This is a cleanup patch to Peter's new OBJT_PHYS VM object type

    and sysv shared memory support for it.  It implements a new
    PG_UNMANAGED flag that has slightly different characteristics
    from PG_FICTICIOUS.

    A new sysctl, kern.ipc.shm_use_phys has been added to enable the
    use of physically-backed sysv shared memory rather then swap-backed.
    Physically backed shm segments are not tracked with PV entries,
    allowing programs which use a large shm segment as a rendezvous
    point to operate without eating an insane amount of KVM in the
    PV entry management.  Read: Oracle.

    Peter's OBJT_PHYS object will also allow us to eventually implement
    page-table sharing and/or 4MB physical page support for such segments.
    We're half way there.

1 files changed, 11 insertions, 2 deletions

diff --git a/sys/vm/vm_object.c b/sys/vm/vm_object.c
index 1b33f78..e5403d1 100644
--- a/sys/vm/vm_object.c
+++ b/sys/vm/vm_object.c
@@ -833,12 +833,14 @@ shadowlookup:
 
 		/*
 		 * If the page is busy or not in a normal active state,
-		 * we skip it.  Things can break if we mess with pages
-		 * in any of the below states.
+		 * we skip it.  If the page is not managed there are no
+		 * page queues to mess with.  Things can break if we mess
+		 * with pages in any of the below states.
 		 */
 		if (
 		    m->hold_count ||
 		    m->wire_count ||
+		    (m->flags & PG_UNMANAGED) ||
 		    m->valid != VM_PAGE_BITS_ALL
 		) {
 			continue;
@@ -1394,6 +1396,13 @@ vm_object_page_remove(object, start, end, clean_only)
 
 	all = ((end == 0) && (start == 0));
 
+	/*
+	 * Since physically-backed objects do not use managed pages, we can't
+	 * remove pages from the object (we must instead remove the page
+	 * references, and then destroy the object).
+	 */
+	KASSERT(object->type != OBJT_PHYS, ("attempt to remove pages from a physical object"));
+
 	vm_object_pip_add(object, 1);
 again:
 	size = end - start;