vm_page_alloc(object, offset, 0);
+			m = vm_page_alloc(object, offset, VM_ALLOC_NORMAL);

 			if (m == NULL) {
 				UNLOCK_AND_DEALLOCATE;
@ -655,7 +655,7 @@ RetryFault:;
 				 * that the copy_object's pager doesn't have
 				 * the page...
 				 */
-				copy_m = vm_page_alloc(copy_object, copy_offset, 0);
+				copy_m = vm_page_alloc(copy_object, copy_offset, VM_ALLOC_NORMAL);
 				if (copy_m == NULL) {
 					/*
 					 * Wait for a page, then retry.
@ -839,6 +839,8 @@ RetryFault:;
 	 */

 	pmap_enter(map->pmap, vaddr, VM_PAGE_TO_PHYS(m), prot, wired);
+	if( ((prot & VM_PROT_WRITE) == 0) && change_wiring == 0 && wired == 0)
+		pmap_prefault(map->pmap, vaddr, entry, first_object);

 	/*
 	 * If the page is not wired down, then put it where the pageout daemon
@ -905,6 +907,11 @@ vm_fault_wire(map, start, end)
 	 */

 	for (va = start; va < end; va += PAGE_SIZE) {
+
+		if( curproc != pageproc &&
+			(cnt.v_free_count <= cnt.v_pageout_free_min))
+			VM_WAIT;
+
 		rv = vm_fault(map, va, VM_PROT_NONE, TRUE);
 		if (rv) {
 			if (va != start)
@ -1019,7 +1026,7 @@ vm_fault_copy_entry(dst_map, src_map, dst_entry, src_entry)
 		 */
 		vm_object_lock(dst_object);
 		do {
-			dst_m = vm_page_alloc(dst_object, dst_offset, 0);
+			dst_m = vm_page_alloc(dst_object, dst_offset, VM_ALLOC_NORMAL);
 			if (dst_m == NULL) {
 				vm_object_unlock(dst_object);
 				VM_WAIT;
@ -1215,7 +1222,7 @@ vm_fault_additional_pages(first_object, first_offset, m, rbehind, raheada, marra
 		 */
 		for (i = 0; i < size; i++) {
 			if (i != treqpage)
-				rtm = vm_page_alloc(object, startoffset + i * NBPG, 0);
+				rtm = vm_page_alloc(object, startoffset + i * NBPG, VM_ALLOC_NORMAL);
 			else
 				rtm = m;
 			marray[i] = rtm;
--- a/sys/vm/vm_glue.c
+++ b/sys/vm/vm_glue.c
@ -59,7 +59,7 @@
 * any improvements or extensions that they make and grant Carnegie the
 * rights to redistribute these changes.
 *
- * $Id: vm_glue.c,v 1.11 1995/01/09 16:05:40 davidg Exp $
+ * $Id: vm_glue.c,v 1.12 1995/01/10 07:32:45 davidg Exp $
 */

 #include <sys/param.h>
@ -236,12 +236,6 @@ vm_fork(p1, p2, isvfork)
 		    pmap_extract(vp->pmap, addr + NBPG * i),
 		    VM_PROT_READ | VM_PROT_WRITE, 1);

-	/*
-	 * and allow the UPAGES page table entry to be paged (at the vm system
-	 * level)
-	 */
-	vm_map_pageable(vp, ptaddr, ptaddr + NBPG, TRUE);
-
 	p2->p_addr = up;

 	/*
@ -339,9 +333,6 @@ faultin(p)
 			    pa, VM_PROT_READ | VM_PROT_WRITE, 1);
 		}

-		/* and let the page table pages go (at least above pmap level) */
-		vm_map_pageable(map, ptaddr, ptaddr + NBPG, TRUE);
-
 		s = splhigh();

 		if (p->p_stat == SRUN)
@ -491,6 +482,7 @@ swapout(p)
 	register struct proc *p;
 {
 	vm_map_t map = &p->p_vmspace->vm_map;
+	vm_offset_t ptaddr;

 	++p->p_stats->p_ru.ru_nswap;
 	/*
@ -515,6 +507,9 @@ swapout(p)
 	vm_map_pageable(map, (vm_offset_t) kstack,
 	    (vm_offset_t) kstack + UPAGES * NBPG, TRUE);

