From owner-freebsd-current  Sat Dec 14 17:10:41 2002
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Date: Sat, 14 Dec 2002 17:10:38 -0800 (PST)
From: Matthew Dillon <dillon@apollo.backplane.com>
Message-Id: <200212150110.gBF1AcB6060179@apollo.backplane.com>
To: Jake Burkholder <jake@locore.ca>,
	"Brian F. Feldman" <green@FreeBSD.ORG>,
	John Baldwin <jhb@FreeBSD.ORG>, Kris Kennaway <kris@obsecurity.org>,
	current@FreeBSD.ORG, alpha@FreeBSD.ORG
Subject: Re: UMA panic under load
References: <XFMail.20021212113400.jhb@FreeBSD.org> <200212150037.gBF0bVSM014040@green.bikeshed.org> <20021214201446.F93389@locore.ca> <200212150105.gBF15LiN060144@apollo.backplane.com>
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X-Loop: FreeBSD.ORG

    What about something like this.  If the vm_refcnt is still being
    decremented too early, could it be moved to just before the thread_exit()
    call?
	
						-Matt


Index: kern/kern_exit.c
===================================================================
RCS file: /home/ncvs/src/sys/kern/kern_exit.c,v
retrieving revision 1.187
diff -u -r1.187 kern_exit.c
--- kern/kern_exit.c	10 Dec 2002 02:33:44 -0000	1.187
+++ kern/kern_exit.c	15 Dec 2002 01:08:21 -0000
@@ -288,7 +288,7 @@
 	 * Can't free the entire vmspace as the kernel stack
 	 * may be mapped within that space also.
 	 */
-	if (--vm->vm_refcnt == 0) {
+	if (vm->vm_refcnt == 1) {
 		if (vm->vm_shm)
 			shmexit(p);
 		vm_page_lock_queues();
@@ -298,7 +298,9 @@
 		(void) vm_map_remove(&vm->vm_map, vm_map_min(&vm->vm_map),
 		    vm_map_max(&vm->vm_map));
 		vm->vm_freer = p;
+		KASSERT(vm->vm_refcnt == 1, ("expected vm_refcnt of 1"));
 	}
+	--vm->vm_refcnt;
 
 	sx_xlock(&proctree_lock);
 	if (SESS_LEADER(p)) {

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