[src/netbsd-1-5]: src/sys/arch/alpha/alpha Pull up rev. 1.146:

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

details:   https://anonhg.NetBSD.org/src/rev/eaa97dc6eb06
branches:  netbsd-1-5
changeset: 489474:eaa97dc6eb06
user:      thorpej <thorpej%NetBSD.org@localhost>
date:      Tue Sep 19 17:48:16 2000 +0000

description:
Pull up rev. 1.146:
Make sure pmap_collect() doesn't remove wired mappings.  Per discussion
w/ Chuq Silvers.  Fixes a panic when a program with wired pages that
has run for a long time when the system is under heavy memory load
exits (specific case was ntpd, reported by Simon Burge).

diffstat:

 sys/arch/alpha/alpha/pmap.c |  41 +++++++++++++++++++++++++++++++++++++----
 1 files changed, 37 insertions(+), 4 deletions(-)

diffs (95 lines):

diff -r 0f49a82b39a3 -r eaa97dc6eb06 sys/arch/alpha/alpha/pmap.c
--- a/sys/arch/alpha/alpha/pmap.c       Tue Sep 19 17:45:12 2000 +0000
+++ b/sys/arch/alpha/alpha/pmap.c       Tue Sep 19 17:48:16 2000 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: pmap.c,v 1.135.2.1 2000/09/19 17:40:46 thorpej Exp $ */
+/* $NetBSD: pmap.c,v 1.135.2.2 2000/09/19 17:48:16 thorpej Exp $ */
 
 /*-
  * Copyright (c) 1998, 1999, 2000 The NetBSD Foundation, Inc.
@@ -154,7 +154,7 @@
 
 #include <sys/cdefs.h>                 /* RCS ID & Copyright macro defns */
 
-__KERNEL_RCSID(0, "$NetBSD: pmap.c,v 1.135.2.1 2000/09/19 17:40:46 thorpej Exp $");
+__KERNEL_RCSID(0, "$NetBSD: pmap.c,v 1.135.2.2 2000/09/19 17:48:16 thorpej Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -484,6 +484,7 @@
  * Internal routines
  */
 void   alpha_protection_init(void);
+void   pmap_do_remove(pmap_t, vaddr_t, vaddr_t, boolean_t);
 boolean_t pmap_remove_mapping(pmap_t, vaddr_t, pt_entry_t *,
            boolean_t, long, struct prm_thief *);
 void   pmap_changebit(paddr_t, pt_entry_t, pt_entry_t, long);
@@ -1285,6 +1286,26 @@
 void
 pmap_remove(pmap_t pmap, vaddr_t sva, vaddr_t eva)
 {
+
+#ifdef DEBUG
+       if (pmapdebug & (PDB_FOLLOW|PDB_REMOVE|PDB_PROTECT))
+               printf("pmap_remove(%p, %lx, %lx)\n", pmap, sva, eva);
+#endif
+
+       pmap_do_remove(pmap, sva, eva, TRUE);
+}
+
+/*
+ * pmap_do_remove:
+ *
+ *     This actually removes the range of addresses from the
+ *     specified map.  It is used by pmap_collect() (does not
+ *     want to remove wired mappings) and pmap_remove() (does
+ *     want to remove wired mappings).
+ */
+void
+pmap_do_remove(pmap_t pmap, vaddr_t sva, vaddr_t eva, boolean_t dowired)
+{
        pt_entry_t *l1pte, *l2pte, *l3pte;
        pt_entry_t *saved_l1pte, *saved_l2pte, *saved_l3pte;
        vaddr_t l1eva, l2eva, vptva;
@@ -1311,6 +1332,8 @@
                PMAP_MAP_TO_HEAD_LOCK();
                PMAP_LOCK(pmap);
 
+               KASSERT(dowired == TRUE);
+
                while (sva < eva) {
                        l3pte = PMAP_KERNEL_PTE(sva);
                        if (pmap_pte_v(l3pte)) {
@@ -1392,7 +1415,9 @@
 
                                        for (; sva < l2eva && sva < eva;
                                             sva += PAGE_SIZE, l3pte++) {
-                                               if (pmap_pte_v(l3pte)) {
+                                               if (pmap_pte_v(l3pte) &&
+                                                   (dowired == TRUE ||
+                                                    pmap_pte_w(l3pte) == 0)) {
                                                        needisync |=
                                                            pmap_remove_mapping(
                                                                pmap, sva,
@@ -2193,12 +2218,20 @@
 #endif
 
        /*
+        * If called for the kernel pmap, just return.  We
+        * handle this case in the event that we ever want
+        * to have swappable kernel threads.
+        */
+       if (pmap == pmap_kernel())
+               return;
+
+       /*
         * This process is about to be swapped out; free all of
         * the PT pages by removing the physical mappings for its
         * entire address space.  Note: pmap_remove() performs
         * all necessary locking.
         */
-       pmap_remove(pmap, VM_MIN_ADDRESS, VM_MAX_ADDRESS);
+       pmap_do_remove(pmap, VM_MIN_ADDRESS, VM_MAX_ADDRESS, FALSE);
 }
 
 /*