[src/netbsd-1-5]: src/sys/arch/i386/i386 Pull up revision 1.136 (via patch, r...

[he <he%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/f413402a1c1c
branches:  netbsd-1-5
changeset: 493013:f413402a1c1c
user:      he <he%NetBSD.org@localhost>
date:      Thu Mar 28 22:45:17 2002 +0000

description:
Pull up revision 1.136 (via patch, requested by chs):
  Avoid accounting errors in pmap_enter() by only updating the counters
  once the operation can no longer fail.  Fixes PR#16028.

diffstat:

 sys/arch/i386/i386/pmap.c |  36 ++++++++++++++++++++++++------------
 1 files changed, 24 insertions(+), 12 deletions(-)

diffs (80 lines):

diff -r 2d3b15862aff -r f413402a1c1c sys/arch/i386/i386/pmap.c
--- a/sys/arch/i386/i386/pmap.c Thu Mar 28 22:40:22 2002 +0000
+++ b/sys/arch/i386/i386/pmap.c Thu Mar 28 22:45:17 2002 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: pmap.c,v 1.94.2.3 2000/10/09 04:46:00 thorpej Exp $    */
+/*     $NetBSD: pmap.c,v 1.94.2.4 2002/03/28 22:45:17 he Exp $ */
 
 /*
  *
@@ -3453,6 +3453,7 @@
        struct pv_head *pvh;
        struct pv_entry *pve;
        int bank, off, error;
+       int ptpdelta, wireddelta, resdelta;
        boolean_t wired = (flags & PMAP_WIRED) != 0;
 
 #ifdef DIAGNOSTIC
@@ -3497,15 +3498,19 @@
        if (pmap_valid_entry(opte)) {
 
                /*
-                * first, update pm_stats.  resident count will not
-                * change since we are replacing/changing a valid
-                * mapping.  wired count might change...
+                * first, calculate pm_stats updates.  resident count will not
+                * change since we are replacing/changing a valid mapping.
+                * wired count might change...
                 */
 
+               resdelta = 0;
                if (wired && (opte & PG_W) == 0)
-                       pmap->pm_stats.wired_count++;
+                       wireddelta = 1;
                else if (!wired && (opte & PG_W) != 0)
-                       pmap->pm_stats.wired_count--;
+                       wireddelta = -1;
+               else
+                       wireddelta = 0;
+               ptpdelta = 0;
 
                /*
                 * is the currently mapped PA the same as the one we
@@ -3561,17 +3566,20 @@
                }
        } else {        /* opte not valid */
                pve = NULL;
-               pmap->pm_stats.resident_count++;
+               resdelta = 1;
                if (wired)
-                       pmap->pm_stats.wired_count++;
+                       wireddelta = 1;
+               else
+                       wireddelta = 0;
                if (ptp)
-                       ptp->wire_count++;      /* count # of valid entrys */
+                       ptpdelta = 1;
+               else
+                       ptpdelta = 0;
        }
 
        /*
-        * at this point pm_stats has been updated.   pve is either NULL
-        * or points to a now-free pv_entry structure (the latter case is
-        * if we called pmap_remove_pv above).
+        * pve is either NULL or points to a now-free pv_entry structure
+        * (the latter case is if we called pmap_remove_pv above).
         *
         * if this entry is to be on a pvlist, enter it now.
         */
@@ -3604,6 +3612,10 @@
         * at this point pvh is !NULL if we want the PG_PVLIST bit set
         */
 
+       pmap->pm_stats.resident_count += resdelta;
+       pmap->pm_stats.wired_count += wireddelta;
+       if (ptp)
+               ptp->wire_count += ptpdelta;
        npte = pa | protection_codes[prot] | PG_V;
        if (pvh)
                npte |= PG_PVLIST;