+	ptaddr = trunc_page((u_int) vtopte(kstack));
+	vm_map_pageable(map, ptaddr, ptaddr + NBPG, TRUE);
+
 	p->p_flag &= ~P_SWAPPING;
 	p->p_swtime = 0;
 }
--- a/sys/vm/vm_kern.c
+++ b/sys/vm/vm_kern.c
@ -61,7 +61,7 @@
 * any improvements or extensions that they make and grant Carnegie the
 * rights to redistribute these changes.
 *
- * $Id: vm_kern.c,v 1.7 1994/08/18 22:36:02 wollman Exp $
+ * $Id: vm_kern.c,v 1.8 1995/01/09 16:05:43 davidg Exp $
 */

 /*
@ -177,7 +177,7 @@ kmem_alloc(map, size)
 	for (i = 0; i < size; i += PAGE_SIZE) {
 		vm_page_t mem;

-		while ((mem = vm_page_alloc(kernel_object, offset + i, 0)) == NULL) {
+		while ((mem = vm_page_alloc(kernel_object, offset + i, VM_ALLOC_NORMAL)) == NULL) {
 			vm_object_unlock(kernel_object);
 			VM_WAIT;
 			vm_object_lock(kernel_object);
@ -331,7 +331,7 @@ kmem_malloc(map, size, canwait)
 	 */
 	vm_object_lock(kmem_object);
 	for (i = 0; i < size; i += PAGE_SIZE) {
-		m = vm_page_alloc(kmem_object, offset + i, 1);
+		m = vm_page_alloc(kmem_object, offset + i, VM_ALLOC_INTERRUPT);

 		/*
 		 * Ran out of space, free everything up and return. Don't need
--- a/sys/vm/vm_map.c
+++ b/sys/vm/vm_map.c
@ -61,7 +61,7 @@
 * any improvements or extensions that they make and grant Carnegie the
 * rights to redistribute these changes.
 *
- * $Id: vm_map.c,v 1.10 1995/01/09 16:05:45 davidg Exp $
+ * $Id: vm_map.c,v 1.11 1995/01/10 07:32:46 davidg Exp $
 */

 /*
@ -313,7 +313,8 @@ vm_map_entry_create(map)
 			vm_page_t m;

 			m = vm_page_alloc(kmem_object,
-			    mapvm - vm_map_min(kmem_map), 0);
+			        mapvm - vm_map_min(kmem_map),
+				    (map == kmem_map) ? VM_ALLOC_INTERRUPT : VM_ALLOC_NORMAL);
 			if (m) {
 				int newentries;

--- a/sys/vm/vm_object.c
+++ b/sys/vm/vm_object.c
@ -61,7 +61,7 @@
 * any improvements or extensions that they make and grant Carnegie the
 * rights to redistribute these changes.
 *
- * $Id: vm_object.c,v 1.17 1995/01/11 20:19:20 davidg Exp $
+ * $Id: vm_object.c,v 1.18 1995/01/13 13:30:24 davidg Exp $
 */

 /*
@ -140,6 +140,7 @@ _vm_object_allocate(size, object)
 	object->flags = OBJ_INTERNAL;	/* vm_allocate_with_pager will reset */
 	object->paging_in_progress = 0;
 	object->copy = NULL;
+	object->last_read = 0;

 	/*
 	 * Object starts out read-write, with no pager.
--- a/sys/vm/vm_object.h
+++ b/sys/vm/vm_object.h
@ -61,7 +61,7 @@
 * any improvements or extensions that they make and grant Carnegie the
 * rights to redistribute these changes.
 *
- * $Id: vm_object.h,v 1.3 1994/11/06 05:07:52 davidg Exp $
+ * $Id: vm_object.h,v 1.4 1995/01/09 16:05:50 davidg Exp $
 */

 /*
@ -98,6 +98,7 @@ struct vm_object {
 	vm_offset_t paging_offset;	/* Offset into paging space */
 	struct vm_object *shadow;	/* My shadow */
 	vm_offset_t shadow_offset;	/* Offset in shadow */
+	vm_offset_t last_read;		/* last read in object -- detect seq behavior */
 	TAILQ_ENTRY(vm_object) cached_list; /* for persistence */
 	TAILQ_ENTRY(vm_object) reverse_shadow_list; /* chain of objects that are shadowed */
 	TAILQ_HEAD(rslist, vm_object) reverse_shadow_head; /* objects that this is a shadow for */
--- a/sys/vm/vm_page.c
+++ b/sys/vm/vm_page.c
@ -34,7 +34,7 @@
 * SUCH DAMAGE.
 *
 *	from: @(#)vm_page.c	7.4 (Berkeley) 5/7/91
- *	$Id: vm_page.c,v 1.15 1995/01/10 09:19:46 davidg Exp $
+ *	$Id: vm_page.c,v 1.16 1995/01/15 07:31:34 davidg Exp $
 */

