Fix a problem in the swap pager that caused some of the pages that

were paged in under low swap space conditions to both loose their
backing store and their dirty bits.  This would cause pages to
be demand zeroed under certain conditions in low VM space conditions
and consequential sig-11's or sig-10's.  This situation was made
worse lately when the level for swap space reclaim threshold was
increased.

1 files changed, 9 insertions, 9 deletions

diff --git a/sys/vm/swap_pager.c b/sys/vm/swap_pager.c
index eb42e47..8cbf3b8 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 1.61 1996/03/02 02:54:17 dyson Exp $
+ * $Id: swap_pager.c,v 1.62 1996/03/03 21:11:05 dyson Exp $
  */
 
 /*
@@ -1045,6 +1045,11 @@ swap_pager_getpages(object, m, count, reqpage)
 		if (swap_pager_needflags & SWAP_FREE_NEEDED_BY_PAGEOUT)
 			pagedaemon_wakeup();
 		swap_pager_needflags &= ~(SWAP_FREE_NEEDED|SWAP_FREE_NEEDED_BY_PAGEOUT);
+		if (rv == VM_PAGER_OK) {
+			pmap_clear_modify(VM_PAGE_TO_PHYS(m[reqpage]));
+			m[reqpage]->valid = VM_PAGE_BITS_ALL;
+			m[reqpage]->dirty = 0;
+		}
 	} else {
 		/*
 		 * release the physical I/O buffer
@@ -1084,9 +1089,9 @@ swap_pager_getpages(object, m, count, reqpage)
 
 			/*
 			 * If we're out of swap space, then attempt to free
-			 * some whenever pages are brought in. We must clear
-			 * the clean flag so that the page contents will be
-			 * preserved.
+			 * some whenever multiple pages are brought in. We
+			 * must set the dirty bits so that the page contents
+			 * will be preserved.
 			 */
 			if (SWAPLOW) {
 				for (i = 0; i < count; i++) {
@@ -1098,11 +1103,6 @@ swap_pager_getpages(object, m, count, reqpage)
 			swap_pager_ridpages(m, count, reqpage);
 		}
 	}
-	if (rv == VM_PAGER_OK) {
-		pmap_clear_modify(VM_PAGE_TO_PHYS(m[reqpage]));
-		m[reqpage]->valid = VM_PAGE_BITS_ALL;
-		m[reqpage]->dirty = 0;
-	}
 	return (rv);
 }