From owner-freebsd-bugs  Sat Dec 11 11:50: 6 1999
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Date: Sat, 11 Dec 1999 11:42:45 -0800 (PST)
From: mitja@ksop-cscp.si
To: freebsd-gnats-submit@freebsd.org
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Subject: kern/15420: 3.3-RELEASE Kernel freeze 
Sender: owner-freebsd-bugs@FreeBSD.ORG
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>Number:         15420
>Category:       kern
>Synopsis:       3.3-RELEASE Kernel freeze
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Sat Dec 11 11:50:01 PST 1999
>Closed-Date:
>Last-Modified:
>Originator:     Mitja Horvat
>Release:        3.3-RELEASE
>Organization:
>Environment:
FreeBSD weha.nonet.si 3.3-RELEASE FreeBSD 3.3-RELEASE #7: Thu Dec  9 00:21:47 CET 1999     root@weha.nonet.si:/usr/src/sys/compile/WOW  i386
>Description:
Kernel freezes under heavy VM load.
>How-To-Repeat:
Spawn few programs that chew up all memory. 
The bug may not show up immediately, so run the programs few times.

This script triggers the problem on two PCs I tested on:
--------------------------------->8--------------------------------
#!/bin/sh
cat << EOF > qq.c
void main(void) {
        for(;;)
                memset(malloc(1000000), 0, 1000000);
}
EOF
cc qq.c -o qq
./qq &
./qq &
./qq &
./qq &
wait
rm -f qq qq.c
--------------------------------->8--------------------------------

>Fix:
The following kernel patch fixes the problem for me, but since this is my 
first FreeBSD hacking attempt, I'm not sure if it's OK.
--------------------------------->8--------------------------------
--- vm_pageout.c.orig   Fri Dec 10 01:49:54 1999
+++ vm_pageout.c        Fri Dec 10 01:54:22 1999
@@ -1136,8 +1136,8 @@
         * make sure that we have swap space -- if we are low on memory and
         * swap -- then kill the biggest process.
         */
-       if ((vm_swap_size == 0 || swap_pager_full) &&
-           ((cnt.v_free_count + cnt.v_cache_count) < cnt.v_free_min)) {
+       if (vm_swap_size == 0 || swap_pager_full || 
+          (cnt.v_free_count + cnt.v_cache_count) < cnt.v_free_min) {
                bigproc = NULL;
                bigsize = 0;
                for (p = allproc.lh_first; p != 0; p = p->p_list.le_next) {
--------------------------------->8--------------------------------


>Release-Note:
>Audit-Trail:
>Unformatted:


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