 /*
@ -601,16 +601,22 @@ vm_page_requeue(vm_page_t mem, int flags)
 *	Allocate and return a memory cell associated
 *	with this VM object/offset pair.
 *
+ *	page_req -- 0	normal process request			VM_ALLOC_NORMAL
+ *	page_req -- 1	interrupt time request			VM_ALLOC_INTERRUPT
+ *	page_req -- 2	system *really* needs a page	VM_ALLOC_SYSTEM
+ *					but *cannot* be at interrupt time
+ *
 *	Object must be locked.
 */
 vm_page_t
-vm_page_alloc(object, offset, inttime)
+vm_page_alloc(object, offset, page_req)
 	vm_object_t object;
 	vm_offset_t offset;
-	int inttime;
+	int page_req;
 {
 	register vm_page_t mem;
 	int s;
+	int msgflg;

 	simple_lock(&vm_page_queue_free_lock);

@ -625,22 +631,20 @@ vm_page_alloc(object, offset, inttime)
 		splx(s);
 		return (NULL);
 	}
-	if (inttime) {
+	if (page_req == VM_ALLOC_INTERRUPT) {
 		if ((mem = vm_page_queue_free.tqh_first) == 0) {
-			for (mem = vm_page_queue_cache.tqh_first; mem; mem = mem->pageq.tqe_next) {
-				if ((mem->object->flags & OBJ_ILOCKED) == 0) {
-					TAILQ_REMOVE(&vm_page_queue_cache, mem, pageq);
-					vm_page_remove(mem);
-					cnt.v_cache_count--;
-					goto gotpage;
-				}
-			}
 			simple_unlock(&vm_page_queue_free_lock);
 			splx(s);
+			/*
+			 * need to wakeup at interrupt time -- it doesn't do VM_WAIT
+			 */
+			wakeup((caddr_t) &vm_pages_needed);
 			return NULL;
 		}
+		if( cnt.v_free_count < cnt.v_pageout_free_min)
+			wakeup((caddr_t) &vm_pages_needed);
 	} else {
-		if ((cnt.v_free_count < 3) ||
+		if ((cnt.v_free_count < cnt.v_pageout_free_min) ||
 		    (mem = vm_page_queue_free.tqh_first) == 0) {
 			mem = vm_page_queue_cache.tqh_first;
 			if (mem) {
@ -649,9 +653,15 @@ vm_page_alloc(object, offset, inttime)
 				cnt.v_cache_count--;
 				goto gotpage;
 			}
-			simple_unlock(&vm_page_queue_free_lock);
-			splx(s);
-			return (NULL);
+			if( page_req == VM_ALLOC_SYSTEM) {
+				mem = vm_page_queue_free.tqh_first;
+				if( !mem) {
+					simple_unlock(&vm_page_queue_free_lock);
+					splx(s);
+					wakeup((caddr_t) &vm_pages_needed);
+					return (NULL);
+				}
+			}
 		}
 	}

@ -661,7 +671,7 @@ vm_page_alloc(object, offset, inttime)
 gotpage:
 	simple_unlock(&vm_page_queue_free_lock);

-	mem->flags = PG_BUSY | PG_CLEAN;
+	mem->flags = PG_BUSY;
 	mem->wire_count = 0;
 	mem->hold_count = 0;
 	mem->act_count = 0;
@ -680,7 +690,8 @@ vm_page_alloc(object, offset, inttime)
 * we would be nearly out of memory.
 */
 	if (curproc != pageproc &&
-	    ((cnt.v_free_count + cnt.v_cache_count) < cnt.v_free_min))
+	    ((cnt.v_free_count + cnt.v_cache_count) < cnt.v_free_min) ||
+		(cnt.v_free_count < cnt.v_pageout_free_min))
 		wakeup((caddr_t) &vm_pages_needed);

 	return (mem);
@ -1109,8 +1120,8 @@ void
 vm_page_test_dirty(m)
 	vm_page_t m;
 {
-	if ((!m->dirty || (m->dirty != vm_page_bits(0, PAGE_SIZE))) &&
-	    pmap_is_modified(VM_PAGE_TO_PHYS(m))) {
+	if ((m->dirty != VM_PAGE_BITS_ALL) &&
+		pmap_is_modified(VM_PAGE_TO_PHYS(m))) {
 		pmap_clear_modify(VM_PAGE_TO_PHYS(m));
 		m->dirty = VM_PAGE_BITS_ALL;
 	}
--- a/sys/vm/vm_page.h
+++ b/sys/vm/vm_page.h
@ -61,7 +61,7 @@
 * any improvements or extensions that they make and grant Carnegie the
 * rights to redistribute these changes.
 *
- * $Id: vm_page.h,v 1.11 1995/01/09 16:05:52 davidg Exp $
+ * $Id: vm_page.h,v 1.12 1995/01/10 09:19:52 davidg Exp $
 */

