[src/trunk]: src/sys/uvm Fix start_hint in "simple" alloc (fencepost error).

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

details:   https://anonhg.NetBSD.org/src/rev/5fc06cf3daa2
branches:  trunk
changeset: 761338:5fc06cf3daa2
user:      matt <matt%NetBSD.org@localhost>
date:      Mon Jan 24 19:13:55 2011 +0000

description:
Fix start_hint in "simple" alloc (fencepost error).
When restarting the loop, make sure end is not above current limit.
Do a quick test to see if the physseg is within the range of desired addresses.

diffstat:

 sys/uvm/uvm_pglist.c |  30 +++++++++++++++++++++---------
 1 files changed, 21 insertions(+), 9 deletions(-)

diffs (84 lines):

diff -r d7790c643d5a -r 5fc06cf3daa2 sys/uvm/uvm_pglist.c
--- a/sys/uvm/uvm_pglist.c      Mon Jan 24 17:52:07 2011 +0000
+++ b/sys/uvm/uvm_pglist.c      Mon Jan 24 19:13:55 2011 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: uvm_pglist.c,v 1.56 2011/01/23 21:29:52 he Exp $       */
+/*     $NetBSD: uvm_pglist.c,v 1.57 2011/01/24 19:13:55 matt Exp $     */
 
 /*-
  * Copyright (c) 1997 The NetBSD Foundation, Inc.
@@ -35,7 +35,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: uvm_pglist.c,v 1.56 2011/01/23 21:29:52 he Exp $");
+__KERNEL_RCSID(0, "$NetBSD: uvm_pglist.c,v 1.57 2011/01/24 19:13:55 matt Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -130,8 +130,7 @@
        int cidx = 0;   /* XXX: GCC */
 #endif
 #ifdef PGALLOC_VERBOSE
-       printf("pgalloc: contig %d pgs from psi %ld\n", num,
-       (long)(ps - vm_physmem));
+       printf("pgalloc: contig %d pgs from psi %zd\n", num, ps - vm_physmem);
 #endif
 
        KASSERT(mutex_owned(&uvm_fpageqlock));
@@ -141,6 +140,12 @@
        alignment = atop(alignment);
 
        /*
+        * Make sure that physseg falls within with range to be allocated from.
+        */
+       if (high <= ps->avail_start || low >= ps->avail_end)
+               return 0;
+
+       /*
         * We start our search at the just after where the last allocation
         * succeeded.
         */
@@ -169,7 +174,7 @@
                         */
                        second_pass = true;
                        try = roundup2(max(low, ps->avail_start), alignment);
-                       limit = min(high, ps->avail_start + ps->start_hint);
+                       limit = min(limit, ps->avail_start + ps->start_hint);
                        skip = 0;
                        continue;
                }
@@ -362,8 +367,7 @@
        struct vm_page *pg;
        bool second_pass;
 #ifdef PGALLOC_VERBOSE
-       printf("pgalloc: simple %d pgs from psi %ld\n", num,
-           (long)(ps - vm_physmem));
+       printf("pgalloc: simple %d pgs from psi %zd\n", num, ps - vm_physmem);
 #endif
 
        KASSERT(mutex_owned(&uvm_fpageqlock));
@@ -380,13 +384,21 @@
        pg = &ps->pgs[try - ps->start];
        second_pass = false;
 
+       /*
+        * Make sure that physseg falls within with range to be allocated from.
+        */
+       if (high <= ps->avail_start || low >= ps->avail_end)
+               return 0;
+
        for (;; try++, pg++) {
                if (try >= limit) {
-                       if (ps->start_hint == 0 || second_pass)
+                       if (ps->start_hint == 0 || second_pass) {
+                               try = limit - 1;
                                break;
+                       }
                        second_pass = true;
                        try = max(low, ps->avail_start);
-                       limit = min(high, ps->avail_start + ps->start_hint);
+                       limit = min(limit, ps->avail_start + ps->start_hint);
                        pg = &ps->pgs[try - ps->start];
                        continue;
                }