 /*
@ -220,6 +220,9 @@ extern simple_lock_data_t vm_page_queue_free_lock; /* lock on free page queue */
 #define VM_PAGE_BITS_ALL 0xffff
 #endif

+#define VM_ALLOC_NORMAL 0
+#define VM_ALLOC_INTERRUPT 1
+#define VM_ALLOC_SYSTEM 2

 void vm_page_activate __P((vm_page_t));
 vm_page_t vm_page_alloc __P((vm_object_t, vm_offset_t, int));
--- a/sys/vm/vm_pageout.c
+++ b/sys/vm/vm_pageout.c
@ -65,7 +65,7 @@
 * any improvements or extensions that they make and grant Carnegie the
 * rights to redistribute these changes.
 *
- * $Id: vm_pageout.c,v 1.29 1995/01/09 16:05:53 davidg Exp $
+ * $Id: vm_pageout.c,v 1.30 1995/01/10 07:32:49 davidg Exp $
 */

 /*
@ -341,7 +341,7 @@ vm_pageout_object_deactivate_pages(map, object, count, map_remove_only)
 		if (object->shadow->ref_count == 1)
 			dcount += vm_pageout_object_deactivate_pages(map, object->shadow, count / 2 + 1, map_remove_only);
 		else
-			dcount += vm_pageout_object_deactivate_pages(map, object->shadow, count / 2 + 1, 1);
+			vm_pageout_object_deactivate_pages(map, object->shadow, count, 1);
 	}
 	if (object->paging_in_progress || !vm_object_lock_try(object))
 		return dcount;
@ -518,8 +518,8 @@ vm_pageout_inactive_stats(int maxiscan)
 			 * heuristic alert -- if a page is being re-activated,
 			 * it probably will be used one more time...
 			 */
-			++m->act_count;
-			++m->act_count;
+			if (m->act_count < ACT_MAX)
+				m->act_count += ACT_ADVANCE;
 		}
 		m = next;
 	}
@ -574,6 +574,7 @@ vm_pageout_scan()
 	 */


+rescan0:
 	vm_pageout_inactive_stats(MAXISCAN);
 	maxlaunder = (cnt.v_inactive_target > MAXLAUNDER) ?
 	    MAXLAUNDER : cnt.v_inactive_target;
@ -620,17 +621,21 @@ vm_pageout_scan()
 			m->flags &= ~PG_REFERENCED;
 			pmap_clear_reference(VM_PAGE_TO_PHYS(m));
 			vm_page_activate(m);
-			++m->act_count;
-			++m->act_count;
+			if (m->act_count < ACT_MAX)
+				m->act_count += ACT_ADVANCE;
 			m = next;
 			continue;
 		}
 		vm_page_test_dirty(m);

 		if ((m->dirty & m->valid) == 0) {
-			if (((cnt.v_free_count + cnt.v_cache_count) < desired_free) ||
-			    (cnt.v_cache_count < cnt.v_cache_min))
+			if (m->valid == 0) {
+				pmap_page_protect(VM_PAGE_TO_PHYS(m), VM_PROT_NONE);
+				vm_page_free(m);
+			} else if (((cnt.v_free_count + cnt.v_cache_count) < desired_free) ||
+			    (cnt.v_cache_count < cnt.v_cache_min)) {
 				vm_page_cache(m);
+			}
 		} else if (maxlaunder > 0) {
 			int written;

@ -684,6 +689,8 @@ vm_pageout_scan()
 				    desired_free - (cnt.v_free_count + cnt.v_cache_count);
 			}
 		}
+		if( (page_shortage <= 0) && (cnt.v_free_count < cnt.v_free_min))
+			page_shortage = 1;
 	}
 	maxscan = cnt.v_active_count;
 	minscan = cnt.v_active_count;
@ -706,6 +713,8 @@ vm_pageout_scan()
 		    (m->flags & PG_BUSY) ||
 		    (m->hold_count != 0) ||
 		    (m->bmapped != 0)) {
+			TAILQ_REMOVE(&vm_page_queue_active, m, pageq);
+			TAILQ_INSERT_TAIL(&vm_page_queue_active, m, pageq);
 			m = next;
 			continue;
 		}
@ -725,6 +734,8 @@ vm_pageout_scan()
 			TAILQ_INSERT_TAIL(&m->object->memq, m, listq);
 			splx(s);
 		} else {
+			m->flags &= ~PG_REFERENCED;
+			pmap_clear_reference(VM_PAGE_TO_PHYS(m));
 			m->act_count -= min(m->act_count, ACT_DECLINE);

 			/*
@ -733,10 +744,6 @@ vm_pageout_scan()
 			if (!m->act_count && (page_shortage > 0)) {
 				if (m->object->ref_count == 0) {
 					vm_page_test_dirty(m);
-
-					m->flags &= ~PG_REFERENCED;
-					pmap_clear_reference(VM_PAGE_TO_PHYS(m));
-
 					--page_shortage;
 					if ((m->dirty & m->valid) == 0) {
 						m->act_count = 0;
@ -745,14 +752,10 @@ vm_pageout_scan()
 						vm_page_deactivate(m);
 					}
 				} else {
-
-					m->flags &= ~PG_REFERENCED;
-					pmap_clear_reference(VM_PAGE_TO_PHYS(m));
-
 					vm_page_deactivate(m);
 					--page_shortage;
 				}
-			} else {
+			} else if (m->act_count) {
 				TAILQ_REMOVE(&vm_page_queue_active, m, pageq);
 				TAILQ_INSERT_TAIL(&vm_page_queue_active, m, pageq);
 			}
@ -764,7 +767,7 @@ vm_pageout_scan()
 	 * We try to maintain some *really* free pages, this allows interrupt
 	 * code to be guaranteed space.
 	 */
-	while (cnt.v_free_count < MINFREE) {
+	while (cnt.v_free_count < cnt.v_free_min) {
 		m = vm_page_queue_cache.tqh_first;
 		if (!m)
 			break;
@ -840,7 +843,7 @@ vm_pageout()
 	 * free_reserved needs to include enough for the largest swap pager
 	 * structures plus enough for any pv_entry structs when paging.
 	 */
-	cnt.v_pageout_free_min = 5 + cnt.v_page_count / 1024;
+	cnt.v_pageout_free_min = 6 + cnt.v_page_count / 1024;
 	cnt.v_free_reserved = cnt.v_pageout_free_min + 2;
 	cnt.v_free_target = 3 * cnt.v_free_min + cnt.v_free_reserved;
 	cnt.v_inactive_target = cnt.v_free_count / 4;
@ -926,8 +929,6 @@ vm_daemon()
 			size = p->p_vmspace->vm_pmap.pm_stats.resident_count * NBPG;
 			if (limit >= 0 && size >= limit) {
 				overage = (size - limit) / NBPG;
-				if (limit == 0)
-					overage += 20;
 				vm_pageout_map_deactivate_pages(&p->p_vmspace->vm_map,
 				    (vm_map_entry_t) 0, &overage, vm_pageout_object_deactivate_pages);
 			}
--- a/sys/vm/vnode_pager.c
+++ b/sys/vm/vnode_pager.c
@ -37,7 +37,7 @@
 * SUCH DAMAGE.
 *
 *	from: @(#)vnode_pager.c	7.5 (Berkeley) 4/20/91
- *	$Id: vnode_pager.c,v 1.19 1995/01/09 16:06:01 davidg Exp $
+ *	$Id: vnode_pager.c,v 1.20 1995/01/11 20:00:10 davidg Exp $
 */

 /*
@ -881,13 +881,15 @@ vnode_pager_input(vnp, m, count, reqpage)
 		counta = (count - reqpage) - 1;
 	bpa = 0;
 	sizea = 0;
-	if (counta) {
-		bpa = getpbuf();
-		count -= counta;
-		sizea = size - count * PAGE_SIZE;
-		size = count * PAGE_SIZE;
-	}
 	bp = getpbuf();
+	if (counta) {
+		bpa = (struct buf *) trypbuf();
+		if (bpa) {
+			count -= counta;
+			sizea = size - count * PAGE_SIZE;
+			size = count * PAGE_SIZE;
+		}
+	}
 	kva = (vm_offset_t) bp->b_data;

 	/*
@ -981,10 +983,7 @@ vnode_pager_input(vnp, m, count, reqpage)
 			 * now tell them that it is ok to use
 			 */
 			if (!error) {
-				if (i != reqpage - 1)
-					vm_page_deactivate(m[i]);
-				else
-					vm_page_activate(m[i]);
+				vm_page_deactivate(m[i]);
 				PAGE_WAKEUP(m[i]);
 			} else {
 				vnode_pager_freepage(m[i]);